Automated partial resuscitative endovascular balloon occlusion of the aorta reduces blood loss and hypotension in a highly lethal porcine liver injury model

Abstract

BACKGROUND Partial and intermittent resuscitative endovascular balloon occlusion of the aorta (pREBOA and iREBOA, respectively) are lifesaving techniques designed to extend therapeutic duration, mitigate ischemia, and bridge patients to definitive hemorrhage control. We hypothesized that automated pREBOA balloon titration compared with automated iREBOA would reduce blood loss and hypotensive episodes over a 90-minute intervention phase compared with iREBOA in an uncontrolled liver hemorrhage swine model. METHODS Twenty-four pigs underwent an uncontrolled hemorrhage by liver transection and were randomized to automated pREBOA (n = 8), iREBOA (n = 8), or control (n = 8). Once hemorrhagic shock criteria were met, controls had the REBOA catheter removed and received transfusions only for hypotension. The REBOA groups received 90 minutes of either iREBOA or pREBOA therapy. Surgical hemostasis was obtained, hemorrhage volume was quantified, and animals were transfused to euvolemia and then underwent 1.5 hours of automated critical care. RESULTS The control group had significantly higher mortality rate (5 of 8) compared with no deaths in both REBOA groups, demonstrating that the liver injury is highly lethal (p = 0.03). During the intervention phase, animals in the iREBOA group spent a greater proportion of time in hypotension than the pREBOA group (20.7% [16.2–24.8%] vs. 0.76% [0.43–1.14%]; p < 0.001). The iREBOA group required significantly more transfusions than pREBOA (21.0 [20.0–24.9] mL/kg vs. 12.1 [9.5–13.9] mL/kg; p = 0.01). At surgical hemostasis, iREBOA had significantly higher hemorrhage volumes compared with pREBOA (39.2 [29.7–44.95] mL/kg vs. 24.7 [21.6–30.8] mL/kg; p = 0.04). CONCLUSION Partial REBOA animals spent significantly less time at hypotension and had decreased transfusions and blood loss. Both pREBOA and iREBOA prevented immediate death compared with controls. Further refinement of automated pREBOA is necessary, and controller algorithms may serve as vital control inputs for automated transfusion. LEVEL OF EVIDENCE Therapeutic/Care Management; Level III.

Investigating the Relationship Between Bleeding, Clotting, and Coagulopathy During Automated Partial Reboa Strategies in a Highly Lethal Porcine Hemorrhage Model

“…Toward this goal, we performed thromboelastography (TEG) to characterize coagulation profile changes and measured plasma biomarkers of endothelial glycocalyx injury in a highly lethal uncontrolled hemorrhage model that incorporated two different automated pREBOA strategies, namely, iREBOA and pREBOA. Our previous study on this cohort found that pigs in the iREBOA group spent significantly more time at hypotension and had increased transfusions and blood loss than pREBOA animals (28). Based on these initial results, we conducted a secondary analysis on the hemodynamic and coagulation profiles and hypothesized that pigs receiving iREBOA would exhibit a more hypercoagulopathic response than pREBOA due to the increased periods of ischemia and frequency of abrupt changes to aortic flow patterns.…”

“…The iREBOA group required significantly more blood transfusions by the end of the intervention (T90), which could potentially contribute to circulating levels of HA and SDC-1 (28,42). Alternatively, both groups received the same automated balloon support and transfusion strategy during surgical hemostasis, which may explain the similar circulating endothelial glycocalyx layer levels by the end of this surgical phase (T120).…”

“…Figure 1 illustrates the experimental study timeline. Further explanations of the physiologic parameters that dictated balloon occlusion strategy and weaning have been previously described by Cambronero et al (28).…”

“…In our experience, this is a necessary step to create a clinically relevant (and translatable) highly lethal noncompressible hemorrhage model (35,36). Further details describing animal preparation and instrumentation have been described in previous publications (24,28).…”

“…One advantage of an automated partial occlusion system is the ability to offer individualized balloon titration strategies to offload supraphysiologic proximal blood pressure while allowing for attenuated flow to distal tissue beds (25,26). There is growing evidence supporting the effectiveness of pREBOA strategies in achieving quick hemodynamic control for NCTH, especially when incorporating autonomous balloon volume titration (26–28). However, the impact of these partial flow conditions on coagulopathy and endothelial glycocalyx shedding remains relatively understudied.…”