Effective volume of 1.5％ lidocaine for obturator nerve block in 50％ of patients undergoing transurethral resection of bladder tumor / 中华麻醉学杂志

ABSTRACT

Objective To determine the effective volume of 1.5％ lidocaine for obturator nerve block (ONB) in 50％ of patients (EV50) undergoing transurethral resection of bladder tumor (TURBT).Methods Thirty-six ASA physical status Ⅰ or Ⅱ patients with bladder tumor,aged 18-64 yr,with body mass index of 19-30 kg/m2,scheduled for elective TURBT and required ONB before TURBT,were enrolled in the study.ONB was performed with 1.5 ％ lidocaine using the pubic approach under the guidance of a nerve stimulator.The volume of 1.5％ lidocaine was determined by up-and-down sequential trial.The initial volume of hdocaine was 10 ml and the ratio between the two successive volumes was 1.1.Successful ONB was considered to be positive response.The EV50 and 95 ％ confidence interval (CI) of 1.5 ％ lidocaine for ONB were calculated.Results The EV50 of 1.5 ％ lidocaine for ONB was 5.53 rnl and the 95 ％ CI was 5.10-6.00 ml.Conclusion The EV50 of 1.5 ％ lidocaine is 5.53 ml when used for ONB in patients undergoing TURBT.