RESUMEN
Persistent pulmonary hypertension of the neonate (PPHN), described initially by Gersony in 1969 as persistent foetal circulation (PFC syndrome), results from a flawed transition from foetal to extrauterine pulmonary circulation. It is primarily characterised by persistence of, or return to, the suprasystemic pulmonary vascular resistance and pressure normally found in the foetus. The increased pulmonary pressure causes right to left shunting through the ductus arteriosus or the foramen ovale, or both. The resulting hypoxaemia and acidosis may produce further pulmonary vasoconstriction and lead to a vicious cycle of shunting, hypoxia and acidosis. Infants with a wide variety of underlying clinical conditions develop PPHN. This condition is reversible, but can cause very severe and unrelenting respiratory failure and ultimate death when uncontrolled. Although vasodilating agents, such as tolazoline, have been used with variable success in the treatment of PPHN, a generally acceptable therapy is still lacking. We report here the use of prostacyclin (epoprostenol, PGI2) in two infants with severe and refractory hypoxaemia secondary to pulmonary vasoconstriction.