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

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.

Single blind randomized controlled clinical trial.

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.

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.

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.

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