Using serial oxygenation index as an objective predictor of survival for antenatally diagnosed congenital diaphragmatic hernia

Abstract

IntroductionBest oxygenation index on day 1 (BOId1) had been shown to predict survival in congenital diaphragmatic hernia (CDH). Serial oxygenation index (OI) may enable better assessment of response to cardiorespiratory support than BOId1. MethodsAll antenatally diagnosed CDH from one tertiary neonatal unit were retrospectively reviewed. Oxygenation index at 6, 12, 24, and 48 hours from birth, as well as BOId1, were compared between survivors and nonsurvivors. The area under the curve and receiver operating characteristic (ROC) curves were used to compare serial OI within the first 24 hours and BOId1 between survivors and nonsurvivors. Statistical significance was set at P < .05. ResultsTwenty-four patients with CDH (13 survivors, 11 nonsurvivors) were included. Both groups were comparable in demographics and variables that could affect outcome. In terms of nonsurvival, ROC curve analysis demonstrated a sensitivity of 78% for serial OI greater than 252 and 56% for BOId1 greater than 8.5, both having a specificity of 100%. The area under the ROC curve for serial OI and BOId1 were 0.96 and 0.85, respectively. The positive predictive value of serial OI (>252) and BOId1 (>11) for nonsurvival were both 100%, with an negative predictive value of 87% and 76%, respectively. ConclusionsOur preliminary study showed that serial OI in the first 24 hours of life is a good predictor of survival. It is simple to use and has the added advantage of assessing response to medical support in CDH. The results support the need for a large prospective study exploring the potential of serial OI to guide management and prognosis.