(1161) The New Global Definition of ARDS Recently Introduced a Subgroup Known as Nonintubated ARDS

Introduction: This study aimed to assess the risk of progression from non-invasive oxygen support to intubation and ARDS severity based on the SpO2:FiO2 ratio among non-intubated ARDS patients.

Methods: This retrospective study included COVID-19 patients admitted to seven hospitals (five in the United States and two in Argentina) from January 2020 to January 2023. Patients meeting the new non-intubated ARDS definition (HFNC with a SpO2:FiO2 ratio ≤315 [with SpO2 ≤97%] or a PaO2/FiO2 ratio ≤300mmHg while receiving ≥30L/min O2 via HFNC), were included. The study evaluated the proportion of patients who progressed to intubation, severity levels using the SpO2:FiO2 ratio cutoff proposed in the New ARDS definition, and mortality.

Results: 965 patients with non-intubated ARDS were included, of whom 27% (n=262) progressed to meet the Berlin criteria within a median of 3 days (IQR 2, 6). The overall mortality was 23% (95% CI 20 to 26%; N=225), and among patients who progressed to the Berlin Criteria, it was 37% (95% CI 31 to 43; N=98). Additionally, the worst SpO2:FiO2 ratio within one day of ARDS diagnosis was correlated with mortality, with mortality rates of 26% (95% CI 23 to 30%; n=177) for patients with SpO2:FiO2 ≤ 148, 17% (95% CI: 12% to 23%; n=38) for those with SpO2:FiO2 between 149 to 234, and 16% (95% CI 8 to 28%; n=10) for patients maintaining a SpO2:FiO2 higher than 235 (p < 0.001).

Conclusions: The non-intubated ARDS criteria encompass a broader spectrum of patients with lower in-hospital mortality compared to the Berlin criteria. The SpO2:FiO2 ratio and ARDS severity cutoff proposed in the New Global ARDS definition are valuable predictors of in-hospital mortality in these patients.