Wang Zhu-Heng, Chen Han, Yang Yan-Lin, Shi Zhong-Hua, Guo Qing-Hua, Li Yu-Wei, Sun Li-Ping, Qiao Wei, Zhou Guan-Hua, Yu Rong-Guo, Yin Kai, He Xuan, Xu Ming, Brochard Laurent J, Zhou Jian-Xin
From the *Department of Critical Care Medicine, Beijing Tiantan Hospital, and †Department of Critical Care Medicine, Daxing Teaching Hospital, Capital Medical University, Beijing, China; ‡Surgical Intensive Care Unit, Fujian Provincial Clinical College Hospital, Fujian Medical University, Fuzhou, Fujian, China; §Intensive Care Unit, Beijing Electric Power Hospital, Capital Medical University, Beijing, China; ‖Keenan Research Centre, St Michael's Hospital, Toronto, Canada; and ¶Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada.
Anesth Analg. 2017 Jul;125(1):176-183. doi: 10.1213/ANE.0000000000001786.
Excessively deep sedation is prevalent in mechanically ventilated patients and often considered suboptimal. We hypothesized that the bispectral index (BIS), a quantified electroencephalogram instrument, would accurately detect deep levels of sedation.
We prospectively enrolled 90 critically ill mechanically ventilated patients who were receiving sedation. The BIS was monitored for 24 hours and compared with the Richmond Agitation Sedation Scale (RASS) evaluated every 4 hours. Deep sedation was defined as a RASS of -3 to -5. Threshold values of baseline BIS (the lowest value before RASS assessment) and stimulated BIS (the highest value after standardized assessment) for detecting deep sedation were determined in a training set (45 patients, 262 RASS assessments). Diagnostic accuracy was then analyzed in a validation set (45 patients, 264 RASS assessments).
Deep sedation was only prescribed in 6 (6.7%) patients, but 76 patients (84.4%) had at least 1 episode of deep sedation. Thresholds for detecting deep sedation of 50 for baseline and 80 for stimulated BIS were identified, with respective areas under the receiver-operating characteristic curve of 0.771 (95% confidence interval, 0.714-0.828) and 0.805 (0.752-0.857). The sensitivity and specificity of baseline BIS were 94.0% and 66.5% and of stimulated BIS were 91.0% and 66.5%. When baseline and stimulated BIS were combined, the sensitivity, specificity, and clinical utility index were 85.0% (76.1%-91.1%), 85.9% (79.5%-90.7%), and 66.9% (57.8%-76.0%), respectively.
Combining baseline and stimulated BIS may help detect deep sedation in mechanically ventilated patients.
深度镇静在机械通气患者中普遍存在，且常被认为并非最佳状态。我们假设脑电双频指数（BIS）这一量化脑电图仪器能够准确检测出深度镇静状态。
我们前瞻性纳入了90例接受镇静治疗的重症机械通气患者。对BIS进行24小时监测，并与每4小时评估一次的里士满躁动镇静量表（RASS）进行比较。深度镇静定义为RASS评分为-3至-5。在一个训练集（45例患者，262次RASS评估）中确定用于检测深度镇静的基线BIS（RASS评估前的最低值）和刺激后BIS（标准化评估后的最高值）的阈值。然后在一个验证集（45例患者，264次RASS评估）中分析诊断准确性。
仅6例（6.7%）患者接受了深度镇静治疗，但76例患者（84.4%）至少有1次深度镇静发作。确定了检测深度镇静的基线BIS阈值为50，刺激后BIS阈值为80，其受试者操作特征曲线下面积分别为0.771（95%置信区间，0.714 - 0.828）和0.805（0.752 - 0.857）。基线BIS的敏感性和特异性分别为94.0%和66.5%，刺激后BIS的敏感性和特异性分别为91.0%和66.5%。当将基线BIS和刺激后BIS结合使用时，敏感性、特异性和临床效用指数分别为85.0%（76.1% - 91.1%）、85.9%（79.5% - 90.7%）和66.9%（57.8% - 76.0%）。
结合基线BIS和刺激后BIS可能有助于检测机械通气患者的深度镇静状态。
