Intramuscular vasopressin: A feasible intervention for prehospital hemodynamic stabilization in porcine hemorrhagic shock and whole blood transfusion

Background: Hemorrhagic shock is the leading cause of preventable prehospital trauma deaths. While arginine vasopressin (AVP) is a well-known hormone with vasopressor effects, its potential for hemodynamic stabilization in prehospital hemorrhagic shock remains underexplored. This study investigated intramuscular (IM) AVP during hemorrhagic shock to evaluate its feasibility and efficacy for prehospital trauma resuscitation. Study Design and Methods: In this randomized, controlled, double-blinded trial, 16 swine (mean [standard deviation, SD] weight 56.2 [3.8] kg) underwent a mean (SD) 1205 (124) mL Class III hemorrhage for 45 min and 45 min of hypotension. Animals were randomized to 40 U IM AVP (n = 7) or NaCl (n = 9), followed immediately by 500 mL autologous whole blood transfusion over 30 and 120 min posttransfusion monitoring of hemodynamic, respiratory, and metabolic parameters. Results: AVP increased systolic arterial pressure 30 min after administration (mean increase: 33.5 mmHg vs. 7.5 mmHg, p < 0.05) and improved cardiac index (CI) 90 min after AVP (mean increase: 19.2% vs. 4.1% decrease, p < 0.05) and stroke volume (mean increase: 37.0% vs. 1.0%, p < 0.05). These effects normalized by 120 min. AVP did not affect respiratory parameters, oxygen delivery, or consumption. Increased serum AVP confirmed systemic uptake (median 68.7 pg/mL vs. 10.0 pg/mL in controls, p < 0.05). Conclusion: IM AVP, combined with whole blood transfusion, transiently stabilized hemodynamics by increasing systemic vascular resistance index, systolic blood pressure, and CI without respiratory compromise. These findings suggest that IM AVP may be a viable intervention for prehospital resuscitation of severe hemorrhagic shock, offering vital short-term stabilization to facilitate transport to definitive care.