Frontal alpha-delta EEG does not preclude volitional response during anaesthesia: prospective cohort study of the isolated forearm technique
Frontal alpha-delta EEG does not preclude volitional response during anaesthesia: prospective cohort study of the isolated forearm technique
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DOI：
10.1093/bja/aex170
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发表时间：
2017-10-01
影响因子：
9.8
通讯作者：
Sanders, R. D.
中科院分区：
文献类型：
--
作者：
Gaskell, A. L.;Hight, D. F.;Sanders, R. D.
背景：孤立前臂试验（IFT）是麻醉期间关联意识（对环境的感知）的金标准测试。额部α - δ脑电模式（见于慢波睡眠）被广泛认为可表明麻醉诱导的无意识状态。我们先验性地提出，一名出现额部α - δ脑电模式的有反应者将推翻这一概念。
方法：在参与一项气管插管后IFT反应性国际多中心研究的三个中心的部分患者中记录额部脑电图。对原始脑电图波形进行功率 - 频谱、麻醉深度指数、排列熵、慢波活动饱和度以及α - δ振幅 - 相位耦合分析。
结果：90名患者中有6名对口头指令有自主反应。在表现出α - δ占优势（δ功率>20分贝，α功率>10分贝）脑电图模式的患者（来自中心1和2）中，有3次反应在插管后立即发生。在这些反应期间获得的功率 - 频谱与这些中心的无反应者相似（P>0.05）。另外3次反应发生在（中心3）未表现出经典α - δ脑电图模式的患者中；这些反应相对于插管发生较晚，并且与中心1和2的患者相比，这些患者同时使用了氯胺酮且挥发性麻醉剂用量较少。所推导的麻醉深度指数均无法有效区分IFT有反应者和无反应者。
结论：在麻醉期间存在额部α - δ脑电图模式的情况下可能出现关联意识。额部脑电图参数不能轻易区分麻醉期间的自主反应性（关联意识的一个标志）和无反应性。
Background: The isolated forearm test (IFT) is the gold standard test of connected consciousness (awareness of the environment) during anaesthesia. The frontal alpha-delta EEG pattern (seen in slow wave sleep) is widely held to indicate anaesthetic-induced unconsciousness. A priori we proposed that one responder with the frontal alpha-delta EEG pattern would falsify this concept.Methods: Frontal EEG was recorded in a subset of patients from three centres participating in an international multicentre study of IFT responsiveness following tracheal intubation. Raw EEG waveforms were analysed for power-frequency spectra, depth-of-anaesthesia indices, permutation entropy, slow wave activity saturation and alpha-delta amplitude-phase coupling.Results: Volitional responses to verbal command occurred in six out of 90 patients. Three responses occurred immediately following intubation in patients (from Sites 1 and 2) exhibiting an alpha-delta dominant (delta power > 20 dB, alpha power > 10 dB) EEG pattern. The power-frequency spectra obtained during these responses were similar to those of non-responders (P > 0.05) at those sites. A further three responses occurred in (Site 3) patients not exhibiting the classic alpha-delta EEG pattern; these responses occurred later relative to intubation, and in patients had been co-administered ketamine and less volatile anaesthetic compared with Site 1 and 2 patients. None of the derived depth-of-anaesthesia indices could robustly discrimate IFT responders and non-responders.Conclusions: Connected consciousness can occur in the presence of the frontal alpha-delta EEG pattern during anaesthesia. Frontal EEG parameters do not readily discriminate volitional responsiveness (a marker of connected consciousness) and unresponsiveness during anaesthesia.