Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA; Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China.
Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.
Br J Anaesth. 2022 Jul;129(1):22-32. doi: 10.1016/j.bja.2022.03.029. Epub 2022 May 18.
Cardiac surgery studies have established the clinical relevance of personalised arterial blood pressure management based on cerebral autoregulation. However, variabilities exist in autoregulation evaluation. We compared the association of several cerebral autoregulation metrics, calculated using different methods, with outcomes after cardiac surgery.
Autoregulation was measured during cardiac surgery in 240 patients. Mean flow index and cerebral oximetry index were calculated as Pearson's correlations between mean arterial pressure (MAP) and transcranial Doppler blood flow velocity or near-infrared spectroscopy signals. The lower limit of autoregulation and optimal mean arterial pressure were identified using mean flow index and cerebral oximetry index. Regression models were used to examine associations of area under curve and duration of mean arterial pressure below thresholds with stroke, acute kidney injury (AKI), and major morbidity and mortality.
Both mean flow index and cerebral oximetry index identified the cerebral lower limit of autoregulation below which MAP was associated with a higher incidence of AKI and major morbidity and mortality. Based on magnitude and significance of the estimates in adjusted models, the area under curve of MAP < lower limit of autoregulation had the strongest association with AKI and major morbidity and mortality. The odds ratio for area under the curve of MAP < lower limit of autoregulation was 1.05 (95% confidence interval, 1.01-1.09), meaning every 1 mm Hg h increase of area under the curve was associated with an average increase in the odds of AKI by 5%.
For cardiac surgery patients, area under curve of MAP < lower limit of autoregulation using mean flow index or cerebral oximetry index had the strongest association with AKI and major morbidity and mortality. Trials are necessary to evaluate this target for MAP management.
心脏手术研究已经证实了基于脑自动调节的个性化动脉血压管理在临床中的重要性。然而，自动调节评估存在变异性。我们比较了使用不同方法计算的几种脑自动调节指标与心脏手术后结果的相关性。
在 240 例心脏手术患者中测量自动调节。平均流量指数和脑氧饱和度指数是通过平均动脉压（MAP）与经颅多普勒血流速度或近红外光谱信号之间的皮尔逊相关来计算的。使用平均流量指数和脑氧饱和度指数确定自动调节的下限和最佳平均动脉压。回归模型用于检查平均动脉压低于阈值的曲线下面积和持续时间与中风、急性肾损伤（AKI）以及主要发病率和死亡率的关系。
平均流量指数和脑氧饱和度指数都确定了 MAP 与 AKI 和主要发病率和死亡率较高相关的脑自动调节下限。基于调整后的模型中估计值的大小和显著性，MAP <自动调节下限的曲线下面积与 AKI 和主要发病率和死亡率的相关性最强。MAP <自动调节下限的曲线下面积的比值比为 1.05（95%置信区间，1.01-1.09），这意味着曲线下面积每增加 1 mmHg h，AKI 的发生几率平均增加 5%。
对于心脏手术患者，使用平均流量指数或脑氧饱和度指数的 MAP <自动调节下限的曲线下面积与 AKI 和主要发病率和死亡率的相关性最强。需要进行试验来评估 MAP 管理的这一目标。
