Bolus injection through an epidural
catheter may result in better distribution of
anesthetic solution in the epidural space compared with continuous infusion of the same
anesthetic solution. In this randomized, double-blind study we compared total
bupivacaine consumption, need for supplemental
epidural analgesia, quality of
analgesia, and patient satisfaction in women who received programmed intermittent epidural boluses (PIEB) compared with continuous epidural infusion (CEI) for maintenance of labor
analgesia. The primary outcome variable was
bupivacaine consumption per hour of
analgesia. Combined spinal
epidural analgesia was initiated in multiparas scheduled for
induction of labor with cervical dilation between 2 and 5 cm. Subjects were randomized to PIEB (6-mL bolus every 30 min beginning 45 min after the
intrathecal injection) or CEI (12-mL/h infusion beginning 15 min the after the
intrathecal injection). The
epidural analgesia solution was
bupivacaine 0.625 mg/mL and
fentanyl 2 microg/mL.
Breakthrough pain in both groups was treated initially with patient-controlled
epidural analgesia (PCEA) followed by manual bolus rescue
analgesia using
bupivacaine 0.125%. The median total
bupivacaine dose per hour of
analgesia was less in the PIEB (n = 63) (10.5 mg/h; 95% confidence interval, 9.5-11.8 mg/h) compared with the CEI group (n = 63) (12.3 mg/h; 95% confidence interval, 10.5-14.0 mg/h) (P < 0.01), fewer manual rescue boluses were required (rate difference 22%, 95% confidence interval of difference 5% to 38%), and satisfaction scores were higher.
Labor pain, PCEA requests, and delivered PCEA doses did not differ. PIEB combined with PCEA provided similar
analgesia, but with a smaller
bupivacaine dose and better patient satisfaction compared with CEI with PCEA for maintenance of epidural labor
analgesia.