Hemodynamic Effects of the Abdominal Aortic and Junctional Tourniquet in a Hemorrhagic Swine Model

Abstract Background Torso hemorrhage constitutes a leading cause of battlefield mortality. The Abdominal Aortic and Junctional (AAJT) uses a pneumatic bladder to compress the aorta reducing pelvic and lower extremity perfusion; however, concern exists over the risk of caval compression exacerbating hypotension following application. Methods Male swine (70-90 kg) were randomized into four groups of 10: presence or absence of hemorrhage and AAJT placement. Following a 40% hemorrhage, a 15-minute period of hypovolemia was observed prior to the AAJT application. All animals received two 500 mL boluses of Hextend separated by 30 minutes. Cardiovascular, pulmonary, and oxygenation values were compared amongst groups. Results The AAJT was effective in reducing blood flow to the femoral arteries in both hemorrhaged and non-hemorrhaged animals ( p < 0.001 for both groups). Hemorrhage resulted in significant decrease in mean arterial pressure (MAP) compared to sham controls (23.5 ± 2.4 vs. 61.6 ±7.8 mmHg respectively, p < 0.001). AAJT application, compared to untreated controls, resulted in a significant in increase in MAP and systemic vascular resistance but not in cardiac output, oxygenation, and central venous pressure. Furthermore, no indication of over-resuscitation injury was present as evidenced by pulmonary artery pressure and pulmonary histology. Conclusions AAJT application in an animal model of severe shock, results in a favorable hemodynamic profile due to afterload support. The current study did not demonstrate any adverse consequences due to caval compression, bowel injury or pulmonary dysfunction. Additionally, there does not appear to be any particular IV fluid economy achieved by AAJT application.