Epidural infusion of low dose bupivacaine after combined spinal-epidural anesthesia using needle through needle method provided no analgesic effect on postoperative pain after caesarian section

BACKGROUND: In order to evaluate the analgesic efficacy of low dose epidural bupivacaine infusion with and without morphine after caesarean section we performed combined spinal-epidural anesthesia (CSEA) using needle through needle method. Three different epidural analgesic regimens were compared retrospectively. METHODS: The number of analgesic use during 24 hours after operation was compared. Patients were categorized into three groups; group N : intraoperative bolus epidural morphine (2.5 mg) alone, group L : bolus morphine (2.5 mg) plus epidural bupivacaine infusion (32 ml of 0.2% bupivacaine) at a rate of 2.1 ml x hr(-1), group M : bolus morphine (2.4 mg) plus epidural bupivacaine-morphine (33 ml of 0.2% bupivacaine containing morphine 2.3 mg) infusion at a rate of 2.1 ml x hr(-1). Used analgesics included pentazocine 15 mg i.m., diclofenac 25 mg suppo. and loxoprofen 60 mg p.o.. RESULTS: The mean number of analgesic use during the first 24 hours in group M (0.29 +/- 0.46) was significantly smaller than those of group N (0.97 +/- 0.91) and group L (0.84 +/- 0.95). Percentage of patients requiring no analgesic during the first 24 hours was significantly less in group M (70.8%) than in group N (33.4%) and group L (42.1%). CONCLUSIONS: A 2.1 ml x hr(-1) infusion of epidural bupivacaine has no analgesic effect after caesarean section under CSEA using NTN method.