Zhu-Heng Wang1, Han Chen, Yan-Lin Yang, Zhong-Hua Shi, Qing-Hua Guo, Yu-Wei Li, Li-Ping Sun, Wei Qiao, Guan-Hua Zhou, Rong-Guo Yu, Kai Yin, Xuan He, Ming Xu, Laurent J Brochard, Jian-Xin Zhou. 1. 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.
Abstract
BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: Combining baseline and stimulated BIS may help detect deep sedation in mechanically ventilated patients.
BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: Combining baseline and stimulated BIS may help detect deep sedation in mechanically ventilated patients.
Authors: Nicholas West; Paul B McBeth; Sonia M Brodie; Klaske van Heusden; Sarah Sunderland; Guy A Dumont; Donald E G Griesdale; J Mark Ansermino; Matthias Görges Journal: J Clin Monit Comput Date: 2018-02-20 Impact factor: 2.502