Acute Respiratory Distress Syndrome in Mechanically-Ventilated Patients with Community-Acquired Pneumonia

Abstract

Question: To assess the incidence, characteristics, aetiology, risk factors and mortality of acute respiratory distress syndrome (ARDS) in ICU patients with community-acquired pneumonia (CAP) using the Berlin definition.

Methods: We prospectively enrolled consecutive mechanically-ventilated ICU adults with CAP over 20 years, compared with mechanically-ventilated patients without ARDS. The main outcome was 30-day mortality.

Results: Among 5,334 patients hospitalized with CAP, 930 (17%) were admitted to the ICU, and 432 required mechanical ventilation; 125 (29%) cases met the Berlin ARDS criteria. ARDS was present in 2% of hospitalized patients and 13% of ICU patients. Based on the baseline PaO₂/FiO₂, 60 (48%), 49 (40%), and 15 (12%) patients had mild, moderate, and severe ARDS, respectively. Streptococcus pneumoniae was the most frequent pathogen, with no significant differences in aetiology between groups. Higher organ system dysfunction and previous antibiotic use were independent risk factors for ARDS in the multivariate analysis, while previous inhaled corticosteroids was independently associated with a lower risk. The 30-day mortality was similar between patients with and without ARDS (25% vs. 30%, p=0.25), confirmed by propensity-adjusted multivariate analysis.

Conclusions: ARDS occurs as a complication of CAP in 29% of mechanically-ventilated patients, but is not related to the aetiology or mortality.