A translational porcine model to assess the graded impact of hemorrhage and aortic occlusion on cardiovascular hemodynamics and renal perfusion

Abstract

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is a lifesaving intervention used to manage non-compressible torso hemorrhage by temporarily occluding the aorta to minimize blood loss and preserve perfusion to vital organs. Partial REBOA (p-REBOA) has been proposed to mitigate ischemic injury associated with full-REBOA (f-REBOA). However, implementation of p-REBOA clinically has been challenging due to our limited understanding of the acute hemodynamics with p-REBOA particularly in relation to cardiac, carotid, and renal perfusion. In this study we developed and utilized a novel porcine model to continuously measure cardiac, carotid, renal and systemic hemodynamic responses to varying degrees of hemorrhagic shock and aortic occlusion. Yorkshire pigs (N=54) underwent instrumentation for continuous hemodynamic monitoring and hemorrhage was induced for 30 minutes to achieve 10%, 20%, or 30% blood volume loss (n=18/group), followed by randomized treatments of either no occlusion, p-REBOA, or f-REBOA occlusion strategies (n=6/group) for 30 minutes. After occlusion, shed blood was re-transfused over 15 minutes, and REBOA balloons were deflated and removed. This was followed by a 3-hour automated resuscitation and critical care period. Renal and carotid perfusion decreased progressively with hemorrhage severity. Interestingly, 30 minutes of f-REBOA resulted in significant ischemia-reperfusion injury where renal perfusion was profoundly suppressed to 40% of baseline renal flow. On the other hand, p-REBOA yielded superior renal perfusion, while maintaining cardiac function and carotid perfusion. p-REBOA also required less fluid and vasopressors. This translational pig model offers new opportunities to assess acute cardiovascular hemodynamics during interventions for the management of hemorrhagic shock.