Nebulized Sodium Nitroprusside (SNP) in Surfactant Depleted Newborn Piglets† 1782

Inhaled nitric oxide (NO) is an effective treatment for respiratory distress syndrome in newborns and adults by selectively reducing pulmonary vascular resistance (PVR) and by improving ventilation/perfusion ratio. Inhaled NO, however, is restricted due to complexity of its delivery. In the present study we tested the hypothesis that the nebulized NO donor SNP would induce pulmonary vasodilatation, and improve oxygenation in surfactant depleted newborn piglets without influencing systemic hemodynamics.Methods: Thirteen instrumented and ventilated newborn piglets were subjected to repeated lung lavages, and then randomly assigned to either the saline group (n=6) or SNP group (n=7). The animals in the SNP group received nebulization of SNP (12 ml of 1.5 mg/mL), and those in the saline group received nebulization of the same volume of saline. Pulmonary and systemic hemodynamic measurements were measured. Arterial and mixed venous blood gases were analyzed. Results: Pulmonary arterial pressure (PAP) and PVR increased after lung lavage while mean arterial blood pressure (MABP) decreased, and systemic vascular resistance (SVR) increased. After nebulized SNP, PAP and PVR decreased while MABP and SVR remained stable. PaO₂ simultaneously increased significantly (p<0.01). The decrease in intrapulmonary shunting, however, was not statistically significant. None of the variables were significantly changed by the nebulized saline.Conclusion: The nebulized SNP produced a selective pulmonary vasodilatation and improved oxygenation in surfactant depleted newborn piglets without influencing systemic hemodynamics. Figure

Figure 1