Shanks Amy M, Avidan Michael S, Kheterpal Sachin, Tremper Kevin K, Vandervest John C, Cavanaugh John M, Mashour George A
From the Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan (AMS, SK, KKT, JCV, GAM), Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (MSA) and Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA (JMC).
Eur J Anaesthesiol. 2015 May;32(5):346-53. doi: 10.1097/EJA.0000000000000123.
Intraoperative awareness with explicit recall is a potentially devastating complication of surgery that has been attributed to low anaesthetic concentrations in the vast majority of cases. Past studies have proposed the determination of an adequate dose for general anaesthetics that could be used to alert providers of potentially insufficient anaesthesia. However, there have been no systematic analyses of appropriate thresholds to develop population-based alerting algorithms for preventing intraoperative awareness.
To identify a threshold for intraoperative alerting that could be applied for the prevention of awareness with explicit recall.
Secondary analysis of a randomised controlled trial (Michigan Awareness Control Study).
Three hospitals at a tertiary care centre in the USA.
Unselected patients presenting for surgery under general anaesthesia.
Alerts based on end-tidal anaesthetic concentration or bispectral index values.
Using case and outcomes data from the primary study, end-tidal anaesthetic concentration and bispectral index values were analysed using Youden's index and c-statistics derived from a receiver operating characteristic curve to determine a specific alerting threshold for the prevention of awareness.
No single population-based threshold that maximises sensitivity and specificity could be identified for the prevention of intraoperative awareness, using either anaesthetic concentration or bispectral index values. The c-statistic for anaesthetic concentration was 0.431 ± 0.046, and 0.491 ± 0.056 for bispectral index values.
We could not derive a single population-based alerting threshold for the prevention of intraoperative awareness using either anaesthetic concentration or bispectral index values. These data indicate a need to move towards individualised alerting strategies in the prevention of intraoperative awareness.
Primary trial registration (Michigan Awareness Control Study) ClinicalTrials.gov identifier: NCT00689091.
术中知晓并伴有明确回忆是一种潜在的严重手术并发症，在绝大多数情况下，这被归因于麻醉浓度过低。过去的研究提出要确定一种适用于全身麻醉的合适剂量，以提醒医护人员可能存在麻醉不足的情况。然而，尚未有系统分析来确定适当的阈值，以开发基于人群的警报算法来预防术中知晓。
确定一个术中警报阈值，可用于预防伴有明确回忆的术中知晓。
对一项随机对照试验（密歇根术中知晓控制研究）进行二次分析。
美国一家三级医疗中心的三家医院。
接受全身麻醉手术的未经过筛选的患者。
基于呼气末麻醉浓度或脑电双频指数值发出警报。
利用原始研究中的病例和结局数据，使用约登指数和从受试者工作特征曲线得出的c统计量，分析呼气末麻醉浓度和脑电双频指数值，以确定预防术中知晓的特定警报阈值。
无论是使用麻醉浓度还是脑电双频指数值，均无法确定一个能使敏感性和特异性最大化的基于人群的单一阈值来预防术中知晓。麻醉浓度的c统计量为0.431±0.046，脑电双频指数值的c统计量为0.491±0.056。
我们无法得出一个基于人群的单一警报阈值，无论是使用麻醉浓度还是脑电双频指数值来预防术中知晓。这些数据表明，在预防术中知晓方面，需要转向个体化的警报策略。
原始试验注册（密歇根术中知晓控制研究）ClinicalTrials.gov标识符：NCT00689091。
