Department of Anesthesiology and Intensive Care Medicine, CHU Besancon, F-25000 Besancon, France.
Br J Anaesth. 2011 Nov;107(5):749-56. doi: 10.1093/bja/aer235. Epub 2011 Aug 8.
Suppression ratio (SR) derived from bispectral index (BIS) monitoring is correlated to EEG burst suppression. It may occur during deep anaesthesia, but also in the case of metabolic or haemodynamic brain injury. The goal of the study was to describe the occurrence of SR and to determine factors associated with SR during propofol-remifentanil general anaesthesia maintenance.
We conducted a post hoc analysis of BIS recordings in consecutive patients included in two multi-centre trials, undergoing non-cardiac surgery using a dual closed-loop BIS controller allowing automated propofol-remifentanil administration. The percentage of time spent with a BIS value between 40 and 60 (T(BIS 40-60)) was measured. Two groups of patients were defined: the SR group, including patients with at least one episode of SR value >10% lasting more than 1 min, and the control group. Factors associated with SR were analysed using a stepwise multivariate analysis.
A total of 1494 patients [age=57 (17) yr; T(BIS 40-60)=76 (17%)] were analysed and 131 (8.7%) patients constituted the SR group. The main independent factors associated with SR were advanced age [odds ratio (95% confidence interval)=4.80 (1.85-12.43) (P=0.027), 10.59 (3.76-29.81) (P<0.0001), for categories of age 60-80 and >80 yr, respectively], history of coronary artery disease (CAD) [2.53 (1.47-4.37) (P=0.001)] and male gender [1.57 (1.03-2.40) (P=0.03)].
The occurrence of SR during BIS-controlled propofol and remifentanil anaesthesia is mainly observed in elderly male patients or in patients with a history of CAD. The mechanisms underlying SR and the potential consequences for the patient's postoperative outcome remain unsolved.
从双频谱指数（BIS）监测中得出的抑制比（SR）与脑电图爆发抑制有关。它可能发生在深度麻醉期间，也可能发生在代谢或血流动力学脑损伤的情况下。本研究的目的是描述 SR 的发生，并确定丙泊酚-瑞芬太尼全身麻醉维持过程中与 SR 相关的因素。
我们对两项多中心试验中连续纳入的患者的 BIS 记录进行了事后分析，这些患者接受了使用双闭环 BIS 控制器的非心脏手术，该控制器允许自动给予丙泊酚-瑞芬太尼。测量 BIS 值在 40 到 60 之间的时间百分比（T（BIS 40-60））。将患者分为两组：SR 组，包括至少一次持续超过 1 分钟的 SR 值>10%的发作的患者，以及对照组。使用逐步多元分析分析与 SR 相关的因素。
共分析了 1494 例患者[年龄=57（17）岁；T（BIS 40-60）=76（17%）]，其中 131 例（8.7%）患者构成了 SR 组。与 SR 相关的主要独立因素是高龄[优势比（95%置信区间）=4.80（1.85-12.43）（P=0.027），10.59（3.76-29.81）（P<0.0001），分别为年龄 60-80 岁和>80 岁组]、冠心病（CAD）病史[2.53（1.47-4.37）（P=0.001）]和男性性别[1.57（1.03-2.40）（P=0.03）]。
在 BIS 控制的丙泊酚和瑞芬太尼麻醉期间，SR 的发生主要发生在老年男性患者或有 CAD 病史的患者中。SR 的潜在机制及其对患者术后结局的潜在影响仍未解决。
