Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
Chin Med J (Engl). 2011 Nov;124(22):3664-9.
Awareness is a serious complication of general anesthesia. In China, the incidence of intraoperative awareness was 1% in patients undergoing total intravenous anesthesia (TIVA). In this study, we compared the incidence of awareness between Bispectral index (BIS)-guided and routine TIVA protocol and evaluated the effect of BIS on preventing awareness.
A prospective, randomized, double-blinded, multicenter controlled trial was performed. Patients (≥ 18 years of age) undergoing TIVA were randomly divided into BIS-guided group (Group A, BIS was monitored and recommended to maintain between 40 - 60) and control group (Group B, BIS was monitored but the screen was covered). The intraoperative BIS values were downloaded and the BIS trends of confirmed awareness cases were analyzed to determine whether light anesthesia existed.
Of the total 5228 patients, 2919 patients were assigned to Group A and 2309 to Group B. Four cases of confirmed awareness (0.14%) were reported in the BIS-guided group and 15 (0.65%) in the control group (P = 0.002, OR = 0.21, 95% confidence intervals: 0.07 - 0.63). The incidence of possible awareness (0.14% vs. 0.26%, P = 0.485) and dreaming (3.1% vs. 3.1%, P = 0.986) was comparable between BIS-guided group and the control group. Among the 19 confirmed awareness cases, intraoperative BIS trends of six cases were downloaded and identified. Five of them showed signs of light anesthesia as BIS > 60 and lasted 19 - 106 minutes, whereas one case had a stable BIS trend and the values were within 60 during the operation. Another five awareness cases were reviewed for anesthesia procedures, of which improper light anesthesia were confirmed.
BIS-guided TIVA (BIS was recommended to maintain between 40 - 60) decreased the risk of awareness compared with routine TIVA. The main reason for awareness was light anesthesia.
意识是全身麻醉的严重并发症。在中国，全静脉麻醉（TIVA）患者术中意识的发生率为 1%。在这项研究中，我们比较了双频谱指数（BIS）指导与常规 TIVA 方案之间的意识发生率，并评估了 BIS 预防意识的效果。
前瞻性、随机、双盲、多中心对照试验。接受 TIVA 的患者（≥18 岁）被随机分为 BIS 指导组（A 组，BIS 监测并建议维持在 40-60 之间）和对照组（B 组，BIS 监测但屏幕被覆盖）。下载术中 BIS 值，并分析确认意识病例的 BIS 趋势，以确定是否存在浅麻醉。
在总共 5228 名患者中，2919 名患者被分配到 A 组，2309 名患者被分配到 B 组。BIS 指导组报告了 4 例（0.14%）确诊的意识，对照组报告了 15 例（0.65%）（P=0.002，OR=0.21，95%置信区间：0.07-0.63）。BIS 指导组和对照组可能意识（0.14%vs.0.26%，P=0.485）和做梦（3.1%vs.3.1%，P=0.986）的发生率相似。在 19 例确诊意识病例中，下载并确定了 6 例病例的术中 BIS 趋势。其中 5 例表现出浅麻醉迹象，BIS>60，持续 19-106 分钟，而 1 例手术过程中 BIS 趋势稳定，数值在 60 以内。另外 5 例意识病例回顾了麻醉程序，其中确认了不当的浅麻醉。
与常规 TIVA 相比，BIS 指导 TIVA（建议维持 BIS 在 40-60 之间）降低了意识风险。意识的主要原因是浅麻醉。
