Impact of ARDS Etiology on the Failure of Noninvasive Ventilation and 28-Day Mortality: A Multicenter Prospective Observational Study

Background: The failure rate of noninvasive ventilation (NIV) remains high in patients with acute respiratory distress syndrome (ARDS). The etiology of ARDS may play an important role in NIV failure.Methods: A multicenter prospective observational study was performed in 17 ICUs in China from September 2017 to December 2019. ARDS patients who used NIV as a first-line therapy were enrolled. The etiology of ARDS was recorded at study entry. Results: A total of 306 patients were enrolled. Of the patients, 146 were classified as having pulmonary ARDS (ARDSp) and 160 were classified as having extrapulmonary ARDS (ARDSexp). NIV improved PaO2/FiO2 from initiation to 24 h of NIV in both groups. However, it improved more slowly in patients with ARDSp than in those with ARDSexp (interaction effect: p < 0.01). ARDSp patients experienced more NIV failure (55% vs. 28%; p < 0.01) and higher 28-day mortality (47% vs. 14%; p < 0.01). The multivariate Cox regression also showed that ARDSp was independently associated with NIV failure (hazard ratio [HR] = 2.81, 95% confidence interval [CI]: 1.89-4.18) and 28-day mortality (HR = 7.49, 95% CI: 4.32-13.01). After propensity matching, 62 patients remained in each group. The baseline data were comparable between the two groups. ARDSp was still independently associated with NIV failure and 28-day mortality (HR = 2.62, 95%CI: 1.49-4.61; and 5.70, 2.59-12.55, respectively). Sensitivity analysis also confirmed these results. Conclusions: Among ARDS patients who used NIV as a first-line therapy, ARDSp was associated with slower improvement in oxygenation, more NIV failure, and higher 28-day mortality than ARDSexp.