Background: Standard cardiopulmonary resuscitation (CPR) is ineffective in treating traumatic cardiac arrest (TCA) following hemorrhagic shock despite fluid resuscitation. CPR adjuncts, including abdominal compressions and external counter pressure, have shown some success in laboratory settings. The Abdominal Aortic and Junctional Tourniquet (AAJT) is a device that occludes both venous and arterial blood at the level of the aortic bifurcation and likely increases thoracic pressure when applied to the abdomen. We developed a swine model of controlled hemorrhage to induce a state of TCA to test the ability of the AAJT to improve the efficacy of CPR.
Methods: Twelve splenectomized, Yorkshire, male swine (70-90 kg) were randomized into two groups: presence or absence of AAJT placement. Controlled hemorrhage was performed at a rate of 2 mL/kg/min until systolic blood pressure reached below 10 mm Hg (defined as cardiac arrest). Following 3 minutes of arrest, the animals underwent CPR using a mechanical compression device along with either the presence or absence of the AAJT. Concurrently, 5 units of whole blood (2,500 mL) were delivered through the jugular vein at 500 mL/min. Efficacy of CPR was assessed by analyzing rates of return of spontaneous circulation (ROSC) and survival. Blood pressure, carotid blood flow, and other hemodynamic values were also compared.
Findings: No significant differences between groups were observed before treatments. The controlled hemorrhage resulted in an average loss of 2,654 ± 323 g of blood over 18.2 ± 3.9 minutes. All animals that had a ROSC survived to the end of the 1-hour observation period. Animals with AAJT survived 83% (5/6) compared to 17% (1/6) of animals without AAJT. Finally, blood pressure, carotid flow, mean pulmonary artery pressure, and end tidal carbon dioxide were all significantly different between groups at the end of the first 10-minute compression period.
Discussion/impact/recommendations: These results suggest that the AAJT could allow for increased CPR efficacy in cases of TCA when used in conjunction with rapid, massive blood transfusions.
Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.