High‐frequency oscillatory ventilation (HFOV) associated with inhaled nitric oxide (iNO) attenuates oxidative lung injury in a saline‐lavaged rabbit model of acute respiratory distress syndrome (ARDS)

Abstract

ARDS has been associated with high mortality rate despite a better understanding of its pathophysiology and recent advances in treatment.ObjectiveTo compare protective conventional mechanical ventilation (CMV) and HFOV associated or not with iNO for lung oxidative stress.MethodsLung injury was induced by tracheal infusion of warm saline. Fifty rabbits were randomly assigned to: a) Control (CG): without ARDS + CMV; b) ARDS + CMV (MVG); c) ARDS + CMV with iNO (MVGNO); d) ARDS + HFOV (HFG) and e) ARDS + HFOV with iNO (HFGNO). In addition, ten rabbits were used for oxidative stress analysis without ARDS and MV treatment, Healthy group (HG). Lung oxidative stress was assessed by total antioxidant performance (TAP) assay.ResultsAll ARDS groups showed worse PaO2/FiO2 (CG: 438.4±87.1 > MVG: 79.9±12.7 = MVGNO: 80.7±24 = HFG: 66.2±34.2 = HFGNO: 56±21; p<0.05), as compared to those of CG. After 4 hours of MV, HFOV groups showed better oxygenation (PaO2/FiO2: CG: 465.9±30.5 = HFG: 399.1±98.2 = HFGNO: 326.9±119 > MVG: 232.7±104 = MVGNO: 218.3±118; p<0.05) and reduced oxidative stress in lung (TAP, % protection: HG: 67.3±4.21 = HFG: 69.0±4.99 = HFGNO: 68.9±4.14 > MVG: 47.6±2.58 = MVGNO: 56.3±2.40 = CG: 59.4±4.52, p<0.05) compared to CMV groups.ConclusionHFOV improves oxygenation and attenuates oxidative lung injury in saline‐lavaged rabbit model of ARDS. [Supported by FAPESP: 2008/08199‐2, USDA 1950‐51000‐065‐08S]