RCT: Early Restrictive vs Liberal Oxygen Strategy in Severe Trauma – No Significant Outcome Difference
22 Dec, 2024 | 17:21h | UTCBackground: The Advanced Trauma Life Support (ATLS) guidelines recommend providing supplemental oxygen to severely injured patients in the early phase after trauma, although the evidence base is limited. Observational research suggests that liberal oxygen administration may raise the risk of death and respiratory complications. Therefore, the TRAUMOX2 trial examined whether an 8-hour restrictive oxygen strategy (targeting an SpO₂ of 94%) could improve outcomes compared with a liberal strategy (12–15 L/min or FiO₂ 0.6–1.0) initiated prehospital or upon trauma center admission.
Objective: To determine whether an early restrictive oxygen approach, as compared with a liberal approach, reduces the composite outcome of death and/or major respiratory complications (pneumonia or ARDS) within 30 days in severely injured adults.
Methods: This investigator-initiated, international, multicenter, open-label, randomized controlled trial enrolled patients aged 18 years or older with blunt or penetrating trauma requiring full trauma team activation and anticipated hospital stay of at least 24 hours. Randomization occurred either prehospital or upon trauma center arrival in a 1:1 ratio to restrictive (lowest dose of oxygen to maintain SpO₂ at 94%) versus liberal therapy (12–15 L/min via nonrebreather mask or FiO₂ 0.6–1.0). The intervention lasted 8 hours, with all other management per standard care. The primary outcome—death or major respiratory complications (pneumonia per CDC criteria or ARDS per the Berlin definition)—was evaluated by blinded assessors within 30 days. Statistical analyses employed logistic regression, adjusted for stratification variables.
Results: Among 1979 randomized patients, 1508 completed the study (median age, 50 years; Injury Severity Score [ISS], 14). The composite primary outcome occurred in 16.1% (118/733) of restrictive-group patients and 16.7% (121/724) of liberal-group patients (odds ratio, 1.01; 95% CI, 0.75–1.37; p=0.94). Mortality alone (8.6% vs 7.3%) and major respiratory complications alone (8.9% vs 10.8%) showed no significant differences between groups. Adverse and serious adverse events were similar, except atelectasis was less frequent in the restrictive group (27.6% vs 34.7%).
Conclusions: In severely injured trauma patients, an 8-hour restrictive oxygen strategy did not significantly reduce death or major respiratory complications compared with a liberal strategy. Both approaches produced similar 30-day outcomes. Nevertheless, restricting oxygen may limit atelectasis and could be a reasonable alternative to giving high-flow oxygen to all trauma patients.
Implications for Practice: Clinicians may choose to target approximately 94% SpO₂ in the early trauma phase without compromising major outcomes. This approach potentially avoids the risks of hyperoxia, though no definitive survival benefit was identified. Pragmatic implementation of a conservative oxygen strategy seems feasible in diverse prehospital and hospital settings.
Study Strengths and Limitations: Notable strengths include multicenter design, randomized enrollment in prehospital and in-hospital settings, and blinded outcome assessment. Limitations include postrandomization exclusions of patients with minor injuries, a relatively short intervention period (8 hours), and an overall open-label design. These factors, along with lower-than-expected event rates, may have limited the power to detect differences in mortality. Commentary from https://bit.ly/bottomline_traumox2 also highlights that the median ISS of 14 indicates moderate rather than extremely severe trauma, possibly contributing to the modest event rates.
Future Research: Large-scale studies with extended intervention durations and targeted subgroups (e.g., severe traumatic brain injury) could clarify optimal oxygen thresholds in trauma care. Ongoing trials with larger sample sizes may better capture smaller but clinically meaningful differences in mortality or complications.