Background: Persistent pulmonary hypertension of the newborn (PPHN) is
defined as the failure of the normal circulatory transition that occurs after birth.
It is a syndrome characterized by marked pulmonary hypertension that causes
hypoxemia and right-to-left intracardiac shunting of blood. The treatment of
severe PPHN remains a challenge in many NICUs despite the development of
various drugs and ventilatory modes. Inhaled nitric oxide has been proven in
many studies to be the accepted modality of choice in term newborns, but is
of limited use in preterm newborns (Soil , 2012).The search for other potential
drugs in the treatment of PPHN continues. Spillers (2010) reviewed a number of
recent studies suggested a role for specific phosphodiesterase (PDE) inhibitors in
the management of PPHN. Sildenafil, a specific PDE5 inhibitor, with its selective
pulmonary vasodilator properties, appears to be the most promising of such agents