Association of flow rate of prehospital oxygen administration and clinical outcomes in severe traumatic brain injury

Abstract

\n Background To prevent hypoxia during prehospital phase is important in severe traumatic brain injury (TBI) but optimal flow rate of prehospital oxygen supply is controversial. The goal of this study is to investigate the association of prehospital oxygen administration flow on clinical outcome in severe TBI patients. Methods This is a cross-sectional observational study using emergency medical services assessed severe trauma database in South Korea. In 2013 and 2015, adult patients with severe blunt TBI (abbreviated injury scale ≥3 in head lesion) without hypoxia (< 94% of oxygen saturation in prehospital pulse oximetry) were included. Main exposure was prehospital oxygen administration flow rate (no oxygen, 1~5 L/min, 6~14 L/min, 15 L/min). Primary outcome was in-hospital mortality. A multivariate logistic regression model was used to association of prehospital oxygen supply and outcomes. Results 1,842 patients with severe TBI were included. The number of patients with no oxygen, low-flow oxygen (1~5 L/min), mid-flow oxygen (6~14 L/min), high-flow oxygen (15 L/min) was 244, 573, 607 and 418. Mortality of each group was 34.8%, 32.3%, 39.9% and 41.1%. Compared with no-oxygen group, adjusted odds (95% CI) for mortality in the low, mid, high-flow oxygen groups were 0.86 (0.62–1.20), 1.15 (0.83–1.60) and 1.21 (0.83–1.73). In the interaction analysis, low-flow oxygen showed lower mortality when prehospital saturation was 94-98% (adjusted odds ratio(AOR): 0.80 [0.67–0.95]) and ≥99% (AOR: 0.69 [0.53–0.91]). High-flow oxygen (15 L/min) showed higher mortality when prehospital saturation was ≥99% in pulse oximetry (AOR: 1.33[1.01~1.74]). Conclusions Prehospital low-flow oxygen administration was associated with lower in-hospital mortality compared with the no-oxygen group in severe TBI patients. High-flow oxygen administration showed higher mortality. Optimal flow of prehospital oxygenation according prehospital saturation could reduce mortality in severe TBI. Trial registration This study used cases retrospectively registered in the emergency medical services assessed severe trauma database.