Comparative evaluation of subarachnoid block with conventional dose Bupivacaine versus low dose Bupivacaine and Fentanyl for Caesarean Section - A RCT study

Abstract

Background: Subarachnoid block (SAB) is the preferred anesthetic technique for elective caesarean deliveries. Local anaesthesia (LA) dose is the main determinant of its success. Anesthesia textbooks recommend bupivacaine in a dose of 11 to 15 mg; this is associated with incidence of maternal arterial hypotension resulting in maternal and neonatal morbidity. The goal of present study was to compare the intraoperative hemodynamics and vasopressors requirement using a low dose bupivacaine-fentanyl (5mg bupivacaine + 25 mcg fentanyl) in combined spinal epidural technique (CSE) to a conventional dose of spinal bupivacaine (11mg) for parturient undergoing cesarean section.

Methods: A prospective, randomized controlled trial enrolled sixty patients, who scheduled for elective caesarean sections and were randomized in two equal groups to receive either low dose in CSE (Study group) or conventional dose via SAB (Control group). MAP, pulse rate, requirement of Inj. ephedrine, time of onset of analgesia, highest level of SAB, requirement of additional IV analgesic, APGAR scores, conversion to GA and bromage score were noted.

Results: Demographic variables and baseline parameters were comparable. Incidence of intraoperative hypotension in study and control group was 7 and 25 respectively with P-value 0.0001. Mean intra-operative ephedrine required for hypotension in study and control group was 7 and 11.14 mg respectively with P-value 0.1331.

Conclusion: Low dose bupivacaine-fentanyl spinal anesthetic in CSE technique had lesser incidence of hypotension and lower requirement of vasopressors compared to conventional dose of spinal bupivacaine. It also had quicker onset of action.