Clinical evaluation of intravenous alone versus intravenous or intraosseous access for treatment of out-of-hospital cardiac arrest

Objective: Obtaining vascular access during out-of-hospital cardiac arrest (OHCA) is challenging. The aim of this study was to determine if using intraosseous (IO) access when intravenous (IV) access fails improves outcomes.

Methods: This was a prospective, parallel-group, cluster-randomised study that compared 'IV only' against 'IV + IO' in OHCA patients, where if 2 IV attempts failed or took more than 90 s, paramedics had 2 further attempts of IO. Primary outcome was any return of spontaneous circulation (ROSC). Secondary outcomes were insertion success rate, adrenaline administration, time to adrenaline and survival outcome.

Results: A total of 1007 patients were included in the analysis. An Intention To Treat analysis showed a significant difference in success rates of obtaining vascular access in the IV + IO arm compared to the IV arm (76.6% vs 61.1% p = 0.001). There were significantly more patients in the IV + IO arm than the IV arm being administered prehospital adrenaline (71.3% vs 55.4% p = 0.001). The IV + IO arm also received adrenaline faster compared to the IV arm in terms of median time from emergency call to adrenaline (23 min vs 25 min p = 0.001). There was no significant difference in ROSC (adjusted OR 0.99 95%CI: 0.75-1.29), survival to discharge or survival with CPC 2 or better in both groups. A Per Protocol analysis also showed there was higher success in obtaining vascular access in the IV + IO arm, but ROSC and survival outcomes were not statistically different.

Conclusion: Using IO when IV failed led to a higher rate of vascular access, prehospital adrenaline administration and faster adrenaline administration. However, it was not associated with higher ROSC, survival to discharge, or good neurological outcome.