THE USE OF PHOSPHODIESTERASE INHIBITOR (DIPYRIDAMOLE) TO WEAN FROM INHALED NITRIC-OXIDE

A full-term, male neonate developed persistent pulmonary hypertension, and responded to high-frequency oscillatory ventilation and inhaled n itric oxide (INO), Discontinuation of INO was attempted three times an d was followed by severe desaturations due to right-to-left shunt thro ugh the parent ductus arteriosus and parent foramen ovale. As a result of this rebound pulmonary hypertension, the neonate was maintained on INO therapy for 6 days, Successful discontinuation was achieved by us ing the phosphodiesterase inhibitor, dipyridamole, We speculate that d uring exogenous INO therapy, endogenous nitric oxide was inhibited, th us cyclic guanosine 3',5'-monophophate, the smooth muscle relaxant, wa s rapidly hydrolyzed, By inhibiting phosphodiesterase, smooth muscle r elaxation occurred, and consequently weaning from INO was achieved.