Identification of pressure passive cerebral perfusion and its mediators after infant cardiac surgery
Identification of pressure passive cerebral perfusion and its mediators after infant cardiac surgery
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DOI：
10.1203/01.pdr.0000147576.84092.f9
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发表时间：
2005-01-01
影响因子：
3.6
通讯作者：
Du Plessis, AJ
中科院分区：
文献类型：
--
作者：
Bassan, H;Gauvreau, K;Du Plessis, AJ
脑血管压力自动调节（CPA）调节与平均动脉血压（MAP）变化相关的脑血流量（CBF）。在患病婴儿中很难识别压力被动脑灌注及其潜在的可改变的生理因素。我们之前验证了近红外光谱衍生的血红蛋白差异 (HbD) 信号（脑氧合血红蛋白脱氧血红蛋白）作为动物模型中 CBF 变化的可靠测量。我们现在试图确定 DeltaHbD 的连续测量是否与大脑中动脉血流速度 (CBFV) 相关，允许识别和量化压力被动状态，并帮助描述潜在的可修改因素。我们招募了 43 名正在接受心脏直视手术和体外循环的婴儿（2 天至 7 个月大）。术后 6 小时和 20 小时，我们测量了不同呼气末 CO2 水平下 HbD、CBFV（通过经颅多普勒）和 MAP 的变化。我们根据 DeltaMAP 和 DeltaHbD 之间显着一致性的相对持续时间为每项研究分配压力被动指数 (PPI)。我们发现 DeltaHbD 和 DeltaCBFV 在两个时间点都存在显着关系。术后 6 小时，我们发现 DeltaMAP 和 DeltaHbD 之间具有高度一致性（一致性 >0.5；PPI 大于或等于 41%），这与 13% 婴儿的 CPA 紊乱一致。呼气末 CO、大于或等于 40 mm Hg 的值以及较高的 MAP 变异性均与自动调节失败的几率增加 (p < 0.001) 相关。这种方法提供了一种识别和量化 CPA 干扰的方法。高 CO2 水平和波动的 MAP 是与 CPA 紊乱相关的两个重要的可预防因素。
Cerebrovascular pressure autoregulation (CPA) regulates cerebral blood flow (CBF) in relation to changes in mean arterial blood pressure (MAP). Identification of a pressure-passive cerebral perfusion and the potentially modifiable physiologic factors underlying it has been difficult to achieve in sick infants. We previously validated the near-infrared spectroscopy-derived hemoglobin difference (HbD) signal (cerebral oxyhemoglobin deoxyhemoglobin) as a reliable measure of changes in CBF in animal models. We now sought to determine whether continuous measurements of DeltaHbD would correlate to middle cerebral artery flow velocity (CBFV), allow identification and quantification of pressure-passive state, and help to delineate potentially modifiable factors. We enrolled 43 infants (2 d to 7 mo old) who were undergoing open cardiac surgery and cardiopulmonary bypass. At 6 and 20 h after surgery, we measured changes in HbD, CBFV (by transcranial Doppler), and MAP at different end-tidal CO2 levels. We assigned a pressure-passive index (PPI) to each study on the basis of the relative duration of significant coherence between DeltaMAP and DeltaHbD. We found a significant relationship between DeltaHbD and DeltaCBFV at both time points. At 6 h after surgery, we showed high concordance (coherence >0.5; PPI greater than or equal to41%) between DeltaMAP and DeltaHbD, consistent with disturbed CPA in 13% of infants. End-tidal CO, values greater than or equal to40 mm Hg and higher MAP variability both were associated with increased odds (p < 0.001) of autoregulatory failure. This approach provides a means to identify and quantify disturbances of CPA. High CO, levels and fluctuating MAP are two important preventable factors associated with disturbed CPA.