PaO₂ and Mortality in Non-Cardiac Surgical ICU Patients: a Retrospective Cohort Study

Background Oxygen therapy is crucial for critically ill patients, but excessive oxygen can be harmful. While guidelines suggest a target oxygen saturation range of 94–98% for general critically ill patients, optimal PaO₂ levels in post-non-cardiac surgery patients who were admitted to the intensive care unit (ICU) remain unclear. Methods This retrospective cohort study utilized the MIMIC-IV database to investigate the association between mean PaO₂ within 48 hours of ICU admission and mortality in patients following non-cardiac surgery. Patients were categorized into four groups based on PaO₂ levels. Cox regression models were used to assess the association between PaO₂ and in-hospital, 30-day, 90-day, and 1-year mortality, adjusting for confounders. Subgroup and sensitivity analyses were conducted to assess the robustness of the findings. Results This retrospective cohort study utilized the MIMIC-IV database to investigate the association between mean PaO₂ within 48 hours of ICU admission and mortality in patients following non-cardiac surgery. Patients were categorized into four groups based on PaO₂ levels. Cox regression models were used to assess the association between PaO₂ and in-hospital, 30-day, 90-day, and 1-year mortality, adjusting for confounders. Subgroup and sensitivity analyses were conducted to assess the robustness of the findings. Conclusion Early hyperoxia (mean PaO₂ up to > 200 mmHg within 48 h) was not associated with increased mortality in non-cardiac surgical ICU patients. Clinicians may individualize oxygenation targets based on clinical needs.