A Prospective Randomized Double Blind Comparative Study to Determine the Efficacy of Norepinephrine and Ephedrine to Maintain Arterial Blood Pressure During Spinal Anesthesia for Cesarean Delivery

Spinal Anesthesia Induced Hypotension(SAIH) continues to be the troublesome complication for obstetric patients undergoing cesarean section under subarachnoid block. Vasopressors are emerging as the cornerstone of treating SAIH in cesarean section patients with the evolving evidence of arterial vasodilatation as the primary cause of hypotension. This study was hypothesized to compare the efficacy of norepinephrine and ephedrine boluses to maintain hemodynamics in cesarean section.

After approval from institutional ethics committee and registration in Clinical Trials Registry India(CTRI ) and informed consent, study was conducted in 110 healthy parturients aged 18-40 years, belonging to ASA physical status I and II, posted for elective cesarean section under spinal anesthesia, were randomly allocated into group N(n=55) and group E(n=55),who received intravenous boluses of norepinephrine 6 g and ephedrine 10mg respectively as prophylaxis(one dose soon after induction) and in treatment of SAIH. The number of vasopressor boluses were recorded as primary objective and hemodynamics, APGAR scores, adverse events were noted.

The number of boluses of vasopressor used was 1.9±1.2 for Ephedrine and 4.72±2.9 for Norepinephrine. At 30,40,50 and 60 minutes after anesthesia, there was significant fall in mean arterial pressure in the norepinephrine group compared to ephedrine group. The incidence of tachycardia was more in ephedrine group and incidence of bradycardia was more in norepinephrine group.

Both the study drugs, ephedrine and norepinephrine are comparably effective in preventing SAIH after prophylactic bolus and effective in maintaining blood pressure intraoperatively, more number of boluses of norepinephrine was required compared to ephedrine.