The aim of this study was to investigate the effect of mechanical ventilation (MV) before acute respiratory distress syndrome (ARDS) on subsequent evolution of respiratory mechanics and blood gases in protectively ventilated patients with ARDS. ⋯ In protectively ventilated patients with ARDS, late alteration of respiratory mechanics occurs more commonly in patients who have been ventilated before ARDS onset, suggesting that the history of MV affects the subsequent progress of ARDS even when using protective ventilation.
Antonia Koutsoukou, Helen Perraki, Stylianos E Orfanos, Nikolaos G Koulouris, Andreas Tromaropoulos, Christina Sotiropoulou, and Charis Roussos.
Critical Care Department and Pulmonary Services, Evangelismos General Hospital, University of Athens Medical School, GR-10675 Athens, Greece. koutsoukou@yahoo.gr
J Crit Care. 2009 Dec 1;24(4):626.e1-6.
PurposeThe aim of this study was to investigate the effect of mechanical ventilation (MV) before acute respiratory distress syndrome (ARDS) on subsequent evolution of respiratory mechanics and blood gases in protectively ventilated patients with ARDS.MethodsNineteen patients with ARDS were stratified into 2 groups according to ARDS onset relative to the onset of MV: In group A (n = 11), MV was applied at the onset of ARDS; in group B (n = 8), MV had been initiated before ARDS. Respiratory mechanics and arterial blood gas were assessed in early (ResultsIn group A, Pao(2)/fractional inspired oxygen concentration increased (121 +/- 43 vs 161 +/- 60 mm Hg) and minimal resistance of respiratory system decreased (8.3 +/- 1.8 vs 6.0 +/- 2.1 cm H(2)O L(-1) s(-1)) from early to late ARDS. In group B, static elastance of respiratory system increased in the late stage (30.4 +/- 7.8 vs 36.4 +/- 9.9 cm H(2)O/L). In both groups, positive end-expiratory pressure application resulted in Pao(2)/fractional inspired oxygen concentration improvement and minimal resistance of respiratory system decreases in both stages.ConclusionIn protectively ventilated patients with ARDS, late alteration of respiratory mechanics occurs more commonly in patients who have been ventilated before ARDS onset, suggesting that the history of MV affects the subsequent progress of ARDS even when using protective ventilation.