When pulse oximetry readings are taken separately in each of the four extremities, oxygenation can be 10% higher in the right arm, the preductal extremity Arterial blood gases will show hypoxemia with or without hypercarbia CXR will show variable findings according to the underlying etiology Aggressive treatment of PPHN should include fluid resuscitation, minimal stimulation including darkening the room and adequate sedation, and maintaining adequate systemic pressures with pressors if needed Use of high-frequency oscillatory ventilation, inhaled nitric oxide, and extracorporeal membrane oxygenation may be lifesaving Any neonate with desaturation, cyanosis, and escalating acute respiratory failure should be admitted to the intensive care unit