Piercing the evidence: intravenous versus intraosseous vascular access during out-of-hospital cardiac arrest.

Out-of-hospital cardiac arrest (OHCA) remains a leading cause of mortality despite advances in resuscitation. Establishing vascular access is essential for the administration of life-saving drugs during cardiopulmonary resuscitation. Intravenous (IV) access has traditionally been recommended as the first-line approach, although this choice is supported by limited evidence. Intraosseous (IO)access, increasingly used for its rapidity and reliability, offers a potential alternative, but human data regarding pharmacokinetics and clinical outcomes are scarce. The IVIO trial was a multicenter randomized controlled study conducted in Denmark, designed to compare IO and IV access in adults with non-traumatic OHCA. A total of 1,479 patients were randomized 1:1 to receive IO (n=731) or IV (n=748) access. Successful access within two attempts was achieved in 92% of IO cases and 80% of IV cases. Sustained return of spontaneous circulation (ROSC), the primary outcome, occurred in 30% of patients in the IO group and 29% in the IV group (Risk Ratio [RR] 1.06; 95% CI, 0.90-1.24; p=0.49). At 30 days, survival was 12% in the IO group compared with 10% in the IV group (RR 1.16; 95% CI, 0.87-1.56), while favorable neurological outcome was observed in 9% versus 8% (RR 1.16; 95% CI, 0.83-1.62). None of these differences reached statistical significance. CT imaging confirmed correct placement in 71% of humeral and 100% of tibial IO accesses, with no severe complications reported. The trial found no significant differences between the two strategies, supporting IO access as an alternative when IV placement is difficult or delayed in OHCA management.