Recovery times from subarachnoid blocks using bupivacaine ...

Recovery times from subarachnoid blocks
using bupivacaine hydrochloride and
tetracaine hydrochloride with and without
epinephrine

MILDRED LEONARD, CRNA, MSN
LINDA MOORE, RN, EdD
ROBERT ALGOZZINE, PhD
JANE GREGORINO, CRNA, MSN
BILL GILES, CRNA, MS
Charlotte,North Carolina

This retrospectivestudy examined the Key words: Bupivacaine hydrochloride,
length of time patientsspent in the local anesthetics, regional anesthesia,
postanesthesiacare unit (PACU)recovering subarachnoid blocks, tetracaine
from a subarachnoidblock with either hydrochloride.
bupivacaine hydrochlorideor tetracaine
hydrochloridewith and without epinephrine Introduction
after totalknee replacementsurgery or total Providing for the shortest stay in the postanesthe-
hip replacementsurgery. One hundred sia care unit (PACU) is desirable in this era of cost
subjects'chartswere reviewed with 50 subjects containment. Local anesthetics given via subarach-
receivinga subarachnoidblock with noid block have differing durations of action,
bupivacaine(25 hadepinephrineaddedto which change dramatically with the addition of
the bupivacaine)and50 subjects receivinga epinephrine. The addition of epinephrine to the
subarachnoidblock with tetracaine(25 had various anesthetics may increase the duration by
epinephrineadded to the tetracaine). as much as 50%.1,2 The goals are to match the dura-
tion of anesthetic agent with the duration of the
There were no statisticaldifferences surgical procedure and minimize the time for re-
among the groupswith respectto age, height, covery of sympathetic, sensory, and motor function.
weight, dose of local anesthetic, and length of
surgicalprocedure.Patientswho received Total hip and total knee replacement surger-
tetracainestayed longerin the PACU ies are frequently performed using a subarachnoid
(64.44 minutes) and took longerto bend their block with a local anesthetic. 2'3 However, if the
knees (73.17 minutes),flex theirhips block is prolonged past the surgical procedure, the
(99.65 minutes), and have returnof sensation patient will have a prolonged stay in the PACU in
(68.88 minutes), compared to those who had order to meet the discharge criteria. Additionally,
receivedbupivacaine(P < .05). When if the patient's block does not last long enough for
epinephrinewas added to the local the completion of the procedure, the anesthetist
anesthetic,itprolongedthe time untilthe may be faced with the necessity of providing gen-
return of knee flexion, hipflexion, and eral anesthesia.
sensation by 66.82, 87.65, and 76.77 minutes
respectively (P<.05). The distribution of the local anesthetic within
the subarachnoid space determines the extent of
260 the neural blockade produced.4 Factors which in-

Journalof the AmericanAssociation of NurseAnesthetists

fluence distribution of the local anesthetic include weight, sex, ASA physical status, local anesthetic
used, time of injection, if epinephrine was used,
age, height, weight, gender, position of the patient position of the patient at the time of the block,
highest dermatome level measured, times of surgi-
at the time of the block, site of injection, force of cal incision and completion, if general anesthesia
was induced, time of admission to PACU, the
injection, basicity, density, specific gravity of the dermatone level on admission to PACU, and times
when the patient could bend knees, lift hips; had
solution, volume injected, and tphheeunsyeleopfhvriansoec. o2,4n,5- return of sensation, and was discharged from
strictors such as epinephrine or PACU. This information was retrieved from the
anesthesia record and the PACU nursing records.
Once the blockade has occurred, duration is Means, standard deviations, and analyses of vari-
ance were used for the statistical analysis of these
dependent upon the concentration of the local an- variables. Follow-up analyses of significant main
effect differences were done using Tukey's least sig-
esthetic around the nerve ending. The block ends nificant difference procedure.

when the local anesthetic diffuses from the nerve Results
There were no statistically significant differ-
end and is absorbed into the vascular system and
ences among the four groups with respect to age,
then metabolized. Tetracaine, an ester, is metabo- height, weight, doses of local anesthetic used for
the subarachnoid block, and initial dermatome
lized by undergoing hydrolysis by pseudocholin- level of anesthesia (Table I). Additionally, length
of surgical times for knee and hip surgeries were
esterase enzyme. Bupivacaine, an amide, is metab- compared and found to not be statistically differ-
ent. Upon arrival in the PACU, the dermatone lev-
olized by enzymatic degradation primarily in the els were found to be not statistically different
(P >.05); however, it was noted that the mean der-
liver. The duration of both can be prolonged by matome level of the tetracaine group was higher
than the dermatome level of the bupivacaine
the addition of a vasoconstrictor such as epineph- group.
rine, probably by decreasing vascular uptake. 23
Total times spent in the PACU, as determined
Other researchers suggest that the mechanism of

action of epinephrine was through a direct analge-

sic affect from the alpha2 adrenergic agonist effect
on the central nervous system. 6

Researchers have found a wide range for the

duration (135 to 523 minutes) of local anesthetics,

both bupivacaine and tetracaine, depending on

the doses and whether epinephrine was or was not
added to the local anesthetic. 7-9 Bupivacaine acts

similarly to tetracaine with one significant differ-

ence. Bupivacaine without belopcinkaedpeh.'r10in1e does not
always produce total motor

The purpose of this study was to determine if

there was a difference in recovery times for pa-

tients undergoing total hip or total knee replace-

ments using bupivacaine or tetracaine with and

without epinephrine. Table I
Total time from blocks to return of knee bend

Methods Means and standard deviations
This was a retrospective study at one large
Local anesthetic Mean Standard
Southeastern medical center. Following approval deviation
by the Institutional Review Board for review of
medical records and the University Protection of Bupivacaine hydrochloride 183.6 37.7
Human Subjects Committee, 75 charts document- Without epinephrine 214.5 68.8
ing total knee replacement surgeries and 75 charts With epinephrine 225.7 57.2
documenting total hip replacement surgeries were 307.7 48.8
identified and compared for length of time for the Tetracaine hydrochloride
surgical procedures. Charts were selected until 25 Without epinephrine
patients were in each group (tetracaine with and With epinephrine
without epinephrine and bupivacaine with and
without epinephrine). Three patients had unsuc- Analysis of variance summary
cessful subarachnoid blocks and required general
anesthesia. One patient with a tetracaine block did Source Mean Degrees
not have loss of sensation and a second block using square of F
bupivacaine with epinephrine did not produce a
satisfactory block. Charts for these four patients freedom value
were not included in the data analysis.
Local 60,111.54 1 22.20*
The other charts were reviewed for age, height, Epinephrine 46,084.79 1 17.02*

Local with 9,230.21 1 3.41
epinephrine 2,707.59 55

Error

*P<.05

June 1997/ Vol. 65/No. 3 261

from time recorded on the nurses' notes of admis- Figure 2
sion to PACU to time of discharge out of the PACU, Total time from subarachnoid block to hip flexion in
were similar for the subjects receiving tetracaine the postanesthesia care unit
without epinephrine (140 minutes) or bupivacaine
with or without epinephrine (136 and 114 minutes, 400
respectively). Patients who had received a sub-
arachnoid block with tetracaine with epinephrine 300
stayed an average of 225 minutes. Patients who re-
ceived a subarachnoid block with tetracaine spent 200
an average of 64 minutes longer in the PACU than
patients who had received a block with bupiva- 100
caine (P<.05). When epinephrine was used in
combination with a local anesthetic, subjects spent upivacaine nupivacaine leuacame leuacainei
an average of 63 minutes longer in the PACU than (n= 14) epinephrine
those patients without epinephrine added (P<.05). (n= 19) epinephrine
Differences in total time spent in PACU are illus- (n= 13) (n=19)
trated in Figure 1.
of time to bend knees (268 minutes) than did the
Figure 1 patients who received the local anesthetic without
Total time spent inthe postanesthesia care unit epinephrine (201 minutes). Differences in time re-
quired to bend knees are illustrated in Figure 3.
250
Means, standard deviations, and analysis of
200 variance summary for time in which the patients
had return of sensation following local anesthetic
150 with or without epinephrine are presented in Table
II. Sensation was determined by review of the
100 PACU nurses' notes documenting either voiding
of return of feeling or meeting criteria for dis-
50 charge from PACU. Simple effect follow-up analy-
sis (Tukey's least significant difference) indicated

uupivacaine uupivacaine lenacame letracainei Figure 3
(n= 25) epinephrine(n = 25) epinephrine Total time from subarachnoid block to knee bend in
the postanesthesia care unit
(n= 25) (n= 25)
350
Subjects who received a subarachnoid block 300
with tetracaine with epinephrine required a signif- 250
icantly longer length of time from time of injec- 200
tion of the subarachnoid block (361 minutes) for 150
return of hip flexion than did subjects receiving 100
tetracaine without epinephrine (252 minutes) or
subjects receiving bupivacaine without epineph- uupivacaine uupivacaine enacaine leuacainei
rine (199 minutes) or with subjects receiving epi- (n= 20)
nephrine (238 minutes). Differences in length of epinephrine(n= 22) epinephrine
time until subjects had return of hip flexion are (n= 21)
illustrated in Figure 2. (n=17)

Means, standard deviations, and analyses of
variance summary for length of time for the pa-
tients in the PACU to bend knees after receiving
the subarachnoid block are presented in Table I.
Patients who received tetracaine required a longer
length of time to bend their knees (268 minutes)
than the patients who had received bupivacaine
(195 minutes). Patients who received the local an-
esthetic with epinephrine required a longer length

Journalof the AmericanAssociation of NurseAnesthetists

Table II Figure 4
Total time from blocks to return of sensation
Total time from subarachnoid block to return of
Means and standard deviations sensory function

Local anesthetic Standard 350

Mean deviation 319.64

Bupivacaine hydrochloride 181.8 38.4 300
Without epinephrine 215.4 57.4
With epinephrine 250 215.38 208.92
208.9 51.1
Tetracaine hydrochloride 319.6 88.3 c,
Without epinephrine
With epinephrine S

= 200

Analysis of variance summary E 150

Source Mean Degrees 100.100

square of F

freedom value

Local 57,816.51 1 15.73* 5500
Epinephrine 66,982.35 1 18.23*
20,735.12 1 5.64* BupivacainBeupivacaine/ Tetracaine Tetracaine/
Local with 3,675.09 53 (n= 20) epinephrine (n= 19) epinephrine
epinephrine
(n= 21) (n= 21)
Error

*P<.05

that the significant mean difference was with tetra- Figure 5
caine with epinephrine (320 minutes) compared to
patients who received bupivacaine with or without Total time from subarachnoid block to cardiovascular
epinephrine (182 and 215 minutes, respectively) or stability
tetracaine without epinephrine (209 minutes). Dif-
ferences in time required for sensation are illus- 250 211.11
tratedin Figure 4.
200 185.5
Means, standard deviations, and analysis of
variance for length of time until cardiac stability 1 181.56
(within 20% of preoperative blood pressure level)
indicated that there was no significant difference 150 143.46
in length of time for subjects receiving either local
anesthetic, with or without epinephrine, for a sub- .E
arachnoid block (P>.05). Comparison of the 100
means of the different groups is presented in Fig-
ure 5. 50

A statistically significant difference in dura- 0
tion of length of stay in the PACU was evident for
patients who received tetracaine with epinephrine. Bupivacaine Bupivacaine/ letracaine letracainei
These patients also had increased time intervals
before they could bend their knees, flex their hips, (n = 21) epinephrine (n= 24) epinephrine
and had return of sensory function.
(n= 24) (n= 25)
Discussion
The significant effects of tetracaine for in- from motor or sensory function. 12 They found that
if discharge was based on hemodynamic stability,
creased length of time until recovery were consis- the patients could have been discharged from the
tent in the areas of sensory and motor return. PACU about 51 minutes earlier than waiting for
There was no difference in hemodynamic stability the regression of the block to T-10 and movement
between tetracaine and bupivacaine with or with- of the toes. In this study, all means for tetracaine
out epinephrine. The above results can be com- and bupivacaine with and without epinephrine
pared to Alexander and associates who found that were significantly higher (bending knees, flexing
hemodynamic stability occurred independently hips, and return of sensation) than the means for
hemodynamic stability. Future studies should con-
sider orthostatic blood pressure testing to deter-
mine potential earlier discharge from PACUs.

An important consideration when determin-

June 1997/ Vol. 65/No. 3 263

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for the relatively young patient with an uncompli-
cated surgical case where heavy intravenous seda- siology. 1991;74:250-257.
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of flexion of hips or bending of knees. Based on of cerebrospinal fluid, and vasopressors on onset and duration of spi-
the significant differences in mean times from car-
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fit must be considered. An additional study, from (10) Pflug AE, Aasheim GM, Beck HA. Spinal anesthesia: Bupiva-
casual observation, may be the need to evaluate caine versus tetracaine. Anesth Analg. 1976;55:489-492.
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and without epinephrine added to the local anes-
thetic. It was observed that those patients with epi- caine. Anesth Analg. 1980;59:743-750.
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done.
AUTHORS
REFERENCES
Mildred Leonard, CRNA, MSN, is a staff anesthetist at Carolinas
(1) Stoelting RK, Miller RD. Basics of Anesthesia. New York: Churchill Medical Center, Charlotte, North Carolina. She completed her BSN at
Livingstone. 1994:163-177. the University of Tennessee, Chattanooga, Tennessee, and her MSN at
(2) Covino BG, Lambert DH. Epidural and spinal anesthesia. In: the University of North Carolina at Charlotte.
Barash PG, Cullen BF, Stoelting RK. ClinicalAnesthesia. Philadelphia:
J.B. Lippincott. 1992:809-840. Linda Moore, RN, EdD, is associate professor at the University of
North Carolina at Charlotte. She completed her BSN at Duke Univer-
sity, Durham, North Carolina, and her MSN and EdD at the University

of Virginia, Charlottesville, Virginia.
Robert Algozzine, PhD, is a professor at the University of North

Carolina at Charlotte. He completed his BS at Wagner College, Staten
Island, New York, an MS at State University of New York at Albany,
and a PhD at Pennsylvania State University, University Park,

Pennsylvania.
Jane Gregorino, CRNA, MSN, is a staff anesthetist at Carolinas

Medical Center. She completed her BSN at Stephens College, Colum-
bia, Missouri, and her MSN at Frances Payne Bolton Nursing/Case
Western Reserve University, Cleveland, Ohio.

Bill Giles, CRNA, MS, is a manager in the Anesthesia Department
at Carolinas Medical Center. He completed his BSN at the University
of Maryland, College Park, Maryland, and his MS at the University of

California at Los Angeles.

264 Journalof the AmericanAssociation of Nurse Anesthetists