Efficacy and safety of CounterFlow in animal models of hemorrhage.

Introduction: Hemorrhage is a major cause of battlefield mortality, contributing to 91% of potentially survivable combat-related deaths. Death from hemorrhage often occurs in pre-hospital settings, and more efficacious hemorrhage control interventions are needed to extend survival and enable casualties to reach definitive surgery. CounterFlow is a novel topical hemostatic agent that uses self-propelling particles to deliver thrombin and tranexamic acid against active bleeding. It achieves and maintains hemostasis at the site of injury through a combination of mechanical, biological, and chemical effects. Methods: All literature in which CounterFlow was tested in animal models of hemorrhage was reviewed to compile its preclinical safety and efficacy as a hemostatic agent. Results: CounterFlow extended survival and halted hemorrhage in multiple animal models that mimicked common and deadly injuries encountered in military and civilian settings, including junctional wounds, surgical bleeding, non-compressible intra-abdominal hemorrhage, and upper gastrointestinal bleeding. Thromboembolism, tissue damage, and toxicity were not observed. Discussion: This narrative review discusses the animal models that have been used to investigate CounterFlow as a hemostatic agent for pre-hospital hemorrhage control. Future directions and potential expansion for civilian use are also considered.