不同剂量右美托咪定对上腹部手术病人七氟烷呼气末有效浓度的影响

目的观察在脑电双频谱指数(BIS)监测下持续静脉输注不同剂量右美托咪定对上腹部手术病人七氟烷最低肺泡有效浓度的影响。方法 60例择期上腹部手术病人随机分成3组:D1和D2组在麻醉诱导前,分别在10 min内静脉输注右美托咪定0.4,0.8μg.kg-1;而D0组给予相同容量的生理盐水。麻醉诱导后,D0组单纯吸入七氟烷维持麻醉;而D1、D2组吸入七氟烷的同时,分别持续静脉输注右美托咪定0.4,0.8μg.kg-1.h-1。术中根据BIS值的变化调节七氟烷吸入浓度,维持BIS值在45～55。距术毕30 min停止右美托咪定的输注,缝合皮肤前关闭七氟烷挥发灌。结果 D0、D1和D2组术中七氟烷呼气末有效浓度分别为(1.7±0.4)%,(1.4±0.2)%和(1.0±0.2)%,D1和D2组较D0组分别降低17.7%和42.6%,其中D2组血流动力学更稳定。结论复合应用右美托咪定可以明显降低上腹部手术病人七氟烷的呼气末有效浓度,减少七氟烷用量,且对稳定血流动力学更有效。

Effects of different doses of dexmedetomidine on end - tidal sevoflurance concentration in patients undergoing elective upper abdominal

Objective To investigate the effects of different doses of dexmedetomidine on end-tidal sevoflurance concentration in patients undergoing elective upper abdominal.MethodsSixty ASA ⅠorⅡ patients undergoing elective upper abdominal surgery under general anesthesia were randomly allocated to one of three groups with 20 patients in each group:0.4,0.8 μg·kg-1 of dexmedetomidine was administered by intravenous infusion in Dl group and D2 group,respectively,and the same volume of physiological saline was infused in D0 group within 10 minutes before anesthesia induction.Intubation anesthesia was maintained with sevoflurance inhalation alone(D0 group) or sevoflurance combined with dexmedetomidine by 0.4 or 0.8 μg·kg-1·h-1 infusion(D1,D2 groups).Bispectral index(BIS) was maintained at 45~55 after tracheal intubation during maintenance of anesthesia.ResultsWhen BIS was maintained at 45~55,the end-tidal sevoflurance concentration was(1.7±0.4)%(D0 group),(1.4±0.2)%(D1 group) and(1.0±0.2)%(D2 group),respectively.Heart rate and arterial pressure were more stable in group D2 than those of two other groups.ConclusionAt the same depth of anesthesia,the end-tidal sevoflurance concentration was greatly reduced when combined with dexmedetomidine,and 0.8 μg·kg-1·h-1 dexmedetomidine combined with sevoflurance has little influence on patients’ hemodynamic condition.