Table 3.

Etiology of systemic hypotension in persistent pulmonary hypertension of the newborn

Mechanism	Causes
Reduced LV afterload	systemic vasodilation from sepsis, hypoxia, sedation or vasodilators such as milrinone, prostacyclin analogs or sildenafil
Reduced LV preload	low pulmonary venous return, high intrathoracic pressure impeding venous return, blood loss, dehydration and septal deviation to the left
Pump failure	ventricular dysfunction from hypoxemia, acidosis, ischemia or inflammation
Structural heart disease	coexisting left ventricular hypoplasia with congenital diaphragmatic hernia (CDH) or severe asymmetric septal hypertrophy due to uncontrolled maternal diabetes