[Hyperbaric bupivacaine: a randomized double-blind trial of different doses with or without fentanyl for cesarean section under spinal anesthesia]

To compare the effects of spinal anesthesia with different doses of hyperbaric bupivacaine with or without fentanyl in patients undergoing cesarean section.Prospective study enrolling 50 ASA 1-2 patients undergoing cesarean section, randomized to 5 treatment groups. Groups A, B, C, and D received 15 microg of fentanyl and group X received no fentanyl. The doses of hyperbaric bupivacaine given in each group were as follows: 10 mg in Group A, 11 mg in group B, 12 mg in group C, 13 mg in group D, and 14 mg in group X.Patients in groups A and B had greater hemodynamic stability than patients in groups C, D, or X (P0.05). The incidence of hypotension was 70% in group C and 80% in groups D and X. The sensory block reached level T4 in groups D and X and the motor block was complete in all cases. Postoperative analgesia lasted longer in group D with a mean (SD) duration of 202 (25) minutes than in group X with a mean duration of 194 (19) minutes. Assessment on a visual analog scale was under 3 in all groups except group A, where 2 patients required administration of propofol.Acceptable operative conditions with a low incidence of hypotension are provided with an 11 mg dose of hyperbaric bupivacaine.