Effect of Nitric Oxide on Oxygenation and Hemodynamics in Infants after Cardiac Surgery

Abstract: We evaluated the effect of nitric oxide (NO) on infants after congenital cardiac surgery. Inhaled NO was administered to 7 infants after congenital cardiac surgery. Inhaled NO concentration ranged from 2.5 to 10 parts per million (ppm). The respiratory index (RI = A‐aDo,/Pao,) decreased from 7.4 ± 2.5 to 4.7 ±3.1 in the high RI group (RI ≥ 3, n = 4) 30 min after NO inhalation. After discontinuation of NO inhalation, RI increased to the preinhalation level. NO inhalation was restarted in 2 patients in the high RI group because of severe worsening of oxygenation. RI was not affected by starting or discontinuing of NO in the low RI group (R1 < 3, n = 3). Systemic blood pressure did not significantly change in the 2 groups. Pulmonary arterial pressure (PAP) was measured in 4 patients, and it decreased by 21, 10, and l0%, respectively, 30 min after NO inhalation in 3 patients, but did not change in the remaining patient. After discontinuation of NO inhalation, PAP increased in all patients, and in 2 cases, PAP was higher than baseline value. NO inhalation is effective in improving oxygenation in infants with a high RI after cardiac surgery. However, careful monitoring of the respiratory and hemodynamic states is required after discontinuing NO inhalation.