Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia
Changes in Alpha Frequency and Power of the Electroencephalogram during Volatile-Based General Anesthesia
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DOI：
10.3389/fnsys.2017.00036
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发表时间：
2017-05-29
影响因子：
3
通讯作者：
Sleigh, Jamie
中科院分区：
文献类型：
--
作者：
Hight, Darren;Voss, Logan J.;Sleigh, Jamie
脑电图（EEG）中α频率（8 - 12Hz）的振荡被认为在手术麻醉期间普遍存在，但这种振荡如何对挥发性麻醉剂浓度的持续变化作出反应的细节尚未得到很好的描述。在临床环境中α振荡缺失的频率如何，α频率和功率对麻醉剂浓度变化的敏感程度如何，以及年龄增长对α频率有何影响，这些都尚不明确。对305名接受七氟烷或地氟烷全身麻醉手术的患者进行了额叶双极脑电图记录。开发了一种基于α范围内峰值频率变化率的稳定性来检测α振荡存在的新方法。拟合线性浓度 - 反应曲线以评估α功率和频率指标对麻醉水平变化的敏感性。约4%的患者中莫名其妙地未出现α振荡。在一半患者中，最大α功率随挥发性麻醉剂浓度的增加而增加，在其余患者中则降低。近90%的患者中，α频率随麻醉剂浓度的增加而降低。年龄增长与对挥发性麻醉剂浓度的敏感性降低以及α频率降低有关，α频率有时会转变为θ范围（5 - 7Hz）。虽然α峰值频率随着挥发性麻醉剂浓度的增加呈现出一致的减慢，但振荡的峰值功率却并非如此，这表明在挥发性麻醉剂麻醉期间，频率可能比传统的基于功率的指标更能反映麻醉深度。即使考虑到老年患者对麻醉剂需求的降低，α振荡也会随着年龄的增长而变慢。
Oscillations in the electroencephalogram (EEG) at the alpha frequency (8-12 Hz) are thought to be ubiquitous during surgical anesthesia, but the details of how this oscillation responds to ongoing changes in volatile anesthetic concentration have not been well characterized. It is not known how often alpha oscillations are absent in the clinical context, how sensitively alpha frequency and power respond to changes in anesthetic concentration, and what effect increased age has on alpha frequency. Bipolar EEG was recorded frontally from 305 patients undergoing surgery with sevoflurane or desflurane providing general anesthesia. A new method of detecting the presence of alpha oscillations based on the stability of the rate of change of the peak frequency in the alpha range was developed. Linear concentration-response curves were fitted to assess the sensitivity of alpha power and frequency measures to changing levels of anesthesia. Alpha oscillations were seen to be inexplicably absent in around 4% of patients. Maximal alpha power increased with increasing volatile anesthetic concentrations in half of the patients, and decreased in the remaining patients. Alpha frequency decreased with increasing anesthetic concentrations in near to 90% of patients. Increasing age was associated with decreased sensitivity to volatile anesthesia concentrations, and with decreased alpha frequency, which sometimes transitioned into the theta range (5-7 Hz). While peak alpha frequency shows a consistent slowing to increasing volatile concentrations, the peak power of the oscillation does not, suggesting that frequency might be more informative of depth of anesthesia than traditional power based measures during volatile-based anesthesia. The alpha oscillation becomes slower with increasing age, even when the decreased anesthetic needs of older patients were taken into account.