Median effective dose of cisatracurium priming accelerating onset of neuromuscular block in patients of different genders / 中华麻醉学杂志

ABSTRACT

Objective To investigate the median effective dose (ED50) of cisatracurium priming accelerating the onset of neuromuscular block in patients of different genders. Methods Ninety ASA Ⅰ or Ⅱ patients aged 18-55 yr undergoing elective abdominal operation under general anesthesia were divided into 2 groups ( n = 45 each) male group (group M) and female group (group F). Neuromuscular block was monitored with accelerograph F (TOF-Watch SX). A single twitch stimulation of ulnar nerve was used to monitor neuromuscular function.Anesthesia was induced with midazolam 0.04 mg/kg and fentanyl 1 μg/kg. Accelerograph F was opened after the patients lost consciousness. The priming dose of cisatracurium was injected intravenously, then fentanyl 5 μg/kg and propofol 2 mg/kg were injected intravenously 3 min later and the left dose of cisatracurium for intubation was injected intravenously 4 min later. Tracheal intubation was performed when the ratio of the single twitch stimulation value to control value (T/Tc). decreased to 10%. Anesthesia was maintained with iv infusion of propofol and remifentanil and inhalation of isoflurane. The priming dose of cisatracurium was determined by up-and-down sequential trial. The initial priming dose was set at 5 μg/kg. The ratio of two successive doses was 1.2. T/Tc, time to 90% block, onset time, maximal neuromuscular block and clinical duration were recorded 4 min after the administration of the priming dose. The ED50 and 95% confidence interval (CI) of cisatracurium priming required to accelerate the onset were caculated. Results Time to 90% block was significantly longer-in group M than in group F (P ＜0.05). No significant difference was found in the other parameters among the groups. The ED50 and 95% CI of cisatracurium priming required to accelerate the onset were 21.36 μg/kg (95% CI 20.52-22.23 μg/kg)in group M and 14.53 μg/kg (95% CI 13.77-15.33 μg/kg) in group F. The ED50 was significantly higher in group M than in group F ( P ＜ 0.05). Conclusion The ED50 of cisatracurium priming accelerating thd onset is 21.36 and 14.53 μg/kg in male and female respectively and it is significantly higher in male than in female.