Nebulization of sodium nitroprusside in lung-lavaged newborn piglets.

The aim of the present study was to test the hypothesis that nebulization of the nitric oxide donor sodium nitroprusside may selectively reduce pulmonary vascular resistance and improve oxygenation in lung-lavaged newborn piglets. Thirteen anesthetized piglets (1-3 d old) were subjected to repeated lung lavages and then randomly assigned to one of the following two groups: 1) an SNP group, which received SNP nebulization, and 2) a saline group, which received saline nebulization. Pulmonary arterial pressure and pulmonary vascular resistance increased significantly after lung lavage, whereas cardiac output decreased significantly in both groups. After SNP nebulization, pulmonary arterial pressure decreased from 32+/-1 to 17+/-1 mm Hg (p < 0.01) and PVR decreased from 255+/-20 to 172+/-15 mm Hg L(-1) min(-1) kg(-1) (p < 0.01). The arterial tension of oxygen concomitantly increased from 9.4+/-4.0 to 17.0+/-3.0 kPa (p < 0.01), and the arterial/alveolar ratio of oxygen tension increased from 0.11+/-0.01 to 0.22+/-0.03 (p < 0.01). Systemic hemodynamics were not modified significantly during nebulization of SNP. On the other hand, all variables were stable during nebulization of saline. These data suggest that SNP nebulization produces a selective pulmonary vasodilatation and improves oxygenation in lung-lavaged newborn piglets.