Programmed Intermittent Epidural Bolus Versus
Continuous Epidural Infusion for Labor Analgesia:
The Effects on Maternal Motor Function and Labor
Outcome. A Randomized Double-Blind Study in
Nulliparous Women
Giorgio Capogna, MD, Michela Camorcia, MD, Silvia Stirparo, MD, and Alessio Farcomeni, PhD
BACKGROUND: Programmed intermittent epidural anesthetic bolus (PIEB) technique may result
in reduced total local anesthetic consumption, fewer manual boluses, and greater patient
satisfaction compared with continuous epidural infusion (CEI). In this randomized, double-blind
study, we compared the incidence of motor block and labor outcome in women who received PIEB
or CEI for maintenance of labor analgesia. The primary outcome variable was maternal motor
function and the secondary outcome was mode of delivery.
METHODS: Nulliparous, term women with spontaneous labor and cervical dilation 4 cm were
eligible to participate in the study. Epidural analgesia was initiated and maintained with a
solution of levobupivacaine 0.0625% with sufentanil 0.5 g/mL. After an initial epidural loading
dose of 20 mL, patients were randomly assigned to receive PIEB (10 mL every hour beginning 60
minutes after the initial dose) or CEI (10 mL/h, beginning immediately after the initial dose) for
the maintenance of analgesia. Patient-controlled epidural analgesia (PCEA) using a second
infusion pump with levobupivacaine 0.125% was used to treat breakthrough pain. The degree of
motor block was assessed in both lower extremities using the modified Bromage score at regular
intervals throughout labor; the end point was any motor block in either limb. We also evaluated
PCEA bolus doses and total analgesic solution consumption.
RESULTS: We studied 145 subjects (PIEB = 75; CEI = 70). Motor block was reported in 37% in
the CEI group and in 2.7% in the PIEB group (P 0.001; odds ratio = 21.2; 95% CI: 4.9 –129.3);
it occurred earlier (P = 0.008) (hazard ratio = 7.8; 95% CI: 1.9 –30.8; P = 0.003) and was more
frequent at full cervical dilation in the CEI group (P 0.001). The incidence of instrumental
delivery was 20% for the CEI group and 7% for the PIEB group (P = 0.03). Total levobupivacaine
consumption, number of patients requiring additional PCEA boluses, and mean number of PCEA
boluses per patient were lower in the PIEB group (P 0.001). No differences in pain scores and
duration of labor analgesia were observed.
CONCLUSIONS: Maintenance of epidural analgesia with PIEB compared with CEI resulted in a
lower incidence of maternal motor block and instrumental vaginal delivery. (Anesth Analg 2011;
X:●●●–●●●)
N
euraxial analgesic techniques, such as epidural
and combined spinal-epidural (CSE) analgesia, are
the most effective modalities for pain relief in
labor. Once analgesia has been established, either by using
an epidural or a CSE technique, the maintenance of anal-
gesia throughout labor until delivery may be obtained with
different techniques. With intermittent epidural bolus in-
jection (top-up) of the analgesic solution, frequent provider
interventions are required, and the parturient may experi-
ence intervals of analgesia after the dose takes effect
alternating with intervals of pain as the analgesia wanes.
Continuous infusion results in a smoother analgesic expe-
rience for the parturient with fewer medical interventions,
but total anesthetic doses are usually larger and motor
block may be more profound.
1
There is some evidence from
anatomical and in vitro studies
2,3
that uniform diffusion of
local anesthetic in the epidural space, which leads to
greater efficacy, is better obtained by the administration of
bolus rather that continuous infusion.
Automated systems designed to administer a bolus at
programmable intervals (programmed intermittent epidu-
ral anesthetic bolus [PIEB] technique) to combine the
advantages of both manual bolus and continuous infusion,
have recently been introduced. Wong et al.
4
compared PIEB
versus continuous epidural infusion (CEI) in induced
parous women. They reported less total local anesthetic
consumption, fewer manual bolus doses because of break-
through pain, and greater patient satisfaction with the PIEB
technique. In their study, they noticed that the beneficial
effect of PIEB was significant in women with longer labors,
and therefore, they hypothesized that PIEB would be of
greater value in parturients with longer labors such as
spontaneously laboring nulliparous women.
Other studies have confirmed these findings in nulliparous
women.
4–6
Previous studies have used either an epidural or
From the Department of Anesthesia, Citta ` di Roma Hospital, Rome, Italy.
Accepted for publication May 25, 2011.
The authors declare no conflicts of interest.
Reprints will not be available from the authors.
Address correspondence to Giorgio Capogna, MD, Department of Anesthe-
sia, Citta ` di Roma Hospital, Via Maidalchini 20, 00151 Roma, Italy. Address
e-mail to dipartimento.anestesia@gruppogarofalo.com.
Copyright © 2011 International Anesthesia Research Society
DOI: 10.1213/ANE.0b013e31822827b8
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XXX 2011 • Volume X • Number X www.anesthesia-analgesia.org 1
DOI: 10.1213/ANE.0b013e31822827b8