Early Cerebral Oxygen Extraction and the Risk of Death or Sonographic Brain Injury in Very Preterm Infants

Abstract

To evaluate the relationship between cerebral fractional tissue oxygen extraction (cFTOE), a measure of oxygen delivery-consumption equilibrium, and the risk of early poor outcome in very preterm infants. Cerebral blood flow, tissue oxygenation index (by near-infrared spectroscopy), and arterial oxygen content were measured, and cerebral oxygen delivery, consumption, and cFTOE were calculated at 3 intervals in the first 72 hours of life in infants ≤ 30 weeks gestational age (GA). A receiver operating characteristic curve was derived with an a priori defined dichotomized outcome of good or poor, defined as death or sonographic brain injury (grade ≥ II intraventricular hemorrhage) by day 7. Seventy-one infants were enrolled, with a mean (SD) GA of 27 (2) weeks. cFTOE demonstrated better discrimination for the study outcome at <24 hours of age than at 48 or 72 hours of age (P = .01). The area under the curve for cFTOE at the initial measurement was no different from that for GA alone (0.87; 95% CI, 0.77-0.95 vs 0.81; 95% CI, 0.69-0.92), but the combined measure of cFTOE and GA had better discrimination (0.96; 95% CI, 0.91-1.0) than either cFTOE (P = .03) or GA (P = .016) alone. A cFTOE of 0.4 had a sensitivity of 82% and specificity of 75% for risk of early poor outcome. Elevated cFTOE values are associated with increased risk of early poor outcome in very preterm infants. Its predictive value is further improved with the addition of GA.