【罂粟摘要】围术期氧浓度与心脏术后认知功能障碍：一项随机对照试验

围术期氧浓度与心脏术后认知功能障碍：

一项随机对照试验

背景：尽管证据表明围术期氧过多或氧和过度心脏术后的常常具有不利影响。氧和过度可能增加氧损伤和神经损伤导致术后不同程度的神经认知功能障碍。因此，本研究验证主要假说是，与氧和过度相比，行心脏手术的老年患者围术期正常氧浓度可减少术后认知功能障碍。

方法：本研究是一项随机双盲的对照试验，纳入了100例体外循环下行冠脉搭桥术65岁及以上的患者，根据围术期给氧浓度的不同，随机均分为2组。正常氧浓度组：体外循环前后以最低氧浓度0.35维持PaO2高于70mmhg, 体外循环期间维持PaO2100-150mmhg；氧和过度组：围术期以氧浓度1维持PaO2，但不考虑PaO2具体情况。主要结局指标采用蒙特利尔电话认知评估（MOCA）量表评估术后第2天的神经认知功能。次要结局指标：术后1,3,6个月神经认知功能，术后谵妄，机械通气时间，重症监护室时间和住院时间。

结果：本研究患者年龄中位数为71岁（四分位数，68-75），基础的神经认知功能分数的中位数是17（16-19）。其中围术期PaO2中位数，氧和过度组是309（285-352）mmhg，正常氧浓度组是153（133-168）mmhg；术后第二天MOCA的中位数，氧和过度组是18（16-20）mmhg，正常氧浓度组是18（14-20）mmhg（P=0.42）。两组术后1,3,6个月神经认知功能及其他的次要指标无统计学差异。

结论：本次随机对照研究结果表明，在行心脏手术老年患者中，与氧和过度组比较，围术期正常氧浓度组未减少术后认知功能障碍。尽管围术期最优的氧和策略尚不清楚，但结果表明围术期氧和过度并不会恶化心脏术后认知功能障碍。

Intraoperative Oxygen Concentration and Neurocognition after Cardiac Surgery: A Randomized Clinical Trial

Background:Despite evidence suggesting detrimental effects of perioperative hyperoxia, hyperoxygenation remains commonplace in cardiac surgery. Hyperoxygenation may increase oxidative damage and neuronal injury leading to potential differences in postoperative neurocognition. Therefore, this study tested the primary hypothesis that intraoperative normoxia, as compared to hyperoxia, reduces postoperative cognitive dysfunction in older patients having cardiac surgery.

Methods:A randomized double-blind trial was conducted in patients aged 65 yr or older having coronary artery bypass graft surgery with cardiopulmonary bypass. A total of 100 patients were randomized to one of two intraoperative oxygen delivery strategies. Normoxic patients (n = 50) received a minimum fraction of inspired oxygen of 0.35 to maintain a Pao₂ above 70 mmHg before and after cardiopulmonary bypass and between 100 and 150 mmHg during cardiopulmonary bypass. Hyperoxic patients (n = 50) received a fraction of inspired oxygen of 1.0 throughout surgery, irrespective of Pao₂ levels. The primary outcome was neurocognitive function measured on postoperative day 2 using the Telephonic Montreal Cognitive Assessment. Secondary outcomes included neurocognitive function at 1, 3, and 6 months, as well as postoperative delirium, mortality, and durations of mechanical ventilation, intensive care unit stay, and hospital stay.

Results:The median age was 71 yr (interquartile range, 68 to 75), and the median baseline neurocognitive score was 17 (16 to 19). The median intraoperative Pao₂ was 309 (285 to 352) mmHg in the hyperoxia group and 153 (133 to 168) mmHg in the normoxia group (P < 0.001). The median Telephonic Montreal Cognitive Assessment score on postoperative day 2 was 18 (16 to 20) in the hyperoxia group and 18 (14 to 20) in the normoxia group (P = 0.42). Neurocognitive function at 1, 3, and 6 months, as well as secondary outcomes, were not statistically different between groups.

Conclusions:In this randomized controlled trial, intraoperative normoxia did not reduce postoperative cognitive dysfunction when compared to intraoperative hyperoxia in older patients having cardiac surgery. Although the optimal intraoperative oxygenation strategy remains uncertain, the results indicate that intraoperative hyperoxia does not worsen postoperative cognition after cardiac surgery.

原文来源：

Anesthesiology Newly Published on December 2020. doi:https://doi.org/10.1097/ALN.0000000000003650

翻译：易菁     编辑：佟睿     审校：曹莹