50% and 95% effective doses of ropivacaine for subarachnoid block in severe preeclamptic patients undergoing cesarean section

Abstract

Objective To examine the ED50 and 95% effective dose(ED95) of ropivacaine for subarachnoid block in severe preeclamptic patients undergoing cesarean section. Methods This study enrolled 250 severe preeclamptic patients undergoing cesarean section. They were randomly divided into 5 groups respectively received 0, 7.5, 10.0, 12.5, 15.0 mg and 17.5 mg ropivacaine(n=50). The use of ropivacaine and phenylephrine, and patients' satisfaction, intraoperative complications, and the neonates' Apgar scores were documented. Results ED50 and ED95 of ropivacaine for successful subarachnoid block were 9.3 mg(95%CI: 8.6-9.9 mg) and 14.9 mg(95%CI: 13.7-16.9 mg) respectively. The sensory block was significantly different among groups 10 min after intrathecal injection(P 0.05). Conclusions Our study showed that the ED50 and ED95 of ropivacaine for subarachnoid block in severe preeclamptic patients undergoing elective cesarean delivery were 9.3 mg and 14.9 mg, respectively. Key words: Ropivacaine; Cesarean section; Severe preeclampsia; Subarachnoid block