Sackey P V, Radell P J, Granath F, Martling C R
Department of Anaesthesiology and Intensive Care Medicine, Karolinska University Hospital Solna, 171 76 Stockholm, Sweden.
Anaesth Intensive Care. 2007 Jun;35(3):348-56. doi: 10.1177/0310057X0703500305.
Bispectral index (BIS) is used for monitoring anaesthetic depth with inhaled anaesthetic agents in the operating room but has not been evaluated as a monitor of sedation depth in the intensive care unit (ICU) setting with these agents. If BIS could predict sedation depth in ICU patients, patient disturbances could be reduced and oversedation avoided. Twenty ventilator-dependent ICU patients aged 27 to 80 years were randomised to sedation with isoflurane via the AnaConDa or intravenous midazolam. BIS (A-2000 XP, version 3.12), electromyogram activity (EMG) and Signal Quality Index were measured continuously. Hourly clinical evaluation of sedation depth according to Bloomsbury Sedation Score (Bloomsbury) was performed. The median BIS value during a 10-minute interval prior to the clinical evaluation at the bedside was compared with Bloomsbury. Nurses performing the clinical sedation scoring were blinded to the BIS values. End-tidal isoflurane concentration was measured and compared with Bloomsbury. Correlation was poor between BIS and Bloomsbury in both groups (Spearman's rho 0.012 in the isoflurane group and -0.057 in the midazolam group). Strong correlation was found between BIS and EMG (Spearman's rho 0.74). Significant correlation was found between end-tidal isoflurane concentration and Bloomsbury (Spearman's rho 0.47). In conclusion, BIS XP does not reliably predict sedation depth as measured by clinical evaluation in non-paralysed ICU patients sedated with isoflurane or midazolam. EMG contributes significantly to BIS values in isoflurane or midazolam sedated, non-paralysed ICU patients. End-tidal isoflurane concentration appeared to be a better indicator of clinical sedation depth than BIS.
脑电双频指数（BIS）用于手术室中监测吸入麻醉剂的麻醉深度，但尚未在重症监护病房（ICU）环境中作为这些药物镇静深度的监测指标进行评估。如果BIS能够预测ICU患者的镇静深度，那么患者的躁动可能会减少，过度镇静也可避免。20名年龄在27至80岁之间、依赖呼吸机的ICU患者被随机分为两组，一组通过AnaConDa使用异氟烷进行镇静，另一组静脉注射咪达唑仑。持续测量BIS（A - 2000 XP，版本3.12）、肌电图活动（EMG）和信号质量指数。根据布卢姆斯伯里镇静评分（Bloomsbury）每小时进行一次临床镇静深度评估。将床边临床评估前10分钟间隔内的BIS中位数与Bloomsbury评分进行比较。进行临床镇静评分的护士对BIS值不知情。测量呼气末异氟烷浓度并与Bloomsbury评分进行比较。两组中BIS与Bloomsbury之间的相关性均较差（异氟烷组的斯皮尔曼等级相关系数为0.012，咪达唑仑组为 - 0.057）。发现BIS与EMG之间存在强相关性（斯皮尔曼等级相关系数为0.74）。呼气末异氟烷浓度与Bloomsbury之间存在显著相关性（斯皮尔曼等级相关系数为0.47）。总之，对于使用异氟烷或咪达唑仑镇静的非瘫痪ICU患者，通过临床评估测量，BIS XP不能可靠地预测镇静深度。在使用异氟烷或咪达唑仑镇静的非瘫痪ICU患者中，EMG对BIS值有显著影响。呼气末异氟烷浓度似乎比BIS更能准确反映临床镇静深度。
