The effect of resuscitative endovascular balloon occlusion of the aorta, partial aortic occlusion and aggressive blood transfusion on traumatic brain injury in a swine multiple injuries model

Large Animal Models of Proximal Aortic Balloon Occlusion in Traumatic Hemorrhage: Review and Identification of Knowledge Gaps Relevant to Expanded Use

BACKGROUND

The aim of this study was to review and summarize the large animal data on resuscitative endovascular balloon occlusion of the aorta (REBOA) for traumatic hemorrhage and identify knowledge gaps pertinent to the proposed broader use of the technique in prehospital situations.

METHODS

A review of published large animal models of traumatic hemorrhage incorporating REBOA with a primary outcome of the effect of aortic occlusion was performed. Data were collected on experimental protocols, hemodynamic effects, resuscitation requirements, mortality, metabolic and tissue consequences of induced ischemia-reperfusion, and effects on hemorrhage volume and other injuries.

RESULTS

A limited number of REBOA studies exist, and there is variability in the species and size of animals used. Various controlled and uncontrolled hemorrhage protocols have been studied, and a number of balloon devices used. Hemodynamic effects of occlusion were consistent as were basic systemic physiological effects. Minimal study of the effects of partial aortic occlusion and hemodynamic and metabolic physiology distal to the balloon has been performed, and partial or complete occlusion times >90 min have not been studied.

CONCLUSIONS

Significant knowledge gaps exist, which are potentially relevant to the expanded use of REBOA. Investigation into the physiology of partial occlusion and the metabolic effects and potential mitigation strategies for large-scale ischemia and reperfusion are particularly needed.

Blood pressure targeting by partial REBOA is possible in severe hemorrhagic shock in pigs and produces less circulatory, metabolic and inflammatory sequelae than total REBOA

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an effective adjunct in exsanguinating torso hemorrhage, but causes ischemic injury to distal organs. The aim was to investigate whether blood pressure targeting by partial REBOA (pREBOA) is possible in porcine severe hemorrhagic shock and to compare pREBOA and total REBOA (tREBOA) regarding hemodynamic, metabolic and inflammatory effects.

METHODS

Eighteen anesthetized pigs were exposed to induced controlled hemorrhage to a systolic blood pressure (SBP) of 50 mmHg and randomized into three groups of thoracic REBOA: 30 min of pREBOA (target SBP 80-100 mmHg), tREBOA, and control. They were then resuscitated by autologous transfusion and monitored for 3 h. Hemodynamics, blood gases, mesenteric blood flow, intraperitoneal metabolites, organ damage markers, histopathology from the small bowel, and inflammatory markers were analyzed.

RESULTS

Severe hemorrhagic shock was induced in all groups. In pREBOA the targeted blood pressure was reached. The mesenteric blood flow was sustained in pREBOA, while it was completely obstructed in tREBOA. Arterial pH was lower, and lactate and troponin levels were significantly higher in tREBOA than in pREBOA and controls during the reperfusion period. Intraperitoneal metabolites, the cytokine response and histological analyses from the small bowel were most affected in the tREBOA compared to the pREBOA and control groups.

CONCLUSION

Partial REBOA allows blood pressure titration while maintaining perfusion to distal organs, and reduces the ischemic burden in a state of severe hemorrhagic shock. Partial REBOA may lower the risks of post-resuscitation metabolic and inflammatory impacts, and organ dysfunction.

Complete and Partial Aortic Occlusion for the Treatment of Hemorrhagic Shock in Swine

Hemorrhage remains the leading cause of preventable deaths in trauma. Endovascular management of non-compressible torso hemorrhage has been at the forefront of trauma care in recent years. Since complete aortic occlusion presents serious concerns, the concept of partial aortic occlusion has gained a growing attention. Here, we present a large animal model of hemorrhagic shock to investigate the effects of a novel partial aortic balloon occlusion catheter and compare it with a catheter that works on the principles of complete aortic occlusion. Swine are anesthetized and instrumented in order to conduct controlled fixed-volume hemorrhage, and hemodynamic and physiological parameters are monitored. Following hemorrhage, aortic balloon occlusion catheters are inserted and inflated in the supraceliac aorta for 60 min, during which the animals receive whole-blood resuscitation as 20% of the total blood volume (TBV). Following balloon deflation, the animals are monitored in a critical care setting for 4 h, during which they receive fluid resuscitation and vasopressors as needed. The partial aortic balloon occlusion demonstrated improved distal mean arterial pressures (MAPs) during the balloon inflation, decreased markers of ischemia, and decreased fluid resuscitation and vasopressor use. As swine physiology and homeostatic responses following hemorrhage have been well-documented and are like those in humans, a swine hemorrhagic shock model can be used to test various treatment strategies. In addition to treating hemorrhage, aortic balloon occlusion catheters have become popular for their role in cardiac arrest, cardiac and vascular surgery, and other high-risk elective surgical procedures.