BACKGROUND: The aim of the study was to investigate whether closed-loop compared to manual bispectral index (BIS)–guided target-controlled infusion of propofol and remifentanil could decrease the incidence of postoperative neurocognitive disorders after elective major noncardiac surgery. METHODS: Patients aged >50 admitted for elective major noncardiac surgery were included in a single-blind randomized (ratio 2:1) trial. The anesthetic protocol was allocated by randomization into either closed-loop or manual BIS-guided propofol and remifentanil titration. The BIS target range was 40–60. All patients had cognitive assessment the day before surgery and within 72 hours after surgery using a battery of neuropsychological tests. The primary outcome was the rate of postoperative neurocognitive disorders. Postoperative neurocognitive disorders were defined as a decrease >20% from baseline on at least 3 scores. Intergroup comparison of the primary outcome was performed using the χ2 test. RESULTS: A total of 143 and 61 patients were included in the closed-loop and manual groups, respectively (age: 66 [8] vs 66 [9] years). The primary outcome was observed in 18 (13%) and 10 (16%) patients of the closed-loop and manual groups, respectively (relative risk [95% confidence interval {CI}], 0.77 [0.38-1.57], P = .47). Intraoperative propofol consumption was lower (4.7 [1.4] vs 5.7 [1.4] mg·kg−1·h−1, mean difference [MD] [95% CI], −0.73 [−0.98 to −0.48], P < .0001) and the proportion of time within the BIS target range higher (84 [77–89] vs 74 [54–81]%, MD [95% CI], 0.94 [0.67-1.21], P < .0001) in the closed-loop group. CONCLUSIONS: Closed-loop compared to manual BIS-guided total intravenous anesthesia provided a significant reduction in episodes of an excessive depth of anesthesia while decreasing intraoperative propofol requirement but no evidence for a reduction of the incidence of postoperative neurocognitive disorders after elective major noncardiac surgery was observed.

中文翻译：

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闭环与手动靶向控制输注丙泊酚和瑞芬太尼后的术后神经认知障碍对接受择期重大非心脏手术的患者：随机对照术后认知功能障碍 - 脑电图指导的麻醉给药试验

背景：本研究的目的是探讨闭环与手动双频指数 (BIS) 指导下的丙泊酚和瑞芬太尼的靶控输注相比是否可以降低择期非心脏大手术后神经认知障碍的发生率。方法：一项单盲随机（比例 2:1）试验纳入了年龄 >50 岁的择期非心脏大手术患者。麻醉方案通过随机分配到闭环或手动 BIS 指导的丙泊酚和瑞芬太尼滴定中。BIS 的目标范围是 40-60。所有患者在手术前一天和手术后 72 小时内使用一系列神经心理学测试进行认知评估。主要结果是术后神经认知障碍的发生率。术后神经认知障碍定义为至少 3 项评分较基线下降 > 20%。主要结果的组间比较使用 χ2 检验进行。结果：闭环组和手动组分别包括 143 和 61 名患者（年龄：66 [8] 岁与 66 [9] 岁）。分别在闭环组和手动组的 18 (13%) 和 10 (16%) 名患者中观察到主要结果（相对风险 [95% 置信区间 {CI}]，0.77 [0.38-1.57]，P = .47）。术中丙泊酚消耗量较低（4.7 [1.4] vs 5.7 [1.4] mg·kg-1·h-1，平均差 [MD] [95% CI]，-0.73 [-0.98 至 -0.48]，P < .0001 ) 和 BIS 目标范围内的时间比例更高 (84 [77-89] vs 74 [54-81]%, MD [95% CI], 0.94 [0.67-1.21], P < .0001) -循环组。结论：