脑电双频指数与镇静-躁动评分评价机械通气患者镇静程度可靠性的比较研究

Comparison of reliability of bispectral index and sedation-agitation scale in assessing the depth of sedation in patients treated with mechanical ventilation

目的探讨脑电双频指数(BIS)评价重症监护室(ICU)危重患者镇静程度的可靠性。方法选择18～65岁、无意识障碍、需持续机械通气(>72h)患者15例。患者入ICU3d7:00停用所有镇痛及镇静剂,待患者完全清醒后静脉泵入异丙酚至BIS目标值为45～60,维持10min后,每间隔10min减少异丙酚泵入量10μg·kg-1·min-1至停止药物泵入。于达到镇静目标以及每次减药后测定BIS值以及镇静躁动评分(SAS)分级。结果BIS值与SAS分级具有良好的相关性(r=0.6494,P<0.01)。但SAS分级在2～4级时,BIS值分布离散度高,相关系数下降(r=0.4566,P<0.01)。随着异丙酚泵入量的逐渐减少,BIS值逐步升高,两者呈现显著的线性负相关(r=0.8076,P<0.01);SAS分级亦显著上升,两者呈现等级负相关(r=0.6551,P<0.01)。结论SAS分级与BIS值在评价ICU机械通气患者镇静程度时存在良好相关性。但在SAS2～4级镇静状态时,BIS能更准确、客观地反映患者镇静程度。

Objective To compare the reliability of bispectral index （BIS） with sedation agitation scale （SAS） in assessing the depth of sedation in ill patients on mechanical ventilation in intensive care unit （ICU）. Methods Fifteen patients, aged 18 - 65 years old, who were receiving mechanical ventilation in ICU for longer than 72 hours and without brain dysfunction, were enrolled in this study. Sedatives and analgesics were suspended at 7：00 am. When patients fully woke up, propofol was infused till BIS score reaching 45- 60. This was maintained for 10 minutes, then propofol dosage was decreased 10μg· kg^-1·min^-1 for every 10 minutes till all the drug was stopped. BIS was consecutively monitored and SAS was assessed in each interval. Results BIS score was markedly correlated with SAS （r=-0. 649 4, P〈0. 01）. Although a significant correlation was still shown （r=-0. 456 6, P〈0.01）, there was wide variability in BIS scores when SAS reached 2 - 4. With decreasing of the propofol dosage, BIS score gradually increased. There was a satisfactory negative correlation between BIS scores and propofol dosage （r= - 0. 8076, P〈0.0l ）. SAS increased also following the decrease in propofol dosage, and a significant negative correlation was shown between SAS and the dosage of propofol （r=- 0. 6551, P〈0.01）. Conclusion SAS is well correlated with BIS in assessing the depth of sedation in patients treated with mechanical ventilation in ICU. BIS is an objective, efficient tool for monitoring the depth of sedation in ICU critical patients who are receiving mechanical ventilation, and it is more reliable than SAS, especially when sedated levels reaching SAS 2 - 4.