Inhaled nitric oxide to newborns and infants after congenital heart surgery on cardiopulmonary bypass - A dose-response study

Twelve patients (median age 3.8 months) with pulmonary hypertension in the postoperative period after congenital heart surgery on cardiopulmonary bypa ss were given inhaled nitric oxide. Effects on cardiovascular and respirato ry systems were measured. Mean pulmonary artery pressure decreased from 33 +/- 2 to 28 +/- 2 mmHg (p < 0.001) and arterial oxygen tension increased fr om 13.3 +/- 2.3 to 16.7 +/- 2.7 kPa (p < 0.05). The mean change in arterial oxygen tension in percent was 29.8 +/- 6.3% (p < 0.05). The response was s ignificant only in the first step from 0 to 3 or 5 ppm with no further sign ificant changes in mean pulmonary artery pressure or oxygenation at higher doses. The decrease in mean pulmonary artery pressure was concomitant with a significant increase in arterial oxygen tension. No dose-response relatio nship was found with increasing doses to 80 ppm.