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PHTLS_ Prehospital Trauma Life Support 8TH

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PHTLS_ Prehospital Trauma Life Support 8TH

PHTLS_ Prehospital Trauma Life Support 8TH


and skin loss are not observed. Ambulation is possible necessary. Do not massage the affected area because doing so
when walking does not cause pain. may cause further tissue damage. As needed, treat the patient for
dehydration with a bolus of IV fluids, and reassess. Depending
• Moderate. Edema, hyperemia, blisters, and mottling are on length of transport, severe pain may develop during passive
present 2 to 3 days after injury. At 7 days, anesthesia rewarming as tissues begin to reperfuse, and it may be necessary
to touch is present to both dorsal and plantar surface to manage the discomfort with adequate opiate analgesia (e.g.,
and toes. Edema persists 2 to 3 weeks, and pain and begin with 5 mg morphine IV as needed).
hyperemia last up to 14 weeks. Some blister sloughing
occurs, but no loss of deep tissue. Some patients will Freezing Cold Injury
have permanent injury.
On the continuum of further peripheral cold tissue exposure
• Severe. Severe edema, blood forced into surrounding beginning with frostnip (no tissue loss), frostbite ranges from
tissues (extravasation), and gangrene are present 2 to mild to severe tissue destruction and possibly the loss of tissue
3 days after injury. Complete anesthesia of the entire due to intense vasoconstriction.8•9•13 The most susceptible body
foot remains at 7 days, with paralysis and muscle wast- parts for frostbite are those tissues with large surface-to-mass
ing in the affected extremities. The injury goes beyond ratios, such as the ears and nose or areas farthest from the body's
the foot into the lower leg. This severe injury produces core, such as the hands, fingers, feet, toes, and male genitalia.
significant tissue loss, resulting in autoamputation These structures are most susceptible to cold injury because
(nonsurgical amputation of dead tissue). Gangrene is a they contain many arteriovenous capillary anastomoses (con-
constant risk until tissue loss is complete. The patient nections) that easily shunt blood away during vasoconstriction.
is expected to have prolonged convalescence and a The body's normal response to lower-than-desirable tempera-
permanent disability. 84 tures is to reduce blood fl.ow to the skin surface to reduce heat
exchange with the environment. The body accomplishes this by
Assessment. Because the patient has experienced mild or vasoconstriction of peripheral blood vessels in an attempt to
moderate cold exposure, it is essential to rule out hypothermia shunt warm blood to the body's core to maintain a normal body
and assess for dehydration. Even though this is not a freezing temperature. Reduction of this blood fl.ow greatly reduces the
injury, NCFI still is an insidious and potentially disabling injury; amount of heat delivered to the distal extremities.
the common finding with these two localized cold injuries is that
the extremity is cooled to the point of anesthesia or numbness The longer the period of exposure to the cold, the more the
while the injury is occurring. blood fl.ow is reduced to the periphery. The body conserves core
temperature at the expense of extremity and skin temperature.
The key to management of NFCI is detection and recogni- The heat loss from the tissue becomes greater than the heat sup-
tion during assessment. During the primary assessment, injured plied to that area.
tissue appears macerated, edematous, pale, anesthetized, pulse-
less, and immobile, but not frozen. Patients complain of clum- When an extremity is cooled to 59°F (15°C), maximal vaso-
siness and stumbling when attempting to walk. After removal constriction and minimal blood fl.ow occur. If cooling contin-
from cold, and during or after rewarming, peripheral blood fl.ow ues to 50°F ( l 0°C), vasoconstriction is interrupted by periods
increases as reperfusion of ischemic tissue begins. Extremities of cold-induced vasodilation (CIVD), known as the "hunt-
change color from white to mottled pale blue while remaining ing response," and an associated increase in tissue tempera-
cold and numb. The diagnosis of trench foot or immersion foot ture caused by an increase in blood fl.ow. CIVD recurs in 5- to
is generally made when these signs have not changed after pas- 10-minute cycles to provide some protection from the cold.
sive rewarming of the feet. From 24 to 36 hours after rewarming, Individuals show differences in susceptibility to frostbite when
a marked hyperemia develops, along with severe burning pain exposed to the same cold conditions, which may be explained
and reappearance of sensation proximally, but not distally. This by the amount of CIVD.
is caused by venous vasodilation. Edema and blisters develop
in the injured areas as perfusion increases. Skin will remain Tissue does not freeze at 32°F (0°C) because cells contain
poorly perfused after hyperemia appears, and the skin is likely to electrolytes and other solutes that prevent tissue from freezing
slough as the injury evolves. Any pulselessness after 48 hours in until skin temperature reaches approximately 28°F (-2.2°C). In
the injured extremity suggests severe, deep injury and a greater cases of below-freezing temperatures, when the extremities are
chance ofsubstantial tissue loss. left unprotected, the intracellular and extracellular fluids can
freeze. This results in the formation of ice crystals. As the ice
Managem ent. Once a possible NFCI is detected, the priorities crystals form, they expand and cause damage to local tissues.
are to eliminate any further cooling, prevent further trauma to the Blood clots may also form, further impairing circulation to the
extremity, and transport the patient. Do not allow the patient to injured area.
walk on an injured extremity. Carefully remove the footwear and
socks. Cover the injured part or extremity with a loose, dry, ster- The type and duration of cold exposure are the two most
ile dressing; protect it from the cold; and begin passive rewarm- important factors in determining the extent of freezing injury.
ing of injured tissue during transport. The affected area may be Frostbite is classified by depth of injury and clinical presenta-
aggravated by the weight of a blanket. No active rewarming is tion.13 The degree of injury in many cases will not be known for
at least 24 to 72 hours after thawing, except in very minor or
severe exposures. Skin exposure to cold that is short in duration

CHAPTER 21 Environmental Trauma I: Heat and Cold 5 6 9

but very intense will create a superficial injury, whereas severe • First-degree frostbite. This epidermal injury is limited
frostbite to a whole extremity can occur during prolonged expo- to skin that has briefcontact with cold air or metal. The
sures. Direct cold injury is usually reversible, but permanent tis- skin appears white or as yellowish plaque at the site
sue damage occurs during rewarming. In more severe cases, even of injury. There is no blister or tissue loss. Skin thaws
with appropriate rewarming oftissue, microvascular thrombosis quickly, feels numb, and appears red with surrounding
can develop, leading to early signs of gangrene and necrosis. edema; healing occurs in 7 to 10 days.
Ifthe injured site freezes, thaws, and then refreezes, the second
freezing causes a greater amount of severe thrombosis and vas- • Second-degree frostbite. This degree of injury
cular damage and tissue loss. For this reason, prehospital care involves all the epidermis and superficial dermis. It
providers need to prevent any frozen tissue that thaws during initially appears similar to first-degree injury; however,
initial field treatment from refreezing. frozen tissues are deeper. Tissue feels stiff to the touch,
but tissue beneath gives way to pressure. Thawing is
Traditional methods of frostbite classification present four rapid; after thawing, superficial skin blister or vesicula-
degrees ofinjury (similar to burns) based on initial physical find- tion occurs, with clear ormilkyfluid after several hours,
ings after freezing and advanced imaging in the hospital after surrounded by ecythema and edema. There is no perma-
rewarming (Figures 21-18 and 21-19), as follows: nent loss of tissue. Healing occurs in 3 to 4 weeks.

• Third-degree frostbite. This degree of injury involves
the epidermis and dermis layers. Frozen skin is stiff,
with restricted mobility. After tissue thaws, skin swells
along with a blood-filled blister (hemorrhagic bulla),
indicating vascular trauma to deep tissues; swelling
restricts mobility. Skin loss occurs slowly, leading to
mummification and sloughing. Healing is slow.

• Fourth-degree frostbite. At this level, frozen tissue
involves full thickness completely through the dermis,
with muscle and bone involvement. There is no mobil-
ity when frozen and passive movement when thawed,
with no intrinsic muscle function. Skin perfusion is
poor, and blisters and edema do not develop. Early
signs of necrotic tissue are evident. A slow mummifi-
cationprocess will occur along with sloughing oftissue
and autoamputation of nonviable tissue.

Figure 21-18 Edema and blister formation 24 hours after Although traditional classification of frostbite is by the
frostbite injury. four degrees of injury, it is easiest for prehospital care provid-
ers in the prehospital setting to classify as either superficial or
Source:© J. Barabe I Custom Medical Stock Photo. deep.00-91 Superficial frostbite (first and second degree) affects
the skin and subcutaneous tissues, resulting in clear blisters
when rewarmed. Deep frostbite (third and fourth degree)
affects skin, muscle, and bone, and the skin has hemorrhagic
blisters when rewarmed. The level of severity and anticipated
tissue loss may vary within a single extremity.92

In special situations, frostbite may occur rapidly, and pre-
hospital care providers may respond to the following:

• Hydrocarbon fluid spills on skin (e.g., Gasoline will
cause rapid evaporation and conduction in below-
freezing temperatures.)

• Touching extremely cold metal with warm skin
• Intense windchill on exposed skin caused by rotary

wind from a medical helicopter

Figure 21-19 Deep second-degree and third-degree frostbite w ith Assessment. On arrival, assess scene safety and then the
hemorrhagic blebs, one day after thawing. patient for ABCs. Remove the patient from the cold, and place
in an area protected from moisture, cold, and wind. Many frost-
Source:© ANT Photo Library I Science Source. bite victims may have additional associated medical conditions,
such as dehydration, hypovolemia, hypothermia, hypoglycemia,


and traumatic injwy. Remove any wet clothing to minimize noncompressive and nonadherent. Fingers and toes should be
individuallyseparated by and protected with sterile cotton gauze.
further body heat loss. When in doubt, treat hypothermia first. Do not drain any blisters. Hands and feet should be splinted and
elevated to reduce edema.
Superficial frostbite is usually assessed through a combination of
IV opiate analgesics are usually required for pain relief and
recognizing the environmental conditions, locating the patient's should be initiated before the tissues have thawed. Initiate IV
NS with a 250-ml bolus to treat dehydration and reduce blood
chief complaint of pain or numbness, and observing discolored viscosity and capillary sludging. Ensure early transport to an
appropriate facility.
skin in the same area. The environmental conditions during
AUempts to begin rewarming ofdeep frostbite patients in
exposure must be below freezing. the field can be Jw,zardous to the patient's eventual recovery
and are not recommended unless prolonged transport times
Frostbite injuries are insidious because the patient may (over 2 lwurs) are involved. If prolonged transport is involved,
thaw the affected part in a warm water bath at a temperature no
have no pain at the injwy site when skin is frozen and covered greater than 98.6°Fto 102°F (37°C to 38.9°C) on the affected area
until the area becomes soft and pliable to the touch (-30 min). If
by a glove or footwear. Detection of the affected area requires refreezing is a concern, do not thaw.

direct visual inspection of highly suspect body regions, as pre- Administer ibuprofen (12 mg/kg up to 800 mg) if available.
Nonsteroidal medications such as ibuprofen help decrease
viously listed. Gentle palpation of the area can determine if the inflammation and pain and inhibit the production of substances
that cause vasoconstriction.
underlying tissue is compliant or hard. Ensure that the patient or
During transport, hydrate the patient by providing some-
prehospital care provider does not rub or massage the affected thing warm (and nonalcoholic) ifit is available, depending on the
patient's level of consciousness and other injuries. Tobacco use
skin, because this will cause further cellular damage to frozen (smoking, chewing, using nicotine patches) should be discour-
aged because nicotine causes further vasoconstriction.
tissues. The patient with superficial freezing will usually com-

plain of discomfort during the manipulation of the frostbitten

area. In patients with deep frostbite, the frozen tissue will be

hard and usually is not painful when touched. After inspection

ofthe affected area, a decision is necessary about the method of

rewarming, which is usually based on transport time to the ED.

The State ofAlaska EMS protocol for frostbite rewarming in

th e prehospital p h a s e s t a t es9 3

1. If transport time is short (1 to 2 hours at most), then Accidental Hypothermia
the risks posed by improper rewarming or refreezing in
the prehospital phase outweigh the risks for delaying Hypothermia is defined as the condition in which the core body
treatment for deep frostbite.
temperature is below 95°F (35°C), as measured by a rectal ther-
2. If transport time will be prolonged (more than 1 to
2 hours), frostbite will often thaw spontaneously. It mometer probe placed at least 6 inches (15 cm) into the rectum.14
is more important to prevent hypothermia than to
rewarm frostbite rapidly in warm water. This does not Hypothermia can be viewed as a decrease in core temperature
mean that a frostbitten extremity should be kept in the
cold to prevent spontaneous rewarming. Anticipate that renders a patient unable to generate sufficient heat produc-
that frostbitten areas will rewarm as a consequence
of keeping the patient warm and protect them from tion to return to homeostasis or normal bodily functions.
refreezing at all costs.
Hypothermia can occur in many different situations, result-

ing from cold ambient air, cold-water immersion, or cold-water

submersion (cold-water near-drowning), and can be intentionally

Management. Patients with superficial frostnip or frostbite induced during surgery. 14 94 95 Immersion ("head out") hypother-
should be placed with the affected area against a warm body ••
surface, such as covering the patient's ears with warm hands or
placing affected fingers into armpits, axillae, or groin regions. mia typically occurs when an individual is accidentally placed
Superficial frostbite only needs to be warmed at normal body
temperatures. into a cold environment without preparation or planning. For

Management of deep frostbite in the prehospital setting example, a person who has fallen into ice water is immediately in
includes first assessing and treating the patient for hypothermia,
if present.92 Provide supportive care and appropriate shelter for danger of becoming a submersion casualty, resulting from "cold
the patient and the affected part to minimize heat loss. Do not
allow the patient to walk on affected feet. Protect fragile tissues shock" gasp reflex, loss of motor skills, hypothermia, and drown-
from further trauma during patient movement. Assess the frost-
bite area. Remove any clothing and jewelry from the affected ing. These unique aspects of submersion incidents can lead to
area and check for loss of sensation.
hypoxia and hypothermia (see later discussion and the chapter
If there is frostbite distal to a fracture, attempt to align the
limb unless there is resistance. Splint the fracture in a manner titled Environmental Trauma II: Drowning, Lightning, Diving,
that does not compromise distal circulation.
and Altitude).
Air dry the affected area and do not rub the tissues. Cover
the affected area with a loose, dry, bulky sterile dressing that is The progression of hypothermia in cold air or cold water

can be delayed as long as the metabolic heat production can

match the loss of heat. Surviving an overwhelming cold expo-

sure is possible, with many reported cases of survival at sea and

in other extreme situations.96•97 Many factors are known to affect

survival after cold exposure, including age, gender, body com-

position (e.g., body surface area to body mass ratio), onset and

intensity of shivering, level of physical fitness, nutritional state,

and alcohol consumption.

CHAPTER 21 Environmental Trauma I: Heat and Cold 571

Hypoglycemia can occur during progressive phases ofhypo- Secondary hypothermia is considered a normal conse-
thermia and may be more common in immersion hypothermia. quence of a patient's systemic disorders, including hypothy-
This occurs due to the rapid depletion of the fuel sources blood roidism, hypoadrenalism, trauma, carcinoma, and sepsis. See
glucose and muscle glycogen by the contracting muscles during Figure 21-20 for a wide variety of medical conditions associated
the shivering process. As the blood glucose stores are depleted with secondary hypothermia. If unrecognized or improperly
through shivering, the brain's hypothalamus, which acts as the treated, hypothermia can be fatal, in some cases within 2 hours.
body's thermoregulatory center, is deprived its primary fuel. Death in patients with secondary hypothermia is often caused
Consequently, a person who has consumed alcohol is at greater by the underlying disease and is potentiated by hypothermia.
risk for hypothermia since alcohol blocks the production of glu- Mortality is greater than 500Ai in cases of secondary hypothermia
cose in the body and inhibits maximal shivering for heat pro- caused by complications of other injuries and in severe cases in
duction. 14 Thus, rapid assessment and effective management of which the core body temperature is below 89.6°F (32°C).14
low blood glucose in the patient with hypothermia are essential
to achieve effective increase in metabolism and shivering during Rapid attention to preventing further body heat loss in the
rewarming. traumatic patient is needed by the prehospital care provider
since mild hypothermia is very common following injury in all
Unlike frostbite, hypothermia leading to death can occur in weather conditions.
environments with temperatures well above freezing. Primary
hypothermia generally occurs when healthy individuals are in Hypothermia and the Trauma Patient
adverse weather conditions, they are unprepared for overwhelm-
ing acute or chronic cold exposure, and there is an involuntary It is all too common to receive patients with hypothermia arriv-
drop of core temperature (below 95°F [35°C]). Deaths by pri- ing at a trauma center and to have further body heat loss during
mary hypothermia are a direct result of cold exposure and are the primary assessment.98•99 The development of hypothermia
documented by the medical examiner as accident, homicide, or that begins in the prehospital setting is related to the effect of
suicide.13 trauma on thermoregulation and the inhibition of shivering as
a primary mechanism for heat production.100 In many patients,

Figure 21-20

Impaired Thermoregulation • Extreme physical exertion
• Central fa ilure • Hypoglycemia
• Anorexia nervosa • Malnutrition
• Cerebrovascular accident • Neuromuscular compromise
• Central nervous system trauma • Recent birth and advanced age with inactivity
• Hypothalamic dysfunction • Impaired shivering
• Metabolic failure
• Neoplasm Increased Heat Loss
• Parkinson's disease • Dermatologic disorder
• Pharmacologic effects • Burns
• Subarachnoid hemorrhage • Medications and toxins
• Toxins • Iatrogenic cause
• Peripheral failure • Emergency childbirth
• Acute spinal cord transection • Cold infusions
• Decreased heat production • Heat-stroke treatment
• Neuropathy • Other associated clinical states
• Endocrinologic failure • Carcinomatosis
• Alcoholic or diabetic ketoacidosis • Cardiopulmonary disease
• Hypoadrenalism • Major infection (bacterial, viral, parasitic)
• Hypopituitarism • Multisystem trauma
• Lactic acidosis • Shock
• Insufficient energy

Source: Data from the 2005 Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Guidelines and 2010 American Heart Association Guidelines for
Cardiopulmonary Hesuscitation and Emergency Cardiovascular.


further heat loss continues after arrival at the hospital due to a practices include anticipating hypothermia, avoiding undressing
multitude of reasons: an exposed patient in a cold ED or trauma patients, taking frequent temperature measurements, maintain-
center, administration of cool resuscitation fluids, open abdomi- ing warm mobile cabin temperatures, and maintaining and pro-
nal or thoracic cavities, the use ofanesthetic and neuromuscular viding only warm IV fluids.108 The potential therapeutic benefits
blocking agents that prevent heat-producing shivering, and fur- of intentionally induced hypothermia are currently under study
ther cold exposure in an operating room environment. 101•102 (Figure 21-22).

In the prehospital setting, the trauma patient should be Immersion Hypothermia
moved off of cold ground as soon as possible and placed in a
warm ambulance. The temperature in the ambulance should Duringimmersion, ifthere is no heat gain or heat loss by the body,
be adjusted to minimize heat loss from the patient and not for water temperature is considered thermoneutral. Thermoneutral
the comfort of the prehospital care provider. Warmed (100°P water temperature is 91°P to 95°P (32.8°C to 35°C), at which
to 108°P [37.8°C to 42.2°C)) IV fluids will also help to maintain temperatures a naked individual passively standing in neck-
the patient's body temperature. level water can maintain a nearly constant core temperature
for at least 1 hour.102•114 Individuals in thermoneutral water are
One cause of higher mortality in hypothermic trauma at almost no risk for the initial immersion cold shock and hypo-
patients is related to the lethal combination of hypothermia, thermia experienced in sudden cold-water exposure.115
acidosis, and coagulopathy (inability of blood to clot nor-
mally). This is lmown as the lethal triad in trauma patients.103 When immersion occurs in water temperature colder
It is essential to assess and treat patients for both trauma than the lower thermoneutral limit, the immediate physiologic
and hypothermia because the coagulopathy is reversible with changes are a rapid decline in skin temperature, peripheral
patient rewarming.99 In one study, 57% of the trauma patients vasoconstriction resulting in shivering, and increased metabo-
admitted to a level I trauma center were hypothermic at some lism, ventilation, heart rate, cardiac output, and mean arterial
point in the continuum of care. The mortality rate has been pressure. To offset any heat loss in water, heat production must
reported to range from 40% to 100%when core temperature falls occur by increasing physical activity, shivering, or both. If not,
below 90°P (32.2°C) in a trauma patient. This rate is in contrast core temperature continues to fall and shivering ceases, and
to a mortality of 200;6 in a primary hypothermic (nontraumatic) these physiologic responses decrease proportionally with the
patient at moderate core temperature levels (82°P to 90°P [28°C fall in core temperature.95
to 32.2°C)).102 Consequently, the mortality rate associated with
hypothermia in the trauma victim is very significant, such that The greatest risk of immersion hypothermia usually begins
the definition of mild, moderate, and severe hypothermia in in water temperature less than 77°P (25°C).116 Because the heat
the trauma patient has resulted in a special classification103•104 dissipation capacity of water is 24 times greater than that of
(Figure 21-21). air, individuals are at risk for more rapid hypothermia in water.
However, continued physical activity (i.e., swimming to keep
This relationship of trauma, hypothermia, and increased warm) in cold water will eventually become a detriment by
mortality has been reported for decades, including recently in increasing convective heat loss to the colder water surrounding
combat casualty patients.105 However, recent clinical studies the body, resulting in a faster onset of hypothermia. This under-
have reported that hypothermia is not an independent risk fac- standing has led to the recommendation for individuals to min-
tor for mortality in trauma patients, but is more closely related imize heat loss during cold-water immersion by using the heat
to iajury severity or multiple organ dysfunction syndrome.1()6.109 escape lessening posture (HELP) or the huddle position when
One study reported that certain prehospital care practices can multiple immersion victims are together116 (Figure 21-23).
influence the severity of hypothermia in trauma patients. These

Figure 21-21

Classification Traditional Trauma

Mild hypothermia 95-89.6°F (35-32°C) 96.8-93.2°F (36-34°()

Moderate hypothermia 89.6-82.4°F (32-28°() 93.2-89.6°F (34-32°()

Severe hypothermia 82.4-68°F(28-20°C) < 89.6°F (32°C)

Profound hypothermia 68-57.2°F (20-14°C)

Deep hypothermia < 57.2°F (14°C)

Source: Surgical Clinics of North America 75(2), Gentilello et al, Advances in management of hypothermia, pp. 243-256, Copyright Elsevier 1995.

CHAPTER 21 Environmental Trauma I: Heat and Cold 5 7 3

Figure 21-22 The lowest recorded core temperature for an infant with
an intact neurologic recovery from accidental hypothermia is
It is well established that the detrimental lethal triad in 59°F (15°C). 117 In an adult, 56.6°F (13.7°C) is the lowest recorded
trauma victims increases mortality. However, there is core temperature for a survivor of accidental hypothermia. This
mounting evidence showing that intentionally induced occurred in a 29-year-old female who struggled to self-rescue for
hypothermia has a beneficial role in shock, organ more than 40 minutes before symptoms of severe hypothermia
transplantation, nontraumatic cardiac arrest, and control of affected muscular contraction.97 She was immersed for more
intracranial pressure from traumatic brain injury.104-110 The than 80 minutes before a rescue team arrived and cardiopul-
fastest growing application of therapeutic hypothermia monary resuscitation (CPR) was initiated during transport to a
treatment in the prehospital setting is for victims of sudden local hospital. After 3 hours of continuous rewarming, her core
nontraumatic cardiac arrest.104-111-112 It is well known that the temperature returned to normal, and she survived with normal
outcome following cardiac arrest is very poor, with only 3% physiologic function.
to 27% of all cardiac arrest patients surviving to discharge.
However, based on the growing amount of evidence for Because vital signs may have decreased to a nearly imper-
increased survival rate with therapeutic hypothermia in ceptible level, the initial impression of a hypothermic patient
the past decade, the International Liaison Committee on may be that he or she is dead. Prehospital care providers man-
Resuscitation and other organizations published an advisory aging patients with hypothermia should not stop treatment inter-
statement in 2003, as did Nolan in 2008 and Noland et al. ventions and declare the patient deceased until the patient has
in 2010, on the role of hypothermia following nontraumatic been rewarmed to over 95°F (35°C) and still has no evidence
cardiac arrest. These statements recommended intentional of cardiorespiratory and neurologic function. The 29-year-old
cooling of the patient to 89.6°F to 93.2°F (32°( to 34°C) hypothermia survivor is only one example of a patient being
for 12 to 24 hours in unconscious adults with spontaneous discharged from the hospital with full neurologic function after
circulation after an out-of-hospital non-traumatic cardiac prolonged CPR in the field. The lesson from this case, and others
arrest.110·112·113 Currently, there is no evidence to support with a similar outcome, is that although the initial impression of
therapeutic hypothermia in the multiple trauma patient. a hypothermic patient may be that he or she is dead, this impres-
sion is not sufficient justification to withhold basic or advanced
life support. Keep the following phrase in mind: Patients are not
dead until they are warm and dead.

Whether intentional or unintentional, cold-water immersion
(head out) occurs throughout the year in the United States as a


Figure 21-23 Techniques for decreasing cooling rates of survivors in cold water. A. Heat escape lessening posture (HELP).
B. Huddle technique.


result of recreational and industrial activities, as well as from extremities, causing finger stiffness, poor coordination,
and loss of muscle power, making it nearly impossible
accidents. If the individual survives the initial submersion inci- to swim, grasp a rescue line, or perform other survival
motor skills.95•116
dent without drowning, he or she is at risk for hypothermia, • Third phase-onset ofhypothermia. Surviving the first
two phases without drowning places an individual at
depending on the water temperature. It is important to note that risk of hypothermia from continued heat loss and core
temperature reduction from immersion longer than 30
the public generally underestimates the amount oftime required minutes. If the victim is not able to remain above the
water surface because of fatigue and hypothermia, he
to become hypothermic in very cold water, thinking that it or she is at risk of becoming a submersion casualty,
leading to aspiration and drowning.81•98 How long an
occurs and results in death rapidly. However, rapid death from individual can survive in cold water depends on many
factors. It has been estimated that a submersion victim
immersion is the result of panic leading to aspiration of water cannot survive for more than 1 hour at a water tempera-
ture of 32°F (0°C), and at a water temperature of 59°F
and drowning, not of hypothermia. The key points to understand (15°C), survival is uncommon after 6 hours.121
• Fourth phase-circum-rescue collapse. In this phase,
are that cold shock is initially the greatest threat and that the fatalities have been observed during all periods ofsurvi-
vor rescue (before, during, and after) despite the appar-
victim should focus more on controlling the gasp reflex and ent stable and conscious condition. Symptoms range
from apparent fainting to cardiac arrest and have been
his or her breathing to survive this initial physiologic response referred to as rewarming shock or postrescue collapse.
Deaths are reported to occur up to 90 minutes postres-
(Figure 21-24). The body's responses to cold-water immersion cue, during transport, and up to 24 hours after rescue.
The three proposed reasons for circum-rescue collapse
can be divided into the following four phases leading to death. It are (1) afterdrop of core temperature, (2) collapse of
arterial blood pressure, and (3) changes in hypoxia, aci-
is important to note that deaths have been reported to occur in dosis, or rapid changes in pH that induce ventricular
fibrillation. It is noted that up to 20% of those who are
all f our p h a se s116 recovered alive during the fourth phase will die due to
: circum-rescue

• First phase-cold shock response. This phase begins For more information about surviving cold-water immer-
with a cardiovascular reflex known as cold shock sion, see Figures 21-25 and 21-26.
response that occurs quickly (within 0 to 2 minutes)
after immersion (may occur in water colder than 68°F Pathophysiologic Effects of Hypothermia on
[20°C]). It begins with rapid skin cooling, peripheral the Body
vasoconstriction, a gasp reflex and the inability to
breath-hold, hyperventilation, and tachycardia.81•94 The Whether from exposure to a cold environment or immersion,
gasp response may lead to aspiration and drowning, the influence of hypothermia on the body affects all major organ
depending on the individual's head location above or systems, particularly the cardiac, renal, and central nervous sys-
below water. These responses can lead to immedi- tems. As the body's core temperature decreases to 95°F (35°C),
ate sudden death or death within minutes following maximal rate of vasoconstriction, shivering, and metabolic rate
immersion because ofseveral conditions in this setting, occurs, with increases in heart rate, respiration, and blood pres-
including syncope or convulsions resulting in drown- sure. Cerebral metabolism oxygen demand decreases by 6% to
ing, vagal arrest, and ventricular fibrillation.95,wH2o 10% per l.8°F (- 1°C) drop in core temperature, and cerebral
metabolism is preserved.
• Secondphase-cold incapacitation. Ifa victim survives
the cold shock phase, significant cooling of peripheral When core temperature falls to between 86°F (30°C) and
tissues, especially in the extremities, occurs over the 95°F (35°C), cognitive function, cardiac function, metabolic rate,
next 5 to 15 minutes of immersion. This cooling has a ventilatory rate, and shivering rate are all significantly decreased
deleterious effect on gross and fine motor skills of the or completely inhibited. At this point, the limited physiologic
defensive mechanisms to prevent heat loss from the body are
Figure 21-24 overwhelmed and core temperature falls rapidly.

If you fall into ice-cold water, remember that you have 1 At a core temperature of 85°F (29.4°C), cardiac output and
minute--1 O minutes-1 hour.* metabolic rate are reduced approximately 50%. Ventilation and
• You have 1 minute to get your breathing under perfusion are inadequate and do not keep up with the metabolic

control, so don't panic.
• You have 10 minutes of meaningful movement to get

out of the water or to attain a stable situation.
• You have up to 1 hour until you become unconscious

from hypothermia if you don't panic or struggle
unnecessarily. If you are wearing a personal flotation
device, you may have another hour until your heart
stops beating as a result of hypothermia.

*Times are subject to individual variability and factors such as body size, water
temperature, and the amount of body immersed.98

CHAPTER 21 Environmental Trauma I: Heat and Cold 5 7 5

Figure 21-25 demand, causing cellular hypoxia, increased lactic acid, and an
eventual metabolic and respiratory acidosis. Oxygenation and
The U.S. Coast Guard and other search-and-rescue blood flow are maintained in the core and brain.
organizations use guidelines to assist in estimating how
long individuals can survive in the cold water. These Bradycardia occurs in a large percentage of patients as a
guidelines are mathematical models that estimate core direct effect of cold on the depolarization of cardiac pacemaker
temperature cooling rate based on the influence of the cells and their slower propagation through the conduction sys-
following variables: tem. It is important to note that the use of atropine, as well as
other cardiac medications, is often ineffective to increase the
• Water temperature and sea state heart rate when the myocardium is cold.8 When core tempera-
• Clothing insulation ture falls below 86°F (30°C), the myocardium becomes irritable.
• Body composition (amount of fat, muscle, and bone) The PR, QRS, and QTC intervals are prolonged. ST-segment and
• Amount of the body immersed in water T-wave changes and J (or Osborne) waves may be present and
• Behavior (e.g., excessive movement) and posture may mimic otherECG abnormalities, suchas an acute myocardial
infarction. The J waves are a striking ECG feature in hypother-
(e.g., HELP. huddle) of the body in the water mic patients and are seen in approximately one-third of moder-
• Shivering thermogenesis122-124 ately to severely hypothennic patients Oess than 90°F [32.2°C)).
The J wave is described as a "humplike" deflection between the
Figure 21-26 QRS complex and the early part of the ST segment.126 The J wave
is bestviewed in the aVL, aVF, and leftlateral leads (Figure 21-27).
Early studies in the 1960s to 1970s suggested that
during accidental immersion in cold water, it was a better Atrial :fibrillation and extreme bradycardia develop and may
option not to self-rescue by attempting to distance-swim continue between 83°F and 90°F (28.3°C to 32.2°C). When the
to safety, but to stay in place, float still in lifejackets, core temperature reaches 80°F to 82°F (26.7°C to 27.8°C), any
or hang on to wreckage and not swim around to keep physical stimulation of the heart can cause ventricular :fibrilla-
warm. More recent research has suggested that self- tion (VF). CPR or rough handling (patient assessment and move-
rescue swimming during accidental immersion in cold ment) of the patient could be sufficient to cause VF. At these
water (50°F to 57°F [10°C to 13.9°C]) is a viable option extremely low core temperatures, pulse and blood pressure are
based on the following conditions: not detectable, and the joints are stiff. The pupils become fixed
and dilated at extremely low core temperatures. Remember,
• The victim has initially survived the cold-shock phase a patient should not be assumed to be dead until he or she is
within the first few minutes of cold-water exposure. rewarmed and still has no signs of life (ECG, pulse, ventilation,
and central nervous system function).
• The victim has decided early to attempt self-rescue
or wait for rescue since decision-making ability will With acute cold exposure, renal blood flow increases
become impaired as hypothermia progresses. because of the shunting of blood during vasoconstriction. This
may result in a phenomenon known as cold diuresis in which
• There is a low probability for rescue by emergency patients produce more urine and may, as a result, become dehy-
responders in the area. drated. At 81°F to 86°F (27.2°C to 30°C), renal blood flow is
depressed by 500Ai. At this moderate to severe hypothennic level,
• The victim can reach shore within 45 minutes of the decrease in cardiac output causes a fall in renal blood flow
swimming based on his or her fitness level and and glomerular filtration rate, which in turn results in acute renal
swimming ability. failure.

• On average, a cold-water immersion victim wearing Assessment
a personal flotation device should be able to swim
approximately a half mile (800 meters) in 50°F It is imperative to assess scene safety on arrival. All emergency
(10°C) water before incapacitation due to muscle responders need to ensure their safety and protection from cold
cooling and fatigue of the arms, rather than general exposure while working in this environment. There should be
hypothermia, occurs. a high suspicion for hypothermia even when the environmen-
tal conditions are not highly suggestive (e.g., wind, moisture,
• Cold water swim distance is about one-third of the temperature).
distance covered in warmer water.125
Assess the patient's ABCs. Take up to 60 seconds to carefully
evaluate the patient's pulse, which may present as very weak or
absent in a patient with moderate to severe hypothermia. Some
patients who are alert may present with vague complaints of
fatigue, lethargy, nausea, vomiting, and dizziness. Neurologic


Figure 21-27 Osborne or J w ave in hypothermic patient.

Source: From 12 Lead ECG: The Art of Interpretation, Courtesy of Tomas B.Garcia, MD.

function is assessed and monitored frequently. Patients with consciousness is not a reliable indicator of the degree of hypo-
severe hypothermia generally present with bradypnea, stupor, thermia; some patients have remained conscious at core tem-
and coma. perature below 80°F (26.7°C).

To accurately measure hypothermic temperatures, a low- When the patient's core temperature falls below 90°F
range rectal thermometer is often necessary. However, rectal (32.2°C), moderate hypothermia is present, and the patient will
temperatures are not usually assessed in the field or widely used probably not complain of feeling cold. Shivering will be absent,
as a vital sign in most prehospital systems. Ambulances that do and the patient's level ofconsciousness will be greatly decreased,
have access to a thermometer usually carry a standard-range possibly to the point of unconsciousness and coma. The patient's
oral or rectal (for infants) thermometer with a lower limit of pupils will react slowly or may be dilated and fixed. The patient's
96°F (35.6°C). Electronic thermometers are not useful in hypo- palpable pulses may be diminished or absent, and systolic blood
thermic situations for accurate readings. 'fympanic membrane pressure may be low or indeterminate. The patient's ventilations
infrared temperature measurement is generally accurate if care- may have slowed to as few as 2 breaths/minute. An ECG may
ful technique is used to assure aiming the probe at the tympanic show atrial fibrillation, the most common dysrhythmia. As the
membrane and not the ear canal, which can affect the reading. In myocardium becomes progressively colder and more irritable at
addition, the ear must be clear of cerumen (ear wax) and blood. about 82°F (27.8°C), VF is observed more often.
Therefore, prehospital care providers need to rely on scene
size-up, patient mental status, skin vitals, and ABCS. Because of the changes in cerebral metabolism, evidence
ofparadoxical undressing may be observed before the patient
Figure 21-28 provides the anticipated physiologic responses loses consciousness. This is an attempt by the patient to remove
with decreasing core temperature. the clothing while in the cold environment, and it is thought to
represent a response to an impending thermoregulatory failure.
Signs of shivering and mental status change are important
in the assessment of suspected hypothermia. Patients with mild The clinical management of hypothermia is based on the fol-
hypothermia (core temperature greater than 90°F [32.2°C]) will lowing three ranges of rectal body temperature as presented by
be shivering and usually show signs ofaltered level ofconscious- the American Heart Association for the use of advanced cardiac
ness (e.g., confusion, slurred speech, altered gait, clumsiness). life support127:
They will be slow in their actions and are usually found in a
nonambulatory state, sitting or lying. Law enforcement person- • Mild hypothermia is above 93°F to below 97°F (33.9°C
nel and prehospital care providers may misinterpret this condi- to 36.1°C).
tion as drug or alcohol intoxication or, in geriatric patients, as
cerebrovascular accident (stroke). However, a patient's level of • Moderate hypothermia is 86° to 93°F (30°C to 33.9°C).
• Severe hypothermia is below 86°F (below 30°C).

CHAPTER 21 Environmental Trauma I: Heat and Cold 5 7 7

37.0 98.6 t1 Normal oral temperature
36.0 9 6 .8
9 5 .0 Increase in metabolic rate and blood pressure and pre-shivering
35.0 93 .2 muscle tone
91.4 Urine temperature 34.8° C; maximum shivering thermogenesis
8 9 .6 Amnesia, dysarthria, and poor judgment develop; maladaptive
Moderate 32.0 8 7 .8 behavior; normal blood pressure; maximum respiratory
31.0 8 6 .0 stimulation; tachycardia, then progressive bradycardia
84.2 Ataxia and apathy develop; linear depression of cerebral
Severe 29.0 82 .4 metabolism; tachypnea, then progressive decrease in
8 0 .6 respiratory minute volume; cold diuresis
28.0 7 8 .8
7 7 .0 Stupor; 25% decrease in oxygen consumption
26.0 7 5 .2 Extinguished shivering thermogenesis
25.0 73 .4
71 .6 Atrial fibrillation and other arrhythmias develop; poikilothermia;
Profound 24.0 6 8 .0 pupils and cardiac output two thirds of normal; insulin
23.0 6 6 .2 ineffective
22.0 64.4
59 .0 Progressive decrease in level of consciousness, pulse, and
20.0 56 .7 respiration; pupils dilated; paradoxical undressing
50 .0
19.0 4 8 .2 Decreased ventricular fibrillation threshold; 50% decrease in
18.0 oxygen consumption and pulse; hypoventilation
13.7 Loss of reflexes and voluntary motion
9.0 Major acid-base disturbances; no reflexes or response to pain

Cerebral blood flow one third of normal; loss of cerebrovascular
autoregulation; cardiac output 45% of normal; pulmonary
edema may develop

Significant hypotension and bradycardia

No corneal or oculocephalic reflexes; areflexia

Maximum risk of ventricular fibrillation; 75% decrease in
oxygen consumption

Lowest resumption of cardiac electromechanical activity; pulse
20% of normal

Electroencephalographic silencing


Lowest infant accidental hypothermia survival

Lowest adult accidental hypothermia survival

92% decrease in oxygen consumption

Lowest therapeutic hypothermia survival

Source: Modified from Danzl OF: Accidental hypothermia. In Auerbach PS: Wilderness medicine, ed 6, St. Louis, 2012, Mosby Elsevier.


Management rewarming effect of warmed IV fluids is minimal at best, and the
prehospital care provider should use good judgment to decide
Prehospital care of the patient with hypothermia consists of pre- whether fluids (orally or IV) are worth the risks of aspiration,
venting further heat loss, gentle handling, initiating rapid trans- coughing, and painful stimuli to the patient. Hot packs or mas-
port, and rewarming. This includes moving the patient away saging of the patient's extremities are not recommended.
from any cold source to a warm ambulance or to a warm shelter
iftransportation is not immediately available (see the Prolonged Typically, active external rewarming occurs only to the tho-
Transport section). After assessing pulse and if no signs of life racic region, with no active rewarming of the extremities. This
are present, CPR should immediately be started.127 Any wet cloth- approach will prevent increased peripheral circulation, causing
ing should be removed by cutting with trauma shears to avoid an increased amount of colder blood returning from the extrem-
unnecessary movement and agitation of the patient. Concern ities to the thorax before central core rewarming. Increased
for initiating ventricular dysrhythmia based on the handling return of peripheral blood can increase acidosis and hyperka-
of the patient should not delay any critical interventions. This lemia and can actually decrease the core temperature ("after-
concern becomes more realistic in severe hypothermic patients drop"). This complicates resuscitation and may precipitate VF.
(core temperature below 86°F [30°C]). The patient's head and
body should be insulated from the cold ground and covered 2010 American Heart
completely with warm blankets or sleeping bags, followed by Association Guidelines
an outer windproof layer to prevent conductive, convective, and for Cardiopulmonary
evaporative heat loss. Resuscitation
and Emergency
If the patient is conscious and alert, he or she should avoid Cardiovascular Care
drinks containing alcohol or caffeine. Anticipate hypoglycemia Science
and assess the patient's blood glucose level. For the patient with
mild hypothermia with normal glucose levels, provide warm, Cardiac Arrest in Special Situations-
high-caloric or glucose fluids. For patients with moderate hypo- Accidental Hypothermia
thermia with low blood glucose concentration, establish IV fluids
and administer 50% dextrose (Dr;o) IV per local medical protocol, Guidelines for resuscitation of a patient with hypothermia
and repeat glucose determination every 5 minutes to determine have evolved over many decades. The most recent revision of
the need for an additional D bolus. the emergency cardiovascular care guidelines by the American
Heart Association (AHA) were published by the AHA in the jour-
50 nal Circui,ation in November 2010.127

Hypothermic patients need high-flow oxygen because they The victim with hypothermia can present many challenges to
have decreased oxygen delivery to the tissues; the oxyhemoglo- the prehospital care provider, particularlythe unconscious patient
bin dissociation curve shifts to the left with a decrease in core with moderate to severe hypothermia. Because severe hypother-
temperature. High-flow oxygen should be delivered using a non- mia is defined by a core temperature ofless than 86°F (30°C), the
rebreathing mask or bag-mask device. Ideally, the patient may patient can present as clinically dead with no detectable pulse or
benefit more ifthe oxygen can be warmed and humidified (108°F respiration because ofthe reduced cardiac output and decreased
to 115°F [42.2°C to 46.1°C]). Ifpossible, warmed oxygen admin- arterial pressure. Historically, the challenge has been to deter-
istered before movement may prevent VF during transport. mine whether to initiate BLS or ALS interventions on these
patients based on the viability of the patient. Furthermore, it may
In unresponsive hypothermic patients, passive rewarming be difficult to determine from bystanders whether these patients
will be insufficient to increase core temperature. These patients had a primary hypothermic exposure or a medical event or trau-
will need an airway adjunct to protect the airway, and this should matic injury that preceded the hypothermia. Other concerns for a
be initiated depending on jaw rigidity. The prehospital care pro- prehospital care provider are protecting the hypothermic patient
vider should not hesitate to definitively support the airway since with a potential irritable myocardium from any rough handling
there is a low risk of triggering a fatal dysrhythmia during an and initiating chest compression for the patient with nondetect-
advanced airway procedure.98 If endotracheal intubation cannot able pulse, in whom both these interventions may initiate VF.127
be successfully achieved without rough handling, continue ven-
Independent ofany scenario that created the primary or sec-
tilation with a bag-mask device and consider another advanced ondary hypothermia, lifesaving procedures should generally not
airway device (e.g., King supraglottic airway, laryngeal mask air- be withheld on the basis of clinical presentation, whether in an
way, nasal intubation). At a minimum, use an oral or nasal pha- urban setting with short transport distances or in the backcoun-
ryngeal airway with bag-mask ventilation. try environment with potentially significant delays in transport,
in which scenario extended patient care may be necessary (see
Intravenous NS, ideally with 5% dextrose, should be warmed later discussion).
to 109°F (42.8°C) and administered without agitating the patient.
The patient with hypothermia should not be given "cold"
(room-temperature) ftuiW> because this could make the patient
colder or could delay rewarming. When NS and dextrose solu-
tions are unavailable, any warm crystalloid solution is satisfac-
tory. Provide a fluid challenge of 500 to 1,000 ml, and prevent
the solution from freezing or becoming colder by placing the IV
bag under the patient to infuse warm fluids under pressure. The

CHAPTER 21 Environmental Trauma I: Heat and Cold 5 7 9

Basic Life Support Guidelines cardiovascular life support (ACLS) procedures are different than
for Treatment of Mild to Severe with a normothermic patient Unconscious patients with hypo-
thermia need a protected airway and should be intubated. Do

Hypothermia not delay airway management based on the concern of initiating
VF. As noted earlier, if a shockable rhythm is detected, defibril-

Patients with hypothermia should be kept in a horizontal posi- late once at 120 to 200 biphasicjoules or 360 monophasicjoules,
tion at all times to avoid aggravating hypotension because these resume CPR, and then defer cardiac drugs and subsequent

patients are often volume-depleted from cold diuresis. It may be defibrillation attempts until core temperature is above 86°F
difficult to feel or detect respiration and a pulse in the patient (30°C). If possible, initiate active rewarming procedures with
with hypothermia. Therefore, it is recommended initially to warm, humid oxygen and warm IV solutions, and package the
assess for breathing and then a pulse up to 60 seconds to confirm patient for transport by preventing further heat loss. It is import-

one of the following: ant to note that passive rewarming is adequate for patients with

mild hypothermia. However, patients with moderate to severe

• Respiratory arrest hypothermia need active rewarming that is generally limited

• Pulseless cardiac arrest (asystole, ventricular tachycar- to procedures performed in an ED or critical care unit. Passive

dia, VF) rewarming procedures alone for these patients are totally inad-

• Bradycardia (requiring CPR) equate to increase core temperature in the prehospital setting,

and EMS personnel should focus on effective techniques in pre-

If the patient is not breathing, start rescue breathing imme- venting further heat loss.14

diately unless the victim is obviously dead (e.g, decapitation, The challenge with ACLS procedures in a patient with hypo-

rigor mortis). Start chest compressions immediately in any thermia is that the heart may be unresponsive to ACLS drugs,

patient with hypothermia who is pulseless and has no detectable pacing, and defibrillation.132 Furthermore, ACLS drugs (e.g.,

signs of circulation.127 If there is a doubt about detecting a pulse, epinephrine, amiodarone, lidocaine, procainamide) can accu-

begin compressions. Never withhold BLS interventions until the mulate to toxic levels in the circulation with repeated admin-

patient is rewarmed. Ifthe patient is determined to be in cardiac istration in the patient with severe hypothermia, particularly

arrest, use the current BLS guidelines. when the patient rewarms. 127 Consequently, it is recommended

An automated external defibrillator (AED) should be used if to withhold IV medications in patients with a core temperature

pulseless ventricular tachycardia or VF is present The current below 86°F (30°C). If a patient with hypothermia initially pres-
emergency cardiovascular care guidelines (see Figure 21-29) rec- ents with a core temperature above 86°F (30°C), or if a patient

ommend that these patients be treated byproviding up to five cycles with severe hypothermia has been rewarmed above this tem-

(2 minutes) of CPR (one cycle is 30 compressions to 2 breaths) perature, IV medications may be administered. However, longer

before checking the ECG rhythm and attempting to shock when intervals between drug administration are recommended than
an AED arrives.128 If a shockable rhythm is determined, give one with standard drug intervals in ACLS.127 The use of repeated

shock, then continue five cycles of CPR. If the patient with hypo- defibrillation is indicated if the core temperature continues

thermia does not respond to one shock with a detectable pulse, to rise above 86°F (30°C), consistent with the current ACLS
further attempts to defibrillate the patient should be deferred and guidelines.128
efforts directed toward effective CPR with an emphasis on rewarm-
Finally, BLS/ACLS procedures performed in the field should

ing the patient to above 86°F (30°C) before attempting further be withheld only if the patient's injuries are incompatible with

defibrillation.128 life, if the body is frozen such that chest compressions are

When performing chest compressions in a patient with impossible, or if the mouth and nose are blocked with ice. 14 127
hypothermia, a greater force is required because chest wall elas- •
ticity is decreased when cold.129 If core temperature is below
Figure 21-29 provides an algorithm of mild, moderate, and severe

hypothermia guidelines for both patients with a pulse and pulse-

86°F (30°C), the conversion to normal sinus rhythm does not less patients.108
normally occur until rewarming above this core temperature is

accomplished.130 Prevention of Cold·
The importance of not declaring a patient dead until the

patient has been rewarmed and remains unresponsive cannot be Related Injuries

overemphasized. Studies ofvictims of hypothermia indicate that The prevention of cold injuries in patients, yourself, and
other prehospital care providers is vital when on the scene.
cold exerts a protective effect on the vital organs. 130 131

Advanced Cardiac Life Support Recommendations to prevent cold-related injuries include the

Guidelines for Treatment of 1. Note the risk factors generally associated with for cold
Hypothermia injury:

The treatment of severe hypothermia in the field remains con- • Fatigue
troversial.127 However, the guidelines for administering advanced • Dehydration


Initial therapy for all patients
• Remove wet garments
• Protect against heat loss and windchill

(use blankets and insulating equipment)
·Avoid rough movement and excess activity
• Monitor core temperature (if available)

• Monitor cardiac rhythm

Pulse and Pulse or
breathing present breathing absent

Assess responsiveness, breathing, and pulse

What is core temperature? ·Start CPR
• Give 1 shock
34°C to 36°C (93.2°F to 96.8°F) (mild hypothermia)
• Passive rewarming • Manual biphasic: Device-specific (typically 120 to
200 J); if unknown, use 200 J
• Monophasic: 360 J
3o·c to 34·c (86°F to 93.2°F)
(moderate hypothermia) • Resume CPR immediately
• Active external rewarming2
• Passive rewarming ·Attempt, confirm, secure airway
• Ventilate with warm, humidified oxygen (if available)
< 30°C (86°F) (severe hypothermia)
• Active internal rewarming sequence (42°C to 46°C 11oa·F to 11s°F])

(see below) • Establish IV access
·Infuse warm normal saline (if available) (43°C (109°F])
• Consider administering a vasopressor.

What is core temperature (if available)?
< 3o·c (B6"F) > 3o·c (B6°F)

Active internal rewarming • Continue CPR • Continue CPR
• Withhold IV medications • Give IV medications as
·Warm IV or 10 fluids (43°C [109°F]) • Limit to one shock for
indicated (but space at
·Warm, humidified oxygen (42°C to 46°C V FN T
(1 oa· F to 11s 0 F]) • Transport to hospital longer than standard
• Warm-water peritoneal lavage • Repeat defibrillation for
(KCl-free fluid)1 V-fibN -tach as core
temperature rises
• Extracorporeal rewarming1
• Esophageal rewarming tubes1 ~

Continue internal rewarming until Notes:
1. Many experts think these interventions should be done only
• Core temperature> 32°C (89.6°F) or
• Return of spontaneous circulation or in-hospital, though practice varies.
• Resuscitative efforts cease 2. Methods include electric warming devices, hot

water bottles, heating pads, radiant heat sources, and warming

Figure 21-29 M odified from American Heart Association (AHA) hypothermia algorithm from the 2005 Cardiopulmonary Resuscitation
and Emergency Card iovascular Care guidelines and 20120 American Heart Association Guidelines for Cardiopulmonary Resuscitation and
Emergency Cardiovascular Care. Note: Peritoneal lavage, extracorporeal rewarming, and esophageal rewarming t ubes are usually hospital-only

Source: Data from: American Heart Association: Handbook of emergency cardiovascular care for healthcare providers, Chicago, 2006, AHA.

• Undemutrition 2. When you cannot stay dry under conditions of cold,
wet, and wind, end your session outdoors and seek
• Lack of cold weather experience shelter as soon as possible.

• African ancestry 3. Remember that individuals with a history of cold injury
• Tobacco use are at a greater risk of a subsequent cold injury.
• Windchill

CHAPTER 21 Environmental Trauma I: Heat and Cold 581

4. Avoid dehydration. 10. Always wear gloves. Frostbite can occur rapidly wh en
5. Avoid alcohol in cold environments. touching metal objects in the cold with your bare hands.
6. Use the huddle technique with others if accidental Mittens are more effective at trapping warm air around
all fingers than are five-finger gloves.
water immersion in cold water occurs. You are more
likely to survive if you remain still in cold water less 11. Understand that the windchill index (Figure 21-30)
than 68°F (20°C) and do not attempt to swim to shore is composed of wind speed and air temperature, and
unless it is n earby. dress for extreme cold with insulated clothing and a
7. Increase your likelihood of survival in cold environ- windproof garment.
ments by:
• Maintaining a will to survive 12. Keep feet dry with socks that transfer moisture from
• Being adaptable and improvising your feet to the footwear.
• Staying optimistic and believing that the event is
13. Do not walk through snow with low-cut shoes. If you
only a temporary situation lack appropriate shoes and protective clothes, attempt
• Maintaining a calm outlook and a sense of to stay in a protected area.

humor 14. Do not lie or rest directly on snow. Lie on tree boughs,
8. Us e body heat to warm extremities that are cold or a sleeping pad, or a poncho. Use a sleeping bag
nearly frozen by placing fingers in the armpits or groin
area. Toes and feet can be placed on another person's 15. Do not wear clothing that will absorb and retain sweat;
stomach. any sweat retained in your clothes will increase heat
9. Keep protective cold weather clothing (e.g., boots, loss and cause shivering.
socks, gloves, winter hat, insulated pants and jacket,
windproof outer sh ell) in your car for unexpected 16. When using lotion, use an oil-based one (e.g.,
car emergencies during cold weather months. ChapStick, Vaseline). Water-based lotions on the face,
Avoid clothing that absorbs moisture, as wet cloth- hands, and ears will increase the risk for frostnip and
ing will exacerbate heat loss (i.e., use wool or frostbite.
17. When protecting the lower extremities from cold
weather, be sure to protect the genital region. Use

Calm Wind Chill Chart
Temperature (°F)
40 35 30 25 20 15 10 5 O -5 -10 -15 -20 -25 -30 -35 -40 -45

5 36 31 25 19 13 7 -5 -11 -1 6 -22 -28 -34 -40 -46 -52 -57 -63

10 34 27 21 15 9 3 -4 -1 0 -1 6 -22 28 -35 -41 -47 -53 -59 -66 -72

15 32 25 19 13 6 0 -7 -1 3 -1 9 -26 -32 -39 -45 -51 -58 -64 -71 -77

20 30 24 17 11 4 -2 -9 -1 5 -22 -29 -35 -42 -48 -55 -61 -68 -74 -81

25 29 23 16 93 -4 -11 -1 7 -24 -31 -37 -44 -51 -58 -64 -71 -78 -84
8 -5 -1 2 -1 9 -26 -33 -39 -46 -53 -60 -67 -73 -80 -87
I' 70 -7 -1 4 -21 -27 34 -41 -48 -55 -62 -69 -76 -82 -89
6 -1 -8 -1 5 -22 -29 -36 -43 -50 -57 -64 -71 -78 -84 -91
ea.. 30 28 22 15

~ 35 28 21 14

40 27 20 13

45 26 19 12 5 -2 -9 -1 6 -23 -30 -37 -44 -51 -58 -65 -72 -79 -86 -93

50 26 19 12 4 -3 -1 0 -1 7 -24 -31 -38 -45 -52 -60 -67 -74 -81 -88 -95

55 25 18 11 4 -3 -11 -1 8 -25 -32 -39 -46 -54 -61 -68 -75 -82 -89 -97

60 25 17 10 3 -4 -11 -1 9 -26 -33 -40 -48 -55 -62 -69 -76 -84 -91 -98

D D DFrostbite Times:
30 minutes 1O minut e s 5 minutes

Wind Chill ("F) = 35.74 + 0.6215T - 35.75(V0·16) + 0.4275T(VO.l6)
Where, T = Air temperature ("F) V = Wind speed (mph)

Figure 21-30 Windchill index.

Source: Courtesy of the National Weat her Service.


sweatpants, long underwear, Lycra tights, Gore-Tex and Altitude for additional situations [e.g., cold-water submer-
pants, or any combination of these garments. sion, lightning strike] in which CPR may be extended longer than
18. To prevent frostbite: 20 to 30 minutes). 134
• Do not wear tight clothing, gloves, or boots that
Heat-Related Illness
restrict circulation.
• Exercise fingers, toes, and face periodically to
keep them warm and to detect numb areas. Provide whole-body cooling as quickly as possible. Think about
using any available access to water. Immerse the body to neck
• Work or exercise with a partner, who watches for level in cool water (maintain body control and protect the air-
warning signs of cold iajury and hypothermia. way), or spray the whole body with water (e.g., IV fluids, saline,
water bottles, water from hydration backpacks), and provide a
• Wear properly insulated clothing, and keep it dry; source of continuous wind current (e.g., natural wind current,
carry extra undergarments, socks, and shoes at fanning with towel, fire ventilation fans). When possible, stay
all times. in contact with medical control to keep them informed of the
patient's status and to receive further medical directions. Stop
• Watch for numbness and tingling.133 body cooling when rectal temperature reaches 102°F (38.9°C).
Then protect the patient from shivering and hypothermia.
Prolonged Transport
As you are cooling the patient, manage the airway in unre-
At times, the location of a patient will result in a delay in trans- sponsive patients and initiate good ventilation with a bag-mask
port or a prolonged transport to an appropriate facility, necessi- device with high-flow oxygen. Insert an IV line, provide a 500-
tating extended prehospital care. Consequently, prehospital care ml NS fluid challenge, and assess vital signs. Patients should
providers may need to consider management options beyond have vital signs assessed after every 500 ml. Total fluid volume
what would be used with a rapid transport. How the patient is should not exceed 1 to 2 liters in the first hour. An additional liter
managed will d epend on the time to definitive care, approved can be considered during the second hour ifprehospital care is
medical protocols, equipment and supplies on hand, additional extended.
personnel and resources, and location ofthe patient and severity
ofthe iajuries. The next priorities are to manage any seizure activity and
hypoglycemiaper medical protocol with diazepam and dextrose,
Some extended care considerations for moderately to respectively. Place the patient in the recovery position, and con-
severely iajured patients from each of the environments dis- tinue the assessment to include level of consciousness, vital
cussed in this chapter are provided here. As with all patient signs, rectal temperature, and blood glucose. Provide supportive
care, it is understood that the first priorities are scene safety, care and basic bodily needs throughout the remaining extended
ABCDEs (airway, breathing, circulation, disability, expose/ care period.
environment), and the use ofstandard assessment and manage-
ment procedures appropriate to these environments. If medical Exercise-Associated Hyponatremia
control is available, always obtain a consult early, and com-
municate routinely throughout the extended care period. Any Correct the presumed low blood sodium concentration. If the
of the procedures listed that fall outside an individual's scope patient can take food by mouth and if such food is available,
of practice are to be used only by other, credentialed medical provide potato chips, pretzels, or other salty food, or a sport
providers. electrolyte or other sodium-containing beverage. An oral sodium
solution has been demonstrated to be an appropriate hypertonic
Also, it is important to know that all agencies have estab- saline treatment.136 In the field, this solution could be prepared
lished guidelines for discontinuation ofCPR. The AHA published by dissolving three to four bouillon cubes in a half cup of water
a discussion on the ethical issues arising from withholding or (125 ml) (-9% saline). Salt tablets given alone are not recom-
withdrawing BLS or ALS resuscitation efforts.128 The Wilderness mended; additional fluid must accompany the tablets, and there
Medical Society recommends that once CPR is initiated, it is the risk of increasing sodium levels too much.
should be continued until resuscitation is successful with an
awake patient, until rescuers are exhausted, until rescuers are Next, establish an IV line and start NS with a flow rate set to
placed in danger, until the patient is turned over to more defin- KVO. Check with medical control to consider a flow rate of 250 or
itive care, or until the patient does not respond to prolonged greater ml/hour based on the estimated delay in transporting the
(30 minutes) resuscitative efforts.134 The National Association patient to the hospital or the presence of severe dehydration or
of EMS Physicians also provides guidelines for the termina- rhabdomyolysis. Do not use hypotonic IV fluids because they
tion of CPR in the prehospital environment (see the Patient will exacerbate cerebral edema and could potentiate the condi-
Assessment and Management chapter).135 If medical control tion, leading to seizure, coma, and death. In a patient with severe
is available, begin patient consult early, if possible, for con- signs or gymptoms (seizure or coma), consider administration
sideration of CPR termination after a total time of 20 minutes,
depending on special patient circumstances (see the chapter
titled Environmental Trauma II: Drowning, Lightning, Diving,

CHAPTER 21 Environmental Trauma I: Heat and Cold 583

of furosemide (a diuretic, if available) to reduce extracellular rewarming phase.) If available, an oral or rectal thermometer
body water content while providing some sodium by infusing should be used t o measure water temperature. A temperature
NS, 250 to 500 ml/hour IV. below that recommended will thaw tissue but is less beneficial
for rapid thawing and for tissue survival. Any greater tempera-
Assess cerebral edema and increased intracranial pressure. ture will cause greater pain and may cause a bum injury. Avoid
Establish a baseline Glasgow Coma Scale score, and reassess active rewarming with intense sources of dry heat (e.g., plac-
every 10 minutes as an indicator of progressive cerebral edema ing near campfire). Continue immersion until tissue is soft and
and increased intracranial pressure (manage per recommenda- pliable, which may take up to 30 minutes. Active motion of the
tions for cerebral edema; see the Head Trauma chapter). extremity during immersion is beneficial, without directed rub-
bing or massaging of the affected part. If immersion warming
Be prepared to manage nausea and projectile vomiting. is not available, the affected parts may be wrapped in loose,
Take one side of a large trash bag and make a hole for the bulky sterile dressings.
patient's head about 12 inches (30 centimeters) below the
rim of the bag. Place the patient's head through the hole so Extreme pain is experienced during rapid thawing. Treat
that the patient can look down into the center of the bag. with morphine, 5 to 10 mg IV, and titrate as needed. Provide ibu-
Also be prepared to manage urine when diuresis begins. profen, 400 mg orally every 12 hours, alone or in combination
Use a large trash bag as a diaper or use a bucket or other with morphine. Aspirin may be given if ibuprofen is not avail-
container. able, although the optimal dosage regimen has not been deter-
mined. (Aspirin is contraindicated in pediatric patients because
Give supplemental oxygen (2 to 4 liters/min by nasal can- of the risk ofReye's syndrome.)
nula) if the patient shows signs of pulmonary distress or for
lethargic or obtunded patients. Manage the airway of unre- The return of normal skin color, warmth, and sensation in
sponsive patients, and initiate good ventilation with a bag-mask the affected part are all favorable signs. Dry all affected parts
device (no hyperventilation; see the Head Trauma chapter), with with warm air (do not towel dry affected parts), and ideally,
oxygen at 10 breaths/minute. apply topical aloe vera on skin, place sterile gauze between toes
or fingers, bandage, splint, and elevate the extremity. Cover any
Assess the patient's blood glucose level, and provide IV extremity with insulating material, and wrap a windproof and
dextrose per protocol to hypoglycemic patients. Monitor for waterproof material (e.g., trash bag) as the outer layer, partic-
seizures, and administer an anticonvulsant (e.g., diazepam, ularly if continuing patient extraction outdoors to a transport
initially 2 to 5 mg IV/intramuscular, and titrate per medi- location.
cal protocol). Place unconscious patients in a left lateral
recumbent position. Continue ongoing assessment of the Hypothermia
Start active rewarming procedures. The key point is to prevent
Cold-Related Illness further heat loss. Administer heated IV fluids (104°F to 109°F
[40°C to 42.8°C]).
Shivering is the single best way for rewarming patients
Start IV fluids KVO before initiation of rewarming procedures. with mild hypothermia in the prehospital setting compared with
If a vein cannot be accessed, the intraosseous route is an alterna- external methods of rewarming. Patients with hypothermia who
tive. In a situation of significant transport delay, active rewarm- are able to shiver maximally can increase their core tempera-
ing should be c onsidered. Rapid, active rewarming can reverse ture by up to 6°F to 8°F (-3°C to 4°C) per hour. External heat
the direct injury of ice crystals in tissues, but it may not change sources are often used but may provide only minimal benefit.84
the injury seventy. It is critical to keep the thawed tissue from For the patient with moderate to severe hypothermia, these heat
refreezing because this significantly worsens the outcome com- sources remain important considerations in the extended-care
pared with passive thawing. When and where to begin active situation when used in combination with the hypothermia insula-
rewarming are key considerations, if active rewarming is to be tion wrap. Some considerations regarding external heat sources
done at all. include the following:

A standard rewarming procedure is to immerse the • Warmed (maximum 108°F [42.2°C]), humidified oxygen
affected extremity in circulating water warmed to between by mask can prevent heat loss during ventilation and
a temperature no greater than 98.6°F and 102°F (37°C and provide some heat transfer to the chest from the respi-
38.9°C) in a large enough container to accommodate the frost- ratory tract.
bitten tissues without them touching the sides or bottom of the
container.93 Water should feel warm, but not hot, to the normal • Body-to-body contact has merit for heat transfer, but
hand. (Note that the temperature range given here is lower many studies fail to show any advantage except in
than that previously recommended; this temperature range patients with mild hypothermia.
decreases pain for the patient while only slightly slowing the


• Electric and portable heating pads provide no addi- waterproof layer. Lay the patient on top of the insulation layer
tional advantage. along with any external heat sources. Add a second insulating
layer on top of the patient. The left side of the hypothermia wrap
• Forced-air wanning has some benefit in minimizing is folded over the patient first, then the right side. The patient's
postcooling core temperature ("afterdrop"); it provides head is covered to prevent heat loss, keeping an opening at the
an effective wanning rate comparable to shivering for face to allow patientassessment.
patients with mild hypothermia.
Assess the patient for hypoglycemia. Providing dextrose
Insulate all patients with hypothermia in the remote setting will ensure that adequate fuel (sugar) is available for muscu-
to minimize heat loss. Prepare a multilayer hypothermia wrap. lar metabolism during shivering and will prevent further hypo-
Place a large, waterproof plastic sheet on the floor or ground. glycemia. Alert patients can consume warm, sugary fluids by
Add an insulation layer ofblankets or a sleeping bag on top of the m o ut h .

• Prehospital care providers will inevitably be faced with environmental encounters such as those described
in this chapter.

• Basic knowledge of common environmental emergencies is necessary to provide rapid assessment and
treatment in the prehospital setting.

• It is not easy to remember this type ofinformation because these problems are infrequently encountered, so
remember the general principles involved.

• For heat-related illness, treat patients with heatstroke with effective, rapid, whole-body cooling to reduce
core temperature quickly.

• For cold-related illness, manage all patients with moderate to severe hypothermia gently, taking the time to
remove them from the cold environment, and begin passive rewanning while monitoring core temperature.
The key is to prevent further body heat loss.

• Remember, drugs and defibrillation are generally ineffective when core temperature is less than 86°F (30°C).
• Patients are not dead until they are warm and dead.
• Remember that you must maintain your own safety. In too many cases, prehospital care providers have lost

their lives as a result of attempting a rescue.

It is a hot summer afternoon with temperatures reaching 102°F(38.9°C). Over the past 30 days, it has been very humid, with temperatures
reaching over 100°F(37.8°C) daily. The ambient temperature has resulted in many heat-related injuries that have required EMS personnel
to transport numerous patients to the EDs of the inner city.

At 1700 hours, your ambulance unit responds to a dispatch for an unresponsive male patient in a vehicle. As your ambulance unit
arrives on scene, you observe a 76-year-old man who appears to be unconscious in a vehicle parked outside of a department store.
Your rapid assessment of the patient's ABCs and level of consciousness reveals that the patient is verbal, but he is saying things that are
illogical and irrational.

• What are the potential causes for this patient's decreased level of consciousness?
• What hallmark signs support a heat-related diagnosis?
• How would you emergently manage this patient at the scene and en route to the ED?

CHAPTER 21 Environmental Trauma I: Heat and Cold 5 8 5

This 76-year-old male victim has been waiting in his car for his spouse to return from the shopping center. He has been exposed to high
heat without effective hydration to offset fluid loss (sweat) and is dehydrated. The patient has a body mass index over 30, placing him
at greater risk of heat-related illness because of obesity.

On the wife's return, she provided additional history indicating that he is taking a diuretic for hypertension, a beta blocker for
coronary heart disease, and an anticholinergic for Parkinson's disease. All three medications are known risk factors for heat-related
illness. This pat ient needs quick assessment of his ABCs and level of consciousness using the AVPU (alert, responds to v erbal stimulus,
responds to painful stimulus, u nresponsive) scale, as he was found in a non-air-conditioned car. Due to his irrational and illogical verbal
statements, his age, and the location, you have a high suspicion for heatstroke.

You rapidly assess for blunt or penetrating trauma and find none. Next, geriatric patients must be assessed for exacerbation of any
underlying medical disease, such as cardiac disease or a neurologic disorder (e.g., stroke). All three of his medical conditions are known
to be made worse with hyperthermia, thereby increasing his mortality risk. It is essential that this patient receive whole-body cooling

You move the patient out of the direct sunlight on the front seat and remove any excess clothing. You use the saline water bottles
from the trauma bag to begin wetting him down from his head to toes. You have your partner start the fan and place the air condi-
tioning on high to increase airflow across the patient's body to increase convective heat transfer. The stretcher is readied to transfer the
patient to the ambulance. Ice water and cool moist towels are readied in the back of the ambulance for t his patient with hyperthermia.

You quickly transfer the patient from his vehicle to the ambulance. The patient's whole body is wetted down with cold wet towels,
and the overhead fans are directed at the patient. The patient is placed on high-flow oxygen, ECG is monitored, and an IV is established
at a KVO rate initially. You are prepared to evaluate rectal temperature to confirm hyperthermia (greater than or equal to104°F [40°C)).
If confirmed, you will provide a 500-ml saline IV bolus. You take a set of vital signs and inform medical control to prepare for a 76-year-
old male patient with heatstroke.

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102. Epstein M. Renal effects of head-out immersion in man: implica-
tions for understanding volume homeostasis. Physiol Rev. 1978;

103. Jurkovich G. Hypothermia in the trauma patient. Adv Trauma.

104. Jurkovich GJ. Environmental cold-induced injury. Surg Clin N Am .

105. Arthurs Z, Cuadrado D, Beekley A, Grathwohl K The impact of
hypothermia on trauma care at the 31st combat support hospital.
Am J Surg. 2006;191(5):610--614.


106. Beilman GJ, Blondett JJ, Nelson AB. Early hypothennia in 123. Tikuisis P. Predicting survival time at sea based on observed body
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tiple organ dysfunction syndrome but not mortality. Ann Surg.
2009;249:845-850. 124. Hayward JS, Errickson JD, Collis ML. Thermal balance and survival
time prediction of man in cold water. Can J Physiol Pharmacol.
107. Mommsen P, Andruszkow H, Fromke C, et al. Effects of accidental 1975;53:21.
hypothermia on posttraumatic complications and outcome in mul-
tiple trauma patients. Injury. 2013;44(1):86-90. 125. Ducharme MB, Lounsbury DS. Self-rescue swimming in cold water:
the latest advice. Appl Physiol Nutr Metab. 2007;32:799.
108. Lapostolle F, Sebbah JL, Couvreur J. Risk factors for the onset of
hypothermia in trauma victims: the Hypotrauma study. Grit Care. 126. Van Mieghem C, Sabbe M, Knockaert D. The clinical vales of the
2012;16(4):Rl42. ECG in noncardiac conditions. Chest. 2004;125:1561.

109. Trentzsch H, Huber-Wagner S, Hildebrand F, et al. Hypothermia for 127. Vanden Hoek TL, Morrison LJ, Shuster M, et al. Part 12.9: car-
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2012;37(2):131. Anwrican Heart Association Guidelines for Cardiopulm onary
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mia after cardiac arrest. An advisory statement by the Advance Life
Support Task Force of the international liaison committee on resus- 128. Morrison LJ, Kierzek G, Diekema DS, et al. Part 3: Ethics. In: 2010
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lll. Alzaga AG, Cerdan M, Varon J. Therapeutic hypothennia 2010;122:S665-S675.
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129. Danz! DF, Lloyd EL. Treatment of accidental hypothennia In:
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131. Bernard MB, Gray TW, Buist MD, et al. Treatment of comatose sur-
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2010 International Consensus on Cardiopulmonary Resuscitation N Engl J Med. 2002;346(8):557.
and Emergency Cardiovascular Care Science With Treatment
Recommendations. Resuscitation. 2010;81S:e l-e25. 132. Reuler JB. Hypothermia: pathophysiology, clinical setting, and man-
agement. Ann Intern Med. 1978;89:519.
ll4. Carlson LD. lmmersion in cold water and body tissue insulation.
A erospace Med. 1958;29:145. 133. Armstrong LE. Cold, windchill, and water immersion. In:
Peiforming in Extreme Environments. Champaign, IL: Human
ll5. Wittmers LE, Savage M. Cold water immersion. In: Pandolf KB, Kinetics; 2000.
Burr RE, eds. Medical Aspects of Harsh Environments. Vol 1.
Washington, DC: Office of the Surgeon General, Borden Institute/ 134. Wilderness Medical Society. Myocardial infarction, acute coronary
TMM Publications; 2001:531-552. syndromes, and CPR. In: Forgey WW, ed. Practice Guidelines for
Wilderness Emergency Care. 5th ed. Guilford, CT: Globe Pequot
ll6. Giesbrecht GG, Steinman AM. lmmersion into cold water. In: Press; 2006.
Auerbach P S, ed. Wilderness Medicine. 6th ed. St. Louis, MO:
Mosby Elsevier; 2012. 135. Siegel AJ, d'Hemecourt P, Adner MM, Shirey T, Brown JL,
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ll8. Tipton MJ. The initial responses to cold-water immersion in man. 136. Position paper of the National Association of EMS Physicians: ter-
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ll9. Keatinge WR, Mcilroy MB, Goldfien A. Cardiovascular responses to
ice-cold showers. J Appl Physiol. 1964;19:1145. Suggested Reading

120. Meltjavic IB, La Prairie A, Burke W, Lindborg B. Respiratory Auerbach PS, ed. Wilderness Medicine. 6th ed. St. Louis, MO: Mosby
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PandolfKB, Burr RE, eds. MedicalAspects of HarshEnvironments. Voll.
121. Cushing TA, Hawkins SC, Sempsrott J, Schoene RB. Submersion Washington, DC: Office of the Surgeon General, Borden Institute/
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6th ed. St. Louis, MO: Mosby Elsevier; 2012.

122. WISSier EH. Probability of surviving during accidental immersion in
cold water. Aviat Space Environ Med. 2003;74:47.

At the completion of this chapter, the reader will be able to do the following:

• Explain why there is no safe place outdoors from • Identify f ive methods for preventing a drowning
ligh t n ing . incident.

• Describe the use of "reverse" triage for multiple • Contrast the signs and symptoms of Type I and
lightning casualties. Type II decompression sickness.

• Identify the key risk factors for high-altitude • Describe two primary treatment interventions for
illness. Type II decompression sickness and arterial gas
• Explain the new recommendation during the
initial ABC (airway, breathing, and circulation) • Discuss the similarities and differences between
management of a drowning incident. acute mountain sickness and high-altitude
cerebral edema.
• Describe three signs or symptoms that can occur
in a patient after a drowning incident.


In a coastal town, a family of four was strolling on the beach with their dog during a chilly winter day. The son tossed a rubber ball
toward the water's edge, and the dog gave chase. In an instant, a large shore-breaking wave swallowed up the dog in the rough surf.
The 17-year-old son was first into the water to attempt to save the dog, only to be overtaken by the water. He w as seen struggling in
the rough surging surf by his parents and sister.

The boy's father and mother both followed him into the surf in an effort to help. Their 19-year-old daughter remained on shore and
called for help on her cell phone. The dog eventually made it back to the shore. The parents were able to pull their son out of the cold
water after finding him submerged and unresponsive. Your paramedic unit arrives to the scene within 7 minutes of the daughter's call.

As you exit the ambulance, you observe an unconscious teenage boy lying partially facedown in sand with surging water close by.
He is still in the surf zone and could be submersed by a wave. You team up with arriving fire department emergency responders to
approach the victim.

• How should you approach the patient in this setting?
• If the patient has no pulse or respirations, what is the next immediate intervention?
• What other concerns do you have for the patient that need to be addressed on scene?

~~ - -.'-_/ Introduction
Each year in the United States, significant
morbidity and mortality are caused by a
variety of environmental conditions, including lightning strikes,
submersion incidents, recreational scuba diving, and high-
altitude climbing (see the Environmental Trauma I: Heat and
Cold chapter for heat and cold conditions). Prehospital care
providers must know the major and minor disorders associated
with each type of environment; understand the anatomy, physi-
ology, and pathophysiology involved; and know how to rapidly
perform patient assessment and management. At the same time,
they must know how to prevent injury to themselves and other
public safety personnel.

Lightning-Related Figure 22-1 A cloud-to-ground light ning strike, w ith streak
Injuries lightning pattern.

Lightning is the most widespread threat to people and property Source:© Jhaz Photography/ShutterStock, Inc.
during the thunderstorm season and is second only to floods in
causing storm-related death in the United States since 1959.1 of Mexico throughout the year (see Figure 22-2 for distribution
The National Weather Service estimates that 100,000 thunder- of lightning flashes in the United States and worldwide).5
storms occur each year in the United States and that lightning Internationally, lightning strikes occur approximately 50 times
is present in all storms. Lightning is reported to start approxi- per second, and it is estimated that one-fifth of these strike the
mately 75,000 forestfires annually and starts 4QOA> of all fires.2 The ground.6•7 Worldwide, rural populations are at the greatest risk
most destructive form of lightning is the cloud-to-ground strike due to the lack of lightning safe structures and prevention edu-
(Figure 22-1). Based on real-time lightning-detection systems, it cation. Consequently, it is estimated that 24,000 fatalities occur
is estimated that cloud-to-ground lightning strikes occur approx- annually and about 10 times more injuries worldwide.8•9
imately 20 million times per year, with as many as 50,000 flashes
per hour during a sununer afternoon.3•4 In the United States, Since the 1950s, the number of deaths from lightning in the
lightning occurs most frequently from June through August, but United States has decreased, possibly because of fewer people
occurs in Florida and along the southeastern coast of the Gulf working outdoors in rural areas, improved warning systems for
approaching storms, increased public education on lightning

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 591



0 .5
0.0 16

Figure 22-2 A. Distribution of lightning ground strikes in the United States, with t he heaviest concentrat ion in the southeast region.
B. Distribution of lightning ground strikes worldwide.

Source: Huffines GR, Orville RE: Lightning ground flash density and t hunderstorm duration in the continent al United Stat es, 1989-1996. 1Appl Meteoro/ 38: 10 13, 1999.

safety, and improved medical care.6 Latest reports indicate that certificates listing lightning as the cause of death.13 Of those who
lightning kills 50 to 300 individuals each year and injures about died during this 16-year period, 1,125 (85%) were male, and 896
1,000.2•10 (68%) were 15 to 44 years of age. The highest death rate from
lightning occurred among those 15 to 19 years of age (6 deaths
The greatestlife threats from lightningstrikes are neurologic per 10,000,000). Analysis shows that about 30% die and 74% of
and cardiopulmonary injuries. A recently published practice the survivors have permanent disabilities. Furthermore, victims
guideline from the Wilderness Medical Society is available for with cranial or leg burns are at a greater risk for death.12 Of the
the prevention and treatment of lightning injuries for prehospi- individuals who died from a lightning strike, 52% were outside
tal and in-hospital care.11•12 These recommendations for medical (25% of whom were at work). Death occurred within 1 hour in
management are graded, based on the quality of the supporting 63% of the lightning victims.6
evidence (see the chapter titled The Science, Art, and Ethics of
Prehospital Care Principles, Preferences, and Critical Thinking). Mechanism of Injury

Epidemiology Injury from lightning can result from the following five
Based on the National Oceanic and Atmospheric Administration
(NOAA) publication called Storm Data, 3,529 deaths (average • Direct strike occurs when a person is in an open envi-
98 deaths per year), 9,818 injuries, and 19,814 property-damage ronment unable to find shelter. It accounts for only 3%
reports occurred during the 36-yearperiod from 1959 to 1994 due to 5%of lightning strikes involving people.
to lightning.1 Figure 22-3 shows the ranking of lightning injuries
and deaths by state from 1959 to 1994. • Side flash or splash contact occurs when lightning hits
an object (e.g., ground, building, tree) and splashes
There were 1,318 lightning deaths between 1980 and 1995 onto a victim or multiple victims. The current will jump
in the United States, on review of medical examiners' death



Alaska: O Rank
Hawaii: 4
• 1-10
A D 11-20
D 21-30
D 31-52


• 1-10
D 11-20
D 21-30

B D 31-52


Figure 22-3 Rank of each state in lightning casualties (deaths and injuries combined) from 1959 to 1994. A. Casualt ies per state.
B. Casualties weighted by state population. C. 2012 lightning fatalities.
Source: A., B. Data from Curran EB, Holle RL, Lopez RE: Lightning fatalities, injuries, and damage reports in the United St ates from 1959-1994. NOAA Tech Memo NWS

SW-193, 1997. C. Data from: m Accessed Jan 7, 2013.

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 5 9 3

from the primary strike object and can splash over to Once lightning or other high-voltage electrical source contacts
a person. Splashes occur from person to person, tree the human body, the heat generated within the body is directly
to person, and even indoors from telephone wire to a proportional to the amount of current, tissue resistance, and
person talking on the phone. duration of contact. As resistance of various tissues increases
(e.g., from nerve< blood< muscle < skin< fat< bone), so does
• Contact occurs when a person is in direct contact the heat generated by the passage of current.
with an object that is struck directly or by a splash. It
accounts for one-third of all lightning injuries. It is easy to assume that lightning injuries are similar to
high-voltage electrical injuries. However, significant differ-
• Step voltage occurs when lightning hits the ground or a ences exist between the two mechanisms of injury. A lightning
nearby object and the current spreads outward radially, strike is direct current (DC) as opposed to alternating current
passing through a person's body in the process. Human (AC), which is responsible for industrial and household electri-
tissue provides less resistance than the ground, and the cal injuries. Lightning produces millions of volts of electrical
current will travel, for example, up one leg and down charge, with currents ranging from 30,000 to 50,000 amps, and
the other, following the path ofleast resistance. Ground the duration of exposure to the body is instantaneous (10 to
current accounts for over 500;6 of lightning injuries. 100 milliseconds). The temperature of lightning varies with
Step voltage is also known as stride voltage or ground the diameter, but the average temperature is approximately
current. 14,430°F (8,000°C).10 In comparison, high-voltage electrical
exposure tends to be a much lower voltage than lightning.
• Upward streamer occurs when current passes up However, the key factor that distinguishes lightning injury from
from the ground and through the victim, but does not high-voltage electrical injury is the duration ofcurrent exposure
within the body.14 Figure 22-4 lists differences between lightning
connect with the downward lightning streamer. The and generator-produced, high-voltage electrical injuries.
energy in this streamer is less as compared to a full
At times, lightning can show injury patterns similar to those
lightning strike and accounts for approximately 1% to seen with high-voltage electricity because of a rare lightning pat-
15% of lightning injuries. Upward streamer is a newer tern that produces a prolonged strike lasting up to 0.5 second.
form oflightningcontactthat has beenrecently identified. This type of lightning, called hot lightning, is capable of causing
deep burns, exploding trees, and setting fires. Lightning can show
Blunt trauma can occur from a shock wave produced by entry and exit wounds on the body, but a more common pathway
lightning, which can propel a person up to 10 yards. In addition, of lightning once it strikes a victim is to pass over the body. This
injuries can result from lightning that causes forest fires, build- is referred to as ajtashover current. A fiashover current can also
ing fires, and explosions.2•14•15 enter the eyes, ears, nose, and mouth. It is theorized that the fiash-
over current flow is the reason why many victims survive lightning
There are six known factors that determine the injury sever- strikes. It is also known that a fiashover current mayvaporize mois-
ity from electrical and lightning current: ture on skin or blast a part of clothing or shoes off a victim. The
immense fiashover current generates large magnetic fields, which
• Type of circuit • .. in turn can induce secondary electric currents within the body and
• Duration of exposure are thought to cause cardiac arrest and other internal injuries.16-17
• Voltage
• Amperage . ..-
• Resistance of tissue
• The pathway of current

Figure 22-4 • • •

Factor Lightning High Voltage

Energy level 30 million volts; 50,000 amperes Usually much lower

Time of exposure Brief, instantaneous Prolonged

Pathway Flashover, orifice Deep, internal

Burns Superficial, minor Deep, internal

Cardiac Primary and secondary arrest, asystole Ventricular fibrillation

Renal Rare myoglobinuria or hemoglobinuria Myoglobinuric renal failure common

Fasciotomy Rarely if ever necessary Common, early, and extensive

Blunt injury Explosive thunder effect Falls, being thrown

Source: Modified table from Cooper MA, Holle RL, Andrews CJ, Blumenthal R: Lightning injuries. In Auerbach PS: Wilderness medicine, ed 6,
St. Louis, 2012, Mosby Elsevier.


Injuries From Lightning in this category also have a permanent disability. Patients may
present at the scene with the following:
Lightning injuries range from minor superficial wounds to major
multisystem trauma and death. Figure 22-5 lists common signs • Immediate effects
and symptoms of lightning injury. As a tool to determine the • Neurologic signs
likely recovery or prognosis from lightning strikes, victims can
be placed in one ofthree injury categories: minor, moderate, and • Seizures
severe. 11•18
• Deafness
Minor Injury
• Cardiac arrest and cardiac injuries
Patients with minor injury are awake and report an unpleasant
and abnormal sensation (dysesthesia) in the affected extremity • Pulmonary injuries
or extremities. In a more serious lightning strike, victims report
they have been hit in the head or state that an explosion hit them, • Confusion, amnesia
because they are unsure of the source. A patient may present at
the scene with the following: • Blindness

• Confusion (short term or hours to days) • Dizziness
• Amnesia (short term or hours to days)
• Temporary deafness • Contusion from shockwave
• Blindness • Blunt trauma (e.g., fractures)
• Temporary unconsciousness • Chest pain, muscle aches
• Temporary paresthesia
• Muscular pain • Tympanic membrane rupture
• Cutaneous burns (rare)
• Transient paralysis • Headache, nausea, postconcussion syndrome
• Delayed effects
Victims present with normal vital signs or with mild, transient
hypertension, and recovery is usually gradual and complete. • Neurologic symptoms and signs
• Memory deficits
Moderate Injury
• Attention deficits
Victims with moderate injury have progressive, single or multi-
system injuries, some ofwhich are life threatening. Some patients • Neuropsychological changes
• Coding and retrieval problems
• Distractibility

• Personality changes

• Irritability
• Chronic pain
• Seizures

Depending on the location of the lightning strike, a strike
affecting the respiratory center of the brain can result in pro-
longed respiratory arrest that may lead to secondary cardiac
arrest as a result of hypoxia.12 Victims in this category may
experience immediate cardiopulmonary arrest , although the
inherent automaticity of the heart may produce a spontaneous

Figure 22-5 •• II • • I

Injuries Signs/Symptoms Treatment

Minor Feeling of strange sensation in extremity; confusion; Scene safety; ABCDEs; medical history and
amnesia; temporary unconsciousness, deafness, secondary assessment; monitor ECG; give oxygen
or blindness; tympanic membrane rupture and transport all patients with mild injuries.

Moderate Disorientation, combativeness, paralysis, fractures, Scene safety; ABCDEs; medical history and
blunt trauma, absent pulses in lower extremities, secondary assessment; monitor ECG; CPR (CAB)
spinal shock, seizures, temporary cardiorespiratory early when needed; give oxygen and transport all
arrest, comatose patients.

Severe Any of the above, otorrhea (fluid leak) in ear canal, CPR (CAB) and advanced lifesaving procedures; use

cardiac fibrillation or cardiac asystole "reverse" triage with multiple patients.

Note: ABCDE, airway, breathing, circulation, disability, expose/environment; CAB, circulation, airway, breathing; CPR, cardiopulmonary resuscitation;
ECG, electrocardiogram.

Source: Data from O'Keefe GM, Zane RD: Lightning injuries. Emerg Med Clin North Am 22:369, 2004; and Cooper MA, Holle RL, Andrews CJ,
Blumenthal R: Lightning injuries. In Auerbach PS: Wilderness medicine, ed 6, St. Louis, 2012, Mosby Elsevier.

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 5 9 5

return to normal sinus rhythm.12 Because immediate cardio- Assessment
pulmonary arrest is the greatest threat, prehospital care
providers need to assess the CABs (circulation, airway, On arrival at the scene, as with any other call, the priority is
breathing) quickly in all lightning-strike victims and contin- the safety of the prehospital care providers and other pub-
uously monitor the electrocardiogram (ECG) for secondary lic safety personnel. Emergency responders must determine
cardiac events. whether there is still a chance of lightning in the area. As a
storm approaches or has passed, there still is a source of dan-
Severe Injury ger that is not always apparent since lightning remains a very
real threat as far as 10 miles away-hence its nickname, the
The mechanism for sudden death from lightning strike is simul- "bolt from the blue."12
taneous cardiac and respiratory arrest. Victims with severe
injury from a direct lightning strike (cardiovascular or neuro- The mechanism of injury may be unclear without a witness
logic injuries) or delays in cardiopulmonary resuscitation (CPR) because lightning can strike during a sunny day. When in doubt
have a poor prognosis. On arrival at the scene, the prehospital about the mechanism of injury, immediately assess for ABCDEs
care provider may find the patient in cardiac arrest with asys- (airway, breathing, circulation, disability, expose/environment)
tole or ventricular fibrillation. Lightning causes a massive DC and any life-threatening conditions, as for any emergency. These
countershock, which simultaneously depolarizes the entire myo- patients do not carry an electrical charge and touching them
cardium.16 The American Heart Association (AHA) recommends poses no risk in providing patient care. Assess the victim's heart
vigorous resuscitation measures for those who appear dead on rhythm with the ECG. Itis common to see nonspecific ST-segment
initial evaluation. This is based on many reports of excellent and T-wave changes such as QT interval prolongation and tran-
recovery after lightning-induced cardiac arrest and on the fact sient T-wave inversions, but more specific evidence of myocar-
that victims in this category are typically young and without dial infarction with Q-wave or ST-segment elevation is rarely
heart disease.15 seen.20

It is not uncommon to observe the initial cardiac arrest with Once the patient is stable, a detailed head-to-toe assessment
spontaneous recovery of electrical activity following the light- is necessary to identify the wide range ofinjuries that can occur
ning strike, but any ongoing respiratory arrest due to a paralyzed with this type of trauma Assess the patient's situational aware-
medullary respiratory center may cause secondary hypoxic car- ness and the neurologic function of all extremities because the
diac arrest.15•19 Ifprolonged cardiac and neurologic ischemia has upper and lower extremities may experience transient paralysis
occurred, it may be very difficult to resuscitate these patients. 10 (known as keraurwparalysis). Lightning victims are known to
Other common findings are tympanic membrane rupture with have an autonomic dysfunction causing dilated pupils, which
cerebrospinal :fluid and blood in the ear canal, ocular injuries, will mimic head trauma 19 Assess the eyes because 55% ofvictims
and various forms of blunt trauma from falls, including soft- have some form of ocular injury. Look for blood and cerebro-
tissue contusions and fractures of the skull, ribs, extremities, spinal fluid in the ear canals; 500A> of these victims will have one
and spine. Many patients in this category have no evidence of or two ruptured tympanic membranes. All victims of lightning
burns. In those patients presenting with cutaneous burns caused injury have a high probability of blunt trauma from being thrown
by lightning, it is generally reported to be less than 20% total against a solid object or being struck by falling objects. Cervical
body surface area spine precautions are needed during the assessment to minimize
further injury.
Injury to the central nervous system (CNS) is common in a
lightning victim and has been classified into four groups of CNS Assess the skin for signs of any burns, ranging from superfi-
injuries12: cial to full thickness. Lightning burns may or may not be apparent
in the field since they develop within the first few hours. Burns
• Group 1 CNS effects (lnunediate and Transient): Loss occur in less the one-half oflightning survivors and in most cases
of consciousness (75%); paresthesias (800.Ai); wealmess are superficial.11•12 It is common to see a feathering appearance
(80%); confusion, amnesia, and headaches in the skin, known as Lichtenberg's figures, but these pat-
terns are not burns and resolve in 24 hours (Figure 22-6). It is
• Group 2 CNS effects (immediate and prolonged): more common to see burns secondary to igniting of clothes and
Hypoxic ischemic neuropathy; intracranial hemor- heating ofjewelry or other objects.
rhage; postarrest cerebral infarction
If the incident involves multiple victims, the principles of
• Group 3 CNS effects (possible delayed neurologic triage should be implemented inunediately. The normal rules
syndromes): Motor neuron diseases and movement oftriage are to focus limited personnel and resources on patients
disorders with moderate and severe injuries and quickly bypass those
patients without respiration and circulation. However, with mul-
• Group 4 CNS effects (trauma from fall or blast): tiple lightning-strike patients, the rule changes to use "reverse"
Subdural and epidural hematomas and subarachnoid triage and "resuscitate the dead," because these patients are
hemorrhage either in respiratory arrest or cardiac arrest and have a high
probability of recovery ifmanaged expeditiously. 12•21 In contrast,


Stabilize any fractures, and package the blunt trauma
patient for cervical spine immobilization. Lightning-strike vic-
tims with minor to severe injuries need to be transported to an
emergency department (ED) for further evaluation and observa-
tion. Transport the patient by either ground or air, as determined
by availability, distance, and time to the hospital and overall risk
to the flight crew and benefit to patient.

As mentioned previously, lightning-strike victims have a
higher probability of a positive outcome from early and effec-
tive resuscitation. However, there is little evidence to suggest
that these patient,s can regain a pulse from prolonged basic life
support (BLS) or advanced life support (ALS) procedures lasting
longer than 20 to 30 minutes.2 Before terminating resuscitation,
all effort,s should be made to stabilize the patient by establishing
an airway, supporting ventilation, and correcting any hypovole-
mia, hypothermia, and acidosis.


With numerous thunderstorms throughout the year, lightning

ground strikes are common. Both prehospital care providers

and the general public must be educated about prevention and

the many lightning myths and misconceptions (Figure 22-7).

Numerous lightning-prevention resources are provided by

such agencies as the National Weather Service/NOAA, National

Lightning Safety Institute, American Red Cross, and Federal

Emergency Management Agency.22•24

Official guidelines are published for lightning-injury

Figure 22-6 Lichtenberg's figures. prevention and treatment by both national and international
Source:© British Association of Plastic, Reconstrudive and Aesthetic Surgeons.
medical commissions and organizations, includingthe Wilderness
other patient,s who have survived a lightning strike have little
likelihood of deteriorating, unless there is associated trauma and Medical Society, the AHA, and the International Commission
occult hemorrhage.
for Mountain Emergency Medicine and Medical Commission of
the International Mountaineering and Climbing Federation
The priorities for managing a lightning victim are to ensure scene (Figure 22-8). a ,15,25
safety for yourself and your crew and to assess any victim for
CAB. If spontaneous respiration or circulation is absent, initi- Prehospital care providers and other public safety per-
ate effective CPR up to five cycles (2 minutes), and evaluate the
heart rhythm with an automated external defibrillator (AED) or sonnel should establish procedures for a severe weather watch
cardiac monitor based on current guidelines. 15Use ALS measures
to manage lightning-induced cardiopulmonary arrest based on that provides storm warnings updated throughout the day as
current AHA guidelines for advanced cardiovascular life support
(ACLS) and pediatric advanced life support (PALS), as discussed one method of safety prevention. There is no place that is 100%
elsewhere.15 Evaluate and treat for shock and hypothermia
Apply high-flow oxygen for all moderately and severely injured safe outdoors. The ambulance is the safest shelter if the pre-
patients. Intravenous fluids should be started at a keep-vein-open
(KVO) rate since patient,s who have been injured by lightning, hospital care providers are near it when no large building is
unlike conventional high-voltage electrical-injured patient,s, do
not have massive tissue destruction and burns requiring a larger available.
amount of fluids. Patient,s who show unstable vital signs or who
have sustained associated trauma may have their fluids titrated One public education motto used is, "If you see it, flee it;
as appropriate.
if you hear it, clear it." Another useful rule is the "30-30 rule."

When the time between seeing lightning and hearing thunder is

30 seconds or less, individuals are in danger and need to seek

appropriate shelter. Following this rule, it is recommended to

resume outdoor activity only after 30 minutes following the last

lightning or thunder, because a passing thunderstorm still is a

threat and lightning can strike up to 10 miles after the storm

passes. 26 27 Another measure of lightning proximity is the "fiash-

to-bang" rule, which states that 5 seconds = 1 mile; that is, fol-

lowing lightning, for every 5 seconds until the sound of thunder,

the lightning is 1 mile away.

For more information about preventing lightning strike, see

Figure 22-9. See Figure 22-10 for information about support for

lightning strike survivors.

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 5 9 7

Figure 22-7 Figure 22-8

General Myths Prehospital care providers servicing mountainous regions
All of the following common beliefs about lightning are are at greater risk for lightning strike, especially those
false: who serve as park rangers, search and rescue members,
and other public safety personnel in high-altitude and
• Lightning strikes are invariably fatal. remote areas. Some general prevention guidelines for
• A major cause of death is burns. these prehospital care providers include the following:
• A victim struck by lightning bursts into flames or is
• Take note of the weather forecast since thunder
reduced to ashes. and lightning in the mountains occur mainly during
• Victims remain charged or electrified after they are summer months in the late afternoons and night.
Thus, the saying, "Up by noon and down by
struck. 2:00 p.m." is used to remind individuals to return to
• Individuals are only at risk for being struck when there lower elevations by the middle to late afternoon to
decrease the risk for lightning strike.
are storm clouds overhead.
• Occupying a building during the storm affords 100% • The best place to get out of a lightning storm in the
mountains is a hut or mountain refuge. Stay away
protection from lightning. from open doors and windows.
• Lightning never strikes the same place twice.
• Wearing rubber-soled shoes and a raincoat will • Tents do not provide any protection from lightning
strike, and tent poles may act as lightning rods.
protect a person.
• Rubber tires in a vehicle are what protect a person • Larger caves and valleys are protective, but small
caves provide little protection if the person is near
from injury. the opening and sidewalls.
• Wearing metal jewelry increases the risk of attracting
• Wet stream beds are more dangerous than open areas.
lightning. • Stay off mountain ridges and summits, power lines,
• Lightning always hits the highest object.
• There is no danger from lightning unless it is and ski lifts.
• Stay clear of the base of taller trees since lightning
• Lightning can occur without thunder. will travel down the trunk to the base. In a forest, it
is best to get into a cluster of smaller trees.
Misconceptions Regarding Patient Care • If caught in the open, do not sit or lie flat. It is best
Some myths and misconceptions held by prehospital care to crouch down with feet or knees together and
providers can adversely affect the care and outcome of keep contact with as small an area of the ground
their patients. as possible to minimize injury from ground current.
Prehospital care providers should try to use some
• If the victim is not killed by lightning, he or she will be insulation between themselves and the ground, such
okay. as a dry pack on which to kneel or sit.
• If in a group, stay apart from each other, but within
• If the victim has no outward signs of injury, the sight, to reduce the number of people injured by
damage cannot be that serious. ground current or side flashes between persons.

• Lightning injuries should be treated similar to other • Consider the use of small, portable lightning detectors
high-voltage electrical injuries. so that advance warning is received and prevention
steps can be implemented before the storm arrives.
• Lightning victims who undergo resuscitation efforts
for several hours might still recover successfully.

Source: Modified from O'Keefe GM, Zane RD: Lightning injuries.
Emerg Med Clin North Am 22:369, 2004; and Cooper MA,
Andrews CJ, Holle RL, Lopez RE: Lightning injuries. In Auerbach PS:
Wilderness medicine, ed 5, St. Louis, 2007, Mosby Elsevier.

Drowning preventable death across all age groups, but is an epidemic in
children.28-3! The World Health Organization estimates that there
Drowning incidents that lead to injury are all too common are approximately 400,000 deaths annually from unintentional
in the United States, accounting for approximately 3,880 submersion incidents, not including deaths from drowning
deaths annually. It is the third leading cause of unintentional resulting from floods, suicide, or homicide.32 Submersion inju-
death worldwide.28 Drowning remains a leading cause of ries have a substantial cost to society; an estimated $3.25 billion


Figure 22-9

The following are guidelines for lightning safety as a storm • Turn off the radio and computer and avoid hardw ired
develops: telephones; use a telephone only in an emergency.

• Find a lightning-safe vehicle or a lightning-safe • Turn off all faucets, electrical appliances, and devices
structure .22•26 before a storm arrives.
• An automobile that is a fully enclosed metal
vehicle is a lightning-safe shelter. Other all-metal The following are guidelines for lightning safety when
mobile transportation-related vehicles such as out doors:
airplanes, buses, vans, and construction equipment
with enclosed mostly metal cabs are also safe. • Avoid using handheld radios, cell phones, or
A cautionary note, however, will emphasize that other electronic signal/communication devices
the "outer metal shield" of a vehicle should not be if possible.
compromised. This means:
- Wi11dows need to be rolled up. • Avoid metal objects such as bikes, tractors,
- Contact must not be made with any interior and fences.
objects such as radio dials, metal door handles,
two-way radio microphones, etc., that connect • Avoid tall objects such as trees, and make yourself
w ith external objects. small.
• All other objects that penetrate from inside to
outside should be avoided. • Avoid areas near pipelines, power lines, and
• Unsafe vehicles include those made of fiberglass and ski lifts.
other plastics, plus small riding machinery or vehicles
without enclosed canopies, such as motorcycles, farm • Avoid open fields.
tractors, golf cars, and all-terrain vehicles. • Avoid open shelters (e.g., carport, bus shelter),
• Metal buildings are lightning-safe places. So, too, are
large permanent structures made of masonry and depending on overall size, because side flashes or
wood. Once again, the caveat is to not become part ground strikes can occur.
of the pathway conducting lightning. This means • Drop ski poles and golf clubs, w hich may attract
avoiding all electrical circuits, switches, powered lightning.
equipment, metal doors and windows, hand rails, • In large public out door events, seek out nearby buses
and so on. Small post-supported structures, such as or minivans.
bus stops, picnic shelters, or baseball field dugouts • Seek to make the smallest contact w ith ground, if
are not safe. possible, to minimize ground contact. In the " lightning
position", t he individual squats w ith the feet together,
The following are guidelines for lightning safety when indoors: hands covering t he ears; a ground pad, backpack,
• Seek a building and stay away from windows, open or some insulation material is placed under t he feet.
An alternative position of comfort is to kneel or sit
doors, fireplaces, bath and shower, and metal objects cross-legged.
such as sinks and appliances. • Do not stand, hug, squat, or huddle near tall t rees;
seek out a low area of low er trees or saplings.
• Seek out ditches unless t here is contact with water.
• If on water, seek shore immediately and move inland,
away from the water. Avoid swimming, boating, or
being near the tallest object on water.1·10

Figure 22-10 or more is spent on these patients each year in the United States
Support for survivors of lightning injury is available from
Lightning Strike & Electric Shock Survivors International, The terminology describing these patients continues to
Inc. (LS&ESSI, Inc.). This nonprofit support group evolve. Thirty-five years ago, drowning was defined as the
is comprised of survivors, their families, and other process by which air-breathing mammals succumb on submer-
interested parties. There are members throughout the sion in a liquid, and near-dr owning was defined as submersion
United States and in more than 13 other countries with at least temporary survival.34 The term secondary
( drowning was used to describe patients who recovered
initially from a submersion i.Itjury, but then died from respira-
tory failure secondary to submersion.35•36 However, this latter
term has come under question lately, and some suggest that it
should not be used.35 Any submersion or immersion incident

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 5 9 9

without evidence ofrespiratoryimpairment should be considered 4 years, the second leading cause of death for ages 4 to 14 years,
a water rescue and not a drowning. Older and more archaic terms and the third leading cause of death of infants (less than 1 year
such as near-drowning, dry drowning, wet drowning, secondary of age).29 Infants are at risk from drowning in bathtubs, buckets,
drowning, and passive drowning have all been abandoned. and toilets.39 The incidence ofsubmersion incident may be 500 to
600 times the rate of drowning.40 The Centers for Disease Control
The more accepted definitions adopted by the World Health and Prevention (CDC) reported that from 2005 to 2009 there
Organization are37: were an average of 3,880 cases of unintentional fatal drowning in
the United States each year, and an estimated 5,789 cases were
• Drowning: The process of experiencing respiratory treated in U.S. hospital EDs each year for nonfatal drowning
impairment from submersion/immersion in liquid. (Figure 22-11).29•30 An additional 347 people died each year from
The victim may live or die after this process, but it is drowning in boating-related incidents.29
known as a drowning incident. The drowning process
begins with respiratory impairment as the person's air- For every child who drowned, three others survived and
way goes below the surface of the water or that water required emergency care for their submersion incident. Each
splashes over the face. 38 week, approximately 40 children die from drowning, 115 are hos-
pitalized, and 12 have irreversible brain injury.31
• Submersion: The entire body, including the airway, has
gone under water. The CDC reported an average of 9,669 submersion casual-
ties (fatal and nonfatal) annually from 2005 to 2009.29 Of these,
• Immersion: Water has splashed or washed over the face fatal incidents occurred in bathtubs (10%), pools (18%), and
andairwayandallowsfor drowning to occurbyaspiration. natural water settings such as lakes, rivers, and oceans (51%).
In comparison, unintentional nonfatal submersion incidents
Epidemiology treated in EDs in the United States were highest for pools (58%),
with natural water settings accounting for 25% and bathtubs lOOAi.
Death by unintentional drowning is the seventh leading cause
of death for all ages, the leading cause of death for ages 1 to

Newborn to 4 3057 513

5 to 14 10 12 252

~ 15 1718 3107

Unknown 29


Male 3486 3057

Female 2301 823


Bathtub 534 403

Pool 3341 683

Natu ra l water (ocean, lakes, rivers) 1460 1982

Other 484 813

Treated/released 2540

Hospitalized 2908

Other 340

Total 5789 3880

*Estimated number.
Source: Data from Centers for Disease Control and Prevention: Annual average Nonfat al and fatal drownings in recreational water settings-
United States, 2005- 2009. MMWR 61 (19):345, 2012.


The nonfatal and fatal injury rates were the highest for children risk for drowning because of higher exposure rates to
4 years of age or younger and for males of all ages. The nonfa- aquatic activities, higher alcohol consumption while
tal rate for males was almost twice that offemales, whereas the at the waterfront, and more risk-taking behavior.34•46
fatal rate for males was almost four times that offemales. • Race. Due to the history of segregation in the United
States, many older African Americans were denied
Submersion Factors access to pools and swimming lessons. Ifa grandparent
or parent does not swim, swimming lessons for chil-
Specific factors place individuals at an increased risk for submer- dren may become a lower priority for the family. Today,
sion incidents.34•35•39•41•42 Recognizing these factors will increase African American children experience more submer-
awareness and assist in the creation of preventive strategies and sion incidents than white children. African American
policies to minimize these occurrences. For infants and young chil- children tend to drown in ponds, lakes, and other nat-
dren, the major risk factor is inadequate supervision, and for ado- ural sources of water.28 The drowning rate of African
lescentsand adults, it is riskybehaviorand use ofdrugs oralcohol.39 American male children has been estimated to be as
high as three times that ofwhite males.47
Submersion factors include the following: • Location. Submersion incidents typically occur in
backyard swimming pools and in the ocean, but also
• Ability to swim. Swimming ability is not consistently occur in buckets.35 Houses in rural areas with open
wells increase the risk of a young child drowning by
related to drowning. White males have a higher inci- sevenfold.34 Other hazardous locations are water bar-
rels, fountains, and underground cisterns.
dence of drowning than white females, even though • Alcohol and drugs. Alcohol is the primary drug associ-
ated with submersion incidents,48•49 most likely because
they are reported to have better swimming ability.34 it causes a loss of sound judgment.46 As many as 20% to
30% ofadult boating fatalities and submersion incidents
One study reported that nonswimmers or beginners involve alcohol use in which the occupants used poor
judgment, were speeding, failed to wear life jackets, or
accounted for 73% of drownings in home swimming handled the watercraft recklessly.34•50
• Underlying disease or trauma. The onset of illness
pools and 82% ofincidents in canals, lakes, and ponds.43 from underlying disease can account for submersion
victims. Hypoglycemia, myocardial infarction, cardiac
• Shallow-water blackout. In an effort to increase their dysrhythmia, depression and suicidal thoughts, and
syncope predispose individuals to drowning incidents.39
underwater swim distance, some swimmers will A recent study reported that the risk of drowning in
people with epilepsy is raised 15- to 19-fold compared
intentionally hyperventilate immediately before going to people in the general population.51 Cervical spine
injuries and head trauma should be suspected in all
underwater. They do this in an effort to lower the par- unwitnessed incidents and injuries involving body surf-
ers, board surfers, and victims diving in shallow water
tial pressure of arterial carbon dioxide (PaC02). Since or water with submerged objects such as rocks or trees
the body's carbon dioxide level provides the stimulus (Figures 22-12 and 22-13).
• Child abuse. A high incidence of child abuse from sub-
to breathe in patients without chronic obstructive pul- mersion incidents is reported, particularly in bathtubs.
A study of children sustaining bathtub submersion
monary disease,44 a decrease in PaC02 decreases the between 1982 and 1992 found that 67'1;6 had historical or
feedback to the respiratory center in the hypothala-
physical :findings compatible with a diagnosis of abuse or
mus to take a breath during breath holding. However, neglect.42 Consequently, itis highly recommended that any
suspicious child-submersion bathtub incident be reported
these swimmers are at risk of a submersion incident to local social services for appropriate investigation.
• Hypothermia. Drowning may result directly from pro-
because the partial pressure of arterial oxygen (Pa02) longed immersion leading to hypothermia. (See the
does not change significantly with hyperventilation. As Cold-Related Disorders sections in the Environmental
Trauma I: Heat and Cold chapter for further discus-
the individual continues to swim underwater, Pa02 will sion of accidental hypothermia.) Hypothermia is
decrease significantly and cause a possible loss of con- defined as a core (central) body temperature less than
96.8°F (36°C). Immersion into water allows for rapid
sciousness and cerebral hypoxia. loss of body heat into the usually cooler water, thus
precipitating hypothermia.
• Accidental cold-water immersion. Another situation

that places individuals at greater risk of drowning is

cold-water immersion (head out). The physiologic

changes that occur with cold-waterimmersion can have

either a disastrous outcome or a protective effect on the

body, depending on many circumstances. Adverse out-

comes are more common, resulting from both cardio-

vascular collapse and sudden death within minutes of

cold-water immersion (see the Environmental Trauma

I: Heat and Cold chapter for more information).

• Age. Drowningis recognized as a youngperson's accident,

with toddlers as the largest group, based on their inquis-

itive nature and a lack of parental supervision. Children

under 1 year of age have the highest drowning ra t e.2945

• Gender. Males account for more than half of submer-

sion victims, with two age-related peak incidences.

The first peak incidence occurs in males at age 2 years,

decreases until age 10 years, and then rises rapidly to

peak again at age 18years. Older males may be more at

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 601

Over the years, controversies have surrounded the patho-

physiology of drowning, mostly about the differences between

drowning in freshwater versus saltwater and whether water

entered or did not enter the lungs.35•37•39 Approximately 15%

of drownings are termed dry drowning because the severe

laryngospasm prevents the aspiration of fluid into the lungs.

The remaining 85% of submersion incidents are considered

wet drownings, in which the laryngospasm relaxes, the glottis

opens, and the victim aspirates water into the lungs.52

Theoretically, there are different effects on the pulmonary

system when freshwater (hypotonic) versus saltwater (hyper-

tonic) enters the lung. In freshwater drowning, the hypotonic

fluid enters the lung and then moves across the alveolus into

the intravascular space, causing a volume overload and dilu-

tional effect on serum electrolytes and other serum compo-

Figure 22-12 Spine board immobilization in water. First the nents. Conversely, in saltwater aspiration, the hypertonic fluid
prehospital care providers bring a spine board to place underneath
the patient. enters the lung, which in turn causes additional fluid from the
Source: Courtesy of Rick Brady.
intravascular space to enter the lung across the alveolus, caus-
ing pulmonary edema and hypertonicity of serum electrolytes.
- -- - l .
It has since been shown that no real differences exist
between wet and dry drowning and freshwater and saltwater

aspiration. 39 53 54 For prehospital care providers, the common

denominator in any of these four submersion scenarios is brain

hypoxia caused by either laryngospasm or water aspiration.

The whole drowning process from immersion or submersion to

hypoxemia, apnea, loss of consciousness that leads to cardiac

arrest, pulseless electrical activity, and asystole usually occurs

in seconds to a few minutes.38 For those victims who survive, the

scene management should be aimed at quickly reversing hypoxia

in these patients, thereby preventing cardiac arrest.

Figure 22-13 Spine board immobilization in water. A cervical collar Surviving Cold-Water Submersion
is placed on the patient to assist in spinal immobilization.
Source: Courtesy of Rick Brady. There are four phases that describe the body's responses and
mechanisms of death during cold-water immersion. These
Mechanism of Injury phases correlate to the 1-10-1 principle55:

A common scenario ofhead-out immersion in water or a whole- 1. Initial immersion and the cold shock response.
body submersion incident begins with a situation that creates The victim has 1 minute to get his or her breathing
a panic response, leading to breath holding, air hunger, and under control.
increased physical activity in effort to stay or get above the
water surface. According to most bystander reports, submer- 2. Short-term immersion and the loss of performance.
sion victims are rarely seen screaming and waving for assistance The victim has 10 minutes of meaningful movement to
while struggling to stay above the surface of the water. Rather, get out of the water.
they are seen either floating on the surface or in a motionless
position, or they dive underwater and fail to come up. As the 3. Long-term immersion and the onset ofhypothermia.
submersion incident continues, a reflex inspiratory effort draws The victim has up to 1 hour until he or she become
water into the pharynx and larynx, causing a choking response unconscious from hypothermia
and laryngospasm. The onset of laryngospasm represents the
first step in suffocation and brain hypoxia, which in turn causes 4. Circum-rescue collapse just before, during, or after
the victim to lose consciousness and submerge underwater even rescue. If the victim survives the first three phases,
further. 38 up to 20% may experience this type of collapse during

In each of these phases, there is wide individual variation
due to body size, water temperature, and amount of the body
that is immersed. Each phase is accompanied by specific sur-
vival hazards for the immersion victim that originate from or are
influenced by a variety of pathophysiologic mechanisms. Deaths
have occurred during all four phases ofimmersion.


In rare cases of prolonged submersion-one case for as These factors in turn cause decreased muscular oxygen
long as 66 minutes-patients have presented to the hospital with demand, which results in smaller muscle oxygen defi-
severe hypothermia and recovered with either partial or full neu- cit, and less carbon dioxide and lactic acid production.
rologic function.56•57 In these submersion incidents, the lowest Thus, the rate of cooling of the patient is increased,
recorded core temperature of a survivor is 56.6°F (13.7°C) in an which may improve resuscitation chances.
adult female.58 In another case, a child survived fully intact after • Cleanliness ofwater. Patients generally do better after
submersion in ice water for 40 minutes, with a core temperature resuscitation if they were submerged in clean rather
of 75°F (23.9°C). After 1 hour of resuscitation, spontaneous cir- than muddy or contaminated water.
culation returned.59 • Quality of CPR and resuscitative efforts. Patients
receiving adequate and effective CPR, combined with
No explanation exists for such cases, but hypothermia proper rewarming and ALS measures, generally do bet-
is thought to be protective. Immersion in cold water may lead ter than patients receiving one or more substandard
to hypothermia within an hour depending on many factors, as measures. Immediate initiation of CPR is a key factor
listed below, because of increased surface heat loss and core for submersion-hypothermia patients. Past and current
cooling. In addition, swallowing or aspiration of cold water may studies reveal that poor CPR technique is directly related
contribute to rapid cooling. Rapid onset of hypothermia during to poor resuscitation outcome.60•61 See the current BLS
freshwater drowning may result from core cooling caused by guidelines as outlined in the AHA hypothermia algorithm
pulmonary aspiration and rapid absorption of cold water and in the Environmental Trauma I: Heat and Cold chapter.62
subsequent brain cooling. • Associated injuries orillness. Patients with an existing
injury or illness, or who become ill or injured in com-
Another factor that may explain why some young children bination with the submersion, do not fare as well as
survive is the mammalian diving reflex. The mammalian diving otherwise healthy individuals.
reflex slows heart rate, shunts blood to the brain, and closes the
airway. Recent evidence suggests that the diving reflex present in Water Rescue
various mammals is active in only 15%to 30% of human subjects,
so while it cannot be consideredthe lone explanation ofwhy some Many water safety organizations recommend the use of highly
children survive, it still may explain part of this phenomenon.34 skilled professionals who regularly train for water rescue,
retrieval, and resuscitation. Ifno professional water rescue teams
Every submersion patient should have full resuscitation are available, however, prehospital care providers must consider
efforts made, regardless of the presence or absence of any of their own safety and the safety of all emergency responders
these factors. The following factors appear to influence the out- before attempting an in-water rescue. The following guidelines
come of a cold-water submersion patient. are recommended to safely rescue a victim out ofthe water:

• Age. Many successful infant and child resuscitations • Reach. Attempt to perform the water rescue by reach-
have been well documented in the United States and ing out with a pole, stick, paddle, or anything so that the
Europe. The smaller mass of a child's body cools faster rescuer stays on land or on a boat. Use caution to avoid
than an adult's body, thus permitting fewer harmful being inadvertently pulled into the water.
by-products ofanaerobic metabolism to form and caus-
ing less irreversible damage (see the Physiology of Life • Throw. When reaching is not possible, throw some-
and Death chapter). thing to a victim, such as a life preserver or rope so that
it floats to the victim.
• Submersion time. The shorter the duration of submer-
sion, the lower the risk for cellular damage caused by • Tow. Once the victim has a rescue line, tow the victim
hypoxia. Accurate information concerning submersion to safety.
time n eeds to be obtained. Submersion longer than
66 minutes is probably fatal. Therefore, a reasonable • Row. If water entry is necessary, it is preferable to use
approachto resuscitation ofa submersionvictim is that a boat or paddleboard to reach the victim and wear a
efforts should be initiated ifthe duration of submersion personal flotation device if entering the water in a boat
is less than 1 hour. or to swim.34

• Water temperature. Watertemperatures of70°F (21.1°C) Swimming rescues are not recommended unless the
and below are capable of inducing hypothermia. The prehospital care provider has been trained appropriately to man-
colder the water, the better the chance ofsurvival, prob- age a victim who can rapidly turn violent from panic, creating
ably because ofthe rapid decrease in brain temperature a potential double drowning. Too many well-intentioned emer-
and metabolism when the body is quickly chilled. gency responders have become additional victims because
their own safety was not the priority. See Figure 22-14 for a few
• Struggle. Submersion victims who struggle less have options for in-water rescue systems, equipment for a submersion
and/or trauma victim (C-spine precaution), and movement when
a better chance of resuscitation (unless their strug- in deep water.
gling efforts are successful in avoiding drowning).
Less struggling means less hormonal release (e.g., epi-
nephrine) and less muscle activity; this translates to
less heat (energy) production and less vasodilatation.

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 6 0 3

Figure 22- 14 Options for in-water rescue equipment and patient packaging. A. Rescue throw lines. B. Tow device. C. In-w ater patient
packing equipment.

Source: Courtesy of Rick Brady.

Predicators of Survival 3. The greater the duration of submersion, the greater the
risk ofdeath or severe neurologic impairment after hos-
The following are important facts and predicators of outcome in pital discharge:
resuscitation of a person who has drowned.38 • 0 to 5 minutes= 10%
• 6 to 10 minutes= 56%
1. Early BLS and ALS are crucial. • 11 to 25 minutes = 88%
2. During drowning, a reduction of brain temperature by • Greater than 25 minutes = 100%

10°C (-18°F) decreases adenosine triphosphate (ATP) 4. Signs of brain stem ir\jmy predict death or severe neu-
consumption by 500!6, doubling the duration of time a rologic impairment and deficits.
brain can survive.


Assessment Assess the patient's oxygen saturation with pulse oximetry
and monitor the end-tidal carbon dioxide levels. Assess for car-
The initial priorities for any submersion patient include34•38: diac rhythm disturbances, since submersion patients often have
dysrhythmias secondary to hypoxia and hypothermia. Assess
1. Prevent injuries to the patient and emergency for altered mental status and neurologic function of all extrem-
responders. ities because many submersion patients develop sustained
neurologic damage. Determine the patient's blood glucose level,
2. Initiate plans early for water extraction and rapid trans- as hypoglycemia may have been the cause for the submersion
port to the ED. incident. Acquire a baseline Glasgow Coma Scale (GCS)
score and continue to assess for trends. Always suspect hypother-
3. Conduct a safe water rescue (consider a possible div- mia and minimize further heat loss. Remove all wet clothing and
ing-related cause and theneedfor spineimmobilization). assess rectal temperature (if the appropriate thermometers are
available and the situation permits) to determine the level of
4. Due to hypoxia, assess the ABCs (airway, breathing, hypothermia, and initiate steps to minimize further heat loss (see
circulation) using the traditional approach, not CAB the Environmental Trauma I: Heat and Cold chapter for manage-
(circulation, airway, breathing). ment of hypothermia).

5. Reverse hypoxia and acidosis with five rescue The following variables are predictive of a more favorable
breaths initially, followed by 30 chest compressions, outcome in submersion patients:
and continue with two breaths thereafter (30:2).
Watch for regurgitation, which is the most common • Children age 3 years and older
complication during rescue breathing (65%) and • Female sex
during CPR (86%). • Water temperature less than 50°F (10°C)
• Duration of submersion less than 10 minutes
6. CPR with only chest compression is not advised in per- • No aspiration
sons who have drowned. • Time to effective BLS less than 10 minutes
• Rapid return of spontaneous cardiac output
7. Restore or maintain cardiovascular stability. • Spontaneous cardiac output on arrival in ED
8. Prevent further loss of body heat and initiate rewarm- • Core temperature less than 95°F (35°C)
• No coma on arrival and GCS score greater than 6
ing efforts in hypothermic patients. • Pupillary responses present

Initially, itis safest to presume that the submersion patient is Management
hypoxic and hypothermic until proved otherwise. Consequently,
all efforts should be made to establish effective respirations Figure 22-15 presents a management tool for persons who have
during water rescue since cardiac arrest from drowning is drowned based on a six-grade classification system and a guide
the result primarily of lack of oxygen. Submersion patients in of medical inteivention for each grade.38 A patient who has
respiratory arrest usually respond after a few rescue breaths. experienced some form of submersion incident, but who is not
Attempts to provide chest compressions when in water too deep presenting with any signs or symptoms at the time of the pri-
to stand are ineffective, so taking time to assess for the presence mary assessment, still needs follow-up care in a hospital after
of a pulse is meaningless and will only delay getting the patient assessment at the scene due to the potential for delayed onset of
to land. symptoms. Many asymptomatic patients (Grade 2) are released
in 6 to 8 hours, depending on clinical findings in the hospital. In
Remove the patient from the water safely. Once on land, one study of 52 swimmers who experienced a submersion inci-
the patient should be placed in a supine position with the trunk dent and were all initially asymptomatic immediately after the
and head in the same position, which is usually parallel to the incident, 21 (40%) went on to develop shortness of breath and
shore. Check for responsiveness and continue rescue breathing respiratory distress due to hypoxemia within 4 hours.64 In gen-
as needed. eral, all symptomatic patients are admitted to the hospital for
at least 24 hours for supportive care and observation because
If the patient is breathing, place the patient in the recov- the initial clinical assessment can be misleading. It is critical to
ery position and monitor for effective respirations and pulse. obtain a good history of the incident detailing the estimate of
Quickly assess the patient for any other life threats, and evaluate submersion time and any past medical history.
for head trauma and cervical spine injuries, particularly if there
is suspicion of trauma associated with the submersion incident All suspected submersion patients should receive high-flow
(e.g., falls, boat accidents, diving into water with underwater oxygen (15 liters/minute) independent of their initial breathing
hazards). However, it has been shown that the typical submer- status or oxygen saturation, based on the concern for delayed
sion casualty has a low chance of traumatic injury, unless the
victim dove into the water.63Acquire the vital signs, and assess all
lung fields of submersion patients because they present with a
wide range of pulmonary distress, including shortness of breath,
rales, rhonchi, and wheezing. Submersion patients can present
without symptoms initially and then deteriorate rapidly with
signs ofpulmonary edema.

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 6 0 5

EVALUATION Check for response to verbal
and tactile stimuli

No answer Answer
Perform pulmonary auscultation
Open the airway and check for ventilation,
if breathing, perform pulmonary auscultation;

if not breathing, give 5 initial breaths
and check carotid pulse

Abnormal Normal

Pulse absent Pulse present

Submersion time Submersion time Rales in all pulmonary fields Rales in some With cough Without cough
>1 hr or obvious s1 hr, no obvious (acute pulmonary edema) pulmonary fields

physical evidence physical evidence
of death of death

Hypotension Normal blood

or shock pressure

GRADE Dead Grade6 Grade 5 Grade4 Grade3 Grade 2 Grade 1 Rescue

INTERVENTION None Start CPR Start artificial Administer high-flow Low-flow Advanced medical None
(ABC sequence), ventilation, oxygen by face mask oxygen attention and
respiratory or orotracheal tube and oxygen should
after return of mechanical ventilation not be required
spontaneous arrest is usually
ventilation, reversed after a Monitor breathing
because respiratory
follow few imposed
intervention breaths; after arrest can still
for grade 4 occur; start
return of
spontaneous crystalloid infusion
ventilation, follow and evaluate for
for grade 4 use of vasopressors

FURTHER Forensic Intensive care unit Emergency If no coexisting conditions,
MANAGEMENT evaluation department evaluate further or

release from the accident site

SURVIVAL 0% 7-12% 56-69% 78-82% 95-96% 99% 100% 100%

Figure 22-15 Drowning management system based on six classification grades for level of severity.
Source: From Ref. 9 Szpilman D, Bierens JLM, Handley A, Orlow shi JP. Drowning. New Engl 1 Med366:2102- 10;2012.

pulmonary distress, particularly ifthe patient develops shortness explaining that many victims develop secondary complications
of breath. Monitor and maintain the patient's oxygen saturation from pulmonary injury. Firm and persistent persuasion is needed
for them to agree to be transported or for them to report to the
greater than 90%. Apply and monitor the ECG, particularly for closest ED for further evaluation and observation. If the patient
pulseless electrical activity or asystole. Obtain intravenous (IV) is adamant about refusing care, the patient must be informed of
access and provide normal saline (NS) or lactated Ringer's (LR) the potential ramifications of refusing care, and a signed refusal
solution at a KVO rate unless the patient is hypotensive, then of care against medical advice must be obtained.
provide a 500-milliliter (ml) fluid bolus and reassess vital signs.
A symptomatic patient with a history of submersion who
Transport all submersion patients to the ED for evaluation. presents with signs of distress (e.g., anxiety, rapid respirations,
Because many submersion patients are asymptomatic, some may difficultybreathing, coughing) is consideredto have a submersion
refuse transportbecause theyhave no immediate chiefcomplaint. pulmonary injury until hospital evaluation has proved otherwise.
If so, take the time necessary to provide good patient education Emphasis should be placed on correcting hypoxia, acidosis,
about the delayed signs and symptoms in a drowning incident,


and hypothermia. Provide cervical spine immobilization in all When a beach rescue (or any location) involves sloping ter-
patients with suspicion of trauma. In unresponsive patients, rain, it is no longer recommended to place a patient in a head-
use suction to clear the airway and keep the airway open down (or head-up) position in an effort to drain the airway.
with an airway adjunct. Hypoxia and acidosis can be corrected Resuscitation efforts are shown to be more successful when the
with effectiveventilationsupport. Patients who are apneicshould patient is placed supine on the ground, parallel to the water,
be supported with bag-mask ventilation. Intubation should be with effective ventilation and chest compressions. Maintaining
considered early to protect the airwayin patients who are apneic a level position on the ground will prevent a decrease in forward
or cyanotic or who have decreased mental status, since submer- blood flow during chest compressions in the head-up position
sion patients swallow large amounts of water and are at risk of or an increase in intracranial pressure in the head-down posi-
vomiting and aspirating stomach contents. Although the value tion. Furthermore, no evidence suggests that lung drainage is
of the Sellick maneuver (cricoid pressure) has been ques- effective with any particular maneuver.
tioned, it may be applied during manual ventilation with a bag-
mask and intubation in an effort to prevent or minimize regur- The Heimlich maneuver has been previously suggested for
gitation and aspiration in this group of patients who are at high use in submersion patients. However, the Heimlich maneuver is
risk. Ifventilations are impaired, the amount of pressure applied designed for airway obstruction and does not remove water from
should be modified to improve the ease of ventilation. Monitor the airway or lungs. Rather, it may induce vomiting in submersion
the ECG for rate and rhythm disturbances and investigate for patients and place them at greater risk for aspiration. Currently,
evidence of a cardiac event that might have preceded or fol- the AHA and the Institute ofMedicine advise against the Heimlich
lowed the submersion incident. Provide lOOOAi oxygen (15 liters/ maneuver except when the airway is blocked with foreign mate-
minute) with a nonrebreathing mask. Obtain IV access and pro- rial.66 If the patient recovers with spontaneous breathing, he or
vide NS or LR solution at a KVO rate. Provide transport to the she should be placed in a lateral recumbent position with head
local ED. slightly lower than the trunk to reduce the risk of aspiration if
the patient vomits. (The Environmental Trauma I: Heat and Cold
Patient Resuscitation chapter outlines ALS procedures regarding resuscitation of a
hypothermic patient. See Figure 21-29 of that chapter for the
Rapid initiation of effective BLS and standard ALS procedures hypothermia algorithm. These guidelines are the same for all
for submersion patients in cardiopulmonary arrest is associ- hypothermic patients regardless of the source of cold exposure.)
ated with the best chance of survival.35 Patients may present in
asystole, pulseless electrical activity, or pulseless ventricular Use the regional EMS medical protocolfor established guide-
tachycardia/ventricular fibrillation. Follow the current version lines that determine the criteria for an obviously dead individual.
of the AHA guidelines for pediatric and adult ALS and ACLS Acceptable guidelines for an obviously dead victim are a normal
for managing these rhythms.62•65 As briefly presented in the rectaltemperature ina patientwho presents withasystole, apnea,
Environmental Trauma I: Heat and Cold chapter, it is currently postmortem lividity, rigor mortis, or other injuries incompatible
recommended to use therapeutic hypothermia in patients who with life. A patient who has been recovered from warm water
remain in a comafrom cardiac arrest caused by ventricularfibril- without vital signs or unsuccessful resuscitative efforts lasting
lation; it might be equally effective for other causes of cardiac 30 minutes may be considered dead on the scene.34•67 Consult
arrest, but it has not been proven beneficial to induce hypother- local medical control early for any individual recovered from
mia for submersion patients.65 cold-water submersion. As stated previously, many individuals
have fully recovered from more than 60 minutes of cold-water
Routine stabilization of the cervical spine during in-water submersion. These submersion patients should be managed as a
rescue is not necessary unless the reasons leading to the sub- hypothermic patient, based on the rectal temperature.
mersion indicate that trauma is likely (e.g., diving, use of water
slide, signs of injury, alcohol use).65 When these indicators are Prevention of Submersion-Related
not present, spinal injury is unlikely. Routine cervical stabiliza-
tion and other means to immobilize the spine during a water Injuries
rescue can cause delays in opening the airway so that rescue
breathing can begin. Prevention strategies are vital in the effort to lower the rates of
submersion incidents in the United States. It is estimated that
The use of CPR during in-water rescue is not recommended 85% of all cases of drowning can be prevented by supervision,
for a number of reasons. Firstly, the depth of chest compressions swimming instruction, technology regulations, and public educa-
is ineffective in water. Besides delaying effective CPR out of tion.38 Many education programs are emphasizing the reduction
water, attempting to provide CPR in water puts rescuers at risk of unintentional water entry of infants and children by encour-
from fatigue, cold water, wave, surge, and current dangers. Place aging the installation of various types of barriers around pools
a greater emphasis on establishing an open airway and providing (e.g., isolation fences, pool covers, alarms) and the use of per-
rescue breathing for patients who are apneic as soon as possible, sonal flotation devices such as life vests.41 Furthermore, CPR
depending on the patient's in-water position, number of rescuers, initiated by a bystander before the arrival of prehospital care
and rescue equipment (e.g., in-water backboard). personnel is associated with improved patient prognosis.40

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 6 0 7

Figure 22-16 • • •I •

History Examination Intervention

Time submerged Appearance Administer oxygen by face mask at
8-1 O liters/minute.
Description of incident Vital signs
Complaints Head and neck trauma Initiate IV line at KVO rate .
Chest examination: lung fields Re-examine patient as needed.
Past medical history ECG monitor
Transport patient to ED.

Description of incident General appearance Administer oxygen by nonrebreathing
mask at 12 to 15 liters/minute.

Time submerged, water temperature, Level of consciousness (AVPU) Initiate IV line at KVO rate; intubate
water contamination, vomiting, type early as needed.
of rescue

Symptoms Vital signs; monitor ECG Transport patient to ED.

On-scene field resuscitation Assess ABCDEs; vital signs; AED or ECG Initiate CPR early; intubate; 100%
monitor oxygen at 12 to 15 liters/minute via
bag-valve mask; consider NG tube
for gastric distension; use ACLS
procedures for VF and asystole; use
ACLS hypothermia algorithm.

Note: ABCDEs, airway, breathing, circulation, disability, expose/environment; ACLS, advanced cardiovascular life support; AED, automated
external defibrillator; AVPU, alert, responds to verbal stimulus, responds to painful stimulus, unresponsive; CPR, cardiopulmonary resuscitation;
ECG, eledrocardiogram; ED, emergency department; IV, intravenous; KVO, keep vein open; NG, nasogastric; VF, ventricular fibrillation.

Source: Modified from Schoene RB, Nachat A, Gravatt AR, Newman AB: Submersion incidents. In Auerbach PS: Wilderness medicine, ed 6,
St. Louis, 2012, Mosby Elsevier.

Prehospital care providers have great opportunities to be • Always swim with others.
advocates of water safety and education in their respective com- • Do not overestimate your swimming capability.
munities, with an emphasis on communication of the risk factor • Always watch your children.
areas previously identified. Furthermore, prevention should be • Swim away from piers, rocks, and stakes.
emphasized to prehospital care providers and otherpublic safety • Avoid drinking alcohol and having a heavy meal
personnel who arrive on the scene so that they do not become
additional submersion victims. A panicked and struggling vic- before swimming.
tim can be a danger to an unprepared in-water rescuer, poten- • Take lost children to the nearest lifeguard tower.
tially resulting in a double drowning. Prehospital care providers • Be aware that 85% of ocean drownings occur in rip
need to assess the problem quickly, control the scene to prevent
bystanders from entering the water, and ensure their own safety. currents.
• Know the weather conditions before going into
Community education regarding submersion incidents
should include the following recommendations: water.
• Never try to rescue someone without knowing
• Beaches
• Always swim near a lifeguard. what you are doing; many people have died in such
• Ask a lifeguard about a safe place to swim. attempts.
• If you are fishing on rocks, be cautious with waves
that may sweep you into the ocean.
• Always enter shallow water feet first.


• Do not dive in shallow water; injury to the cervical to scuba-related injuries and fatalities caused by dysbarism, or
spine could result. altered environmental pressure, which accounts for the major-
ity of the serious diving medical disorders. The mechanism of
• Keep away from marine animals. injury is based on the principles ofgas laws when breathing com-
• Read and heed signs and flags posted on the pressed gases (e.g., oxygen, carbon dioxide, nitrogen) at varying
underwater depths and pressures, as will be described in detail
beach. in subsequent sections.

• Residential pools and other water sources The associated causes for diving fatalities have not changed
• Adult supervision is necessary, closely observing significantly in recent history. The most frequently cited prob-
all children. lem is insufficient gas (air) or running out of gas. Other com-
• Set rules for water safety. mon factors included entrapment or entanglement, buoyancy
• Never leave a child alone near a pool or a source of control, equipment misuse or problems, rough water, and emer-
water, such as a bathtub or bucket. gency ascent. The principal injuries or causes of death included
• Install a four-sided fence that is at least 4 feet drowning or asphyxia due to inhalation of water, air embolism,
(1.2 meters [m]) tall around the pool with a and cardiac events. Older divers were at greater risk of cardiac
events, with men at higher risk than women, although the risks
self-closing and self-latching gate. were equal at age 65.75

• Do not allow children to use arm buoys or other Most scuba-related injuries caused by dysbarism pres-
air-filled swim aids. ent with signs (e.g., ear squeeze on descent) and symptoms
either immediately or within 60 minutes after surfacing, but
• Know how to use an approved life jacket. some symptoms are delayed up to 48 hours after individuals
• Avoid toys that will attract children around pools. depart the dive site and return home. Consequently, with the
• Tum offpump filters when using pools. increasing number of scuba divers today flying to and from
• Use cordless or cell phones near pool to prevent popular dive sites in the United States, Caribbean, and other
remote locations, there is a greater possibility of responding
leaving the poolside to answer the telephone to diving-related injuries at locations distant from the actual
elsewhere. dive site. Prehospital care providers need to recognize these
scuba-related disorders, provide initial treatment, and initiate
• Keep rescue equipment (e.g., shepherd's hook, life plans early for transport to the local ED or for treatment at the
preserver) and a telephone by the pool. closest recompression chamber.73

• Do not try or allow hyperventilation to increase Epidemiology
underwater swim time.
Divers Alert Network (DAN) compiles an extensive morbidity
• Do not dive in shallow water. and mortality database based on casualty data provided from
• Provide swimming lessons for all children by age participating recompression chambers in North America. In 2000,
they published a report summarizing 11 years (1987 to 1997) of
4 years.68 data.75 They also publish annual reports, which can be found
on their website.76 The majority of scuba-related diving injuries
• After the children have finished swimming, secure occur in the United States and North America during the months
the pool so they cannot return (locks or audible of May to September, with August as the peak month. Europe
alarms on gates are recommended). comes in a distant second in reported deaths. Three to four times
more male divers are injured than female divers. The primary
• All family members and others watching children cause of diving-related injury is decompression sickness. From
should learn first aid and CPR.12 1970 to 2006, the number of diving-related deaths ranged from
66 to 147 per year.75 In 2007, the most recent year for which data
Recreational Scuba- are available at the time of this publication, almost 85% of the
Related Injuries deaths occurred in males, with most of the deaths in divers 40 to
59 years of age. The causes of death were drowning (86%), car-
Recreational diving using self-contained underwater breath- diovascular factors (9%), arterial gas embolism (3%), and decom-
ing apparatus (scuba) is a common activity enjoyed by many pression sickness (1%). Even though drowning was the leading
age groups. The popularity of this activity continues to grow, cause offatalities, it is unclear what led to the drowning, such as
with more than 400,000 new certified divers each year, now equipment issues, lack of air, entanglement, narcosis, panic, dis-
totaling over five million scuba divers in the United States.69•70 orientation, hypothermia, heart attack, or arterial gas embolism.
Relative to the increasing number of new divers each year, the

injury rate is low, but the concern for medical fitness to dive
has increased because of the diversity of divers, increasing
age, low physical fitness, and underlying medical conditions.
Water is an unforgiving environment when problems occur.
Currently, there are medical guidelines that indicate relative
and temporary health risks and absolute contraindications for
scuba diving.7(}.74

Injuries to divers occur from many underwater hazards
(e.g., shipwrecks, coral reefs) orfrom handling hazardous marine
life. However, more often, prehospital care providers respond

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 6 0 9



eQn) 1000

.Qci 600
z::i 400


87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04


- DAN notified
- Report submitted

US and Canadian residents

Figure 22-17 Annual diving injuries.
Source: Data courtesy of Divers Alert Networke (DAN").




~ 100

0 80



0 1975 1980 1985 1990 1995 2000 2005
1970 Year

Figure 22-18 Annual number of U.S. and Canadian diving fatalities. The number of U.S. and Canadian fatalities recorded annually has
varied substantially from year to year from 1970 to 2007.

Source: Data courtesy of Divers Alert Networ~ (DAN").

Many drowning deaths during scuba diving are actually arterial (2) the problems that occur from breathing compressed gases at
gas embolism leading to secondary drowning.75 See Figures 22-17 elevated partial pressure, such as decompression siclmess.
and 22-18 for a summary of annual diving injuries and fatalities
from the DAN 2008 annual report.77 Barotrauma associated with scuba diving relates directly
to the pressure effects of air and water on the diver. When
Mechanical Effects of Pressure standing at sea level, the atmospheric pressure is 760 torr,
which is essentially the same as 760 millimeters of mercury
Scuba-related diving iltjuries incurred by the changing atmo- [mm Hg)) or 14.7 pounds per square inch (psi) on the body.
spheric pressure, or dysbarism, can be separated into two types: This amount of pressure is also lmown as 1 atmosphere
(1) the conditions when a change in pressure from the underwa- ( 1 atm). As a diver descends deeper in water, the absolute
ter environment results in tissue trauma or barotraumain closed pressure increases 1 atm for every 33 feet (10 m) of seawater.
air spaces in the body (e.g., ears, sinuses, intestines, lungs) and Consequently, a depth of 33 feet of seawater is equivalent to
2 atm (air [1 atm] and 33 feet of water [1 atm)) of pressure on


Figure 22-19 • • . . .. •

Depth (FSW) PSIA ATA Torr or mm Hg (absolute)

Sea level 14.7 760

33 29.4 2 1520

66 44.1 3 2280

99 58.8 4 3040

132 73.5 5 3800

165 88.2 6 4560

198 102.9 7 5320

Note: ATA, atmosphere absolute; FSW, feet seawater; mm Hg, millimeters of mercury; PSIA. pounds per square inch absolute.

the body. Figure 22-19 lists common units of pressure in the Gas !.::\ Gas
underwater environment. bubble bubble bubble
volume oe9\'<:I diameter
When a diver descends under the increasing pressure of
seawater, the effect of the forces exerted on the body differs 100% 1ATA 100%
dependingon the tissue compartments. The force appliedto solid
tissue acts in similar fashion to a fluid medium, and the diver is 50% 79%
generally unaware of compressive force. The air in air-contain-
ing spaces of the body is compressed as the diver descends. 33% c:: i4fiiC ,, <o'O'ti. c:: 69%
Conversely, these gases expand as the diver ascends toward the ·c0;; 63%
surface. Boyle's law and Henry's law explain the effects of pres- 25% 03ATA gf~'t-. 0 58%
sure on the body when underwater. "~' -~
Boyle's Law c. a.Q)
17% E
Boyle's law states that the volume of a given mass of gas is E
inversely proportional to the absolute pressure found in that u0
environment. Stated another way, as a diver descends in the 0
water to a greater depth, the pressure increases and the volume Q) ()
of the gas (e.g., the volume in the lung or ear) decreases. The
reverse is also true, the volume ofthe gas (e.g., in the lung or ear) 0
increases in size when the diver returns toward the surface. This
is the principle behind the effects of barotrauma and arterial gas 4ATA
embolism in the body. Figure 22-20 shows the effects of pressure
on the volume and diameter of a gas bubble. \'b'l-'t-.

5ATA Q 54%



Henry's Law

At a constant temperature, the amount of gas that will dissolve Figure 22-20 Boyle's law. The volume of a given quantity of gas at
in a liquid is directly proportional to the partial pressure of that constant temperature varies inversely with pressure.
gas outside the liquid. Henry's law is fundamental in the under-
standing of how gas from a compressed air cylinder (scuba tank) Barotrauma
behaves in the body as the diver descends in the water. For exam-
ple, the increasing partial pressure of nitrogen will cause it to Barotrauma, also lmown as squeeze, is the most common form
dissolveinthefluids ofthe body'stissues asthe pressureincreases
during descent. On return toward the surface, nitrogen will bub- of scuba-related diving i.njury.78 Although many forms of baro-
ble out of the fluid solution in the tissues. Henry's law describes traumas cause pain, most resolve spontaneously and do not
the principle that explains why decompression siclmess occurs. require EMS involvement or recompression chamber therapy.

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 611

However, some pulmonary overpressurization injuries are very No pressure changes are permitted (e.g., diving or flying) in
serious. During scuba diving, barotrauma occurs within noncom- patients with middle-ear squeeze. Patients may need deconges-
pressible, gas-filled body cavities (e.g., sinuses). If the pressure tants if the TM has not ruptured to open up the eustachian tube
in these spaces cannot equalize during a dive as ambient pres- and allow the pressure to equalize. Antiemetics such as prochlor-
sure increases, vascular engorgement, hemorrhage, and mucosa! perazine (Compazine) or ondansetron (Zofran) may be necessary
edema result from decreasing air volume when the diver for vertigo and vomiting. Transport the patient in an upright
descends, and tissue disruption results from increasing air vol- positionorposition ofcomfort. Antibiotics may be prescribed with
ume when the diver ascends. The various forms of barotraumas ruptured TM to prevent infection. The patient should be referred
are described next. for audiometric evaluation to assess possible hearing loss.

Barotrauma of Descent Sinus Squeeze

Mask Squeeze Normally, pressure in the sinuses equalizes easily as the diver
is descending and ascending. Pressure develops by the same
This form of barotrauma generally occurs in inexperienced or mechanism as the middle ear squeeze, but sinus squeeze is not
inattentive divers who fail to equalize the pressure in their face as common. As a diver descends, there is an inability to main-
mask by increasing the external water pressure during their tain pressure in the sinuses, and a vacuum develops in the sinus
descents. Examine the soft tissue around the patient's eyes and cavity, causing intense pain, mucosa! wall trauma, and bleeding
conjunctiva!tissues for capillary rupture. Signs and symptoms of in the sinus cavity. This squeeze may be caused by congestion,
mask squeeze include skin ecchymoses and conjunctiva! hemor- sinusitis, mucosal hypertrophy (enlargement or thickening), rhi-
rhage. Mask barotrauma is self-limited and treatment is no diving nitis, or nasal poyps.78A reverse sinus squeeze during ascent can
until the tissue damage clears. Management includes providing a occur as well (see later discussion on Sinus Barotrauma).
cold compress over the eyes, encouraging the patient to rest, and
providing pain medication as needed. Examine the patient's nose for discharge. Signs and symp-
toms ofsinus squeeze include severe pain over the affected sinus
Tooth Squeeze or bloody discharge, usually from frontal sinuses.

A very infrequentfinding, this form of barotrauma occurs in div- No specific management is needed at the scene unless
ers when gas is trapped in the interior portion of a tooth after extensive bleeding is observed, in which case, treat the patient
receiving a dental filling, recent tooth extractions, or a root for epistaxis (nosebleed) by pinching firmly on the fleshy part of
canal, or with defective dental restorations. During descent, the the patient's nostrils just below the nasal bones. Transport in a
tooth can fill with blood or can implode with increasing exter- position of comfort.
nal pressure. During ascent, any air forced into the tooth will
expand, causing either pain or explosion ofthe tooth. To prevent Internal-Ear Barotrauma
tooth squeeze, it is recommended that divers do not dive for
24 hours after any dental treatment. Although much less common than middle-ear squeeze, this is the
most serious form of ear barotrauma because it may lead to per-
Examine the affected tooth to see if it is intact. Signs and manent deafness.79 Internal-ear barotrauma occurs when a diver
symptoms of tooth squeeze include pain and a fractured tooth. descends and has failed attempts to equalize the middle ear.
Refer the patient for dental evaluation and give pain medication Further forceful attempts can result in a large rise in middle-ear
as needed. pressure and can rupture the round window structure.

Middle-Ear Squeeze Examine the ear canal for any discharge. Signs and symp-
toms include roaring tinnitus, vertigo, hearing loss, a feeling of
This type ofsqueeze occurs in 40% of scuba divers and is consid- fullness or "blockage" in the affected ear, nausea, vomiting, pal-
ered the most common diving injury.79 Ear squeeze occurs near lor, diaphoresis (sweating), disorientation, and ataxia (loss of
the surface of the water, when the greatest changes in pressure muscular coordination).
occur as the diver descends. Divers need to begin equalizing
their middle ear early as they start to descend so a pressure dif- The patient should avoid strenuous activities and loud
ferential across the tyrnpanic membrane (TM) leading to rupture noises, with no pressure changes (e.g., diving or flying). Transport
of the eardrum does not occur. The diver will experience pain the patient in an upright position. Early medical consultation
and vertigo if the TM ruptures, allowing water to enter the mid- with DAN or an ED is recommended because it may be difficult
dle ear. Divers with upper respiratory infection or allergies may to determine if this is inner-ear decompression sickness and if
have difficulty equalizing their middle ear during a dive. there is an immediate need for recompression chamber therapy.

Examine the ear canal for blood caused by ruptured TM. Barotrauma of Ascent {Reverse Squeeze}
Signs and symptoms of middle-ear squeeze include pain, vertigo,
conductive hearing losses with TM rupture, and vomiting. Alternobaric Vertigo

This is an unusual form of barotrauma in that it occurs as
expanding gas moves through the eustachian tube and unequal
pressure develops in the middle ear, which can cause vertigo.


Although the symptoms are brief, vertigo can trigger panic in div- not escape, there is a rupture of the alveoli, which in tum causes
ers, leading to other forms of injury caused by a rapid ascent to one of many forms of injury, depending on the amount of air
the surface (e.g., air embolism, drowning). that escapes outside the lung and its final location. A common
scenario is a diver who has a rapid and uncontrollable ascent
Examine the ear canal for any discharge; assess any hearing to the surface caused by running out of air, panic, or a dropped
loss. Signs and symptoms of altemobaric vertigo are short in weight belt. These types ofinjuries are collectively called pulmo-
duration, resulting in transient vertigo, pressure in the affected nary overpressurization syndrome (POPS), or burst lung.
ear, tinnitus, and hearing loss.
The five forms of POPS are:
No specific intervention is required; diving is not
recommended until any hearing loss returns. Provide decon- 1. Overdistension with local injury
gestants as needed and according to the EMS system's policies 2. Mediastinal emphysema
and procedures. No transport to the ED is needed if symp- 3. Subcutaneous emphysema
toms resolve quickly, and the patient may follow up with his or 4. Pneumothorax
her primary care provider. If symptoms persist, transport for 5. Arterial gas embolism
evaluation is appropriate.
Overdistension with Local Injury. This is the mildest form
Sinus Barotrauma of POPS, with only a small, isolated lung barotrauma. Auscultate
the lung fields for diminished breath sounds. Chest pain may
This form of sinus squeeze can occur on ascent when some form or may not be present. Blood is often seen in the sputum
of blockage in the sinus openings prevents expanding gas from (hemoptysis).
escaping. The expanding gas puts pressure on the mucosa! lining
of the sinus, causing pain with hemorrhage. Sinus barotrauma Ensure that the patient rests in a position of comfort, and
occurs in divers with upper respiratory infections or allergies. It treat the patient's symptoms as needed. Monitor the patient's vital
is common for divers to take a decongestant before a dive as a signs and OXYgen saturation with pulse oximetry; provide OXYgen
preventive measure to help equalize the middle ear when diving. at 2 to 4 liters/minute with nasal cannula. Transport the patient
However, the vasoconstrictive benefits can wear off at depth, in position of comfort. The patient needs further medical evalu-
causing mucosa! tissue expansion and forming a sinus blockage ation to rule out a more severe form of POPS and should avoid
of expanding gas during the return to the surface. further pressure exposure (e.g., diving or commercial flying).

Examine the nose for discharge. Signs and symptoms of Mediastinal Emphysema. This is the most common form of
sinus barotraumainclude severe pain over the affected sinus and POPS, caused by escaping gas from ruptured alveoli entering the
bloody discharge, usually from the frontal sinuses. interstitial space to the mediastinum. This condition is usually
benign. Examine the lung fields for diminished breath sounds.
No specific management is needed at the scene unless Signs and symptoms include hoarseness, neck fullness, and
extensive bleeding is observed, in which case treat for epistaxis minor substemal chest pain; often a dull ache or tightness wors-
by pinching firmly on the fleshy part of the patient's nostrils, just ens with breathing and coughing. Examine the patient's chest and
below the nasal bones. Transport the patient in a position of neck for subcutaneous emphysema. In severe cases, the diver
comfort. presents with chest pain, dyspnea, and difficulty swallowing.

Gastroi ntestinaI Squeeze Ensure that the patient rests in a position ofcomfort. Monitor
the patient's vital signs and OXYgen saturation with pulse oxim-
This type of barotrauma occurs when expanding gas in the gut etry; provide OXYgen at 2 to 4 liters/minute with nasal cannula.
becomes trapped as the diver surfaces. Gastrointestinal (GI) Usually, mediastinal emphysema requires no specific treatment or
barotrauma occurs in novice divers who frequently perform recompression therapy. Rare cases need to be medically evaluated
Valsalva maneuvers in the head-down position, which forces air to rule out other causes of chest pain and severe forms of POPS.
into the stomach. It can also occur in divers who chew gum when Transport the patientin a supine position. The patientshould avoid
diving or who have consumed carbonated beverages or other further pressure exposure (e.g., diving or commercial flying).
gas-producing foods before diving.
Subcutaneous Emphysema. With subcutaneous emphy-
Examine the abdominal quadrants. Signs and symptoms of sema, air escaping from ruptured alveoli continues to move supe-
GI squeeze include abdominal fullness, belching, and flatulence. riorly into the neck and clavicle regions of the chest. Examine
the lung fields for diminished breath sounds. Signs and symp-
GI squeeze normally resolves on its own and rarely needs toms of subcutaneous emphysema include swelling, crepitus,
medical attention. If the pain and fullness do not resolve, hoarseness, sore throat, and difficulty swallowing.
transport for evaluation is appropriate. Only in severe cases is
recompression chamber therapy needed. No specific treatment is required besides rest. Monitor the
patient's vital signs and OXYgen saturation with pulse oximetry,
Pulmonary Overinflation Barotrauma and provide OXYgen by nasal cannula at 2 to 4 liters/minute. The
patient needs further medical evaluation to rule out more severe
Pulmonary overinfl.ation is a serious form of barotrauma forms of POPS. Transport the patient in the supine position. The
resulting from the expansion of gas in the lungs during ascent.
Normally the diver eliminates expanding gas with normal exha-
lations when returning to the surface. Ifthe expanding gas does

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 613

patient should avoid further pressure exposure (e.g., diving or of nitrogen bubbles, makes it more difficult to oxygenate the
commercial flying). patient, and may worsen cerebral edema.82 Currently, it is recom-
mended that all AGE patients be placed in a supine position in
Pneumothorax. Pneurnothorax is seen in less than l OOAi the field and during transport. The supine position also provides
of POPS cases b ecause air must escape through the visceral a greater rate of nitrogen bubble washout.83•84
pleura around the lung, which presents greater resistance than
air escaping through the interstitial space between the lung Decompression Sickness
and visceral pleura. If the diver is at depth when a pulmonary
rupture occurs, a tension pneurnothorax can result as the vol- Decompression sickness (DCS) is directly related to Henry's law.
ume of escaping gas expands as the diver continues toward the When scuba divers breathe compressed air containing oxygen
surface. Examine the lung fields for diminished breath sounds. (21%), carbon dioxide (0.03%), and nitrogen (79%), the amount
Signs and symptoms will vary based on the size of the pneumo- of gas that will be dissolved in liquid is directly proportional to
thorax and include sharp chest pain, diminished breath sounds, the partial pressure of gas in contact with liquid. Oxygen is used
breathlessness, subcutaneous emphysema, and dyspnea. in the body for tissue metabolism when in solution and does not
form gas bubbles during ascent from depth.
Provide ongoing assessment to monitor for conversion
from simple to tension pneurnothorax. Ensure rest in a position Nitrogen, an inert gas not used for metabolism, is the pri-
of comfort. Monitor the patient's vital signs and oxygen satura- mary source of concern in DCS. Nitrogen is five times more
tion with pulse oximetry and provide oxygen by nasal cannula soluble in fat than in water and becomes dissolved in tissue pro-
at 2 to 4 liters/minute. Provide standard ALS management of portionately to the increasing ambient pressure. Consequently,
tension pneurnothorax with 14-gauge needle thoracostomy as the deeper underwater the diver goes and the longer the diver
necessary. Transport the patient in a position of comfort. The stays at depth, the greater the amount of nitrogen that dis-
patient needs further medical evaluation to rule out more severe solves into tissue. As the diver ascends toward the surface, the
forms of POPS and should avoid further pressure exposure absorbed nitrogen must be eliminated. If there is inadequate
(e.g., diving or commercial flying). Recompression therapy is time to eliminate nitrogen during ascent, nitrogen comes out of
generally not necessary. solution in the tissues in the form of intravascular gas bubbles,
causing obstruction of the vascular and lymphatic systems and
Arterial Gas Embolism. This is the most feared complica- tissue distension, and activating inflammatory responses.85
tion of POPS and, after drowning, is a leading cause of death
in divers, accounting for about 30% of fatalities.80 Arterial gas Most divers experience DCS within the first hour after sur-
embolism (AGE) can occur from any of the four POPS con- facing, although some will present with symptoms up to 6 hours
ditions previously presented as a result of air escaping and after surfacing. Only 2% of divers will have delayed symptoms
forming an air embolism. AGE typically occurs in divers who between 24 and 48 hours after surfacing. Traditionally, symp-
have an uncontrolled ascent to the surface without appro- toms of DCS are categorized as Type I, a mild form involving
priate exhalation, causing an overinflation pulmonary injury. cutaneous, lymphatic, and musculoskeletal systems, or Type 11,
However, AGE can occur in divers who surface slowly without a severe form involving neurologic and cardiopulmonary sys-
underlying lung pathology. During ascent, once the pulmonary tems (Figure 22-21). Mild symptoms of DCS include fatigue and
overinflation bursts alveoli, air enters the pulmonary venous malaise. However, mild symptoms can be precursors to more
capillary circulation; the gas bubbles enter the left atrium and severe signs and symptoms, such as numbness, weakness, and
left ventricle, t hen exit the heart through the aorta, and are paralysis.
distributed to the cerebral, coronary, and other systemic vas-
culature. Gas bubbles can enter the coronary circulation, Studies now suggest that it is more important clinically to
causing an occlusion resulting in cardiac dysrhythmia, cardiac describe DCS by the region of the body affected and not as Type
arrest, or myocardial infarction.81 If gas bubbles enter t he cere- I or Type II.70 This suggestion is applicable for prehospital care
bral circulation, the diver presents with signs and symptoms providers to ensure that even patients with mild DCS symptoms
similar to an acute stroke. are treated aggressively with lOOOAi oxygen and an early consult
for recompression therapy. Many divers with the mild form of
Unlike decompression sickness, which can present with DCS will not have a medical evaluation. Divers may delay up to
delayed symptoms hours after diving, symptoms of AGE appear 32 hours before seeking medical care for DCS because denial of
either immediately at the water surface or typically within DCS is a common finding in the scuba diving population.88
2minutes. Any loss ofconsciousness once a diversurfaces mustbe
presumed to be AGE until proved otherwise.81 The primary treat- Figure 22-21
ment for AGE is recompression chamber (hyperbaric) therapy.
The term decompression illness (DCI) has been proposed
Historically, it was recommended that patients with AGE be to encompass Type I and Type II DCS and AGE.86·87
placed in the Trendelenburg position for transport, based on the
belief that this would help keep bubbles from circulating in the
systemic vasculature. However, recent evidence has shown that
the head-down position does not prevent systemic circulation


Several factors predispose a diver to DCS.89•90 Some risk Limb Pain (Type I DCS)
factors are lrnown to enhance the uptake of nitrogen in tissues
during descent and slow the release of nitrogen during ascent. This form of DCS results from bubble formation in the musculo-
Certain host and environmental factors, as well as equipment skeletal system, typically occurring in one or morejoints. The most
failures and improper technique, increase the risk for DCS common joints involved are the shoulder and elbow, followed by
(Figure 22-22). the lrnee, hip, wrist, hand, and ankle.00 This pain is described as a
severe tendonitis, jointpain with a grating sensation on movement.
Figure 22-22 The pain starts gradually, presenting as a deep, dull ache of mild to
severe intensity. Victims often attempt to relieve their pain by fl.ex-
ion oftheirjoints, hence the common name for this condition-the
bends. Although this form ofDCS is not life threatening, it indicates
that bubbles are present in the venous circulation. It can lead to
more severe forms ifleft untreated.

Host Factors Cutaneous and Lymphatic (Type I DCS)
• Lack of fitness
• Advancing age This form of DCS is uncommon. It represents inadequate elim-
• Female sex ination of bubbles forming in the skin or lymphatic systems.
• Hypothermia Cutaneous skin bends are uncommon and usually not serious,
• Alcohol or drug use but signs of mottling and marbling are considered precursors
• Patent foramen ovale (hole in the wall between the of delayed neurologic problems.61 Symptoms include an intense
right and left atria) rash that progresses to a red patchy or bluish discoloration of
• Obesity the skin.83 Lymphatic obstruction can result in swelling and an
• Sleep deprivation orange-peel appearance (peau d'orange).
• Dehydration
• Inadequate nutrition Cardiopulmonary (Type II DCS)
• Heavy exertion at depth or fatigue
• Underlying medical illness (e.g., asthma) This severe form of DCS is referred to as the chokes and results
• Prior history of DCS when venous bubbles overwhelm the pulmonary capillary sys-
tem. Hypotension can occur from a massive venous air embolism
Environmental Factors in the lung. Symptoms include nonproductive cough, substernal
• Extremes of temperature chest pain, cyanosis, dyspnea, shock, and cardiopulmonary
• Rough seas arrest. This disorder resembles acute respiratory distress syn-
• Flying after diving drome (see the Airway and Ventilation chapter).91
• Heavy exercise at depth
• Nitrogen narcosis (state of confusion/euphoria similar Spinal Cord (Type 11 DCS)
to alcohol intoxication from nitrogen entering the
blood under pressure) The white matter of the spinal cord is vulnerable to bubble
• Elevated arterial carbon dioxide tension formation, and nitrogen is highly soluble in spinal cord tis-
• Low water temperature sue (myelin). The most common site for this form of DCS
is the lower thoracic spine, followed by the lumbar/sacral
Equipment Failures and Improper Technique and cervical regions.88 Common signs and symptoms include
• Violating the decompression tables low back pain and "heaviness" in the legs. With this form of
• Difficulty with buoyancy DCS, the patient often gives a vague statement in an effort to
• Rapid ascent describe "strange sensations," or paresthesia, which can prog-
• Running out of air ress to wealrness, numbness, and paralysis. Bowel and blad-
• Regulator malfunction der dysfunction, leading to urinary retention, also has been
• Unfamiliar or improper equipment reported.92

Source: From Barratt DM. Harch PG. Van Meter K: Decomoression Assessment of AGE and DCS
illness in divers: A review of the literature. Neurologist 8: 186, 2002 .
Reprinted by permission of Lippincott Williams & Wilkins. A standardized approach for patients with AGE and DCS is pro-
vided to ensure that consistent care is given. It is recommended
that all patients with scuba-related diving iajuries be examined

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 6 1 5

for signs and symptoms of AGE and DCS because the primacy Figure 22-23
and essential lifesaving treatment is recompression chamber

Arterial Gas Embolism Diving Emergencies (Remember: Call local EMS fi rst ,
then DAN!)
About 5% of all AGE patients present with immediate apnea,
unconsciousness, and cardiac arrest. Others present with signs 1-919-684-9111
and symptoms similar to acute stroke, with loss of conscious- Nonemergency Medical Questions
ness, stupor, confusion, hemiparesis, seizure, vertigo, visual 1-800-446-2671 or 1-919-684-2948
changes, sensory changes, and headache. Monday-Friday, 8:30 a.m. to 5:00 p.m. (Esn
All Ot her Inquiries
Decompression Sickness 1-800-446-2671 or 1-919-684-2948
1-919-490-6630 (fax)
Type I DCS is characterized by deep pain in a joint, includ- Contact Information to Send a Letter
ing minor forms of cutaneous pruritus (severe itching) and Divers A lert Network
obstruction of lymph vessels (lymphedema). Type II DCS is The Peter B. Bennett Center
characterized by symptoms involving the CNS, ranging from 6 West Colony Place
weakness and numbness to paralysis. Durham, NC 27705 USA

Obtain a dive profile and medical history of the events that Source: Dat a courtesy of Divers Alert Network" (DAN").
led to the diving-related injury from a fellow diver, including:
position. For any scuba-related diving injury, if air evacuation is
• Time of onset ofsigns and symptoms provided by helicopter or other nonpressurized aircraft, it is rec-
• Source of breathing medium (e.g., air or mixed gases; ommended to fly as low as possible (e.g., 500 feet [150 m]), but
not to exceed 1,000 feet (300 m) to minimize further expansion
heliox) of air bubbles (Boyle's law) and further dysbarism trauma.70•84
• Dive profile (dive activity, depth, duration, dive fre-
Definitive treatment for specific barotraumas, including
quency, surface interval, interval between dives) AGE and DCS, is to administer 100% oxygen by mask at two to
• Dive location and water conditions three times the atmospheric pressure at sea level in a recompres-
• Dive risk factors sion chamber.94 (For further discussion of recompression cham-
• Underwater medical and equipment problems on ber treatment methods for scuba-related diving injuries, see
the U.S. Navy Diving Manual or other sources.70·94) The patient
ascent and descent immediately benefits, based on the principles of Boyle's law, by
• Whether the diver was attempting a no-decompression increasing the ambient pressure and decreasing the size of bub-
bles formed and increasing the oxygen concentration in tissues.
dive or a decompression dive Figure 22-24 describes recompression and hyperbaric oxygen
• Rate of ascent therapy.
• Decompression stop(s)
• Postdive activity level Figure 22-25 summarizes signs and symptoms ofbarotrauma
• Postdive aircraft travel, with type and duration and its treatment . Figure 22-26 summarizes signs and symptoms
• Past and present medical history (especially a history of DCS and its treatment.

of previous DCS) Prevention of Scuba-Related Diving
• Medication use Injuries
• Current use of alcohol or illicit drugs93
Millions of certified scuba divers need frequent skill refresher
Management training to prevent and recognize scuba-related dive inju-
ries. Many scuba professionals in the United States, such as
Ensure the ABCs, protect the patient's airway, and initiate BLS
or ALS procedures as required. Initiate lOOOAi oxygen at 12 to
15 liters/minute, and give NS or LR (no dextrose) IV fluid ther-
apy (1 to 2 ml/kg/hour). Monitor the patient's vital signs, pulse
oximetry, and ECG. Check and treat the patient's blood glucose
as required. Control any seizures. Protect the patient from hypo-
thermia, and consult early with local medical control or DAN for
the closest recompression chamber (primacy treatment) (see
Figure 22-23 for DAN contact information). Standard recompres-
sion therapy with 100% hyperbaric oxygen is given according to
the U.S. Navy treatment tables.94 Transport the patientin a supine


Figure 22-24

The goals of recompression therapy for scuba-related diving perfusion. During recompression treatment, patients with
injuries caused by pulmonary overinflation barotrauma and AGE or DCS normally will receive recompression t reatment
decompression sickness (DCS) are to compress the bubbles at 2.5 to 3.0 atm for 2 to 4 hours while breathing
and increase oxygen delivery to tissues. Recompression 100% oxygen. Longer and repeated treatment will be
therapy includes the following mechanisms: necessary if the patient has no clinical improvement of
• Reduces volume of the bubbles where they are
circulated to the pulmonary capillaries and filtered out Recompression treatment principles include the
following :
• Promotes reabsorption of bubbles in solution
• Increases oxygen delivery to the tissues • Any painful or neurologic signs or symptoms occurring
• Corrects hypoxia within 24 hours of a dive are caused by DCS until
• Provides an increased diffusion gradient for nitrogen proved otherwise.
• Reduces edema
• Reduces blood vessel permeability • Any painful or neurologic signs or symptoms occurring
All divers with arterial gas embolism (AGE) and DCS within 48 hours of flying after diving are caused by
must be considered early for recompression in a hyperbaric DCS until proved otherwise.
treatment facility because the treatment is more successful
if started within 6 hours after the onset of symptoms. • Contact the DAN 24-hour emergency hotline for
Divers are not always near a recompression chamber when consultation at 919-684-9111.
symptoms occur, and there can be considerable delays
getting to a chamber by ground or by arranging for air • Every diver with signs or symptoms of DCS should
transport. Contact the Diver's Alert Network (DAN) to receive recompression treatment.
consult for diving medical assistance and to determine the
closest recompression chamber (see Figure 22-23). • Never fail to treat doubtful cases.
In the meantime, place the patient in a supine position. • Early treatment improves outcomes, whereas delayed
Nitrogen washout can be increased by providing 100%
oxygen by mask and by starting an IV fluid line with treatment worsens outcomes.
normal saline or lactated Ringer's solution at 1 to 2 ml/kg/ • Long delays should never preclude treatment because
hr to ensure adequate intravascular volume and capillary
divers respond to recompression therapy days to weeks
after injury.
• Monitor the patient closely for signs of relief from or
progression of symptoms.
• Inadequate treatment can lead to a recurrence.
• Continue to treat until clinical plateau.

Source: Modified from: Tibbles PM, Edelsberg JS: Hyperbaric oxygen therapy. N Engl J Med 334(25):1642, 1996; from Barratt OM, Harch PG, Van
Meter K: Decompression illness in divers: A review of the literature. Neurologist 8: 186, 2002; and from Van Hoesen KB, Bird NH: Diving medicine. In
Auerbach PS: Wilderness medicine, ed 6, St. Louis, 2012, Mosby Elsevier.

lifeguards, fire and law enforcement personnel, search and effective communication and appropriate continuity of field
rescue members, Coast Guard members, and Department of care. This training should include scenario-based consults with
Defense employees, depend on local prehospital care provid- local medical control and DAN.
ers to provide initial and follow-up medical care and transport
to local hospitals or recompression chambers. Collaboration Medical Fitness to Dive
among dive teams and local EMS agencies to develop medi-
cal scenarios during dive training is strongly encouraged. This Prehospital care providers responding to diving-related inci-
should include frequent scuba training in varying underwater dents must assess divers, in all ages groups, not onlyfor primary
conditions and locations, along with in-water rescue scenarios diving disorders related to a submersion incident (e.g., DCS,
and initial medical care, which are paramount to responding AGE) but also for underlying medical conditions (e.g., cardiac,
safely and effectively for in-water swimmer/diver rescues and pulmonary, neurologic, endocrine, psychiatric, or a combina-
recoveries. Scuba training coordination among medical dive tion of both medical and dysbaric disorders). Ideally, all new
team members and local prehospital care providers will ensure divers should be cleared medically before the start of scuba

CHAPTER 22 Environmental Trauma II: Lightning, Drowning, Diving, and Altitude 6 1 7

Figure 22-25 : . • •• ••

Type Signs/Symptoms Treatment*

Mask squeeze Corneal injection, conjunctiva! hemorrhage Self-limited; rest, cold compresses, pain

Sinus squeeze Pain, bloody nasal discharge Pain medication, decongestants, antihistamines

Middle-ear squeeze Pain, vertigo, tympanic membrane rupture, Decongestants, antihistamines, pain
hearing loss, vomiting medication; may need antibiotics; avoid
diving and flying

Internal-ear Tinnitus, vertigo, ataxia, hearing loss Bed rest; elevate head; avoid loud noises; stool
barotraumas softeners; avoid strenuous activity; no diving
or flying for months

External-ear Difficulty wit h Valsalva maneuver, earache, Maintain dry ear canal; antibiotics may be
barotraumas bloody discharge, possible tympanic needed for infection
membrane rupture

Tooth squeeze Tooth pain whi le diving Self-limited; pain medication

Alternobaric vertigo Pressure, pain in affected ear, vertigo, tinnitus Usually short lived; decongestants; prohibit
diving until resolution with normal hearing

Pulmonary Substernal pain, voice change, dyspnea, Assess ABCs, neurologic functions; 100%
barotraumas subcutaneous emphysema oxygen 12 to 15 liters/minute nonrebreathing
mask; transport patient lying supine; need to
rule out AGE

Subcutaneous Substernal pain and crepitus, brassy voice, neck Rest; avoid diving and f lying; oxygen and
emphysema swelling, dyspnea, bloody sputum recompression therapy only in severe cases

Pneumothorax Sharp chest pain, dyspnea, diminished breath 100% oxygen 12 to 15 liters/minute
sounds nonrebreathing mask; monitor pulse
oximet ry; transport in position of comfort;
assess for tension pneumothorax

Tension pneumothorax Cyanosis, distended neck veins, tracheal 14-gauge needle thoracentesis; 100% oxygen
deviation 12 to 15 liters/minute nonrebreathing mask;
monitor pulse oximetry

Arterial gas embolism Unresponsiveness, confusion, headache, visual Assess ABCs, neurologic functions; initiate
BLS/ALS; control seizures; 100% oxygen 12
(AG E) disturbances, seizure to 15 liters/minute nonrebreat hing mask;
transport patient lying supine; glucose-free
IV fluid therapy (1 to 2 ml/kg /hr); monitor
ECG; consult DAN (919-684-8111 ) for closest
recompression chamber (primary treatment)

*Good patient educat ion on scene for minor barotrauma injuries is important because some of these injuries are self-limiting and others need
physician evaluation; others need patient referral to the family physician or emergency department and w ill not necessitate EMS transport.
ABCs, airway, b reathing, circulation; ALS, advanced life support; BLS, basic life support; DAN, Divers Alert Network; ECG, electrocardiogram.
Source: From Clenney TL, Lassen LF: Recreational scuba diving injuries. Am Fam Physician 53(5):1761, 1996; Salahuddin M, James LA, Bass ES.
SCUBA Medicin e: A First-Responder's Guide to Diving Injuries. Curr Sports Med Reports 10(3):134-139, 2011. and Van Hoesen KB and Bird NH:
Diving medicine. In Auerbach PS: Wilderness medicine, ed 6, St. Louis, 2012, Mosby Elsevier.

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