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

Background: Respiratory distress and acute lung injury (ALI) are severe com plications 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 rando mly to either a negative control group (N-Control, n = 9) with only sham la parotomy, or groups(n = 9 each) for induction of I/R by occlusion of superi or mesenteric artery, followed by treatment with (1) surfactant at 100 mg/k g (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 ventilati on was provided for 120 minutes with variable peak insufflation pressure an d Fro, to achieve adequate arterial pH, PaO2, and PaCO2. Blood gas values, dynamic lung compliance (Cdyn), and airway resistance (Raw) were measured d uring the 2-hour treatment. Lung wet-to-dry weight ratio (W/D), histopathol ogy, and morphometric analysis of alveolar expansion (V-v) were determined at the end of the experiment. Results: After 120 minutes of treatment, the SNO group had the highest Pao( 2) and Cdyn values, close to that of the N-Control group. The Surf, NO, and SNO groups had higher V-v and lower CV (V-v) values than the P-Control, bu t modest decrease of W/D values. The NO group had moderately improved Pao, but Cdyn and V-v were as low as that of the P-Control, The lungs of the SNO group had significantly alleviated edema and neutrophil infiltration compa red with the P-Control. Conclusions: The combined surfactant and iNO treatment alleviated rat ALI i nduced by I/R, and exerted effects better than the use of surfactant or iNO alone. Copyright (C) 2001 by W.B. Saunders Company.