Conventional mechanical ventilation can injury intact lungs in severe trauma patients

Abstract

Introduction: Conventional mechanical ventilation (MV) may cause additional lung injury in ALI/ARDS due to overdistention of aerated lung regions (high Vt) and cyclic lung reopening (low PEEP level). Hyperproduction of inflammatory mediators is one of the side effects in these cases. This factor could delay or prevent resolution of respiratory failure [1,2]. However, it is not clear whether conventional mechanical ventilation damages intact lungs. The aim of this study was to evaluate the effects of conventional and protective mechanical ventilation on intact lungs in patients with severe trauma. Methods: A prospective, randomized controlled trial in trauma patients with mechanical ventilation for extrapulmonary indications. The protocol was approved by the local ethics committee. Seventy-eight patients were randomized to conventional (Vt 10 to 12 ml/kg IBW, PEEP 5 cmH2O - n = 39) or protective (Vt 5 to 6 ml/kg IBW, PEEP 10 cmH2O - n = 39) mechanical ventilation. TNFalpha, IL-1beta and IL-6 levels in plasma and BAL fluids were measured on 1, 2, 3, 5 and 7 days of MV. Frequency of ALI (AECC criteria) and VAP were evaluated. The endpoints of this study were the length of MV, LOS in ICU and outcome on 28 days. Results: In first 3 days ALI was revealed in 26 patients (66.6%) in the conventional and 10 patients (26.5%) in the protective MV groups (P = 0.001; OR 4.375, 95% CI 2.227 to 8.189). ARDS occurred in four patients (10,2%) of the conventional MV group (LIS >2) and no one in the protective MV group (P