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Physiol Meas. 2018 Dec 7;39(12):125004. doi: 10.1088/1361-6579/aae54d.
Post-resuscitation reperfusion following hypoxic-ischemia (HIE) is associated with secondary brain injury in neonates.
To quantify the association between perfusion exceeding autoregulatory limits and brain injury.
Continuous mean arterial blood pressure (MABP) and cerebral near-infrared spectroscopy (NIRS) data were prospectively collected from infants with HIE. Cerebral oximetry index (COx) was calculated as a moving correlation coefficient between MABP and NIRS. Upper and lower limits of autoregulation were identified by transition from negative to positive correlation. The proportion of time MABP above (hyperperfusion) and below (hypoperfusion) autoregulatory limits was calculated during therapeutic hypothermia (days 1-3).
Sixteen infants were included; injury was noted in 7/16. There was no significance in hyperperfusion burden between injured and uninjured infants during day one (7% versus 10%, p = 0.88) or two (4% versus 2%, p = 0.88), but there was a marked increase for injured infants on day three (54% versus 14%, p = 0.02). There was a corollary decrease in hypoperfusion for injured versus uninjured infants on day 3 (6% versus 24%, p = 0.05).
HIE infants with brain injury have a late failure of cerebral autoregulation, manifested as a hyperperfusion burden, suggesting pathologic events are active on day 3 of hypothermia. This finding may help to identify infants which might need additional neuroprotection.
缺氧缺血后再灌注（HIE）与新生儿的继发性脑损伤有关。
定量研究灌注超过自身调节范围与脑损伤之间的关系。
对患有 HIE 的婴儿进行前瞻性连续平均动脉血压（MABP）和近红外光谱（NIRS）数据采集。脑氧饱和度指数（COx）作为 MABP 和 NIRS 之间的移动相关系数计算。通过从负相关到正相关的转变来确定自身调节的上下限。在治疗性低温（第 1-3 天）期间，计算 MABP 高于（高灌注）和低于（低灌注）自身调节范围的时间比例。
共纳入 16 名婴儿；其中 7/16 例发生损伤。在第一天（7%对 10%，p=0.88）和第二天（4%对 2%，p=0.88），损伤组和未损伤组之间的高灌注负担没有显著差异，但在第三天，损伤组婴儿的高灌注负担显著增加（54%对 14%，p=0.02）。与未损伤组相比，损伤组婴儿在第三天的低灌注负担减少（6%对 24%，p=0.05）。
有脑损伤的 HIE 婴儿存在迟发性脑自动调节功能障碍，表现为高灌注负担，这表明在低温治疗的第 3 天，病理性事件仍在活跃。这一发现可能有助于识别可能需要额外神经保护的婴儿。
