Epidural anesthesia for cesarean section. The effect of morphine-bupivacaine administered epidurally for intra and postoperative pain relief.

Abstract

Two groups of mothers who underwent elective cesarean section under epidural analgesia, were studied with the aim of comparing the analgesic potency and side effects of two solutions: morphine-bupivacaine and morphine-saline. Each group comprised 100 patients. The intraoperative anesthesia was established with bupivacaine plain, 5 mg/ml, in amount 85-125 mg. Immediately after the infant was delivered, the mothers received a single epidural dose of 3 mg of preservative-free morphine chloride mixed with either 5 ml of 0.25% bupivacaine (Group I) or 0.9% saline (Group II). The intraoperative observations showed "good effect" without need for supplementation of analgesia in 82 mothers in Group I, compared with 61 mothers in Group II (p less than 0.001). The postoperative observations showed that 82 mothers in Group I were satisfied with a single dose of morphine for more than 24 hours, while in Group II the corresponding number was 63 (p less than 0.01). A significant difference in the incidence of nausea and vomiting was found between the groups; 7 of the mothers experienced nausea and 4 vomited in Group I and 17 experienced nausea and 13 vomited in Group II (p less than 0.05, for both variables). Respiratory depression was seen in one mother during surgery immediately after supplementation of morphine-bupivacaine analgesia with ketamine. Other side effects, such as itching, bradycardia and Horner's triad were rare. It may be concluded that a single epidural dose of morphine in bupivacaine will augment intraoperative analgesia and prolong postoperative analgesia. Less favorable results were obtained when morphine in saline was used. Synergism between bupivacaine and morphine is suggested.