Effects of intraosseous epinephrine in a cardiac arrest swine model.

ABSTRACT

BACKGROUND: Interruptions in cardiopulmonary resuscitation (CPR) to obtain vascular access reduces blood flow to vital organs. Tibial intraosseous (TIO) access may be a faster alternative to intravenous (IV) access for delivery of vasoactive medications. The purpose of this study was to examine the differences in pharmacokinetics and pharmacodynamics of TIO- and IV-delivered epinephrine. MATERIALS AND METHODS: A prospective, between subjects, experimental design comparing Cmax, Tmax, return of spontaneous circulation (ROSC), and time to ROSC. Adult male swine were divided into three equal groups (n = 7) all received CPR and defibrillation the second group received IV epinephrine and the third group received tibial intraosseous epinephrine. Swine were placed in cardiac arrest for 2 min before CPR was initiated. After 2 min of CPR, epinephrine was delivered by IV or TIO, and serial blood samples were collected over 4 min. RESULTS: There were no significant differences between IV versus TIO epinephrine in achieving ROSC, time to ROSC, and Cmax. A one-way analysis of variance demonstrated a significant difference between the IV and TIO groups in Tmax (P = 0.025). A Fisher exact test demonstrated a significant difference between IV epinephrine versus CPR/Defib only (P = 0.035) and TIO epinephrine versus CPR/Defib only (P = 0.010) in achieving ROSC. A multivariate analysis of variance showed significant differences in IV versus intraosseous epinephrine concentration at specific time intervals 60 (P = 0.023), 90 (P = 0.001), and 120 (P < 0.000) sec. CONCLUSIONS: In the context of ROSC, epinephrine delivered via TIO route is a clinically relevant alternative to IV administration. When IV access cannot be immediately obtained in cardiac arrest patients, TIO access should be considered.