Full text of DOI:10.1007/BF03017388

600
OBSTETRICAL AND PEDIATRIC ANESTHESIA
The addition of hydromorphone to epidural
fentanyl does not affect analgesia in early labour
[L’addition d’hydromorphone à l’injection épidurale de fentanyl n’affecte pas
l’analgésie au début du travail]
Robert K. Parker DO, Neil Roy Connelly MD, Tanya Lucas MD, Uzma Faheem MD, Asad Syed Rizvi MD,
Mervat El-Mansouri MD, Nikhil Thakkar MD, Ramchander Kamasumadram MD, Kelly Dixon RN,
Steven M. Dunn MD, Charles Gibson RN MA
Purpose: Epidural fentanyl after a lidocaine and epinephrine test
dose, provides adequate analgesia and allows for ambulation during
early labour. The current study was designed to determine the
influence of hydromorphone added to an epidural fentanyl bolus
(e.g., whether there is an increase in duration of analgesia).
Methods: Forty-four labouring primigravid women, at less than 5
cm cervical dilation, who requested epidural analgesia were
enrolled in this randomized, double-blind study. After a 3 mL test
dose of lidocaine with epinephrine, patients received fentanyl 100
µg (in 10 mL volume). They randomly received the fentanyl with
either saline or hydromorphone (300 µg).
bolus de fentanyl épidural. Entre autres, l’analgésie est-elle prolongée?
Méthode : Quarante-quatre primigestes en travail chez qui la dilata-
tion du col était de moins de 5 cm et qui avaient demandé une anal-
gésie épidurale ont été recrutées pour l’étude randomisée et à double
insu. Après avoir reçu une dose test de 3 mL de lidocaïne avec de
l’épinéphrine, les patientes ont eu 100 µg de fentanyl (dans un volume
10 mL). Elles ont reçu de façon aléatoire le fentanyl et, soit une solu-
tion salée, soit de l’hydromorphone (300 µg). Après l’administration de
l’analgésique initial, les scores de douleur et les effets secondaires ont
été enregistrés pour chaque patiente à dix, 20 et 30 min et à toutes
les 30 min par la suite par un observateur objectif.
After administration of the initial analgesic, pain scores and side
effects were recorded for each patient at ten, 20, and 30 min, and
every 30 min thereafter, by an observer blinded to the technique
used.
Results: The patients were taller in the hydromorphone group (P
< 0.04). There were no other demographic differences between
the two groups. The mean duration prior to re-dose was not sig-
nificantly different in the group that received hydromorphone (135
± 52 min) compared to the control group (145 ± 46 min). Side
effects were similar between the two groups. No patient in either
group experienced any detectable motor block.
Conclusion: In early labouring patients, the addition of hydromor-
phone (300 µg) to epidural fentanyl (100 µg after a lidocaine and
epinephrine test dose) neither prolongs the duration of analgesia
nor affects the ability to ambulate, and cannot be recommended
according to the current study.
Résultats : La seule caractéristique personnelle différente entre les
patientes des deux groupes était que les patientes ayant reçu l’hydro-
morphone étaient plus grandes (P < 0,04). Que ce soit avec l’hydro-
morphone (135 ± 52 min) ou la substance témoin (145 ± 46 min),
le temps moyen précédant une seconde dose était comparable. Les
effets secondaires ont été similaires dans les deux groupes. Aucune
patiente n’a expérimenté de blocage moteur détectable.
Conclusion : Au début du travail, l’ajout d’hydromorphone (300 µg)
à l’administration péridurale de fentanyl (100 µg après une dose test
de lidocaïne et d’épinéphrine) ne prolonge pas l’analgésie et n’affecte
pas la capacité de marcher. Il ne peut être recommandé selon la
présente étude.
E previously showed that epidural fen-
tanyl or sufentanil, after a lidocaine-epi-
nephrine
test
dose,
provides
W
approximately two hours of analgesia,
Objectif : L’administration épidurale de fentanyl suivant une dose test
de lidocaïne et d’épinéphrine fournit une analgésie adéquate et per-
met de marcher au début du travail obstétrical. La présente étude
cherchait à déterminer l’influence d’un ajout d’hydromorphone au
while allowing patients to ambulate.1–6 Fentanyl is the
most commonly chosen opioid at our institution for
early labour ambulatory epidurals based on its low
From the Department of Anesthesiology, Baystate Medical Center, Springfield, Massachusetts, USA.
Address correspondence to: Dr. Neil Roy Connelly, Department of Anesthesiology, Baystate Medical Center, 759 Chestnut Street,
Springfield, Massachusetts 01199, USA. Phone: 413-794-4325; Fax: 413-794-5349; E-mail: neil.roy.connelly@bhs.org
Accepted for publication January 8, 2002.
Revision accepted March 18, 2002.
CAN J ANESTH 2002 / 49: 6 / pp 600–604

Parker et al.: EPIDURAL HYDROMORPHONE AND LABOUR
601
cost and the fact there was a lack of significant anal-
gesic difference compared to sufentanil.3
100 µg with normal saline to a total volume of 10 mL;
group HYD: fentanyl 100 µg and hydromorphone
300 µg with normal saline to a total volume of 10 mL.
Patients were placed in the recumbent position
with left uterine displacement. VAS scores and the
severity of side effects were recorded ten, 20, and 30
min after the administration of the study infusion and
every 30 min thereafter. Observations were performed
by an individual blinded to the analgesic technique. At
the time of each assessment, vital signs, modified
Bromage motor scale scores,7 pruritus, nausea, vomit-
ing and sedation were evaluated. Motor block was
defined as none, partial (just able to move the knees),
almost complete (able to move the feet only), or com-
plete (unable to move the lower extremities). Pruritus
was rated as none, minimal (present with minimal
symptoms), moderate (bothersome but not requiring
therapy), or severe (requiring therapy). Sedation was
categorized as none (awake), mild (drowsy), moderate
(sleepy) or severe (unarousable). The fetal heart rate
pattern was evaluated at each interval and any changes
were documented. After the first 30 min, patients
were allowed to ambulate with assistance provided
there was no detectable motor block and the fetal
heart rate pattern was reassuring. Oxygen saturation
was monitored while patients were at bedrest. The
time at which each patient requested additional anal-
gesia was recorded, vital signs were documented, pain
and side effect assessments were performed, and the
study period was concluded. The epidural anesthetics
were subsequently managed by the anesthesia team, as
appropriate, for the remainder of labour. The length
of labour, incidence of Cesarean delivery, incidence of
postdural puncture headache (PDPH), and neonatal
Apgar scores were recorded.
A plan for treating inadequate analgesia was standard-
ized. If a patient did not experience adequate analgesia
20 min after the initial study dose, 15 mL of 0.125%
bupivacaine would be administered via the epidural
catheter. If this did not provide relief after an additional
20 min, 10 mL of 2% lidocaine would be administered.
If this did not result in an adequate level of analgesia,
then the epidural catheter would be replaced.
Before this study was instituted, a power analysis
was performed assuming: a duration of fentanyl anal-
gesia of 124 42 min,1,3 a hydromorphone analgesia
duration of 165 45 min; 90% power, and an alpha of
0.05. This yielded a required sample size of 21
patients per group.
In a pilot study, hydromorphone 300 µg following
a lidocaine-epinephrine test dose demonstrated an
analgesic onset time of greater than 20 min, which was
determined to be too long to be clinically useful. We
postulated that combining a “quick-onset” short-act-
ing opioid (i.e., fentanyl) with a longer-onset, longer-
acting opioid (i.e., hydromorphone) would achieve
the benefits of both medications: a quick-onset, long
duration “ambulatory” epidural. We thus undertook
this study to determine the influence of hydromor-
phone on the duration of analgesia when administered
along with fentanyl after a lidocaine and epinephrine
test dose, in primigravid patients during the early first
stage of labour.
Methods
Before this study was initiated, Institutional Review
Board approval was obtained. Forty-four primigravid
ASA physical status I or II obstetric patients, at greater
than 36 weeks of gestation, who had requested labour
analgesia, gave written informed consent. Patients were
excluded if cervical dilation was greater than 5 cm, if
they had received iv opioid agonists or agonist/antago-
nists, had pre-eclampsia, or had a contraindication to
fentanyl or hydromorphone. A normal fetal heart rate
pattern (absence of decelerations) was required for
inclusion in the study. Patients were randomized to
group C (control) or group HYD (hydromorphone)
using a random series of 44 numbers generated with
Microsoft Excel’s Randbetween function.
Before the procedure began, the patients’ vital
signs (blood pressure, heart rate, and respiratory rate)
were documented, and the patients were asked to
relate any symptoms of pruritus, nausea, or vomiting.
Each patient also completed a baseline assessment
using a 100-mm visual analogue scale (VAS) for pain,
with 0 representing no pain and 100 being the worst
possible pain. Each patient received a minimum of
500 mL of Ringer’s lactate solution intravenously. All
procedures were performed with patients in the sitting
position. A lumbar epidural catheter was inserted
approximately 5 cm into the epidural space by using a
Tuohy-Schiff needle (B-Braun Medical, Bethlehem,
PA, USA). The patients then received a test dose of 3
mL of 1.5% lidocaine with 1:200,000 epinephrine. If
the test dose was negative for intravascular injection
(heart rate within 15 beats·min–1 of baseline values in
two minutes of monitoring) and intrathecal injection
(no spinal block after three minutes of monitoring),
the patient was given one of two epidural injections in
a double-blinded fashion as follows: group C: fentanyl
Demographic data were analyzed by using analysis
of variance. Pain scores were analyzed by using the
Mann- Whitney U test. Presence or absence of side
effects was analyzed by contingency testing. A Kaplan-

602
CANADIAN JOURNAL OF ANESTHESIA
TABLE
Group
Age
(yr)
Height
(cm)
Weight
(kg)
Gestational
age (weeks)
Cesarean
section (n)
Forceps/
vacuum(n)
Cervical
dilation
at initial
dose
Cervical
dilation
at re-dose
Hydromorphone/
fentanyl
Fentanyl
27
26
6
7
167
162
7
8
84 16
86 18
40
40
1
2
9/21
6/21
0/21
1/21
2.9 1.2
3.1 1.1
5.1 2.4
4.6 2.0
Data are expressed as mean SD. The patients in the hydromorphone group were significantly taller (P < 0.04) than the patients in the
control group. There were no other statistically significant differences between the groups.
Meier plot of the patients remaining comfortable over
time was generated. Data are expressed as mean SD.
Significance was determined at the P <0.05 level.
Results
Forty-four patients were enrolled in the study. All
patients, except one, achieved adequate initial analge-
sia with the epidural fentanyl; this patient did not get
comfortable following the administration of epidural
local anesthetic, but analgesia was achieved following
replacement of the epidural catheter. One patient’s
data were excluded due to a protocol violation: a
bupivacaine infusion was initiated immediately after
the epidural medication was administered. These
patients’ data were excluded from analysis. The
patients in the HYD group were significantly taller
than those in group C (P < 0.04). There were no
other differences in demographic variables, cervical
FIGURE 1 The visual analogue scale (VAS) pain scores for the
two groups at time intervals up to 2.5 hours. The box represents
the 25th–75th percentiles and the median is represented by the
solid line. The extended bars represent the 10th–90th percentiles.
Pain scores were not obtained following administration of addi-
tional analgesic medication. There were no significant differences
between the groups at any time period.
dilation at the time of enrollment, rupture of mem-
branes, or oxytocin use between the two study groups
(Table). Baseline VAS pain scores and the incidence of
nausea and pruritus were similar in the two groups.
The median VAS scores in both groups were
decreased 81% and 69% by the 10-min evaluation in
the C and HYD groups, respectively (P = not signifi-
cant). At 20 min, VAS scores were reduced by 88%
(C) and 83% (HYD; P = not significant). There was no
significant difference in pain scores between the
groups at any of the time points (Figure 1). The dura-
tion until re-dose was not significantly different
between the C (145 46 min) and the HYD groups
(135 52 min; Figure 2).
Before administration of the study analgesic, 12
patients had experienced nausea (six in C, six in HYD)
and five patients had vomited (three in C, two in
HYD). During the entire study period, nine patients
experienced nausea (two in C, seven in HYD) and two
patients vomited (two in C, zero in HYD). Four
patients experienced mild sedation at least once dur-
ing the study period (two in group C, two in group
HYD). No patient experienced moderate or severe
sedation. At no time, did any patient experience severe
pruritus. No patient required specific treatment for
nausea, vomiting, or pruritus. There were three
patients who reported at one time interval the pres-
ence of moderate pruritus (one in C, two in HYD).
Two patients delivered without the need for a re-
dose (both in C group; P = not significant). The inci-
dence of Cesarean delivery was not significantly
different between the groups (six in C; nine in HYD);
none of the patients required a Cesarean delivery
before the need for a re-dose. One patient had an acci-
dental dural puncture; no patient, in either group,
developed symptoms of a PDPH.
During the study period, motor block, as reflected
by the Bromage score, was absent (score of 0) in all
patients. Seventeen patients (39%) ambulated at least

Parker et al.: EPIDURAL HYDROMORPHONE AND LABOUR
603
side effects and efficacy with hydromorphone 600 µg
vs morphine 3 mg. One-third of patients in the HYD
600 µg group received iv diphenhydramine to treat
pruritus.10 With this current study we were reluctant
to increase the hydromorphone dose above 300 µg
risking the increase in side effects.
In treating patients with ambulatory epidural injec-
tions, we prefer the epidural opioid technique, rather
than the combined spinal epidural (CSE) technique,
because the former avoids an added step, the expense
of a CSE needle, and the necessity of an intentional
dural puncture.1–6 The accidental dural puncture rate
using the epidural technique has been reported to be
0.69–4.2%.11,12 We had one accidental dural puncture
in our study of 44 patients (with epidural catheters
placed by residents in a teaching institution).
FIGURE 2 Kaplan-Meier plot of the percent of patients in each
group who continued to remain comfortable.
When epidural fentanyl (50 µg) is combined with
clonidine (120 µg) the mean duration of analgesia was
80 min.13 In a study comparing CSE with epidural
fentanyl (100 µg in 10 mL volume) the mean duration
of analgesia with epidural fentanyl was 83 min.14 In a
study utilizing 40 µg epidural fentanyl with 20 mL
0.08% bupivacaine, the analgesic duration was shown
to be 91 24 min.15 These times are significantly less
than the analgesia in our previous studies of epidural
opioids,1–4 as well as in the current study (135–145
min). However, Breen et al.’s study population
included both primigravidous and multigravidous
patients.14 Any study only evaluating primigravidous
patients in early labour (and excluding multigravidous
patients) probably results in patient groups with
longer labour and is the probable reason for the
longer and more consistent duration of analgesia in
our studies. The analgesic duration in both groups in
the current study is consistent with that of epidural
fentanyl or sufentanil when utilized for labour pain
management.1–4 Whether the hydromorphone result-
ed in no effect due to a change in the intensity of pain
as labour progressed (such that opioid alone is inade-
quate), or that the analgesic duration of hydromor-
phone in labour is not significantly different than that
of fentanyl, remains unclear. A study of postCesarean
delivery pain found no difference between epidural
morphine 3 mg and hydromorphone 600 µg.10 While
postCesarean delivery pain and labour pain cannot be
equated, these results leave a question unanswered.
Namely, whether 300 µg hydromorphone is adequate
to demonstrate the prolonged duration we had
hypothesized. Further studies should include a dose-
response analysis.
once during their labour (ten in C, seven in HYD).
Apgar scores at birth were comparable between
groups.
Discussion
Epidural analgesia allowing ambulation during labour
is increasingly popular, in part because of the per-
ceived importance of preservation of motor power. We
have successfully utilized epidural opioids following a
lidocaine-epinephrine test dose to provide satisfactory
analgesia without a significant motor block.1–6
The current study compared 100 µg of fentanyl
after a lidocaine and epinephrine test dose in primi-
gravid patients with and without concomitant hydro-
morphone (300 µg). The goal of the hydromorphone
was to prolong the duration of analgesia. We did not
find any prolongation of analgesia by the addition of
hydromorphone. While the average height was 5 cm
taller in the HYD group, it is unlikely that this affect-
ed the findings of this study. We chose the dose of
hydromorphone for this study by extrapolation from
postCesarean delivery data in which patients used an
average of 300–400 µg of epidural hydromorphone
per four-hour period when utilizing patient-controlled
epidural analgesia.8,9 Use of a higher dose (e.g., > 500
µg) may have improved the analgesia. However, use of
large epidural hydromorphone doses (900 µg) has
been associated with significant side effects including
nausea, vomiting, pruritus, and urinary retention,
without causing an improvement in analgesia when
compared to a lower dose (300 µg)8. An additional
study in postCesarean patients demonstrated similar
Use of a lidocaine and epinephrine test dose has
been implicated in a decreased ability for parturients
to ambulate.16 However, all patients in Cohen’s study

604
CANADIAN JOURNAL OF ANESTHESIA
Saunders, 1978: 144.
received an initial 12 mL epidural bolus of bupivacaine
(0.0625% or 0.125%) in addition to the lidocaine-epi-
nephrine test dose. Epidural 0.1% bupivacaine with
sufentanil, as part of a patient-controlled epidural
analgesia technique, results in detectable motor block
in approximately 20% of patients.17 Our use of epidur-
al opioid after a test dose, without the use of adjuvant
local anesthetic, does not result in significant motor
block.1–6 We believe that when sufficient opioid is uti-
lized initially, an initial bolus of local anesthesia is
avoided, and ambulation can be achieved without
eliminating the test dose. Although the usefulness of
the test dose has been challenged recently,16 we
believe that it does improve the ability to detect
intravascular and intrathecal catheter placement.
We have demonstrated satisfactory results with
epidural fentanyl after a lidocaine and epinephrine test
dose for the management of labouring patients.
Adding hydromorphone 300 µg does not prolong the
analgesic duration. When performing an ambulatory
epidural in early labour, after a lidocaine and epineph-
rine test dose, we found no advantage in adding
hydromorphone 300 µg to fentanyl.
8 Parker RK, White PF. Epidural patient-controlled anal-
gesia: an alternative to intravenous patient- controlled
analgesia for pain relief after cesarean delivery. Anesth
Analg 1992; 75: 245–51.
9 Parker RK, Sawaki Y, White PF. Epidural patient-con-
trolled analgesia: influence of bupivacaine and hydro-
morphone basal infusion on pain control after cesarean
delivery. Anesth Analg 1992; 75: 740–6.
10 Halpern SH, Arellano R, Preston R, et al. Epidural
morphine vs hydromorphone in post-Caesarean section
patients. Can J Anaesth 1996; 43: 595–8.
11 Norris MC, Grieco WM, Borkowski M, et al.
Complications of labor analgesia: epidural versus com-
bined spinal epidural techniques. Anesth Analg 1994;
79: 529–37.
12 Gleeson CM, Reynolds F. Accidental dural puncture
rates in UK practice. International Journal of Obstetric
Anesthesia 1998; 7: 242–6.
13 Buggy DJ, MacDowell C. Extradural analgesia with
clonidine and fentanyl compared with 0.25% bupiva-
caine in the first stage of labour. Br J Anaesth 1996;
76: 319–21.
14 Breen TW, Giesinger CM, Halpern SH. Comparison of
epidural lidocaine and fentanyl to intrathecal sufentanil
for analgesia in early labour. International Journal of
Obstetric Anesthesia 1999; 8: 226–30.
Acknowledgement
The authors appreciate the secretarial assistance of Ms.
Lynda Paglia.
15 Campbell DC, Zwack RM, Crone LAL, Yip RW.
Ambulatory labor epidural analgesia: bupivacaine ver-
sus ropivacaine. Anesth Analg 2000; 90: 1384–9.
16 Cohen SE, Yeh JY, Riley ET, Vogel TM. Walking with
labor epidural analgesia. The impact of bupivacaine
concentration and a lidocaine-epinephrine test dose.
Anesthesiology 2000; 92: 387–92.
17 Fischer C, Blanié P, Jaouën E, Vayssière C, Kaloul I,
Coltat JC. Ropivacaine, 0.1%, plus sufentanil, 0.5
µg/ml, versus bupivacaine, 0.1%, plus sufentanil, 0.5
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