Supplementary Material for: Cerebral Oxygenation, Superior Vena Cava Flow, Severe Intraventricular Hemorrhage and Mortality in 60 Very Low Birth Weight Infants

Background: Brain vulnerability in the critically ill preterm newborn may be related to the burden of cerebral hypoxygenation and hypoperfusion during the immediate postnatal period. Objective: We determined the association between adverse outcomes [death or high grade intraventricular hemorrhage (IVH)] and continuous cerebral tissue oxygen saturation (rSO₂), superior vena cava flow (SVCf) and cerebral fractional oxygen extraction (CFOE) in very low birth weight (VLBW) infants during the first 48 h of life. Methods: We studied a prospective cohort of 60 VLBW infants admitted to our neonatal intensive care unit within the first 6 h of life between March 2010 and June 2012. rSO₂ (expressed as a number of summary measures) was continuously monitored with near-infrared spectroscopy (INVOS 5100 Somanetic) during the first 48 h of life, SCVf was measured at 4-6, 12, 24 and 48 h after birth, and CFOE was calculated. Results: The mean gestational age was 27.9 (SD 2.39); 8 infants died (13.3%) and 7 developed IVH grade III-IV: 1 in the alive group and 6 in the deceased group (p < 0.001). The odds ratio for death was 1.08 (95% CI: 1.015-1.15, p = 0.016) for each 10 periods of rSO₂ values <40% in the first 48 h, and 4.2 (95% CI: 1.27-14.05, p = 0.019) for SVCf values <40 ml/kg/min. Among alive babies, mean CFOE decreased at 24, 36 and 48 h; among deceased babies it did not (p < 0.001). In the multivariate analyses, these results retained significance. Conclusions: Both rSO₂ ≤40% and SVCf <40 ml/kg/min independently increase the risk of death. The trend in CFOE supports the ischemic-hypoperfusion hypothesis as a mechanism for cerebral damage.