Hyperoxaemia in acute trauma is common and associated with a longer hospital stay: a multicentre retrospective cohort study

Background:<bold> </bold>Trauma poses a significant global health challenge. Despite advancements in the management of severely injured patients, (poly)trauma continues to be a primary contributor to morbidity and mortality worldwide. In the context of trauma resuscitation, supplemental oxygen is commonly administered generously as suggested by guidelines. Yet, it remains uncertain whether the trauma population might derive advantages from a more conservative approach to supplemental oxygen. Methods:<bold> </bold>In this retrospective cohort study from two Swiss trauma centers, severely injured adult (> 16 years) trauma patients with an Injury Severity Score (ISS) >= 16 were divided into four groups according to the first blood gas analysis taken: hypoxaemia (PaO2 < 10.7 kPa/80 mmHg), normoxaemia (PaO2 10.7-16.0 kPa/80-120 mmHg), which served as reference, moderate hyperoxaemia (PaO2 > 16.0-40 kPa/120-300 mmHg) and severe hyperoxaemia (PaO2 > 40 kPa/300 mmHg). The primary outcome was 28-day mortality. Length of hospital stay (LOS) and length of intensive care unit stay (LOS-ICU) were analyzed as secondary outcomes. Results:<bold> </bold>Of 1,189 trauma patients, 41.3% had hyperoxaemia (18.8% with severe hyperoxaemia) and 19.3% had hypoxaemia. No difference was found for 28-day mortality (hypoxaemia: 15.7%, normoxaemia: 14.1%, hyperoxaemia: 13.8%, severe hyperoxaemia: 16.0%, p = 0.846). Patients with severe hyperoxaemia had a significant prolonged LOS (median 12.5 [IQR 7-18.5] days vs. 10 [7-17], p = 0.040) and extended LOS-ICU (3.8 [1.8-9] vs. 2 [1-5] days, p = 0.149) compared to normoxaemic patients. In multivariable analysis, oxygen group was not associated with the primary outcome 28-day mortality or LOS-ICU. Severe hyperoxaemia patients had a tendency towards longer hospital stay (adjusted coefficient 2.23 days [95% CI: - 0.32; 4.79], p = 0.087). Conclusion:<bold> </bold>Hyperoxaemia was not associated with an increased 28-day mortality when compared to normoxaemia. However, both moderate and severe hyperoxaemia is frequently observed in trauma patients, and the presence of severe hyperoxaemia showed a tendency with extended hospital stay compared to normoxaemia patients. Robust randomized controlled trials are imperative to thoroughly evaluate the potential correlation between hyperoxaemia and outcomes in trauma patients .