Association Between Hyperoxia, Supplemental Oxygen, and Mortality in Critically Injured Patients

OBJECTIVES: Hyperoxia is common among critically ill patients and may increase morbidity and mortality. However, limited evidence exists for critically injured patients. The objective of this study was to determine the association between hyperoxia and in-hospital mortality in adult trauma patients requiring ICU admission. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, retrospective cohort study was conducted at two level I trauma centers and one level II trauma center in CO between October 2015 and June 2018. All adult trauma patients requiring ICU admission within 24 hours of emergency department arrival were eligible. The primary exposure was oxygenation during the first 7 days of hospitalization. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Primary outcome was in-hospital mortality. Secondary outcomes were hospital-free days and ventilator-free days. We included 3,464 critically injured patients with a mean age of 52.6 years. Sixty-five percent were male, and 66% had blunt trauma mechanism of injury. The primary outcome of in-hospital mortality occurred in 264 patients (7.6%). Of 226,057 patient-hours, 46% were spent in hyperoxia (oxygen saturation > 96%) and 52% in normoxia (oxygen saturation 90-96%). During periods of hyperoxia, the adjusted risk for mortality was higher with greater oxygen administration. At oxygen saturation of 100%, the adjusted risk scores for mortality (95% CI) at Fio₂ of 100%, 80%, 60%, and 50% were 6.4 (3.5-11.8), 5.4 (3.4-8.6), 2.7 (1.7-4.1), and 1.5 (1.1-2.2), respectively. At oxygen saturation of 98%, the adjusted risk scores for mortality (95% CI) at Fio₂ of 100%, 80%, 60%, and 50% were 7.7 (4.3-13.5), 6.3 (4.1-9.7), 3.2 (2.2-4.8), and 1.9 (1.4-2.7), respectively. CONCLUSIONS: During hyperoxia, higher oxygen administration was independently associated with a greater risk of mortality among critically injured patients. Level of evidence: Cohort study, level III.