脑电双频指数在老年患者靶控输注异丙酚麻醉中的价值

Bispectral index in monitoring and evaluating induction of anesthesia with target-controlled infusion of propofol in elderly patients

目的评价脑电双频指数(bispectral index,BIS)在靶控输注异丙酚麻醉诱导过程中预测老年患者麻醉深度的精确程度。方法40例年龄60～80岁老年全麻手术患者,美国麻醉医师协会(American Society of Anesthesiologists,ASA)Ⅰ～Ⅱ级,靶控输注异丙酚诱导,最初血浆靶浓度设置在0.5μg/L,每隔5 min增加0.5μg/L,直至改良清醒镇静(modified observer′s assessment of alertness/sedation,MOAA/S)评分为0后5 min停止。试验中监测患者BIS、平均动脉压(mean arterial pressure,MAP)、心率(heart rate,HR)、MOAA/S评分、靶控输注系统预测血浆部位浓度值。结果(1)BIS值随MOAA/S评分下降而下降,在MOAA/S评分为0～1、1～2、3～4、4～5时BIS值下降均有统计学意义(P<0.05)。MAP在MOAA/S评分3～2时下降有统计学意义(P<0.05)。HR在各级MOAA/S评分时差异无统计学意义(P>0.05)。(2)BIS、MAP、HR与MOAA/S评分的等级相关系数分别为0.929、0.421、0.085。BIS、MAP、HR在区分不同MOAA/S评分时的预测概率(prediction probability,Pk)分别为0.94、0.67、0.54。(3)BIS与异丙酚靶控输注预测效应部位浓度存在线性回归关系(决定系数r2=0.833,P<0.01)。结论在老年患者靶控输注异丙酚平稳麻醉诱导状态下,BIS能够准确地区分清醒和麻醉后的不同意识水平,可靠地预测麻醉深度。

Objective To evaIuate the accuracy of bispectral （BIS） as an indicator of anesthesia depth in the elderly patients in induction of anesthesia with target controlled infusion of propofol. Methods Forty ASA （American Society of Anesthesiologists） Ⅰ-Ⅱ patients scheduled for an operation under general anesthesia were anesthetized with target-controlled infusion of propofol. Target plasma concentration was 0.5μg/L at the beginning,and increased by 0.5μg/L every 5 rain,till 5 min after the level of- MOAA/S （modified observer＇s assessment of alertness/sedation ） was 0. BIS, mean arterial pressure （MAP）, heart rate （ HR ）, MOAA/S level,and the effect-site concentration of propofol were recorded. Results （1） BIS values declined with the decrease of MOAA/S levels. BSI values were statistically different between level 0 and 1 ,level 1 and 2,level 3 and 4,level 4 and 5 of MOAA/ S （P〈0.05）. The difference of MAP had statistical significance between level 3 and level 2 of MOAA/S （ P〈0.05 ）. HR values had no statistical difference between the two levels ofMOAA/S （P〉0.05）. （2）The spearman rank correlation co-efficients between BIS,MAP,HR and the level of MOAA/S were 0. 929,0. 421 ,and 0. 085,respectively. The prediction probabilities （ Pk ） to differ- entiate different levels ofMOAA/S forBIS, MAP, and HR were 0.94,0.67, and 0.54, respectively. （3）There was linear regression relationship between BIS and the effect-site concentration of propofol （ the coefficient of determination R2 was 0. 833, P〈0.01）. Conclusion During the induction of the elderly patients with target-controlled infusion of propofol,the BIS is accurate as an indicator of awakeness and different levels of consciousness after anesthesia,and can reliably predict the anesthesia depth.