老年人脑电双频指数、异丙酚血药浓度与镇静深度的相关性

目的：探讨老年手术患者椎管内麻醉后应用异丙酚镇静,脑电双频指数、异丙酚血药浓度和镇静深度之间的相关性。方法：48例ASAⅠ-Ⅱ级择期手术患者,分为老年组（65-85岁）和年轻组（18-40岁）,每组24例。为尽快达到稳态血药浓度,采用靶控输注方式给药。异丙酚靶浓度从0.5μg/mL起逐渐增加,直至患者对轻推无反应（意识消失）,每个浓度维持5min。连续记录EEG参数,在每一稳态血药浓度末,记录BIS、95%SEF,桡动脉取血（高效液相色谱法测定异丙酚血药浓度）,并评定镇静深度（OAA/S评分法）。用Spearman’s等级相关进行相关分析,并计算预测概率（Pk）值。结果：两组BIS（r=0.935-0.955）与镇静水平的相关性优于血药浓度（r=-0.849-0.870）和95%SEF（r=0.503-0.571）,BIS的Pk值高（0.942-0.972）。在同一镇静评分（OAA/S 41）时,老年组BIS值明显高于年轻组（P〈0.01）,而血药浓度低于年轻组（P〉0.05）。结论：BIS在监测异丙酚镇静水平及预测意识消失方面有重要价值,在同一镇静评分时,老年人BIS值高于年轻人。

Study for the Correlation Among Bispectral Index and Blood Propofol Concentration with Level of Sedation in the Elderly

Objective：To determine the relationship of bispectral index（BIS） and blood propofol concentration with levels of sedation in elderly patients during operation under intrathecal anesthesia.Methods：Forty-eight ASAⅠ-Ⅱ patients scheduled for elective surgery on lower abdomen or lower extremities under epidural or combined spinal-epidural anesthesia were studied.There were two groups of 24 patients each：the elderly group（65-85yr）,and the young group（18-40yr）.The target-controlled infusion（TCI） was used to achieve a rapid induction and maintenance of a target blood concentration of propofol.Blood concentration of propofol was started from 0.5 ug /mL and gradually increased until loss of consciousness.Each concentration was maintained for 5min.BIS and 95%SEF were continuously monitored and recorded at the end of each blood concentration.At each concentration arterial blood samples were obtained for determination of propofol concentration by high performance liquid chromatography,and the level...更多 of consciousness or sedation was evaluated using the observer＇s assessment of alertness/sedation scale（OAA/S）.The BIS and the measured propofol concentration were correlated with the OAA/S score using nonparametric Spearman＇s rank-correlation analysis.The prediction probability（Pk） was also calculated.Results：The BIS correlated with OAA/S score better in both groups（r=0.935-0.955） than the measured propofol concentration（r=-0.849-0.870） and 95% SEF（r=0.503-0.571）.The Pk for BIS ranged from 0.942-0.972,indicating a very high performance for correctly predicting probability of unconsciousness.The elderly group exhibited higher BIS values and lower plasma propofol concentration than the young group at the same OAA/S score（4-1）.Conclusion：BIS appears to be a valuable monitoring of the level of sedation and loss of consciousness in both the elderly and young,but the elderly has higher BIS values than the young at the same sedation score.