Prognostication using SpO(2)/FiO(2) in invasively ventilated ICU patients with ARDS due to COVID-19 – Insights from the PRoVENT-COVID study()

BACKGROUND: The SpO(2)/FiO(2) is a useful oxygenation parameter with prognostic capacity in patients with ARDS. We investigated the prognostic capacity of SpO(2)/FiO(2) for mortality in patients with ARDS due to COVID–19. METHODS: This was a post-hoc analysis of a national multicenter cohort study in invasively ventilated patients with ARDS due to COVID–19. The primary endpoint was 28–day mortality. RESULTS: In 869 invasively ventilated patients, 28–day mortality was 30.1%. The SpO(2)/FiO(2) on day 1 had no prognostic value. The SpO(2)/FiO(2) on day 2 and day 3 had prognostic capacity for death, with the best cut-offs being 179 and 199, respectively. Both SpO(2)/FiO(2) on day 2 (OR, 0.66 [95%–CI 0.46–0.96]) and on day 3 (OR, 0.70 [95%–CI 0.51–0.96]) were associated with 28–day mortality in a model corrected for age, pH, lactate levels and kidney dysfunction (AUROC 0.78 [0.76–0.79]). The measured PaO(2)/FiO(2) and the PaO(2)/FiO(2) calculated from SpO(2)/FiO(2) were strongly correlated (Spearman's r = 0.79). CONCLUSIONS: In this cohort of patients with ARDS due to COVID–19, the SpO(2)/FiO(2) on day 2 and day 3 are independently associated with and have prognostic capacity for 28–day mortality. The SpO(2)/FiO(2) is a useful metric for risk stratification in invasively ventilated COVID–19 patients.