Effect of vascular access strategy on long-term outcomes in patients with out-of-hospital cardiac arrest: a randomised clinical trial

Objective: The Intravenous versus Intraosseous Vascular Access for Out-of-Hospital Cardiac Arrest (IVIO) trial was a randomised clinical trial that investigated initial vascular access strategy for out-of-hospital cardiac arrest. The current manuscript presents outcomes at 6 months and 1 year. Methods: Adults with non-traumatic out-of-hospital cardiac arrest, in whom vascular access was indicated, were randomised to initial intraosseous or intravenous access. The allocated method was attempted up to two times. Prespecified 6-months and 1-year outcomes included survival, survival with a favourable neurological outcome, defined as a modified Rankin Scale score of 0–3, and health-related quality-of-life assessed using the EuroQoL 5-Dimension 5-Level questionnaire on domains of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Results: Of the 1479 patients included in the main manuscript primary analyses, three were lost to follow-up for 1-year survival. At 1 year, 82 patients (11%) in the intraosseous group and 68 patients (9%) in the intravenous group were alive (risk ratio 1.24; 95% confidence interval 0.91–1.67). Survival with a favourable neurological outcome was observed in 76 patients (10%) and 61 patients (8%), respectively (risk ratio 1.28; 95% confidence interval 0.93–1.77). Among survivors, the mean EQ-5D-5L numeric score was 83 in the intraosseous group and 76 in the intravenous group (mean difference 7; 95% confidence interval 1–13). Conclusion: Long-term outcomes were similar between patients who received initial intraosseous versus intravenous vascular access during adult out-of-hospital cardiac arrest. These findings do not support a difference in patient outcomes between the two vascular access strategies. Trial registration: EU Clinical Trials number 2022-500744-38-00; ClinicalTrials.gov number NCT05205031.