Prehospital adenosine, lidocaine, and magnesium has inferior survival compared with tactical combat casualty care resuscitation in a porcine model of prolonged hemorrhagic shock

BACKGROUND Adenosine, lidocaine, and magnesium (ALM) is a cardioplegic agent shown to improve survival by improving cardiac function, tissue perfusion, and coagulopathy in animal models of shock. We hypothesized prehospital ALM treatment in hemorrhagic shock would improve survival compared to current Tactical Combat Casualty Care (TCCC) resuscitation beyond the golden hour. METHODS Swine were randomized to: (1) TCCC, (2) 2 mL·kg^-1 vehicle control (VC), (3) 2 mL·kg^-1 ALM + drip, (4) 4 mL·kg^-1 ALM + drip, 5) 4 mL·kg^-1 ALM + delayed drip at 0.5 mL·kg^-1·h^-1, 6) 4 mL/kg VC, 7) 4 mL·kg^-1 ALM for 15 minutes + delayed drip at 3 mL·kg^-1·h^-1. Animals underwent pressure controlled hemorrhage to mean arterial pressure (MAP) of 30 mm Hg (S = 0). Treatment was administered at T = 0. After 120 minutes of simulated prehospital care (T = 120) blood product resuscitation commenced. Physiologic variables were recorded and laboratories were drawn at specified time points. RESULTS Tactical Combat Casualty Care demonstrated superior survival to all other agents. The VC and ALM groups had lower MAPs and systolic blood pressures compared with TCCC. Except for the VC groups, lactate levels remained similar with correction of base deficit after prehospital resuscitation in all groups. Kidney function and liver function remained comparable across all groups. Compared with baseline values, TCCC demonstrated significant hypocoagulability. CONCLUSION Adenosine, lidocaine, and magnesium, as administered in this study, are inferior to current Hextend-based resuscitation for survival from prolonged hemorrhagic shock in this model. In survivors, ALM groups had lower systolic blood pressures and MAPs, but provided a protective effect on coagulopathy as compared to TCCC. Adenosine, lidocaine, and magnesium do not appear to be a suitable low volume replacement to current TCCC resuscitation. The reduced coagulopathy compared to TCCC warrants future studies of ALM, perhaps as a therapeutic adjunct.