Minidose Bupivacaine – Fentanyl Spinal Anesthesia for Cesarean Section In Preeclamptic Parturients

Background:Spinal anesthesia for cesarean section is associated with a high incidence of hypotension. The synergism between intrathecal opioids and local anesthetics may make it possible to achieve reliable spinal anesthesia with minimal hypotension using a minidose of local anesthetic. Methods: Forty-four preeclamptic parturients undergoing cesarean section were randomized in two groups of 22 patients. Group A received a spinal anesthetic of bupivacaine 6 mg plus fentanyl 20 µg , and group B received 12 mg bupivacaine. Hypotension was defined as a 30% decrease in systolic and diastolic pressure from baseline. Hypotension was treated with intravenous ephedrine boluses 2.5-5 mg up to maximum 50 mg. Results: All patients had satisfactory anesthesia. Five of 22 patients in group A required ephedrine, a single dose of 5 mg. Seventeen 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 71.2%, 64.5% and 70.3% versus 59.9%, 53.5% and 60.2% respectively for group A versus group B. Conclusion: A “minidose” of 6 mg bupivacaine in combination with 20 µg fentanyl may provide satisfactory spinal anesthesia for cesarean section in the preeclamptic patient. The minidose combination caused dramatically less hypotension than 12 mg bupivacaine and nearly eliminated the need for vasopressor support of blood pressure.