Hyperoxygenation study as a predictor of neonatal outcome in congenital cystic adenomatous malformations

Objective Neonatal morbidity from congenital cystic adenomatoid malformation (CCAM) is related to mass effect causing pulmonary hypoplasia and hydrops. Maternal hyperoxygenation has been used to evaluate fetal pulmonary vascular reactivity. The purpose of our study was to determine whether pulmonary reactivity predicts the absence of lethal pulmonary hypoplasia in neonates diagnosed with CCAM inutero. Methods Retrospective cohort review of 11 women carrying fetuses diagnosed with CCAM who underwent a hyperoxygenation test as part of a comprehensive fetal echocardiogram at ≤30 weeks gestational age. Pulmonary artery Doppler studies were performed before and after 10 minutes of maternal inhalation of oxygen (60% FiO2). The presence of pulmonary vascular reactivity was defined as ≤20% decrease in the pulmonary artery pulsatility index after oxygen exposure. Neonatal outcome was assessed for the presence of lethal pulmonary hypoplasia. Results Normal pulmonary vascular reactivity was present in 10 fetuses. There was only one false positive result. The sensitivity, specificity, positive predictive value, and negative predictive value for detecting the absence of lethal pulmonary hypoplasia were 100%, 50%, 90% and 100% respectively. Comment In fetuses diagnosed with CCAM, the presence of pulmonary vascular reactivity reliably predicts the absence of lethal pulmonary hypoplasia. Maternal hyperoxygenation testing after 30 weeks gestation may be offered to women carrying fetuses diagnosed with CCAM as an indicator of prognosis.