Intraosseous compared to intravenous drug resuscitation in out-of-hospital cardiac arrest.

AIMS: Although the intraosseous (IO) route is increasingly used for vascular access in out-of-hospital cardiac arrest (OHCA), little is known about its comparative effectiveness relative to intravenous (IV) access. We evaluated clinical outcomes following OHCA comparing drug administration via IO versus IV routes.

METHODS: This retrospective cohort study evaluated Emergency Medical Services (EMS)-treated adults with atraumatic OHCA in a large metropolitan EMS system between 9/1/2012-12/31/2014. Access was classified as IO or IV based on the route of first EMS drug administration. Study endpoints were survival to hospital discharge, return of spontaneous circulation (ROSC) and survival to hospital admission.

RESULTS: Among 2164 adults with OHCA, 1800 met eligibility criteria, 1525 of whom were treated via IV and 275 principally via tibial-IO routes. Compared to IV, IO-treated patients were younger, more often women, had unwitnessed OHCA, a non-cardiac aetiology, and presented with non-shockable rhythms. IO versus IV-treated patients were less likely to survive to hospital discharge (14.9% vs 22.8%, p=0.003), achieve ROSC (43.6% vs 55.5%, p<0.001) or be hospitalized (38.5% vs 50.0% p<0.001). In multivariable adjusted analyses, IO treatment was not associated with survival to discharge (odds ratio (OR) (95% confidence interval) 0.81 (0.55, 1.21), p=0.31), but was associated with a lower likelihood of ROSC (OR=0.67 (0.50, 0.88), p=0.004) and survival to hospitalization (OR=0.68 (0.51, 0.91), p=0.009).

CONCLUSION: Though not independently associated with survival to discharge, principally tibial IO versus IV treatment was associated with a lower likelihood of ROSC and hospitalization. How routes of vascular access influence clinical outcomes after OHCA merits additional study.