Traumatic non-compressible hemorrhage is a leading cause of civilian and military mortality and its treatment requires massive transfusion of blood components， especially platelets. However， in austere civilian and battlefield locations， access to platelets is highly challenging due to limited supply and portability， high risk of bacterial contamination and short shelf-life. To resolve this， we have developed an I.V.-administrable 'synthetic platelet' nanoconstruct (SynthoPlate)， that can mimic and amplify body's natural hemostatic mechanisms specifically at the bleeding site while maintaining systemic safety. Previously we have reported the detailed biochemical and hemostatic characterization of SynthoPlate in a non-trauma tail-bleeding model in mice. Building on this， here we sought to evaluate the hemostatic ability of SynthoPlate in emergency administration within the 'golden hour' following traumatic hemorrhagic injury in the femoral artery， in a pig model. We first characterized the storage stability and post-sterilization biofunctionality of SynthoPlate in vitro. The nanoconstructs were then I.V.-administered to pigs and their systemic safety and biodistribution were characterized. Subsequently we demonstrated that， following femoral artery injury， bolus administration of SynthoPlate could reduce blood loss， stabilize blood pressure and significantly improve survival. Our results indicate substantial promise of SynthoPlate as a viable platelet surrogate for emergency management of traumatic bleeding.