Comparison of the hemodynamic effects of ropivacaine versus bupivacaine for elective cesarean delivery under combined spinal–epidural anesthesia: a randomized controlled trial

BACKGROUND: Women with term pregnancies undergoing cesarean delivery under combined spinal and epidural anesthesia (CSEA) usually present with hemodynamic variability and a high incidence of hypotension. Among the commonly used anesthetic drugs for CSEA, ropivacaine reduces the incidence of hypotension compared with bupivacaine. However, most studies have focused on blood pressure and heart rate measurements to evaluate the effects of these two anesthetic drugs on parturients. This study aimed to compare maternal cardiac output and hemodynamic parameters, such as cardiac preload and afterload, of ropivacaine and bupivacaine using transthoracic echocardiography. METHODS: Eighty-two parturients scheduled for elective caesarean deliveries under CSEA anesthesia were randomly assigned to receive 0.5% bupivacaine 7.5-8.5 mg (n = 41) or 0.5% ropivacaine 11-12.5 mg (n = 41) with different medication doses used for different height-ranges. Cardiac output, stroke volume (SV), ejection fraction, end-diastolic volume, end-diastolic volume, and systemic vascular resistance (SVR) were measured using transthoracic echocardiography before anesthesia; at 1, 5, and 10 min after CSEA; at delivery; and 1-2 min after the oxytocin administration. The primary outcome was the change in cardiac output (CO) at 5 min. Secondary outcomes included maternal hemodynamic, anesthetic efficacy, maternal side effects and fetal outcome data. RESULTS: Normalized cardiac output was higher in the ropivacaine group at 5 min after CSEA (92.7%; 95% confidence interval (CI): 87.1-98.3%) than in the bupivacaine group (79.8%; 95% CI: 74.2-85.3%) (P = 0.001). CO, SV, end-diastolic volume, and blood pressure were greater, systemic vascular resistance and phenylephrine dosage were lower, and the incidence of bradycardia was lower in the ropivacaine group. The 1-minute Apgar score was higher in the ropivacaine group (P = 0.043). Other neonatal outcomes were similar between the groups. CONCLUSIONS: Compared to bupivacaine, ropivacaine demonstrated higher cardiac output (CO), stroke volume (SV), blood pressure, and an improved 1-minute neonatal Apgar score in elective cesarean deliveries under combined spinal-epidural anesthesia (CSEA). TRIAL REGISTRATION: Registration number: ChiCTR220006454. Date of registration: October 11, 2022.