Work

Prehospital oxygen-therapy and mortality in patients treated by emergency medical services: a prospective, observational multicenter study

Year: 2025

Type: article

Abstract: BACKGROUND: Oxygen supply is a common procedure performed by emergency medical services (EMS); however, whether prehospital oxygen or fraction of inspired oxygen (FiO 2 ) therapy predict mortality has not been studied to date.This study aims to determine mortality associated with oxygen therapy in unselected patients with acute disease who underwent prehospital care.METHODS: This was a prospective, observational, cohort, multicenter, EMS-delivery, ambulance-based study.Adults with unselected acute disease who were managed by EMS and evacuated with high priority to the emergency department of four hospitals in three Spanish provinces.Epidemiological variables, on-scene vital signs, and prehospital blood analysis data were collected.The primary outcome was short-(2-, 7-, and 30-day), medium-(90-and 180-day), and long-term (365-day) all-cause cumulative mortality.The samples were a priori split according to thresholds of their received FiO 2 (FiO 2 =0.21, that is without oxygen therapy; FiO 2 between 0.22 and 0.49; and FiO 2 ≥0.5).The categorical variables FiO 2 , epidemiological variables, vital signs, prehospital point-of-care testing (POCT) and patient outcomes were fitted with a logistic regression model.Additionally, a propensity score matching and a survival analysis were used. RESULTS:The final sample included 7,494 patients, 70.3% of whom did not receive oxygen therapy, 15% with a FiO 2 between 0.22 and 0.49, and 14.7% with a FiO 2 ≥0.5.The 2-day mortality was 0.4%, 5.3%, and 22.9% respectively (P<0.001).The 365-day mortality was 9.9%, 33.1%, and 50.5% respectively (P<0.001).Finally, the FiO 2 predictive capacities 2-,30-, and 365-day mortality were AUC=0.870(95%CI: 0.840-0.899),0.810 (95%CI: 0.784-0.837),0.704 (95%CI: 0.679-0.728),respectively.CONCLUSION: Prehospital oxygen therapy by thresholds of FiO 2 was linked to death and allowed mortality prediction.This finding could provide an aid for EMS providers, allowing to assess more individualized patient risk.

Source: World Journal of Emergency Medicine

DOI: 10.5847/wjem.j.1920-8642.2025.084