ED 50 and ED 95 of Intrathecal Bupivacaine Coadministered with Sufentanil for Cesarean Delivery Under Combined Spinal-epidural in Severely Preeclamptic Patients

Abstract

Background: Spinal anesthesia was considered as a reasonable anesthetic option in severe preeclampsia when cesarean delivery is indicated, and there is no indwelling epidural catheter or contraindication to spinal anesthesia. However, the ideal dose of intrathecal bupivacaine has not been quantified for cesarean delivery for severe preeclamptic patients. This study aimed to determine the ED 50 and ED 95 of intrathecal bupivacaine for severely preeclamptic patients undergoing elective cesarean delivery. Methods: Two hundred severely preeclamptic patients are undergoing elective cesarean delivery under combined spinal-epidural anesthesia enrolled in this randomized, double-blinded, dose-ranging study. Patients received 4 mg, 6 mg, 8 mg, or 10 mg intrathecal hyperbaric bupivacaine with 2.5 μg sufentanil. Successful spinal anesthesia was defined as a T6 sensory level achieved within 10 minutes after intrathecal drug administration and/or no epidural supplement was required during the cesarean section. The ED 50 and ED 95 were calculated with a logistic regression model. Results: ED 50 and ED 95 of intrathecal bupivacaine for successful spinal anesthesia were 5.67 mg (95% confidence interval [CI]: 5.20-6.10 mg) and 8.82 mg (95% CI: 8.14-9.87 mg) respectively. The incidence of hypotension in Group 8 mg and Group 10 mg was higher than that in Group 4 mg and Group 6 mg (P 0.05). Conclusion: Our study showed that the ED 50 and ED 95 of intrathecal bupivacaine for severely preeclamptic patients undergoing elective cesarean delivery were 5.67 mg and 8.82 mg, respectively. In addition, decreasing the dose of intrathecal bupivacaine could reduce the incidence of maternal hypotension.

Keywords

• Bupivacaine; Cesarean Section; Dose-response; Severe Preeclampsia; Spinal