Pathophysiology of persistent pulmonary hypertension of the newborn-cellular basis and lessons from animal studies

Persistent pulmonary hypertension of the newborn (PPHN) is a syndrome of failed circulatory adaptation at birth due to the delay in or impairment of the normal fall in pulmonary vascular resistance that occurs following delivery. This chapter highlights the biochemical, physiological, and cellular changes during normal and abnormal cardiovascular transition at birth using information from human studies and various animal models of PPHN. The clinical relevance of these findings, applied physiology, and therapeutic strategies to correct these abnormalities are also discussed. Current treatment for infants is limited to inhaled nitric oxide and off-label use of agents approved for pulmonary hypertension in adults. Hence, there is a dire need to develop evidence-based strategies to evaluate new medications and approaches for the treatment of PPHN.