Epidemiology of the acute respiratory distress syndrome and the prognostic validity of SpO2:FiO2 under the expanded Global definition.

Summary

In a prospective cohort of 950 critically ill sepsis patients, 49% met ARDS criteria under the 2023 Global definition versus 45% under the Berlin definition over 6 days. The Global definition allowed ARDS classification a median 3.0 hours earlier. SFR (SpO2/FiO2) correlated moderately with PaO2/FiO2 and predicted 30-day mortality; patients meeting only the Global definition had lower mortality than those meeting Berlin criteria.

Key Findings

• In 950 sepsis ICU patients, 466 (49%) met ARDS criteria under the Global definition vs 427 (45%) under the Berlin definition during 6-day follow-up.
• Global definition allowed ARDS qualification a median 3.0 hours earlier than Berlin definition.
• SpO2/FiO2 ratio (SFR) predicted 30-day mortality and showed moderate correlation with PaO2/FiO2.

Clinical Implications

Adoption of the Global definition and use of SFR could increase ARDS detection and allow earlier recognition in patients on high-flow nasal oxygen; SFR may be used for bedside prognostication when arterial blood gas is unavailable, though patients identified only by Global criteria may have better short-term outcomes.

Limitations

• Cohort limited to critically ill sepsis patients; generalizability to non-sepsis ARDS or broader populations may be limited.
• Follow-up limited to 6 days for ARDS ascertainment; longer trajectories and late-onset ARDS may be missed.

Future Directions

External validation in broader ICU populations including non-sepsis ARDS, assessment of SFR thresholds across devices and SpO2 ranges, and evaluation of how earlier Global-based diagnosis affects management and outcomes in randomized implementation studies.