Targeted Regional Optimization in Action: Dose-dependent End-organ Ischemic Injury with Partial Aortic Occlusion in the Setting of Ongoing Liver Hemorrhage

Introduction:Targeted regional optimization (TRO) describes partial resuscitative endovascular balloon occlusion of the aorta strategy that allows for controlled distal perfusion to balance hemostasis and tissue perfusion. This study characterized hemodynamics at specific targeted distal flow rates in a swine model of uncontrolled hemorrhage to determine if precise TRO by volume was possible.Methods:Anesthetized swine were subjected to liver laceration and randomized into TRO at distal flows of 300mL/min (n=8), 500mL/min (n=8), or 700mL/min (n=8). After 90min, the animals received damage control packing and were monitored for 6h. Hemodynamic parameters were measured continuously, and hematology and serologic labs obtained at predetermined intervals.Results:During TRO, the average percent deviation from the targeted flow was lower than 15.9% for all cohorts. Average renal flow rates were significantly different across all cohorts during TRO phase (P<0.0001; TRO300=63.1±1.2; TRO500=133.70±1.93; TRO700=109.3±2.0), with the TRO700 cohort having less renal flow than TRO500. The TRO500 and TRO700 average renal flow rates inverted during the intensive care unit phase (P<0.0001; TRO300=86.20±0.40; TRO500=148.50±1.45; TRO700=181.1±0.70). There was higher blood urea nitrogen, creatinine, and potassium in the TRO300 cohort at the end of the experiment, but no difference in lactate or pH between cohorts.Conclusion:This study demonstrated technical feasibility of TRO as a strategy to improve outcomes after prolonged periods of aortic occlusion and resuscitation in the setting of ongoing solid organ hemorrhage. A dose-dependent ischemic end-organ injury occurs beginning with partial aortic occlusion that progresses through the critical care phase, with exaggerated effect on renal function.