DIAGNOSTIC CRITERIA FOR ADULT RESPIRATORY DISTRESS SYNDROME: TIME FOR REAPPRAISAL

Abstract To assess whether current diagnostic criteria for the adult respiratory distress syndrome (ARDS) may limit research to patients with the severest manifestations of lung injury, 50 patients with a range of severity of respiratory failure and risk factors for ARDS were studied. In 28 patients ARDS did not develop; in 9 it did; and the other 13 met the diagnostic criteria at their first assessment. Plasma concentration of neutrophil elastase-α 1 -antitrypsin complex was higher in all groups than in controls. For all patients, plasma elastase-complex was related to worsening hypoxia and to increased bronchoalveolar lavage protein content. Elastase-complex was present in all bronchoalveolar lavage samples and was related to protein content and differential neutrophil counts. Patients at risk of or with ARDS had a spectrum of respiratory failure to which intravascular and intra-alveolar neutrophil elastase release and capillary permeability were related. This suggests that the state recognised as ARDS is not a distinct pathophysiological entity.