Cerebral Blood Volume Within 6 Hours of Birth in Hypoxic–Ischemic Encephalopathy Assessed Using Time-Resolved Near-Infrared Spectroscopy

Abstract The impact of the cerebral blood volume (CBV) within 6 hours of birth (early CBV) on the prognosis of hypoxic–ischemic encephalopathy (HIE) remains unknown. Therefore, we investigated whether the early CBV, measured using time-resolved near-infrared spectroscopy (tNIRS), is an early predictor of adverse outcomes in neonates with HIE. This single-center retrospective study included neonates diagnosed with any grade of HIE between 2017 and 2024. Therapeutic hypothermia was initiated in neonates with moderate or severe HIE, but not in those with mild HIE. Early CBV was measured within 6 hours of birth using tNIRS. A short-term adverse outcome was defined as a moderate-to-severe injury detected on magnetic resonance imaging. A total adverse outcome included death before discharge, cerebral palsy, and unfavorable developmental assessment at approximately 2 years of age. Among 215 eligible neonates with mild-to-severe HIE, 94 (44%) who underwent tNIRS were enrolled in this study. Of these, 38 (40%), 46 (49%), and 10 (11%) had mild, moderate, and severe HIE, respectively. Multivariate logistic regression analyses adjusted for the initial HIE severity and therapeutic hypothermia administration revealed that early CBV was significantly associated with a short-term adverse outcome (n = 70; odds ratio, 4.78; 95% confidence interval: 1.55–14.7; p = 0.006), but not with a total adverse outcome. The receiver operating characteristic curve for short-term adverse outcomes showed that the cut-off value of early CBV was 2.91 mL/100 g. The area under the curve of early CBV was 0.64 (95% confidence interval: 0.49–0.79) and when combined with amplitude-integrated electroencephalography, it was 0.75 (95% confidence interval: 0.61–0.88). Early CBV has the potential to predict short-term adverse outcomes and improves the predictive ability when combined with amplitude-integrated electroencephalography. However, further investigations are needed because of the wide confidence intervals.