RESUMEN
AIM: To observe the effects of norepinephrine (NE) on the cardiopulmonary and lung injury in goats with acute respiratory distress syndrome (ARDS) induced by endotoxin. METHODS: A model of septic ARDS was induced by intravenous infusion of low dose endotoxin in six goats. Then 40?10~ -6 NO inhalation was applied to the animals. After 30 min, combined intravenous infusion of NE at concentration of 0.5 mg?kg~ -1 ?min~ -1 was conducted. The dynamic changes in gas exchange and hemodynamics were measured with the aid of Swan-Ganz catheter. Arterial blood gas analysis before and after the onset of ARDS, 30 min after NO inhalation and combined NE was detected. Histology of the lung was also observed. RESULTS: Inhalation of NO rapidly reduced mean pulmonary arterial pressure (MPAP), increased PaO_2, decreased P_ (A-a) O_2 and Qs/Qt in septic ARDS goats. These decrease and increase were more significant than those in NO inhaled alone when animals received NE. The combination of NO inhalation and NE injection resulted in increase in mean arterial pressure. NO inhalation did not ameliorate lung injury and combined NE intravenous injection ameliorated lung injury. CONCLUSION: Injection of low dose norepinephrine improves the beneficial effects of inhaled nitric oxide on lung gas exchange and ameliorates lung injury in goats with acute respiratory distress syndrome induced by endotoxin.