地氟醚、异氟醚对老年患者维库溴铵肌松效应的影响

Effects of desflurane and isoflurane on the vecuronium-induced neuromuscular block in the elderly patients

目的 观察吸入等效浓度地氟醚、异氟醚对老年患者维库溴铵肌松效应的影响。方法 30例ASA Ⅰ～Ⅱ级老年患者分为3组,均吸入N2O:O2(50％:50％),其中Des组和lso组分别吸入等效浓度地氟醚(6％)和异氟醚(1.15％),对照组为无吸入组。麻醉诱导用咪达唑仑、异丙酚和芬太尼。所有患者经颈内静脉注入总量为40 μg/kg的维库溴铵。用丹麦产TOF GUARD加速度仪进行肌松监测。维库溴铵40μg/kg分为4等份分次静注,记录每次注药(10μg/kg)后的起效时间及最大阻滞效应。用累积剂量法建立3组患者的剂量反应曲线。在最后一次注药后记录:T1恢复到25％、75％、90％的时间(T225％、T175％、T190％);TOF比值恢复到70％的时间以及恢复指数。结果 与对照组(Con)相比,Des组和Iso组维库溴铵ED50,和ED95值均明显缩小(P<0.05),且Des组比Iso组的缩小更明显(P<0.05)。3组的起效时间差异均无显著性(P>0.05)。两个吸入麻醉药组的T125％、T175％和T190％明显长于对照组(P<0.05),且Des组又明显高于Iso组(P<0.05)。两个吸入麻醉药组的TOF比值恢复到70％的时间和恢复指数RI均明显高于对照组(P<0.05),但在两个吸入麻醉药组之间差异无显著性(P>0.05)。结论地氟醚、异氟醚均能明显影响老年患者维库溴铵的肌松效应,地氟醚的影响大于异氟醚。

Objective The study was designed to compare the effects of desflurane and isoflurane on the vecuronium-induced neuromuscular block in the elderly patients. Methods Thirty ASA class I - II elderly patients aged over 70 yr undergoing elective surgery under general anesthesia were randomly divided into 3 groups: desflurane group ( I , n = 10) ; isoflurane group ( II , n = 10) and 3 control group ( III , n = 10). Anesthesia was induced with midazolam 0.02-0.05 mg· kg-1 , propofol 0.5-2.0 mg · kg-1 and fentanyl 2-5μg· kg-1 maintained with inhalation of 6% desflurane(1 MAC) +50% N2O in oxygen (group I ) or 1.15% isoflurane + 50% N2O in oxygen(group II ) or 50% N2O in oxygen (group III ) supplemented with intermittent iv boluses of propofol and fentanyl when necessary. Neuromuscular block was monitored using accelograph (TOF GUARD , Denmark) .A total dose of vecuronium 40 mg ·kg-1 was divided with 4 equal doses of 10μg · kg-1 , 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) .The cumulative dose-response curves of the 3 groups were established. The onset time and maximum depression of T1 of the initial dose and 3 incremental doses were recorded. After the last increment of 10 μg·kg-1, the time for T1 to returned to 25% ,75% ,90% and TOF ratio(T4/T1) to 70% were recorded. The recovery index was also calculated.Results The demographic data were comparable between the 3 groups. The ED50 and ED95 were significantly lower in desflurane and isoflurane groups than those in control group(P < 0.05) .There was no significant difference in the onset time between the 3 groups ( P > 0.05 ) . The time for T1 to return to 25 % , 75 % and 90 % was significantly longer in desflurane and isoflurane group than that in the control group. The recovery from vecuronium-induced neuromuscular block was slower in desflurane group than that in isoflurane group( P < 0.05). But there was no significant difference in the TOF ratio and recovery index between desflurane and isoflurane groups. Conclusions Both desflurane and isoflurane significantly potentiate the neuromuscular block induced by vecuronium and desflurane causes greater potentiation than equipotent isoflurane.