Study of Epinephrine Resuscitation in a Swine Hypovolemic Cardiac Arrest Model

This study will determine the effects and pharmakinetics of administration of epinephrine by bone (intraosseous (IO)), by vein (intravenous (IV)), and by endotracheal (EO) routes in a shock or hypovolemic (low blood volume) model of cardiac arrest.   Yorkshire Cross Swine will be used for this study, which will contain 7 groups, each with 7 swine. The seven groups will consist of CPR only, CPR with defibrillation, IV epinephrine (EPI),  Sternal IO (EPI), Tibia IO (EPI), Humerus IO (EPI) and Endotracheal (double dose EPI). In summary, all swine will be sedated, anesthesized, and placed on mechanical ventilation with appropriate monitors applied. Arterial and venous catheters will be inserted, as well as the appropriate IO device. After stabilization, 31% (Class III hemorrhage) of the swines' blood will be removed followed by albumin replacement. After 5 minutes stabilization they will be placed into cardiac arrest via direct electrical current to the ventricle. After 2 minutes in cardiac arrest EPI will be administered per group protocol and CPR initiated. Eight blood samples will be drawn on each swine at the following times after EPI injection- 0.5 min, 1 min, 1.5 min, 2 min, 2.5 min, 3 min, 4 min and 5 min.

Our previous work with IO/IV/ET adminstration of epinephrine in cardiac arrest showed differences in pharmokinetics between the routes. However, with the body shunting blood to the lungs, heart, and brain and away from bone marrow and other organs for survival, the effectiveness of IO adminstration has not been determined.

It is generally thought that IO administration is equivalent to IV administration, as IO infusions have been used in military casualties including hemorrhage, traumatic injury, dehydration, cardiovascular collapse, and burns. This study will produce the data that are needed to determine if dose alterations are warranted when administering epinephrine through an IO catheter in a cardiac arrest, hypovolemic model.  The implications of the findings of this study can be applied in any military or civilian facility where patients may have cardiac arrest with hemorraghic shock.