repeated as necessary (if still on 20ppm, repeat once a day). MetHb levels are not
required once below 5 PPM. If a baby never had a response, wean off quicker. Never
discontinue INO abruptly even in neonates that had no response to INO- sudden
decompensation and crisis can be precipitated by intense pulmonary vasoconstriction if
INO is suddenly discontinued.
Alternate therapies: Alternate agents are needed when oxygenation fails to improve with
INO and/or PPHN persists by ECHO. These agents are often needed in babies with
CDH. If a baby with PPHN fails to respond to INO and other measures, consider
alveolar capillary dysplasia (ACD) in the differential.
- Type V Phosphodiesterase inhibitor (sildenafil): Blocks degradation of cGMP and
works synergistically with NO. Usually given by oral or NG tube at a dose of 0.5-2mg/kg
repeated every 6-8 hours. IV sildenafil is available- speak to the pharmacist about the
dosing. IV sildenafil use needs approval of attending neonatologist. IV sildenafil is
associated with higher incidence of hypotension - Inhaled prostacyclin analogs (iloprost, prostacyclin) are given by nebulizer, usually for
babies on a ventilator. Prostacyclin increases cAMP levels in smooth muscle cell.
Iloprost is the preferred agent since it can be given by intermittent nebulization, every 2-
6 hours, depending on the duration of response.
Phosphodiesterase III inhibitor, Milrinone: This is given by continuous infusion and
usually started without a bolus in neonates. Usual doses are 0.2-0.5
micrograms/Kg/Min. IV milrinone can cause hypotension and is typically used in