Difference in rocuronium-induced muscle relaxation between patients of Buyi and Han nationality

Objective To determine whether there is any difference in rocuronium-induced muscle relaxation between patients of Buyi and Han nationality.Methods Sixty ASA Ⅰ or Ⅱ patients of both sexes aged 20-55 yr,with body mass index of 20-25 kg/m2,undergoing laparoscopic or arthroscopic surgery under general anesthesia,were divided into 2 groups ( n =30 each):Han group (group H) and Buyi group (group B).Anesthesia was induced with midazolam,fentanyl and TCI of propofol (Cp=2-3 μg/ml).Tracheal intubation was facilitated with rocuronium 0.6 mg/kg.The patients were mechanically ventilated.PETCO2 was maintained at 30-35 mm Hg.Neuro-muscular (N-M) function was monitored by accelerography.N-M block was assessed by single stimulation of ulna nerve after loss of consciousness.The onset time,maximal N-M block time,clinical muscle relaxation time (from injection d rocuronium to 25％ recovery),75％ recovery time (from injection of rocuronium to 75％ recovery) and recovery index were recorded.The plasma concentration of albumin and α1-acid glycoprotein were measured by ELISA and biochemical analysis respectively.Results The onset time was significantly longer and plasma α1-acid glycoprotein concentration lower in group B than in group H.There was no significant difference in maximal N-M block time,clinical muscle relaxation time,75％ recovery time,recovery index and plasma albumin concentration between the 2 groups.Conclusion The onset time of rocuronium-induced N-M block is longer in patients of Buyi nationality as compared with patients of Han nationality.Lower plasma α1 -acid.glycoprotein concentration may be involved in the underlying mechanism. Key words: Androstanols; Ethnic groups; Han nationality; Neuromuscular blockade