Unfortunately, at the time of discharge, the continued patency of the PFO and PDA will maintain balance between the lungs and the body. Some unoxygenated blood will shunt right to left across the PDA into the aorta and out to the body while the rest will go to the lungs to be oxygenated. Then, the cycle starts over with the RV ejecting mixed red and blue blood into the PA, delivering some oxygen to the body, but most importantly, blood flow to the system. If the PFO is closed or restrictive to delivering oxygenated blood to the RA, the infant will appear more cyanotic at birth. In HLHS, the PDA ceases blood flow to the body, resulting in profound systemic shock, hypoxemia, and cyanosis.
Metabolic acidosis befalls rapidly with ensuing multiple organ failure.
The fear is that the PDA closes when the infant is geographically remote from appropriate medical attention. The reversibility of this scenario depends on how quickly the PDA is reopened. A blue neonate can throw even the best of clinicians offsides, therefore, an explanation about cyanosis and other differential diagnoses can help you make the right call. Peripheral cyanosis in newborns is a common response to the cold and improves with warming or movement . Acrocyanosis of the hands and feet is also normal for the first few days of life and is related to the inability of the immature sympathetic nervous system to regulate blood flow to the skin.