Despite all advances in neonatal intensive care, severe pulmonary hypertension in the neonate is still a syndrome with a high morbidity and mortality. Several strategies have been tried with a variable degree of success. In the last 5 years, Nitric Oxide (NO) has emerged as a potential therapeutic agent to lower pulmonary artery pressure and improve PPHN. Since September 1994 all newborn infants admitted to our NICU with PPHN weithing>1500 g and who met ECMO criteria were treated with NO. PPHN was diagnosed by clinical and echocardiographic criteria. All infans had a rigth to left shunt documented by pulse doppler echocardiogram at time of treatment with NO. Concentration of NO and NO2 were monitored with Draeger eletrochemical devices(PACI and PACII) and metahemoglobin was assessed in every baby. A total of 9 infants met the entry criteria. Mean birth weight was 2698 ± 661g and G.A. was 36.4 ± weeks. PPHN was due to HMA(5), MA(1), sepsis(1) and pneumonia(2). Infants were critically ill before NO with a mean pH=7.23±.11, PaO2=35.5 ± 13 mm Hg, PaCO2=41.5± 12 mmHg, SaO2=73± 15% on 100% oxygen and maxinal ventilatory support(OI=18.5±34). Oxygen saturation improved within 15 min after the start of NO with reversal of right to left shunt in all babies. Mean response time was 16 ± 7 min. The response seems to be greater in the sickest babies, our results are summarized below: Table We did not observe adverse effects on systemic arterial pressure. Only one patient showed hypotension concomintant with NO use. We observed no other complication with NO treatment and metaheglobin levels did not reach 1.5 mg% in any baby. Eight out of nine patients survived and were discharged home. Our results show that NO is very effective in sick babies with PPHN, preventing the use of ECMO and improving survival.

Table 1
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