Abstract Background Out-of-hospital cardiac arrest (OHCA) remains a critical emergency with low survival rates despite advanced prehospital interventions. Early epinephrine administration, particularly in non-shockable rhythms, improves outcomes. While intravenous (IV) access is the standard route for drug delivery, it is often difficult to obtain in the prehospital setting. Intraosseous (IO) access offers a viable alternative, but its comparative survival benefit remains unclear. Few studies have examined the impact of IO access on outcomes relative to patients who received no prehospital vascular access. This study aims to assess survival outcomes among OHCA patients receiving different prehospital vascular access strategies. Methods This retrospective cohort study included adult patients with non-traumatic OHCA in Taoyuan, Taiwan (June 2021–June 2024). Patients were categorized into four groups: IV, IO (humerus), failed IV, and no-access attempt. Primary outcomes were survival to discharge and favorable neurological status (CPC 1–2); secondary outcomes included prehospital ROSC and survival over 2 hours. Multivariable logistic regression adjusted for confounders. Results Among 4,424 patients, the IO group had the highest rates of ROSC (13.0%), 2-hour survival (28.0%), and discharge survival (16.6%), while the failed IV group had the lowest. IO access was associated with better outcomes than no-access attempt, with or without epinephrine. IO patients receiving epinephrine had the highest estimated survival and neurological outcomes. Each minute delay in epinephrine administration reduced survival odds by 4%. Conclusions Prehospital vascular access—especially IO—was linked to improved OHCA survival and neurological outcomes. Prompt IO access should be considered when IV attempts fail.
Lin et al. (Wed,) studied this question.