Dose-response relationship of levobupivacaine for spinal anesthesia in patients undergoing cesarean section / 中华麻醉学杂志

ABSTRACT

Objective To investigate the dose-respeuse relationship of levobupivacaine for spinal anesthesia in patients undergoing cesarean section.Methods Sixty ASA Ⅰ or Ⅱ patients aged 25-35 yr weighing 60-90 kg scheduled for elective cesarean section under spinal anesthesia were enrolled in this study.Spinal puncture was performed at the L3,4 interspace.A 25 G spinal needle was inserted into the subarachnoid space cephalad.The patients were randomized to receive levobupivacaine 7.5 mg (group L1 ),10 mg (group L2),12.5 mg (group L3) or 15 mg (group L4) diluted to 3 ml with 5% glucose over 30 s (n = 15 each).The degree of pain was evaluated at the time of skin incision using visual analogue scales (VAS) (0 = no pain and 10 = worse pain ever).Effective analgesia was defined as VAS = 0.Spinal analgesia was inadequate when VAS≥1 and then 1% lidocaine 5-10 ml was given epidurally.The doses of levobupivacaine for effective analgesia in 50% and 95% of patients ( ED50 and ED95 ) and 95 % confidence interval were calculated by Probit method.Results The ED50 of levobupivacaine was 9.0 mg (95% confidence interval 7.8-9.9 mg) and ED95 13.2 mg (95% confidence interval 11.6-17.6 mg) for spinal anesthesia.Conclusion The ED50 and ED95 of levobupivacaine for spinal anesthesia in patients undergoing cesarean section are 9.0 mg and 13.2 mg respectively.