ABSTRACT
Objective To investigate the difference of neuromuscular blocking effect of cis-atracurium under sevoflurane anesthesia between the genders. Methods 30 ASA Ⅰ or Ⅱ patients aged from 18 to 45 years who scheduled for laparoscopic operation were divided into two groups, male group( M group, n = 15 ) and female group ( F group,n = 15). After induction of Anesthesia all cases were maintained with remifentanyl 3μg/L(TCI) and sevoflurane.After 40 minutes of stable end-tidal anaesthetic concentration, a total dose of cisatracurium 45 μg/kg was divided into 3 equal doses( 15μ g/kg each) ,which was administered accumulatively in each patient. The next dose was given when the effect of the previous dose had reached its peak ( T1 was no longer depressed in the height of 3 successive stimuli).Neuromuscular block was monitored using accelograph(TOF GUARD,Denmark). The onset time and maximum depression of T1 of the initial dose and 2 incremental doses were recorded. The cumulative dose-response curves of the two groups were established. The effective dose to obtain 50% and 95% neuromuscular block( ED5o and ED95 ,respectively) were calculated from individual dose-response curves. After the lastincrement of 15 μg/kg, the time for T1 to return to 25% ,50% ,75% and TOF ratio(T4/T1 )to 70% were recorded. The recovery index( RI)was also calculated.Results The mean ED5o and ED95(95% confidence interval)of cisatracurium of women were 22.2( 15.8 ～27.2)and 38.4 ( 32.1 ～ 54.4) μg/kg during sevoflurane (1.3MAC) anaesthesia, while the data of men were 25.6 ( 19.7 ～30.8) μg/kg and 42.8 ( 36.3 ～ 58.2 ) μg/kg, the difference between groups had no statistical significance ( P ＞0. 05). There was no significant difference in the TOF ratio ( T4/T1 ) to 70% and recovery index between the two groups( P ＞0.05 ). The onset time of F group was shorter than M group. The time for T1 to return to 25% ,50% and TOFR 0.7 was significantly longer in the F group than in the M group (P ＜ 0.05). Conclusion The neuromuscular blocking effect of cis-atracurium under 1.3MAC sevoflurane anesthesia remained no difference between genders. But the onset time of women was much faster. Furthermore the effect on the time for T1 to return to 25% ,50% and TOFR 0.7 were greater than men.