Spinal anaesthesia with minidose of bupivacaine - Fentanyl for cesarean section in preeclamptic parturients

Abstract

Background: Spinal anaesthesia for cesarean section is associated with the high incidence of hypotension. The synergism between intrathecal opioids and local anesthetics may make it possible to achieve reliable spinal anaesthesia with minimal hypotension using a minidose of local anesthetic. Methods: This prospective study was performed from February 2005 to August 2005 on Fourty four preeclamptic parturients undergoing cesarean section in Alzahra Hospital of Tabriz Medical Science University .Patients randomized into two groups of 22 patients. Group A undergone spinal anesthetic with bupivacaine 6mg plus fentanyl 20 ?g and Group B with 12 mg bupivacaine. Hypotension was defined as a 30% decrease in systolic and diastolic pressure from baseline and was treated with intravenous ephedrine boluses 2/5-5 mg up to maximum 50mg. Results: All patients had sufficient anaesthesia. 5 of 22 patients in group A required, a single dose of ephedrine(5mg). 17 of 22 patients in group B required vasopressor support of blood pressure. The lowest recorded systolic, diastolic and mean blood pressures as fractions of the baseline pressures were, respectively, 71.2%, 64.5% and 70.3% versus 59.9%, 53.5% and 60.2% for group A versus group B. Conclusion: A "minidose" of 6mg bupivacaine in combination with 20 ?g fentanyl provides sufficient spinal anaesthesia for cesarean section in the preeclamptic patients. The minidose combination caused significantly less hypotension than 12 mg bupivacaine and almost eliminated the need for vasopressor support of blood pressure.