EVOLUTION OF BRONCHOALVEOLAR CELL-POPULATIONS IN THE ADULT-RESPIRATORY-DISTRESS-SYNDROME

To characterize the evolution of inflammation in the adult respiratory distress syndrome (ARDS) and test the hypothesis that sustained alveo lar inflammation is associated with a poor outcome in patients with AR DS, we performed fiberoptic bronchoscopy and bronchoalveolar lavage (B AL) in 125 patients and compared BAL cells and protein concentrations in survivors and nonsurvivors. ARDS followed sepsis syndrome in 35 pat ients, major trauma in 41, and other causes in 49. When possible, BAL was performed on Days 3, 7, and 14 after the onset of ARDS. Sixty-five patients (52%) had more than one BAL. We first performed analyses on each BAL day using information from all 212 BAL in the 125 patients (c ross-sectional analysis). AII patients had increased leukocytes and to tal protein in the first BAL (Day 3 after onset of ARDS). In patients with ARDS following sepsis, the percentage of BAL polymorphonuclear le ukocytes (PMN) was higher on Day 7 (p= 0.11) and particularly Day 14 ( p = 0.02) in patients who died; there was a consistent trend of a high er PMN concentration on all days in patients who died then in those wh o lived. In patients with ARDS following trauma and other risks, howev er, BAL PMN measures did not distinguish survivors from patients who d ied. Analysis of serial data from the patients with more than one BAL showed that alveolar macrophages (AM) increased in survivors of ARDS, both in absolute numbers and as a percentage of total cells; this patt ern was most pronounced in the sepsis patients. The cross-sectional da ta analysis suggests that sustained alveolar inflammation occurs frequ ently in patients with ARDS following sepsis and is associated with a high mortality.