麻醉深度与术后并发症的关系研究
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Anaesthetic depth and complications after major surgery: an international, randomised controlled trial
背景与目的
研究报道麻醉深度增加和术后生存率降低之间存在一定的关系；但尚缺乏来自随机对照试验的证据。本研究的目的是比较接受大手术的浅麻醉或深麻醉的老年患者术后一年的全因死亡率。
方 法
在本国际试验中，研究者从7个国家的73个中心招募了60岁及以上、合并症严重、手术时间超过2小时、预计住院时间至少2天的患者。在知晓分组前，麻醉科医师依据患者具体情况制定恰当的平均动脉压（MAP）目标范围，并确任患者是否需要区域麻醉作为联合麻醉。随机化分组BIS目标为50和35（分别为BIS50和BIS35组）。主要指标为术后1年内全因死亡率。
结 果
2012年12月19日至2017年12月12日期间，对7个国家73个医疗中心的患者进行筛选。在18026例符合标准的患者中，6644例患者被纳入试验，作为意向治疗人群被随机分配入治疗组或对照组（BIS 50组3316例，BIS 35组3328例）。每个试验点纳入的患者中位数为48例（IQR 20-145），患者平均年龄为72岁（SD 7）。4221例（63%）为男性，2423例（37%）为女性，3107例（46%）行癌症手术，3053例（46%）行腹部手术。与BIS 35组相比，BIS 50组MAP高出3.5mmHg（4%），且挥发性麻醉药使用降低0.26MAC（30%）。在麻醉维持期间，2602例(39%)患者吸入的平均MAC小于0.7。BIS 50组中患者1年死亡率为 6.5%（212例），BIS 35组为7.2%（238例），HR 0.88（95%CI 0.73-1.07），且区组间死亡率无异质性（HR 0.89，0.74-1.07）。BIS 50组954例（29%）发生3级不良事件，BIS 35组909例（27%）发生4级不良事件，BIS 50组265例（8%）发生4级不良事件，BIS 35组259例（8%）。最常见的不良事件是感染、血管疾病、心脏疾病和肿瘤。
结 论
在大手术后并发症风险增加的患者中，麻醉深度与患者术后1年死亡率无直接关系。
原始文献摘要
Short TG, Campbell D, Frampton C,et al. Anaesthetic depth and complications after major surgery: an international, randomised controlled trial. Lancet. 2019 Oct 18. pii: S0140-6736(19)32315-3. doi: 10.1016/S0140-6736(19)32315-3.
BACKGROUND: An association between increasing anaesthetic depth and decreased postoperative survival has been shown in observational studies; however, evidence from randomised controlled trials is lacking. Our aim was to compare all-cause 1-year mortality in older patients having major surgery and randomly assigned to light or deep general anaesthesia.
METHODS: In an international trial, we recruited patients from 73 centres in seven countries who were aged 60 years and older, with significant comorbidity, having surgery with expected duration of more than 2 h, and an anticipated hospital stay of at least 2 days. We randomly assigned patients who had increased risk of complications after major surgery to receive light general anaesthesia (bispectral index [BIS] target 50) or deep general anaesthesia (BIS target 35). Anaesthetists also nominated an appropriate range for mean arterial pressure for each patient during surgery. Patients were randomly assigned in permuted blocks by region immediately before surgery, with the patient and assessors masked to group allocation. The primary outcome was 1-year all-cause mortality. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12612000632897, and is closed to accrual.
FINDINGS: Patients were enrolled between Dec 19, 2012, and Dec 12, 2017. Of the 18 026 patients screened as eligible, 6644 were enrolled, randomly assigned to treatment or control, and formed the intention-to-treat population (3316 in the BIS 50 group and 3328 in the BIS 35 group). The median BIS was 47·2 (IQR 43·7 to 50·5) in the BIS 50 group and 38·8 (36·3 to 42·4) in the BIS 35 group. Mean arterial pressure was 3·5 mm Hg (4%) higher (median 84·5 [IQR 78·0 to 91·3] and 81·0 [75·4 to 87·6], respectively) and volatile anaesthetic use was 0·26 minimum alveolar concentration (30%) lower (0·62 [0·52 to 0·73] and 0·88 [0·74 to 1·04], respectively) in the BIS 50 than the BIS 35 group. 1-year mortality was 6·5% (212 patients) in the BIS 50 group and 7·2% (238 patients) in the BIS 35 group (hazard ratio 0·88, 95% CI 0·73 to 1·07, absolute risk reduction 0·8%, 95% CI -0·5 to 2·0). Grade 3 adverse events occurred in 954 (29%) patients in the BIS 50 group and 909 (27%) patients in the BIS 35 group; and grade 4 adverse events in 265 (8%) and 259 (8%) patients, respectively. The most commonly reported adverse events were infections, vascular disorders, cardiac disorders, and neoplasms.
INTERPRETATION: Among patients at increased risk of complications after major surgery, light general anaesthesia was not associated with lower 1-year mortality than deep general anaesthesia. Our trial defines a broad range of anaesthetic depth over which anaesthesia may be safely delivered when titrating volatile anaesthetic concentrations using a processed electroencephalographic monitor.
麻醉学文献进展分享
贵州医科大学高鸿教授课题组
翻译：王贵龙 编辑：何幼芹 审校：王贵龙