Kyle K Sokol, MD1, George E Black, MD1, Robert Shawhan, MD1, Matthew J Eckert, MD1, B W Starnes, MD2, Matthew J Martin, MD1. 1Madigan Army Medical Center, 2University of Washington
Objectives: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as a promising adjunct to non-compressible torso hemorrhage (NCTH). As the leading cause of potentially preventable deaths on the battlefield, NCTH is currently treated with gauze packing in the pre-hospital setting with variable results and outcomes. Our study objectives are to describe the placement and physiologic impact of a novel REBOA device in treatment of uncontrolled junctional hemorrhage. We hypothesize that this device can be successfully deployed without fluoroscopic guidance, will increase survival times, minimize intraaortic barotrauma, and effectively function in the setting of profound shock dyshomeostasis.
Methods: Adult swine (35-50kg) underwent a hemorrhage and ischemia/reperfusion injury protocol to produce shock physiology and dilutional coagulopathy similar to major trauma victims. Five animals have been randomized to REBOA (N=3/10) vs standard gauze packing (GP) (N=2/10). After bilateral iliac vessel exposure via direct cutdown, the REBOA device was placed via 8Fr needle over a 0.035 J-wire (100cm). A complex contra-lateral groin soft tissue and vascular injury was then created, followed by 30 sec of free bleeding and gauze packing for 5 min. The GP control group received no further intervention. The REBOA group had the aortic balloon inflated until the pressure release valve opened to alleviate excess pressure. Residual hemorrhage from the injury site was measured. Endpoints included blood loss, time to death (MAP <20mmHg) or survival to 45 minutes. Native and balloon-exposed aortae were harvested and histopathology assessed for local endothelial injury.
Results: Preliminary data currently exists on 5 swine between the GP (N=2) and REBOA (N=3) groups and all animals to date were acquired after previous hemorrhage model studies. Baseline mean arterial pressures (mm Hg) were similar in the GP and REBOA groups (38 vs 35; p=0.80), and both groups had similar coagulation profiles (INR [1.4 vs 1.2; p=0.16], PTT [17.9 vs 18.4; p=0.285], Fibrinogen [97 vs 109; p=0.97]). Amount of free hemorrhage (g) was similar (415 vs 354; p=0.54); however, residual hemorrhage (RH) trended higher in the GP group but did not reach significance (402 vs 285; p=0.40). REBOA group had a significantly higher survival time (min) (45 vs 7.6; p=0.005), with all REBOA subjects surviving the duration of the study. The REBOA device was successfully pre-positioned into the distal aorta and gross examination upon necropsy showed no signs of aortic wall disruption.
Conclusion: Preliminary results of this study are assuring that this novel REBOA device can be successfully implemented and deployed without fluoroscopic guidance. This device showed a significant increase in survival time in the setting of uncontrolled junctional hemorrhage despite various states of previously induced hemorrhagic shock and coagulopathy. On gross examination of the aorta, there were no visible signs of aortic rupture possibly as result of the balloon inflation pressure release valve; however, histopathology remains to be determined.