P0746 - Monitoring Neonates at Risk for Periventricular-Intraventricular Hemorrhage and Post-Hemorrhagic Ventricular Dilatation: Evaluating the Use of Near-Infrared Spectroscopy

Background: Post-hemorrhagic ventricular dilatation (PHVD) is a significant complication of periventricular-intraventricular hemorrhage (PIVH) in preterm infants and is associated with adverse neurodevelopmental outcomes. Approximately 25-40% of preterm infants with PHVD require shunt placement, though the optimal timing of placement to prevent further brain injury remains unclear. The purpose of this single center study was to evaluate the utility of near-infrared spectroscopy (NIRS) and its’ detection of regional cerebral oxygen saturation (rScO2) as indicators of cerebral perfusion in very low birth weight (VLBW) preterm infants at risk for PIVH and PHVD.

Methods: NIRS was used to measure rScO2 in preterm infants with birthweight < 1250 grams within 24 hours of cranial ultrasound examinations to diagnose and follow the development of PIVH and PHVD. Ventricular size was estimated by measurement of the frontal-occipital horn ratio (FOR) and rScO2 was averaged at bedside over thirty minutes. FOR was calculated by adding the largest biventricular width of the anterior cerebral ventricles to that of the occipital ventricles and dividing their sum by twice the greatest intracranial diameter. PHVD was defined as FOR > 0.55. NIRS data were analyzed with respect to FOR and degree of IVH, among time and other clinical markers. Statistical analyses were performed using the Pearson, Kendall’s, ANOVA and Games-Howell tests as well as the Generalized Estimation Equation (GEE) model.

Results: 106 premature infants were studied with serial FOR and rScO2 measurements. There were 90 (85%) with FOR<0.55 and 16 (15%) with FOR > 0.55. There were 54 (51%), 29 (27%), and 23 (22%) in IVH 0, 1-2, and 3-4 groups, respectively. Generally, there was a significant negative correlation between rScO2 and FOR, r= -0.54, p<0.001. Although the correlation between rScO2 and FOR was significant for IVH 1-2 (p=0.004) and for IVH 3-4 (p<0.001), it was not significant for IVH 0. While there was a significant correlation between gestational age in weeks and anterior horn width, rScO2 was not significantly associated with either variable. The rScO2 significantly increased by increasing hematocrit (p<0.001) but there was not any significant association between PaCO2, MABP, and rScO2.

Conclusions: These results show a significant correlation between a marker of decreased cerebral perfusion and increasing ventricular size. There was a consistent decrease in rScO2 with PHVD independent of IVH severity, suggesting a critical relationship between increasing ventricular dilatation and brain oxygenation. This study suggests the potential utility of NIRS in helping to determine the optimal timing of cerebrospinal fluid diversion procedures. More data are needed to better assess the degree of decreasing rScO2 within and between cohorts of progressive PHVD. A future area of interest is using NIRS in conjunction with cerebrospinal fluid concentrations of biomarkers to help delineate when to repeat or escalate neurosurgical interventions.