OBJECTIVE To determine whether ventilator-related fluctuations in cerebral blood volume (CBV) are associated with cerebral pressure passivity. STUDY DESIGN In a prospective study of newborns undergoing positive-pressure ventilation, we calculated coherence between continuous mean arterial pressure (MAP) and cerebral near-infrared spectroscopy hemoglobin difference (HbD). Significant HbD-MAP coherence indicated cerebral pressure passivity. CBV changes were measured as the spectral power of total hemoglobin (SHbT) at the ventilator frequency. A regression model tested whether SHbT predicts cerebral pressure passivity and/or death/brain injury, controlling for birth gestational age and other factors. RESULTS We studied 68 subjects with prematurity (n = 19), congenital heart disease (n = 11), and hypoxic-ischemic encephalopathy (n = 38). SHbT, sedative use, and pCO2 were positively associated, and circulating hemoglobin negatively associated, with cerebral pressure passivity (p < 0.001), which was positively associated with brain injury (p < 0.001). CONCLUSION In sick newborns, ventilator-related CBV fluctuations may predispose to cerebral pressure passivity, which may predispose to an adverse neonatal outcome.

中文翻译：

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危重婴儿的脑静脉容积变化和压力自动调节。

目的 确定呼吸机相关的脑血容量 (CBV) 波动是否与脑压被动相关。研究设计 在一项对接受正压通气的新生儿的前瞻性研究中，我们计算了连续平均动脉压 (MAP) 和大脑近红外光谱血红蛋白差值 (HbD) 之间的相干性。显着的 HbD-MAP 一致性表明脑压被动。CBV 变化被测量为呼吸机频率下总血红蛋白 (SHbT) 的频谱功率。回归模型测试了 SHbT 是否预测脑压被动和/或死亡/脑损伤，控制出生胎龄和其他因素。结果 我们研究了 68 名患有早产 (n = 19)、先天性心脏病 (n = 11) 和缺氧缺血性脑病 (n = 38) 的受试者。SHbT, 镇静剂使用和 pCO2 与脑压被动呈正相关，循环血红蛋白呈负相关（p < 0.001），后者与脑损伤呈正相关（p < 0.001）。结论 在生病的新生儿中，呼吸机相关的 CBV 波动可能导致脑压被动，这可能导致不良的新生儿结局。