Pulmonary Hypertension (PPHN) present in newborns with congenital diaphragmatic hernia is a common occurrence. Pulmonary Hypertension is an increased pressure in the arteries supplying blood to the lungs. This increased pressure shunts blood away from the lungs and decreases the supply of oxygen to the body. This shunting of blood away from the lungs is normal blood flow while the baby is inside the uterus because the baby is not breathing on his/her own. However, once a baby is born these arteries in the lungs need to relax so that blood can flow through the lungs and exchange gases. These gases are exchanged when the blood rids itself of carbon dioxide and pick up oxygen to supply the body. Pulmonary hypertension is a life-threatening complication. If the oxygen levels are low more aggressive treatment options, include nitric oxide therapy and a heart bypass machine (ECMO) can be attempted.
Nitric Oxide (NO) is a gas that dilates the pulmonary blood vessels and lowers pulmonary blood pressure. By supplying NO directly into the lungs the pulmonary vasculature (blood vessels in the lungs) relaxes but the systemic blood vessels (blood vessel in the body) do not. This lowers the pressure in the lungs but not the blood pressure in the general body. Blood is able to circulate through the lungs and pick up oxygen and rid itself of carbon dioxide. Unfortunately NO treatment works more effectively in babies with pulmonary hypertension from other causes and may not work as well for children with congenital diaphragmatic hernias.
Some of the most commonly used drugs prescribed to treat pulmonary hypertension include:
- epoprostenol (Flolan),
- bosentan (Tracleer),
- intravenous treprostinil (Remodulin),
- inhaled iloprost (Ventavis),
- sildenafil (Viagra, Revatio),
- calcium channel blockers (such as nifedipine),
- sitaxsentan (Thelin) – not FDA approved in the U.S., and
- ambrisentan (Letairis)
The most common drug used to treat congenital diaphragmatic hernia infants for Pulmonary Hypertension is sildenafil.
Pulmonary Hypertension Association http://www.phassociation.org/