Surfactant and inhaled nitric oxide in rats alleviate acute lung injury induced by intestinal ischemia and reperfusion

Abstract

Background: Respiratory distress and acute lung injury (ALI) are severe complications of intestinal ischemia and reperfusion injury (I/R). The authors hypothesize that a combined surfactant and inhaled nitric oxide (iNO) may alleviate I/R-induced ALI. Methods: Adult rats (body weight 285 to 315 g, n = 45) were allocated randomly to either a negative control group (N-Control, n = 9) with only sham laparotomy, or groups (n = 9 each) for induction of I/R by occlusion of superior mesenteric artery, followed by treatment with (1) surfactant at 100 mg/kg (Surf), (2) iNO at 20 ppm (NO), (3) both surfactant and iNO (SNO), or (4) no surfactant no iNO (a positive control, P-Control). Mechanical ventilation was provided for 120 minutes with variable peak insufflation pressure and FIO2 to achieve adequate arterial pH, PaO2, and PaCO2. Blood gas values, dynamic lung compliance (Cdyn), and airway resistance (Raw) were measured during the 2-hour treatment. Lung wet-to-dry weight ratio (W/D), histopathology, and morphometric analysis of alveolar expansion (VV) were determined at the end of the experiment. Results: After 120 minutes of treatment, the SNO group had the highest PaO2 and Cdyn values, close to that of the N-Control group. The Surf, NO, and SNO groups had higher VV and lower CV (VV) values than the P-Control, but modest decrease of W/D values. The NO group had moderately improved PaO2 but Cdyn and VV were as low as that of the P-Control. The lungs of the SNO group had significantly alleviated edema and neutrophil infiltration compared with the P-Control. Conclusions: The combined surfactant and iNO treatment alleviated rat ALI induced by I/R, and exerted effects better than the use of surfactant or iNO alone. J Pediatr Surg 36:980-984. Copyright © 2001 by W.B. Saunders Company.