Oxygen saturation and mortality for acute pulmonary embolism: multinational retrospective cohort study

Among patients with acute pulmonary embolism (PE), we aimed to evaluate for an association between oxygen saturation (SatO₂ ) and 30-day post-PE mortality.

Between January, 2001 and April, 2025, we conducted a retrospective cohort study of 38,739 non-hypotensive patients with acute PE enrolled from 18 countries in the Registro Informatizado de la Enfermedad Tromboembólica (RIETE) registry. Outcomes included 30-day all-cause and PE-specific mortality. We used hierarchical logistic regression to assess for an association between baseline SatO₂ and outcomes. We aimed to identify optimal SatO₂ cut-off points that maximized sensitivity and specificity in relation to mortality from receiver operating characteristic (ROC) curves. RIETE is registered with ClinicalTrials.gov, NCT02832245.

Baseline SatO₂ was significantly associated with mortality, where lower SatO₂ had worse outcomes. Using a reference SatO₂ of >96%, patients in the lower SatO₂ strata had higher rates of all-cause death (odds ratio [OR] 0.96 for SatO₂ 94-96%; 1.23 for SatO₂ 90-93%; and 1.81 for SatO₂ <90%) and PE-related mortality (OR 1.68 for SatO₂ 94-96%; 2.04 for SatO₂ 90-93%; and 3.95 for SatO₂ <90%). The optimal cut-off point to identify patients at low-risk for short-term mortality was SatO₂ of 96% (sensitivity of 86.1% and negative predictive value of 96.7%); while SatO₂ of 90% (specificity of 77.2% and positive predictive value of 7.9%) identified patients at increased risk for mortality.

Among non-hypotensive patients diagnosed with PE, we found an inverse association between baseline SatO₂ and odds of all-cause and PE-associated mortality over the subsequent 30 days. A SatO₂ cutoff value of 96% for the highest SatO₂ group while breathing room air might help better identify patients with acute PE at low-risk for mortality. Future studies should assess the contribution of SatO2 in addition to established prognosticators to predicting the risk of death.

ROVI.