Hagihira Satoshi, Takashina Masaki, Mori Takahiko, Ueyama Hiroshi, Mashimo Takashi
Department of Anesthesiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
Anesthesiology. 2004 Apr;100(4):818-25. doi: 10.1097/00000542-200404000-00011.
The authors previously reported changes in electroencephalographic bicoherence during isoflurane anesthesia combined with epidural anesthesia. Here, they examined the influence of noxious stimuli on electroencephalographic bicoherence as well as on the Bispectral Index (BIS) and the 95% spectral edge frequency (SEF95).
The authors enrolled 48 elective abdominal surgery patients (aged 22-77 years; American Society of Anesthesiologists physical status I or II). Raw electroencephalographic signals as well as BIS and SEF95 were recorded on a computer using a BIS monitor (A-1050) and Bispectrum Analyzer (BSA) for BIS (the authors' original software). Using BSA for BIS, the authors evaluated the two peak heights of electroencephalographic bicoherence. Anesthesia was induced with 3 mg/kg thiopental and was maintained with, in air-oxygen, 1.0% isoflurane or 1.5% sevoflurane. After confirming the steady state, the authors recorded baseline values. In experiment 1, they administered 3 microg/kg fentanyl 5 min after incision and investigated the changes in electroencephalographic derivatives at 5 and 10 min after incision. In experiment 2, they administered a similar dose of fentanyl 5 min before incision and investigated the changes in electroencephalographic derivatives immediately before and 5 min after incision.
In experiment 1, after incision, both peak heights of electroencephalographic bicoherence significantly decreased but returned to control values after fentanyl administration. By contrast, after incision, BIS and SEF95 showed individual variability. In experiment 2, although fentanyl itself did not affect all electroencephalographic derivatives before incision, the variables remained unchanged after incision.
Noxious stimuli decreased the peak heights of electroencephalographic bicoherence, an effect that was counteracted by fentanyl analgesia.
作者之前报道了异氟烷麻醉联合硬膜外麻醉期间脑电图双相干性的变化。在此，他们研究了有害刺激对脑电图双相干性以及脑电双频指数（BIS）和95%频谱边缘频率（SEF95）的影响。
作者纳入了48例择期腹部手术患者（年龄22 - 77岁；美国麻醉医师协会身体状况分级为I或II级）。使用BIS监测仪（A - 1050）和用于BIS的双谱分析仪（BSA，作者的原始软件）在计算机上记录原始脑电图信号以及BIS和SEF95。使用用于BIS的BSA，作者评估了脑电图双相干性的两个峰值高度。用3mg/kg硫喷妥钠诱导麻醉，并在空气 - 氧气中用1.0%异氟烷或1.5%七氟烷维持麻醉。确认达到稳态后，作者记录基线值。在实验1中，他们在切口后5分钟给予3μg/kg芬太尼，并研究切口后5分钟和10分钟时脑电图衍生指标的变化。在实验2中，他们在切口前5分钟给予相似剂量的芬太尼，并研究切口前即刻和切口后5分钟时脑电图衍生指标的变化。
在实验1中，切口后，脑电图双相干性的两个峰值高度均显著降低，但在给予芬太尼后恢复到对照值。相比之下，切口后，BIS和SEF95表现出个体差异。在实验2中，尽管芬太尼本身在切口前并未影响所有脑电图衍生指标，但切口后这些变量保持不变。
有害刺激降低了脑电图双相干性的峰值高度，芬太尼镇痛可抵消这一效应。
