Prognosis of pathogen-proven acute respiratory distress syndrome diagnosed from a protocol that includes bronchoalveolar lavage: a retrospective observational study

BACKGROUND: To treat patients with acute respiratory distress syndrome (ARDS), it is important to diagnose specific lung diseases and identify common risk factors. Our facility focuses on using bronchoalveolar lavage (BAL) to identify precise risk factors and determine the causative pathogen of ARDS within 24 h of intensive care unit (ICU) admission. This study evaluated the prognoses of pathogen-proven ARDS patients who were diagnosed or identified with risk factors using a diagnostic protocol, which included BAL, compared with the prognoses of pathogen-unproven ARDS patients. METHODS: This retrospective observational study was conducted in the ICU at a tertiary hospital from October 2015 to January 2019. We enrolled patients with respiratory distress who were on mechanical ventilation for more than 24 h in the ICU and who were subjected to our diagnostic protocol. We compared the disease characteristics and mortality rates between pathogen-proven and pathogen-unproven ARDS patients. RESULTS: Seventy ARDS patients were included, of whom, 50 (71%) had pathogen-proven ARDS as per our protocol. Mortality rates in both the ICU and the hospital were significantly lower among pathogen-proven ARDS patients than among pathogen-unproven ARDS patients (10% vs. 50%, p = 0.0006; 18% vs. 55%, p = 0.0038, respectively). Pathogen-proven ARDS patients were independently associated with hospital survival (adjusted hazard ratio, 0.238; 95% confidence interval, 0.096–0.587; p = 0.0021). CONCLUSIONS: Our diagnostic protocol, which included early initiation of BAL, enabled diagnosing pathogen-proven ARDS in 71% of ARDS patients. These patients were significantly associated with higher hospital survival rates. The diagnostic accuracy of our diagnostic protocol, which includes BAL, remains unclear.