Minimum effective dose of intrathecal bupivacaine in combination with sulfentanil for caesarean section

Abstract

Objective To determine the minimum dose of intrathecal bupivacaine in combination with sulfentanil for caesarean section with sequential experimental method.Methods Thirty cases with a singleton full-term pregnancy for caesarean section and under combined spinal-epidural anesthesia (CSEA) were enrolled in this study.Spinal puncture was performed at the L3-4 interspace.Patients were injected intrathecally with sulfentanil 5.0 μ g and bupivacaine.The minimum local analgesic dose was determined by up-and-down sequential experiment.The initial dose of the spinal bupivacaine was decided to be 7.5 mg.If succeeded,the next case would receive bupivacaine of a lower dose if failed,the dose of bupivacaine would be increased in the next case.The dose of spinal bupivacaine increased / decreased by 0.5 mg each time.The clinical efficacy was assessed by the motor block of the lower limb,the block height,and the duration of block.If Bromage scale were Ⅲ since anesthesia was induced after 10 min and the maximum plane of sensory block was maintained at T6 since anesthesia was induced after 60 min were defined as a success.Result The minimum local analgesic dose of intrathecal bupivacaine in combination with sulfentanil 5.0 μ g for caesarean section was 5.12 mg (95％ confidence interval 7.8～9.9 mg).Conclusion Determining by sequential experiment method,the minimum local analgesic dose of intrathecal bupivacaine in combination with sulfentanil 5.0 μ g for caesarean section is 5.12 mg. Key words: Bupivacaine; Sulfentanil; Anesthesia; Spine; Caesarean section; Minimum efective-dose