CONTEMPORARY NEONATAL INTENSIVE CARE MANAGEMENT IN CONGENITAL DIAPHRAGMATIC HERNIA: DOES THIS OBVIATE THE NEED FOR FETAL THERAPY?

Abstract

The management of congenital diaphragmatic hernia (CDH) in the newborn infant has changed radically since the first successful outcomes were reported 60 years ago. Then it seemed a surgical problem with a surgical solution – do an operation, remove the intestines and solid viscera from the thoracic cavity, repair the defect and allow the lung to expand. CDH in that era was regarded as the quintessential neonatal surgical emergency. The expectation was that urgent surgery would result in improvement in lung function and oxygenation. That approach persisted up to the 1980s when it was realized that the problem was far more complex and involved both an abnormal pulmonary vascular bed as well as pulmonary hypoplasia. The use of systemically delivered pulmonary vasodilator therapy, principally tolazoline, became a focus of interest in the 1980s with small case reports and case series suggesting improved survival. In the 1990s, based on studies that showed worsening thoracic compliance and gas exchange following surgical repair, deferred surgery and pre-operative stabilization became the standard of care. At the same time extracorporeal membrane oxygenation (ECMO) was increasingly used either as part of pre-operative stabilization or as a rescue therapy after repair. Other centres chose to use high frequency oscillatory ventilation (HFOV). Despite all these innovations the survival in live born infants with CDH did not improve to more than 50% in large series published from high volume centres. However, in the past 10 years there has been an appreciable improvement in survival to the extent that many centres are now reporting survival rates of greater than 80%. Probably the biggest impact on this improvement has been the recognition of the role that ventilation induced lung injury plays in mortality and the need for ECMO rescue. This has ushered in an era of a lung protective or “gentle ventilation” strategy which has been widely adopted as a standard approach. While there have been these radical changes in postnatal management attempts have been made to improve outcome with prenatal interventions, starting with prenatal repair, which was abandoned because of preterm labour. More recently there has been increasing experience in the use of balloon occlusion of the trachea as a prenatal intervention strategy with patients being selected based on prenatal predictors of poor outcome. This approach can only be justified if those predictors can be validated and the outcomes (death or serious long term morbidity) can be shown to be better than those currently achievable, namely 80% survival in high volume CDH centres rather than the 50–60% survival frequently quoted in historical papers.