Median effective dose of ciprofol inhibiting responses to insertion of laryngeal mask airway when combined with alfentanil / 中华麻醉学杂志

ABSTRACT

Objective:To determine the median effective dose (ED 50) of ciprofol inhibiting responses to insertion of laryngeal mask airway in the patients when combined with alfentanil. Methods:American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ patients of either sex, aged 40-64 yr, with body mass index of 20-30 kg/m 2, undergoing elective general anesthesia, were enrolled. Midazolam 0.025 mg/kg was intravenously injected for anesthesia induction, the baseline mean arterial pressure and heart rate were recorded 5 min later, and the average value of three times was considered as the baseline value. Ciprofol and alfentanil 10 μg/kg were intravenously injected in sequence, rocuronium 0.6 mg/kg was intravenously injected when BIS value < 60, 2 min later a laryngeal mask airway was placed, and mechanical ventilation was performed. Positive response was defined as increase in the maximum mean arterial blood pressure or heart rate more than or equal to 20% of the baseline value within 3 min after placement of the laryngeal mask airway or as the occurrence of body movement, bucking, frowning, mouth and face twitching, tearing, laryngospasm or the BIS value failing to drop below 60. The study was performed by the Dixon′s up-and-down method. The initial dose of ciprofol was 0.4 mg/kg, and the ratio between the two successive doses was 1.1. If a positive response occurred, the dose was increased in the next patient, otherwise the dose was reduced. The ED 50 and 95% confidence interval of ciprofol inhibiting responses to insertion of laryngeal mask airway were calculated by the probit method. Results:The ED 50(95% confidence interval) of ciprofol inhibiting responses to insertion of laryngeal mask airway was 0.291(0.231-0.318) mg/kg when combined with alfentanil 10 μg/kg. Conclusions:The ED 50 of ciprofol inhibiting responses to insertion of laryngeal mask airway is 0.291 mg/kg in the patients when combined with alfentanil 10 μg/kg.