Background:   Data have been unclear about the roles of interosseous (IO) vs IV access in out-of-hospital cardiac arrest (OHCA). One randomized controlled trial of prehospital providers showed increased rate of initial success and decreased time to access in IO vs IV. However, subsequent retrospective trials have shown decreased likelihoods of sustained return of spontaneous circulation (ROSC), survival, and favorable neurologic outcome. Our objective was to determine if there was a difference in survival for IO vs IV access in OHCA in our patient population. Methods:  This was a retrospective, observational study at an urban academic hospital. Three resuscitation bays were continuously videotaped to capture resuscitations of OHCA patients. Each resuscitation was analyzed by two independent observers for standardized metrics as well as type of access. If no time to IV access was recorded, only IO access by prehospital providers was assumed. Data was analyzed by contingency tables with Fisher\u27s exact test as well as Spearman rank correlation analysis. Results: A total of 47 cases were captured for analysis. 36 patients presented with prehospital IO access and 11 patients obtained IV access in the emergency department (ED). Overall, 91.7% of patients with prehospital IO access died, compared to 100% of patients with IV access. In addition, of the 47 cases, 35 patients received IV access in the ED and 12 did not. Patients who received IV access in the ED had higher overall survival (32/35 or 91% vs 12/12 or 100%). Conclusion: In this retrospective, observational study, there were trends towards survival for OHCA patients who had received prehospital IO access as well as those patients who received IV access in the ED. Future directions include analyzing data from a larger sample size, as well as analyzing specific data on what access patients have and anatomic site of IO access
