Severity of Hypoxemia and Effect of High-Frequency Oscillatory Ventilation in Acute Respiratory Distress Syndrome

RATIONALE: High-frequency oscillatory ventilation (HFOV) is theoretically beneficial for lung protection, but the results of clinical trials are inconsistent, with study-level meta-analyses suggesting no significant effect on mortality. OBJECTIVES: The aim of this individual patient data meta-analysis was to identify acute respiratory distress syndrome (ARDS) patient subgroups with differential outcomes from HFOV. METHODS: After a comprehensive search for trials, two reviewers independently identified randomized trials comparing HFOV with conventional ventilation for adults with ARDS. Prespecified effect modifiers were tested using multivariable hierarchical logistic regression models, adjusting for important prognostic factors and clustering effects. MEASUREMENTS AND MAIN RESULTS: Data from 1,552 patients in four trials were analyzed, applying uniform definitions for study variables and outcomes. Patients had a mean baseline PaO2/FiO2 of 114 ± 39 mm Hg; 40% had severe ARDS (PaO2/FiO2