Median effective dose of dezocine inhibiting responses to insertion of laryngeal mask airway when combined with propofol in elderly patients / 中华麻醉学杂志

ABSTRACT

Objective To determine the median effective dose(ED50)of dezocine inhibiting re-sponses to insertion of laryngeal mask airway(LMA)when combined with propofol in the elderly pa-tients.Methods American Society of Anesthesiologists physical statusⅠorⅡ patients, aged 66-75 yr, with body mass index of 20-25 kg∕m2, were included in this study.Anesthesia was induced with dezocine at the initial dose of 0.2 mg∕kg and propofol which was simultaneously administered by target-controlled infu-sion.The initial target plasma concentration of propofol was 1 μg∕ml, and the concentration was increased in increments of 0.5 μg∕ml every 3 min until the target concentration 3 μg∕ml was achieved.LMA was inserted when bispectral index value reached 50-60.The dose of dezocine was determined using the up-and-down method.The response to insertion of LMA was defined as positive when patients developed coughing, laryn-gospasm and∕or body movement during insertion or within 3 min after insertion.The dose of dezocine was in-creased∕decreased in the next patient if the insertion response was positive or negative.The ratio between the two successive doses was 0.8.The ED50and 95% confidence interval of dezocine inhibiting responses to in-sertion of LMA were calculated.Results When combined with propofol, the ED50of dezocine inhibiting re-sponses to insertion of LMA was 0.126 mg∕kg, and the 95% confidence interval was 0.110-0.143 mg∕kg.Conclusion The ED50of dezocine inhibiting responses to insertion of LMA is 0.126 mg∕kg when combined with propofol in the elderly patients.