Tatsumi K, Hirai K, Furuya H, Okuda T
Department of Anesthesiology, Nara Medical University, Japan.
Anesth Analg. 1995 May;80(5):940-3. doi: 10.1097/00000539-199505000-00014.
We investigated the effects of sevoflurane on the middle latency auditory evoked response (MLR) and the power spectrum of the electroencephalogram (EEG) in 10 elective surgical patients. The MLR and the EEG power spectrum were recorded with a surface electrode placed at the central (Cz) scalp location. End-tidal sevoflurane concentrations of 0%, 0.25%, 0.5%, 0.75%, 1.0%, and 1.5% in 50% nitrous oxide and oxygen were studied. The Na, Pa, and Nb components of the MLR increased in latency and decreased in amplitude in a dose-dependent manner at increasing concentrations of sevoflurane. The latencies for Na, Pa, and Nb increased in a linear fashion (correlation coefficients: r = 0.81, r = 0.81, and r = 0.89, respectively). The EEG delta power was dominant with increasing sevoflurane concentration, and was significantly increased at sevoflurane concentrations of 1.0%-1.5%. The beta power, median power frequency (MPF), and 95% spectral edge frequency (SEF) decreased significantly according to the increases by 0.5% sevoflurane. Regarding the changes evoked by 0.25% sevoflurane, the Nb latency of the MLR responded significantly under 0.75% of sevoflurane. At these low concentrations of sevoflurane, the MLR seemed to be more sensitive to changes in anesthetic concentration than the various EEG variables.
我们研究了七氟醚对10例择期手术患者的中潜伏期听觉诱发电位（MLR）及脑电图（EEG）功率谱的影响。MLR和EEG功率谱通过置于头皮中央（Cz）位置的表面电极进行记录。研究了在50%氧化亚氮和氧气中七氟醚呼气末浓度分别为0%、0.25%、0.5%、0.75%、1.0%和1.5%时的情况。随着七氟醚浓度增加，MLR的Na、Pa和Nb成分潜伏期延长，波幅降低，呈剂量依赖性。Na、Pa和Nb的潜伏期呈线性增加（相关系数分别为：r = 0.81、r = 0.81和r = 0.89）。随着七氟醚浓度增加，EEG的δ波功率占主导，在七氟醚浓度为1.0% - 1.5%时显著增加。七氟醚浓度每增加0.5%，β波功率、中位功率频率（MPF）和95%频谱边缘频率（SEF）显著降低。关于0.25%七氟醚引起的变化，MLR的Nb潜伏期在七氟醚浓度低于0.75%时反应显著。在这些低浓度七氟醚时，MLR似乎比各种EEG变量对麻醉浓度变化更敏感。
