Median Effective Dose Of Sufentanil For Spinal Anesthesia When Combined With Ropivacaine In Patients Undergoing Labor Analgesia

Objective To determine the median effective dose(ED₅₀)of sufentanil for spinal anesthesia when combined with ropivacaine in patients undergoing labor analgesia.Method Thirty-Two ASA ? or ? parturients;Aged20-35 yr,undergoing labor analgesia under combined spinal-epidural anesthesia,were enrolled in this study.Combined spinal-epidural anesthesia was performed at L2,3 interspace.The mixture of sufentanil and3 mg ropivacine was injected into the subarachnoid space over 20 s. The initial dose of sufentanil was 3?g.The dose was increased by 0.5?g in the next patient.The ED₅₀ and 95% confidence interval were calculated by probit method.Result The ED₅₀ of sufentanil was 1.110?g?95%confidence interval0.763-1.392?g?.conclusion When combined with ropivacaine 3 mg,the ED₅₀ of sufentanil for spinal anesthesia is 1.110?g in patients undergoing labor analgesia.