Department of Pediatrics, Neonatology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, USA.
Department of Anesthesiology, Critical Care Medicine, and Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, USA.
Pediatr Res. 2019 Aug;86(2):242-246. doi: 10.1038/s41390-019-0403-y. Epub 2019 Apr 19.
Cerebrovascular critical closing pressure (CrCP) is the arterial blood pressure (ABP) at which cerebral blood flow ceases. Preterm ABP is low and close to CrCP. The diastolic closing margin (diastolic ABP minus CrCP) has been associated with intraventricular hemorrhage in preterm infants. CrCP is estimated from middle cerebral artery cerebral blood flow velocity (CBFV) and ABP waveforms. However, these estimations have not been validated due to a lack of gold standard. Direct observation of the CrCP in preterm infants with hypotension is an opportunity to validate synchronously estimated CrCP.
ABP and CBFV tracings were obtained from 24 extremely low birth weight infants. Recordings where diastolic CBFV was zero were identified. The gold standard CrCP was delineated using piecewise regression of ABP and CBFV values paired by rank ordering and then estimated using a published formula. The measured and estimated values were compared using linear regression and Bland-Altman analysis.
Linear regression showed a high degree of correlation between measured and calculated CrCP (r = 0.93).
This is the first study to validate a calculated CrCP by comparing it to direct measurements of CrCP from preterm infants when ABP is lower than CrCP.
脑血管临界关闭压（CrCP）是指脑血流停止时的动脉血压（ABP）。早产儿的 ABP 较低且接近 CrCP。舒张期关闭间隙（舒张压 ABP 减去 CrCP）与早产儿脑室出血有关。CrCP 可通过大脑中动脉脑血流速度（CBFV）和 ABP 波形进行估计。然而，由于缺乏金标准，这些估计尚未得到验证。低血压早产儿 CrCP 的直接观察为同步验证同步估计的 CrCP 提供了机会。
从 24 名极低出生体重儿中获得 ABP 和 CBFV 描记图。确定舒张压 CBFV 为零的记录。使用通过按秩排序对 ABP 和 CBFV 值进行配对的分段回归来描绘金标准 CrCP，然后使用已发表的公式进行估计。使用线性回归和 Bland-Altman 分析比较测量值和估计值。
线性回归显示测量和计算的 CrCP 之间具有高度相关性（r=0.93）。
这是第一项通过比较直接测量的 CrCP 与当 ABP 低于 CrCP 时的早产儿 CrCP 来验证计算的 CrCP 的研究。
