Full text of DOI:10.1007/BF03019865

1176
REPORTS OF INVESTIGATION
Yaakov Beilin MD,*†
Sharon E. Abramovitz MD,†
Jeffrey Zahn MD,†
Sean Enis BA,†
Sabera Hossain MS‡
Improved epidural anal-
gesia in the parturient
in the 30° tilt position
Purpose: To compare the incidence of incomplete analgesia when epidural local anesthetic is administered with
the parturient supine in a 30° leftward tilt or in the left lateral decubitus position.
Methods: After placement of a multiorifice catheter 5 cm into the epidural space, 293 women in active labour
were randomly positioned either to the left lateral decubitus position (lateral group) or supine with a 30° leftward
tilt (tilt group) and then received 13 mL bupivacaine 0.25%. The success of the epidural block was determined
by asking the patient if she required additional medication 15 min later. The incidence of complications (fetal heart
rate decelerations, hypotension, and ephedrine usage) was noted.
Results: In the lateral group, 38% required additional medication compared with 24% in the tilt group (P =
0.006). There were no differences between groups in the incidence of maternal hypotension or fetal heart rate
decelerations, but more women (10%) received ephedrine in the lateral than in the tilt group (4%), P = 0.035.
Conclusions: Placing the parturient supine with a 30° leftward tilt is associated with a greater success rate of
labour epidural analgesia without an increase in complications than in women in the left lateral decubitus position.
This advantage should be considered when positioning the parturient after epidural catheter placement.
Objectif : Comparer l’incidence d’analgésie incomplète lorsqu’un anesthésique local épidural est administré
chez une parturiente installée en décubitus dorsal, inclinée à 30o vers la gauche, ou en décubitus latéral gauche.
Méthode : Après la mise en place d’un cathéter à orifices multiples à 5 cm dans l’espace épidural, 293 femmes
en travail actif ont été installées, en décubitus latéral gauche (groupe latéral), ou en décubitus dorsal avec une incli-
naison de 30o vers la gauche (groupe incliné) et ont reçu 13 mL de bupivacaïne à 0,25 %. La réussite du blocage
épidural a été établie en demandant aux patientes, 15 min plus tard, si l’analgésie était suffisante. L’incidence de
complications (décélération de la fréquence cardiaque fœtale, hypotension et usage d’éphédrine) a été notée.
Résultats : Dans le groupe latéral, 38 % des femmes ont demandé des médicaments supplémentaires en com-
paraison de 24 % dans le groupe incliné (P = 0,006). Il n’y a pas eu de différence intergroupe quant à l’incidence
d’hypotension maternelle ou de décélération de la fréquence cardiaque fœtale, mais davantage de femmes (10
%) ont reçu de l’éphédrine dans le groupe latéral, comparé au groupe incliné (4 %), P = 0,035.
o
Conclusion : L’installation d’une parturiente en décubitus dorsal, inclinée à 30 vers la gauche, comparée à la
position de décubitus latéral gauche, est associée à un taux de succès plus élevé d’analgésie épidurale pendant le
travail sans complications additionnelles. C’est un avantage à considérer quand on cherche une position appro-
priée pour une parturiente après la mise en place d’un cathéter épidural.
From the Departments of Anesthesiology,† and Obstetrics, Gynecology & Reproductive Sciences,* and Biomathematical Sciences,‡
Mount Sinai School of Medicine, New York, NY 10029.
Address correspondence to: Yaakov Beilin MD, The Mount Sinai Medical Center, Department of Anesthesiology, Box 1010, One Gustave
L. Levy Place, New York, NY 10029-6574, USA. Phone: 212-241-7467; Fax: 212-426-2009; E-mail: yaakov.beilin@mountsinai.org
This work was presented in part at the annual meeting of the American Society of Anesthesiologists, Dallas, TX, October 11, 1999.
Accepted for publication August 31, 2000.
CAN J ANESTH 2000 / 47: 12 / pp 1176–1181

Beilin et al.: PATIENT POSITION A N D EPIDURAL ANALGESIA
1177
PIDURAL analgesia is widely used to alle-
viate labour pain. To avoid aortocaval com-
pression with a resultant decrease in blood
epidural needle to a depth of 5 cm into the epidural
space. No local anesthetic was injected through the
epidural needle before epidural catheter placement.
The patient was then positioned either on her left
side (lateral group) or supine with a 30° leftward tilt
(tilt group) depending on group assignment.
Maternal position was standardized by placing the
patient completely on her left side in the lateral group
and by placing the same firm foam bolster with a 30°
incline under the patient’s right hip in the tilt group.
A computer generated random numbers program was
utilized to assign patients to each group. The results
of the randomization were sealed in opaque envelopes
and opened sequentially by the anesthesiologist after
the woman requested labor analgesia.
E
pressure after the placement of an epidural
catheter and administration of local anesthetic, the
parturient should not be positioned supine.1
Commonly, a wedge with a 30° angle is placed under
the right hip to displace the uterus from the great
blood vessels.2 Nonetheless, fetal heart rate decelera-
tions occur when the patient is in this position. Some
believe that occult aortocaval compression occurs
when the parturient is in this position which can lead
to fetal heart rate decelerations, and have therefore
recommended that the parturient should be posi-
tioned in the left lateral decubitus position.3
Three studies have assessed if patient position
effects the quality of analgesia in the parturient.4-6
Two did not contain a control group4, 5 and they all
included a relatively small number of patients: their
results have been inconclusive. The primary purpose
of this study was to determine if there is a difference
in the incidence of incomplete analgesia when local
anesthetic is administered into the epidural space for
labor analgesia while the parturient is positioned in
the left lateral decubitus position vs supine with left
uterine displacement. Additionally, we assessed the
incidence of complications (fetal heart rate decelera-
tions, hypotension, and ephedrine usage) between the
two groups.
After positioning, attempts to aspirate blood or
cerebrospinal fluid (CSF) via the catheter were made
using a 3 mL syringe. If blood was aspirated the pro-
cedure was repeated at another interspace: if CSF was
aspirated the study was concluded. If there was no
aspirate, a 3 mL test dose of bupivacaine 0.25% with-
out epinephrine was administered through the
catheter. The presence of clinical signs of an intravas-
cular injection were sought for the following two to
three minutes by asking the woman if she felt dizzy,
had tinnitus, or had a metallic taste in her mouth. Five
minutes after the test dose, if there were no clinical
signs of subarachnoid injection as evidenced by the
woman’s ability to move her legs and the absence of
hypotension, an additional 10 mL bupivacaine 0.25%
were administered in two divided doses five minutes
apart. If there were clinical signs of an intravascular or
subarachnoid catheter placement the patient was with-
drawn from the study.
The adequacy of analgesia was assessed 15 min after
the last dose of local anesthetic had been administered
(25 min after the test dose) by asking the woman at
the peak of a contraction if she required additional
medication to treat pain. She was asked to indicate
only if she required additional medication for pain,
not pressure. If she verbalized that she needed addi-
tional medication she was asked to point to the loca-
tion of the pain. The presence and location of any
non-anesthetized area was confirmed by the anesthe-
siologist using an alcohol preparation to detect differ-
ences in cold perception. Confirmed unsatisfactory
sensory blockade was classified as complete (failed
epidural) if the patient had no areas of sensory block-
ade, and incomplete if the patient had missed seg-
ments of analgesia. All women (those who required
additional medication and those who did not) were
asked to rate their level of pain on the same verbal pain
scale. Analgesia was considered adequate if the patient
Methods
The protocol was approved by our institutional review
board and written informed consent was obtained
from each patient prior to the onset of painful con-
tractions. Women in active labour who were having
contractions at least once every five minutes and who
requested epidural analgesia were enrolled in this
prospective randomized study. Women with spinal
column disorders including scoliosis and herniated
discs, and women who had undergone spine surgery,
were excluded from participation.
Prior to placement of the epidural catheter the
patient was asked to quantify her level of pain on a ver-
bal 0 to 10 scale with zero representing “no pain” and
10 the “worst pain imaginable.” All patients received
a 500 to 1000 mL fluid bolus of a crystaloid solution
iv as per our protocol. All epidural catheters were
placed with the woman in the sitting position. Using
an 18-gauge Hustead needle, the epidural space was
identified via a midline approach at the L2-3 or L3-4
interspace using the loss-of-resistance-to-air tech-
nique. Then, a 20-gauge multiorifice catheter was
threaded through the cranially directed tip of the

1178
CANADIAN JOURNAL OF ANESTHESIA
reported that she did not require additional medica-
tion. The highest dermatomal level of analgesia was
assessed in all women with an alcohol preparation on
both the right and left side of the abdomen.
sis of incomplete analgesia, hypotension, ephedrine
use, or catheter replacement because of fetal heart rate
changes that mandated changing the maternal posi-
tion before the 15 min evaluation, but were included
in the analysis of fetal heart rate changes. No patient
was excluded because the epidural catheter was
threaded into the subarachnoid space, nor was any
patient excluded because of the presence of clinical
signs of an intravascular or subarachnoid placement
following the test dose. Six patients (four in the later-
al group and two in the tilt group), required catheter
replacement and were not included in the analysis of
incomplete analgesia. This left 145 patients in the lat-
eral group and 139 parturients in the tilt group for the
analysis of incomplete analgesia. Demographic data
and initial labor characteristics of the two groups are
presented in Table I.
No woman had a failed epidural. At 15 min, more
women in the lateral group required additional medica-
tion (n=55, 38%) than in the tilt group (n=33, 24%), P
= 0.008. The results remained the same after control-
ling for parity and cervical dilation in the analysis.
Overall, the pain scores were higher in the lateral group
than in the tilt group, P = 0.003, and the pain scores
were higher in those who did not have adequate anal-
gesia vs those who had adequate analgesia in both
Groups. Among patients requiring more medication,
the most common location of the pain was on the right
side at the T1 2 or L1 dermatome (Table II). In the lat-
eral group, the median highest dermatome level of anal-
gesia was T9 and T on the right and left side,
respectively, P = 0.000110, and in the tilt group the medi-
If the patient had a missed segment 15 min after
the last dose of medication, women in the lateral
group were turned supine with a 30° leftward tilt and
an additional 5 mL bupivacaine 0.25% were adminis-
tered and the patient was reassessed 15 min later.
Women in the tilt group who had a missed segment
also received an additional 5 mL bupivacaine 0.25%
but their position was not changed. If the patient was
still in pain after this dose, the epidural catheter was
replaced and the study was concluded. Patients who
needed catheter replacement were excluded from the
analysis of incomplete analgesia.
Blood pressure was measured on the upper arm in
all patients and was recorded every three minutes dur-
ing the study period. Hypotension was defined as a
greater than 20% decrease in systolic BP from baseline
value during the 25 min study period. Treatment with
ephedrine was at the discretion of the anesthesiologist.
Fetal heart rate was monitored throughout the study,
using either a Doppler ultrasound transducer or fetal
scalp ECG electrode and any evidence of severe fetal
heart rate decelerations, defined as a fetal heart rate <
100 beats·min–1, were recorded.
Statistical analyses
A power analysis, performed before the study was ini-
tiated, revealed that enrolling 266 women would pro-
vide 80% power to detect a two-fold increase in the
incidence of inadequate analgesia between the groups
assuming a 15% incidence of incomplete analgesia in
the tilt group and 30% in the lateral group. This was
based on a two tail test at the 5% level of significance.
Differences between groups were analyzed with the
chi square test or Wilcoxon rank sum test, as appro-
priate. Differences were considered statistically signif-
icant at P < 0.05.
an highest dermatome level of analgesia was T9 and T
8
on the right and left side, respectively, P = 0.0359.
Hypotension occurred in eight patients (5%) in the
lateral group and in seven patients (5%) in the tilt
group, but more women received ephedrine in the lat-
eral group (n=15, 10%) than in the tilt group (n=6,
4%), P = 0.026. Fetal heart rate decelerations occurred
six times (4%) in the lateral group and seven times
(5%) in the tilt group. Catheter replacement was
required in four cases (3%) in the lateral group and in
two cases (1%) in the tilt group.
Results
We enrolled 377 patients and studied 300. Patients
were not studied either because they did not request
an epidural anesthetic or because they requested anal-
gesia when the research team was unavailable. Of the
300, seven were excluded because of protocol devia-
tions. The most common protocol deviation was
administering an incorrect volume or concentration of
bupivacaine. Of the 293 women who participated in
the study, 149 were randomized to the lateral group
and 144 to the tilt group. Three patients (all random-
ized to the tilt group) were not included in the analy-
Discussion
We found that when women were positioned supine
with a 30° left tilt they had a greater incidence of ade-
quate analgesia 15 min after the last dose of local anes-
thetic is administered than when they are positioned
on their left side. The incidence of inadequate analge-
sia and the spread of local anesthetic when a patient is
positioned on the left side vs supine with a leftward tilt
has not been satisfactorily addressed previously. In the

Beilin et al.: PATIENT POSITION A N D EPIDURAL ANALGESIA
1179
TABLE I Patient demographic and labor characteristics*
Lateral group
149
Tilt group
n
144
Position
Age (yr)
Height (cm)
Weight (kg)
Left lateral decubitus
33 (18-41)
165 (150-180)
75 (51-120)
48
Supine with 30° tilt
32 (19-43)
164 (127-178)
74 (56-157)
49
Primiparous (%)
Pitocin use (%)
82
92
Initial pain score (0-10)
Cervical dilatation at epidural catheter placement
7 (3-10)
2 (0-7)
7 (3-10)
2 (0-6)
* Data are presented as median and range
TABLE II Success rate and location of inadequate analgesia
Lateral Group
Tilt Group
P
n
145
139
Position
Left lateral decubitus
55 (38%)
2 (0-10)
Supine with 30° tilt
33 (24%)
1 (0-10)
Additional medication
Overall pain score at 15 min†
Pain score in those who
required additional medication†
Pain score in those who did not
require additional medication†
Location of pain*
Right
0.006
0.003
5 (1-10)
0.5 (0-6)
4 (2-10)
0 (0-5)
0.53
0.36
30 (51%)
20 (34%)
4 (7%)
19 (54%)
10 (29%)
2 (6%)
Middle
Rectum
Left
5 (8%)
4 (11%)
Dermatomal level of pain*
T8 through T
1 (2%)
3 (9%)
6 (17%)
20 (57%)
3 (9%)
3 (9%)
2 (1%)
9
T1 0 or T
12 (22%)
34 (58%)
8 (14%)
3 (5%)
T1 2 or L11 1
L2 through -L
4
S2 through-S4
Replaced catheters
4 (3%)
* In patients who required additional medication
† Data are presented as median and range
non-pregnant patient presenting for surgery two sep-
arate investigators found a higher dermatomal level of
analgesia on the dependent side of the abdomen.7,8
These patients all received large volumes (15-20 mL)
of concentrated local anesthetics (lidocaine 2% or
bupivacaine 0.75%). The results should not be extrap-
olated to the parturient receiving smaller volumes of
more dilute local anesthetics.
anesthetic than is usually administered during labour.
Rolbin et al.4 and Husemeyer and White5 found a
higher dermatomal level of analgesia on the dependent
side of the abdomen in the parturient who received an
epidural anesthetic for labour while positioned in the
lateral decubitus position. Rolbin et al.4 enrolled 34
patients and used lidocaine 1.5%, and Husemeyer and
White enrolled 100 women and used bupivacaine
0.25%. However, neither study4,5 utilized a control
group, and in both studies the medication was admin-
istered via the epidural needle rather than via the
catheter. In addition, both investigators enrolled too
few patients to make any definitive conclusions.
Norris et al.9 found no differences in the quality or
highest dermatomal level of anesthesia on the depen-
dent side of the abdomen when the parturient was
positioned on her side while receiving an epidural anes-
thetic for Cesarean delivery. However, they studied
women undergoing Cesarean delivery, who tend to
receive a greater volume of a more concentrated local
Shapiro et al.6 did not find a difference in pain scores
among women randomized to different positions dur-

1180
CANADIAN JOURNAL OF ANESTHESIA
ing the administration of epidural medication. One
group received epidural medication while positioned
supine with a 20° tilt, a second group received epidural
medication while on their left side and 10 min later
were turned supine with a 20° tilt, and a third group
received the epidural medication while on their left side
and five minutes later were turned to the right side and
five minutes after that were turned supine with a 20°
tilt. The study period continued after the patient was
supine. A major flaw with this study is that all patients
were supine during the evaluation period and any effect
of patient position on the spread of local anesthetic and
subsequent pain scores may have been mitigated.
Eberle et al.1 0 noted a greater incidence of asym-
metric blocks in women placed in the left lateral decu-
bitus position than in those positioned supine with 30
tilt. However, their study was primarily designed to
assess the effect of maternal position on fetal heart rate
abnormalities and not incomplete analgesia, so a for-
mal evaluation of the quality of the block, (pain scores,
dermatomal levels, etc.,) was not reported.
Defining adequate analgesia in the context of the
woman in labour is complex. Some parturients expect
complete pain relief, whereas others prefer to experi-
ence some pain so that they can participate more fully
in the labour experience. We defined adequate analge-
sia as one where the patient did not request addition-
al medication at the peak of a contraction 15 min after
the last dose of local anesthetic. Clinically, anesthesiol-
ogists administer more medication based on patient
request and not based on the results of a pain score.
However, for completeness, we also assessed a pain
score at 15 min.
We found that women in the lateral group requested
additional medication (38%) more often than women in
the tilt group (24%). Our overall incidence of inade-
quate analgesia (31%) after the initiation of labour
epidural analgesia, although seemingly high, is consis-
tent with the results of previous studies that have care-
fully assessed the incidence of incomplete analgesia after
the initiation of labour epidural analgesia.11,12
The etiology of unblocked dermatomes after the
placement of an epidural catheter and administration
of local anesthetic is unknown. Proposed theories
include slow injection of small volumes of local anes-
thetic, presence of an epidural septum, midline adhe-
sions, placement of the epidural catheter through an
intervertebral foramen, and placement of the epidural
catheter into the anterior epidural space.1 3 We have
also confirmed that patient position plays a role in
determining the spread of local anesthetic. Women in
the lateral group had incomplete analgesia more often
than women in the tilt group, and in both Groups the
highest dermatomal level of analgesia was significantly
higher on the left side than the right.
Although we found that the initial analgesia was bet-
ter when the supine position with 30° leftward tilt was
utilized, administering additional medication and
changing patient position corrected the problem in
most women. Only four catheters in the lateral group
and two in the tilt group required replacement. We
excluded these six women from the analysis of incom-
plete analgesia because the incomplete analgesia may
have been related to a technical problem with catheter
placement and unrelated to patient position. Labour
pain can be distressing to the parturient and it is best if
the pain can be treated as quickly as possible without
additional medication or catheter manipulation. It is
possible that if we had waited more than 15 min after
the last dose of bupivacaine, 25 min after the test dose,
our success rate may have been greater. However, for
ethical reasons, we did not want to expose the patient
to more than 25 min of inadequate analgesia prior to
ending the study protocol. Furthermore, Eisenach et
al.1 4 found that the onset of action of 10 mL bupiva-
caine 0.25% is 8.7 0.8 min, so that 15 min should
have been adequate.
We were unable to document a difference between
groups in the incidence of fetal heart rate decelerations
during the study period. This evaluation was performed
during the study period by the anesthesiologists and we
only sought obvious (fetal heart rate < 100 beats·min- 1)
decelerations. More subtle decelerations may have been
detected if the analysis had been done after delivery by
an obstetrician blinded to group assignment. Our results
are different from those of Preston et al.3 who found a
greater incidence of severe fetal heart rate decelerations
when women were positioned supine with left uterine
displacement (15%) than when placed in the left lateral
decubitus position (0%). They enrolled only 73 patients
in their study and used a one-tailed statistical test to
check for difference between groups and, as they
acknowledged, the possibility of a sampling error leading
to a type 1 error in a small study sample should be con-
sidered.3 Our results are consistent with those of Eberle
et al.1 0 who also did not notice a difference in fetal heart
rate decelerations between those placed supine with left-
ward tilt and those placed on their left side.
We were unable to find a difference between
groups in the incidence of hypotension (5% in both
groups), but ephedrine was administered more often
in the lateral group. Overall, the incidence of
ephedrine use (n=21, 7%) was greater than the inci-
dence of hypotension (5%). Clinically, anesthesiolo-
gists may treat decreases in systolic BP that are less
than a 20% decline from baseline. Ephedrine use was

Beilin et al.: PATIENT POSITION A N D EPIDURAL ANALGESIA
1181
Lateral position and epidural anesthesia for Cesarean
section. Anesth Analg 1988; 67: 788–90.
10 Eberle RL, Norris MC, Eberle AM, Naulty JS, Arkoosh
VA. The effect of maternal position on fetal heart rate
during epidural or intrathecal labor analgesia. Am J
Obstet Gynecol 1998; 179: 150–5.
11 Beilin Y, Bernstein HH, Zucker-Pinchoff B. The optimal
distance that a multiorifice epidural catheter should be
threaded into the epidural space. Anesth Analg 1995;
81: 301–4.
12 D’Angelo R, Foss ML, Livesay CH. A comparison of
multiport and uniport epidural catheters in laboring
patients. Anesth Analg 1997; 84: 1276–9.
greater in the lateral group than in the tilt group.
Since ephedrine use was not standardized or con-
trolled, it is difficult to determine from our study
design why this was the case.
Although many anesthesiologists use lower concen-
trations of local anesthetics with an opioid for epidural
labour analgesia, bupivacaine 0.25% is still commonly
used and we wanted to study the impact of patient posi-
tion without the influence of opioids. The results of our
study, however, are limited to the conditions of the cur-
rent study, i.e., 13 mL of bupivacaine 0.25%.
In conclusion, placing the patient supine with a 30°
leftward tilt for 15 min after the administrations of 13
mL bupivacaine 0.25% is associated with a greater suc-
cess rate of epidural analgesia without an increase in
complications as compared to those placed in the left
lateral decubitus position.
13 Collier CB. Why obstetric epidurals fail: a study of
epidurograms. Int J Obstet Anesth 1996; 5: 19–31.
14 Eisenach JC, Grice SC, Dewan D. Epinephrine
enhances analgesia produced by epidural bupivacaine
during labor. Anesth Analg 1987; 66: 447–51.
Acknowledgments
The authors express appreciation to James B.
Eisenkraft MD, for his critical review of this manu-
script; and to Carol A. Bodian DRPH, for help with the
statistical analyses.
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