The ability of the newborn infant to adapt to the extra-uterine environment is critical to sur- vival. All systems of the body undergo important physiological changes at the time of delivery [1]. Arguably none is more critical to survival than the adaption of the lungs [2]. In utero, the fetus receives a constant supply of oxygen and nutri- ents via the placenta and umbilical vessels, with carbon dioxide excretion also managed via the maternal circulation. The lungs are lled with uid secreted by the respiratory epithelium [3] which is important for promoting lung growth. Some congenital malformations of the lungs or airways may not a ect the fetus or its develop- ment in utero, even anomalies incompatible with extra-uterine life. Hydrops fetalis is a recognised complication of larger lesions, including those that a ect the arterial circulation. During the rst gasp immediately a er birth, the neonate lls the airways down to alveolar level with air to com-
mence extra-uterine gas exchange [2]; simulta- neously, decreasing pulmonary vascular pressure to allow increased blood ow to the lungs [4]; additionally, reabsorption of the fetal lung uid occurs [5]. A preterm neonate born at