Intrathecal fentanyl as adjunct to hyperbaric bupivacaine in spinal anesthesia for caesarean section.

Objective: To compare the effect of adding fentanyl to intrathecal bupivacaine on the onset, duration and quality of spinal anesthesia and its effect of mother and neonate.

Design: Single blind randomized controlled clinical trial.

Place And Duration Of Study: Department of Anesthesiology, Surgical Intensive Care Unit and Pain Management, Dow University of Health Sciences and Civil Hospital, Karachi, from January 2003 to June 2004.

Patients And Methods: Sixty young adult females, ASA physical status I and II, with singleton pregnancy undergoing elective or emergency cesarean section under spinal anesthesia were randomly allocated to receive spinal anesthesia either by using 0.75% hyperbaric bupivacaine 1.5 ml with 0.25 ml normal saline or 0.75% hyperbaric bupivacaine 1.5 ml with 0.25 ml fentanyl (12.5 microg). Blood pressure, heart rate, respiratory rate, oxygen saturation, sensory level, motor block, pain score and side effects were observed every 2 minutes for first 20 minutes, then at-5 minute interval throughout the surgery, thereafter at 30 minutes interval until the patient complained of pain.

Results: Comparing the bupivacaine group, time to achieve highest sensory level was significantly shorter in fentanyl group (*p < 0.05), while the duration of complete analgesia (time from injection to first report of pain) lasted significantly more longer in fentanyl group (184+/-20 minutes) than bupivacaine group (126+/-10 minutes). Duration of effective analgesia was also significantly more prolonged in fentanyl group (p < 0.05). There was no significant difference in the incidence of side effects between the two groups.

Conclusion: Addition of fentanyl to intrathecal bupivacaine results in faster onset with improved peri-operative anesthesia without increasing the side effects.