Epidural analgesia with 4 mg of morphine following caesarean section: effect of injected volume

Abstract
The efficacy and side effects of epidural bolus injection of 4 mg of morphine in a volume of 2 ml, 10 ml, or 20 ml (groups I, II and III) for postoperative analgesia after caesarean section (60 patients) were evaluated. All patients had epidural anaesthesia established up to T4 level with 0.5% bupivacaine 18-20 ml, supplemented with 2% lidocaine with adrenaline, when necessary. Morphine 4 mg in either of the three volumes was injected through the epidural catheter in random order after delivery of the baby. Six patients in each group reported no pain during the 24-h follow-up period. No additional pain medication during the 24 h after surgery was required in 11, 14 and 10 patients in groups I, II and III, respectively. Most of the others managed with the addition of a single dose of rectal ketoprofen. There were no differences in analgesic therapy between the groups. Pruritus was the most common adverse effect (18/20, 19/20 and 18/20 in groups I, II and III, respectively). 10/20, 12/20 and 14/20 (N.S.) patients had nausea and vomiting in groups I, II and III, respectively. Metoclopramide, prescribed for persistent nausea, was given to 4/20 patients in group I, 6/20 patients in group II and 9/20 patients in group III (N.S.). After removal of the urinary catheter 7/20 patient in group III required carbachol for urinary retention compared to 3/20 and 4/20 patients in groups I and II (N.S.).(ABSTRACT TRUNCATED AT 250 WORDS)