Liu J, Singh H, White P F
Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, Dallas 75235-9068, USA.
Anesth Analg. 1997 Jan;84(1):185-9. doi: 10.1097/00000539-199701000-00033.
The bispectral (BIS) index and 95% spectral edge frequency (SEF) of the electroencephalograph (EEG) have been used to study the anesthetic and sedative effects of intravenously (i.v.) administered drugs. This prospective study was designed to evaluate the effectiveness of the BIS index and 95% SEF for assessing the level of propofol-induced sedation and amnesia during regional anesthesia. Ten consenting adult patients undergoing surgery with regional anesthesia were administered propofol in increments of 10-20 mg i.v., every 5-10 min until they became unresponsive to tactile stimulation (i.e., mild prodding or shaking). The BIS index and 95% SEF were continuously recorded from a bifrontal montage (Fp1-Cz and Fp2-Cz) using the Aspect B500 monitor. The depth of sedation was assessed clinically at 5- to 10-min intervals using the observer's assessment of alertness/sedation (OAA/S) scale, with 1 = no response to tactile stimulation to 5 = wide awake. Each patient was shown a picture of an animal (cat) prior to administration of an initial dose of propofol, 40 mg i.v.. Subsequently, patients were administered intermittent bolus doses of propofol, 10-20 mg i.v., and shown different pictures upon achieving OAA/S scores of 4, 3, and 2 during the onset of and recovery from propofol-induced sedation. Picture recall was tested upon arrival of the patient in the postanesthesia care unit (PACU). Of the two EEG variables studied, the BIS index exhibited a better correlation with the OAA/S scores during both the onset (Spearman's rho = 0.744) and recovery (Spearman's rho = 0.705) phases of propofol-induced sedation. With the increasing depth of sedation, there was a progressive decrease in the BIS index (OAA/S score of 5, BIS = 94.5 +/- 2.9; 4, 93.3 +/- 3.3; 3, 89 +/- 6.1; 2, 80.1 +/- 8.7; 1, 75.6 +/- 7.5; mean +/- SD). Conversely, there was a progressive increase in the BIS value during recovery from propofol sedation (OAA/S score of 1, BIS = 75.6 +/- 7.5; 2, 82.4 +/- 10.5; 3, 84.9 +/- 5.9; 4, 93.8 +/- 0.8). Although the changes in the 95% SEF values were less consistent during the onset phase, this EEG variable increased from 16.4 +/- 5.0 to 19.3 +/- 5.6 as the OAA/S score increased from 1 to 4 during the recovery phase. Patient recall of the intraoperative pictures decreased with increasing depth of sedation and decreasing BIS values (OAA/S:% BIS:% recall = 5:94.5 +/- 2.9:100%; 4:93.4 +/- 3:63%; 3:87.3 +/- 6.1:40%; 2:80.8 +/- 8.3:0%; 1:75.6 +/- 7.5:0%). The BIS index appears to be a useful variable for assessing the depth of propofol-induced sedation. Increasing depth of sedation was associated with a significant decrease in intraoperative picture recall.
脑电双频指数（BIS）和脑电图（EEG）的95%频谱边缘频率（SEF）已被用于研究静脉注射药物的麻醉和镇静效果。这项前瞻性研究旨在评估BIS指数和95% SEF在区域麻醉期间评估丙泊酚诱导的镇静和遗忘水平的有效性。10名接受区域麻醉手术的成年患者同意参与研究，静脉注射丙泊酚，每次10 - 20mg，每5 - 10分钟一次，直至对触觉刺激（即轻度戳刺或摇晃）无反应。使用Aspect B500监测仪从双侧额叶导联（Fp1 - Cz和Fp2 - Cz）连续记录BIS指数和95% SEF。每隔5 - 10分钟使用观察者警觉/镇静评估（OAA/S）量表进行临床镇静深度评估，1 = 对触觉刺激无反应至5 = 完全清醒。在静脉注射初始剂量40mg丙泊酚之前，向每位患者展示一张动物（猫）的图片。随后，患者静脉注射10 - 20mg丙泊酚间歇推注剂量，并在丙泊酚诱导的镇静开始和恢复期间达到OAA/S评分为4、3和2时展示不同图片。患者到达麻醉后护理单元（PACU）时测试图片回忆。在研究的两个脑电图变量中，BIS指数在丙泊酚诱导的镇静开始阶段（Spearman等级相关系数rho = 0.744）和恢复阶段（Spearman等级相关系数rho = 0.705）与OAA/S评分表现出更好的相关性。随着镇静深度增加，BIS指数逐渐降低（OAA/S评分为5时，BIS = 94.5 ± 2.9；4时，93.3 ± 3.3；
