Predicting the Limits of Cerebral Autoregulation During Cardiopulmonary Bypass
Predicting the Limits of Cerebral Autoregulation During Cardiopulmonary Bypass
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DOI：
10.1213/ane.0b013e31823d292a
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发表时间：
2012-03-01
影响因子：
5.7
通讯作者：
Hogue, Charles W.
中科院分区：
文献类型：
--
作者：
Joshi, Brijen;Ono, Masahiro;Hogue, Charles W.
背景：平均动脉压（MAP）目标是在心肺转流（CPB）过程中根据经验选择的。我们以前已经表明，近红外光谱（NIRS）可用于临床监测脑血流自动调节。本研究的假设是，使用基于NIRS的方法的实时自动调节监测在描绘CPB期间自动调节下限（LLA）时的MAP比基于年龄、术前病史和术前血压的经验性测定更准确。232例接受冠状动脉旁路移植术和/或瓣膜手术同时行大脑中动脉经颅多普勒监测和近红外光谱监测。计算MAP与脑血流速度之间以及MAP与NIRS数据之间的连续移动Pearson相关系数，以生成平均速度指数和脑血氧指数。当自动调节时，脑血流量和MAP之间没有相关性（即，平均流速和脑血氧指数接近0）;当MAP低于LLA时，平均流速和脑血氧指数接近1。LLA定义为平均速度指数随MAP下降而增加至>= 0.4时的MAP。进行线性回归，以评估术前收缩压，MAP，MAP从基线下降10%，平均脑血氧指数与MAP在LLA.RESULTS：平均动脉压在LLA为66毫米汞柱（95%预测区间，43至90毫米汞柱）的225例患者中，这一限制进行了观察之间的关系。校正年龄、性别、既往卒中、糖尿病和高血压后，术前MAP与LLA之间无相关性（P = 0.829），但脑血氧指数值>0.5与LLA相关（P = 0.022）。219例（94.4%）患者的脑血氧指数可识别LLA。平均流速指数与脑血氧指数的LLA平均差异为-0.2 +/- 10.2 mmHg（95% CI，-1.5至1.2 mmHg）。术前收缩压与更高的LLA相关（P = 0.046），但仅适用于收缩压
BACKGROUND: Mean arterial blood pressure (MAP) targets are empirically chosen during cardiopulmonary bypass (CPB). We have previously shown that near-infrared spectroscopy (NIRS) can be used clinically for monitoring cerebral blood flow autoregulation. The hypothesis of this study was that real-time autoregulation monitoring using NIRS-based methods is more accurate for delineating the MAP at the lower limit of autoregulation (LLA) during CPB than empiric determinations based on age, preoperative history, and preoperative blood pressure.METHODS: Two hundred thirty-two patients undergoing coronary artery bypass graft and/or valve surgery with CPB underwent transcranial Doppler monitoring of the middle cerebral arteries and NIRS monitoring. A continuous, moving Pearson correlation coefficient was calculated between MAP and cerebral blood flow velocity and between MAP and NIRS data to generate mean velocity index and cerebral oximeter index. When autoregulated, there is no correlation between cerebral blood flow and MAP (i.e., mean velocity and cerebral oximetry indices approach 0); when MAP is below the LLA, mean velocity and cerebral oximetry indices approach 1. The LLA was defined as the MAP at which mean velocity index increased with declining MAP to >= 0.4. Linear regression was performed to assess the relation between preoperative systolic blood pressure, MAP, MAP in 10% decrements from baseline, and average cerebral oximetry index with MAP at the LLA.RESULTS: The MAP at the LLA was 66 mm Hg (95% prediction interval, 43 to 90 mm Hg) for the 225 patients in which this limit was observed. There was no relationship between preoperative MAP and the LLA (P = 0.829) after adjusting for age, gender, prior stroke, diabetes, and hypertension, but a cerebral oximetry index value of >0.5 was associated with the LLA (P = 0.022). The LLA could be identified with cerebral oximetry index in 219 (94.4%) patients. The mean difference in the LLA for mean velocity index versus cerebral oximetry index was -0.2 +/- 10.2 mm Hg (95% CI, -1.5 to 1.2 mm Hg). Preoperative systolic blood pressure was associated with a higher LLA (P = 0.046) but only for those with systolic blood pressure