Subarachnoid fentanyl augments lidocaine spinal anesthesia for cesarean delivery

Fentanyl at doses of 6.25 microgram or more, when to hyperbaric bupivacaine for spinal anesthesia for cesarean delivery, has been reported to markedly increase the duration of analgesia. In this study, subarachnoid fentanyl 15 micrograms was evaluated as the sole adjunct to hyperbaric lidocaine spinal anesthesia in parturients undergoing cesarean delivery at term, to determine its effect on the duration of analgesia and side effects perioperatively.

Twenty-eight parturients scheduled for elective cesarean delivery at term were randomized to one of two groups in a prospective, double-blind fashion. Patients in group F received 15 micrograms fentanyl in addition to 80 mg hyperbaric lidocaine for subarachnoid anesthesia, while patients in group N received 0.3 mL normal saline in addition to 80 mg hyperbaric lidocaine. Visual analog pain scores were recorded preoperatively and at regular intervals until the first patient request for additional analgesia. The occurrence of side effects (nausea, vomiting, pruritus, shivering) was recorded at intervals for 4 hours postinduction. All patients received patient-controlled analgesia after delivery, and analgesic requirements for 24 hours postinduction were recorded.

There was no difference between groups with respect to visual analog pain scores intraoperatively. The mean duration of effective analgesia was increased in the patients receiving fentanyl from 71 minutes to 101 minutes (Student's t-test, P < .01). No difference was observed between groups with regard to 4-hour or 24-hour analgesic requirements. Patients in group F were significantly less likely to experience nausea (Fisher's exact test, P < .05) and vomiting (chi-square test, P < .05) in the immediate perioperative period, but no differences were noted between groups in the incidence of pruritus or shivering.

The addition of fentanyl 15 micrograms to hyperbaric lidocaine for subarachnoid anesthesia for cesarean delivery increases the duration of effective analgesia by approximately 30 minutes compared to plain hyperbaric lidocaine, and provides a protective effect regarding nausea and vomiting in the perioperative period.