A single-center prospective randomized controlled study was conducted to assess the effect of targeted mild hypercapnia (TMH) on cerebral oxygen saturation (rSO) in patients undergoing off-pump coronary artery bypass grafting (CABG). A prospective randomized controlled study involving 100 patients undergoing off-pump CABG at U. N. Mehta Hospital, Ahmedabad, Gujarat, India. Patients were randomized to either the TMH (PaCO 45-55 mmHg) or the targeted normocapnia (TN; PaCO 35-45 mmHg) group, containing 50 patients in each group. Monitoring of rSO, heart rate, mean arterial pressure (MAP), PaCO, and peripheral oxygen saturation was done at baseline, after induction, after left internal mammary artery harvesting, at each grafting (distal and proximal), after protamine, and after shifting to the intensive care unit. The standardized minimental-state examination (SMMSE) was performed preoperatively and at 8, 12, and 24 hours postextubation. Data were analyzed using an independent sample t test. The TMH group had higher MAP during grafting (p < 0.001) and higher rSO on both sides during distal and proximal grafting (p < 0.001) and after protamine (p < 0.05), as compared to the TN group. Compared to preoperative values, SMMSE scores in the TN group were significantly lower at 12 and 24 hours postextubation (p < 0.001). TMH during grafting increased the cerebral blood flow and rSO when hemodynamic instability was very common. It has a protective role on the brain and helps maintain cognition postoperatively.

中文翻译：

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轻度高碳酸血症对非体外循环冠状动脉搭桥术患者脑氧饱和度影响的前瞻性随机预试验

一项单中心前瞻性随机对照研究旨在评估靶向轻度高碳酸血症（TMH）对接受非体外循环冠状动脉旁路移植术（CABG）患者脑氧饱和度（rSO）的影响。一项前瞻性随机对照研究，涉及 100 名在印度古吉拉特邦艾哈迈达巴德联合国梅塔医院接受非体外循环 CABG 的患者。患者被随机分为 TMH（PaCO 45-55 mmHg）组或目标正常碳酸血症（TN；PaCO 35-45 mmHg）组，每组 50 名患者。在基线、诱导后、左内乳动脉采集后、每次移植时（远端和近端）、鱼精蛋白后和移位后监测 rSO、心率、平均动脉压 (MAP)、PaCO 和外周血氧饱和度到重症监护室。术前以及拔管后 8、12 和 24 小时进行标准化简易精神状态检查 (SMMSE)。使用独立样本 t 检验分析数据。与 TN 组相比，TMH 组在移植期间具有较高的 MAP (p < 0.001)，在远端和近端移植期间 (p < 0.001) 以及鱼精蛋白后 (p < 0.05) 两侧的 rSO 较高。与术前值相比，TN 组的 SMMSE 评分在拔管后 12 小时和 24 小时显着降低（p < 0.001）。当血流动力学不稳定很常见时，移植期间的 TMH 会增加脑血流量和 rSO。它对大脑有保护作用，有助于术后维持认知。