Hemodynamic effects of simultaneous administration of intravenous ephedrine and spinal anesthesia for cesarean delivery

Study Objective: To evaluate the hemodynamic effects of an intravenous (IV) ephedrine bolus given simultaneously with spinal anesthesia for cesarean d elivery. Design: Randomized, prospective double-blind study. Setting: Tertiary-care academic medical center. Patients: 40 ASA physical status I and II nonlaboring women undergoing elec tive cesarean delivery of term, uncomplicated, singleton pregnancies. Interventions: After a 10 mL/kg IV lactated Ringers bolus given over 15 min utes, patients simultaneously received an IV dose of 2 mL (10 mg) ephedrine or 2 mL saline, and an intrathecal close of 12 mg (1.6 mL 0.75%) bupivacai ne with 10 mu g of fentanyl. Hypotension, defined as a 20% decrease in mean arterial pressure (MAP) was treated with 10-mg IV doses of ephedrine. Measurements: Hemodynamic (heart rate and MAP) and non-invasive thoracic im pedance (cardiac index, stroke index, and systemic vascular resistance inde x) measurements at baseline and at 1-minute intervals until the time of del ivery. Total fluid, supplemental ephedrine, and Apgar scores were recorded. Data were evaluated using analysis of variance (ANOVA), ANOVA for repeated measures, and Mannn-Whitney U-tests where appropriate, with P < 0.05 consi dered significant. Main Results: Significant changes from baseline in MAP, systemic vascular r esistance index, heart rate, and cardiac index were observed in both groups after spinal anesthesia. However, there were no differences between the ep hedrine and saline groups in the incidence and severity of change from the baseline. The overall incidence of hypotension was 70% in both groups. No d ifference in total fluid or supplemental ephedrine use was observed. Conclusions: 10 mg of IV ephedrine given at the time of spinal anesthesia, and after a 10 mL/kg lactated Ringers fluid bolus, does not diminish the in cidence or severity of hypotension in parturients undergoing cesarean deliv ery. (C) 2000 by Elsevier Science Inc.