Kochs E, Bischoff P, Pichlmeier U, Schulte am Esch J
Department of Anesthesiology, University Hospital Eppendorf, Hamburg, Germany.
Anesthesiology. 1994 May;80(5):1026-34. doi: 10.1097/00000542-199405000-00012.
The aim of this study was to investigate topographic changes in electroencephalographic (EEG) power and frequency induced by abdominal surgery during anesthesia with 0.6% or 1.2% isoflurane in 66% nitrous oxide.
Forty-six patients (aged 41 +/- 13 yr) scheduled for elective abdominal surgery were studied. The trachea of each patient was intubated and the lungs ventilated. Patients were randomly assigned to one of four groups: anesthesia was maintained with 0.6% (group 1, n = 12; group 2, n = 11) or 1.2% end-tidal isoflurane (group 3, n = 12; group 4, n = 11) in 66% nitrous oxide. Data were recorded over 20 min. Groups 1 and 3 were studied without surgery (as controls). In groups 2 and 4 recording was started 6 min before skin incision. The EEG was acquired via 17 scalp electrodes placed in standard International 10-20 locations (reference Cz). Absolute and relative power densities were calculated in selected frequency bands. EEG maps of spectral power densities were coded according to a continuous color spectrum.
During baseline recordings, alpha activity was dominant at frontal areas in groups 1 and 2. In comparison, in groups 3 and 4, delta and theta activities were dominant at frontal leads. In group 2, the start of surgery resulted in increases in delta activity and decreases in alpha activity that were most dominant frontally (delta +181% and alpha -61%, F3). The delta shift was attenuated at 1.2% isoflurane (group 4, delta +44%, F3), but decreases in alpha activity (-53%, F3) were comparable to those in group 2. The EEG response in all frequency bands was attenuated at parietotemporal recording sites at both isoflurane concentrations.
The current data demonstrate graded EEG responses induced by abdominal surgery during anesthesia with 0.6% or 1.2% isoflurane in 66% nitrous oxide. Spatial heterogeneities in absolute spectral power densities were reflected by color changes in the EEG maps. The topographic EEG analysis indicates that these changes were most dominant at frontal areas. The increases in delta and decreases in alpha activities may be related to intraoperative "paradoxical" electrophysiologic arousal phenomena.
本研究旨在调查在66%氧化亚氮中使用0.6%或1.2%异氟烷麻醉期间腹部手术诱发的脑电图（EEG）功率和频率的地形变化。
对46例计划进行择期腹部手术的患者（年龄41±13岁）进行研究。每位患者均行气管插管并机械通气。患者被随机分为四组：在66%氧化亚氮中分别用0.6%（第1组，n = 12；第2组，n = 11）或1.2%的呼气末异氟烷维持麻醉（第3组，n = 12；第4组，n = 11）。记录20分钟的数据。第1组和第3组在无手术情况下进行研究（作为对照）。第2组和第4组在皮肤切开前6分钟开始记录。通过放置在标准国际10 - 20位置（参考点Cz）的17个头皮电极采集脑电图。计算选定频段的绝对和相对功率密度。频谱功率密度的脑电图图谱根据连续色谱进行编码。
在基线记录期间，第1组和第2组额叶区域以α波活动为主。相比之下，第3组和第4组额叶导联以δ波和θ波活动为主。在第2组中，手术开始导致δ波活动增加和α波活动减少，最明显的是额叶（δ波增加181%，α波减少61%，F3点）。在1.2%异氟烷时（第4组，δ波增加44%，F3点）δ波的变化减弱，但α波活动的减少（-53%，F3点）与第2组相当。在两个异氟烷浓度下，顶颞记录部位所有频段的脑电图反应均减弱。
当前数据表明在66%氧化亚氮中使用0.6%或1.2%异氟烷麻醉期间腹部手术诱发的脑电图反应呈分级变化。绝对频谱功率密度的空间异质性通过脑电图图谱的颜色变化反映出来。脑电图地形分析表明这些变化在额叶区域最为明显。δ波增加和α波活动减少可能与术中“反常”电生理唤醒现象有关。
