Humerus intraosseous administration of epinephrine in normovolemic and hypovolemic porcine model

Objective: Compare the maximum concentration (Cmax), time to maximum concentration (Tmax), mean concentration, rate of return of spontaneous circulation (ROSC), time to ROSC, and odds of ROSC when epinephrine is administered by humerus intraosseous (HIO) compared to intravenous (IV) routes in both a hypovolemic and normovolemic cardiac arrest model. Design: Prospective, between subjects, randomized experimental study. Setting: TriService Facility. Subjects: Twenty-eight adult Yorkshire Swine were randomly assigned to four groups: HIO normovolemia; HIO hypovolemia; IV normovolemia; and IV hypovolemia. Intervention: Swine were anesthetized. The hypovolemic group was exsanguinated 31 percent of their blood volume. Subjects were placed into arrest. After 2 minutes, cardiopulmonary resuscitation (CPR) was initiated. After another 2 minutes, 1 mg epinephrine was given by IV or HIO routes; blood samples were collected over 4 minutes. Hypovolemic groups received 500 mL of 5 percent albumin following blood sampling. CPR continued until ROSC or for 30 minutes. Main outcome measures: ROSC, time to ROSC, Cmax, Tmax, mean concentrations over time, odds of ROSC. Results: Cmax was significantly higher, the Tmax, and the time to ROSC were significantly faster in the HIO normovolemic compared to the HIO hypovolemic group (p < 0.05). All seven in the HIO normovolemic group achieved ROSC compared to three of the HIO hypovolemic group. Odds of ROSC were 19.2 times greater in the HIO normovolemic compared the HIO hypovolemic group. Conclusion: The HIO is an effective route in a normovolemic model. However, the findings indicate that sufficient blood volume is essential for ROSC in a hypovolemic scenario.