BACKGROUND Despite clinical reports of poor outcomes, the degree to which resuscitative endovascular balloon occlusion of the aorta (REBOA) exacerbates traumatic brain injury (TBI) is not known. We hypothesized that combined effects of increased proximal mean arterial pressure (pMAP), carotid blood flow (Q_carotid), and intracranial pressure (ICP) from REBOA would lead to TBI progression compared with partial aortic occlusion (PAO) or no intervention. METHODS Twenty-one swine underwent a standardized TBI via computer Controlled cortical impact followed by 25% total blood volume rapid hemorrhage. After 30 minutes of hypotension, animals were randomized to 60 minutes of continued hypotension (Control), REBOA, or PAO. REBOA and PAO animals were then weaned from occlusion. All animals were resuscitated with shed blood via a rapid blood infuser. Physiologic parameters were recorded continuously and brain computed tomography obtained at specified intervals. RESULTS There were no differences in baseline physiology or during the initial 30 minutes of hypotension. During the 60-minute intervention period, REBOA resulted in higher maximal pMAP (REBOA, 105.3 ± 8.8; PAO, 92.7 ± 9.2; Control, 48.9 ± 7.7; p = 0.02) and higher Q_carotid (REBOA, 673.1 ± 57.9; PAO, 464.2 ± 53.0; Control, 170.3 ± 29.4; p < 0.01). Increases in ICP were greatest during blood resuscitation, with Control animals demonstrating the largest peak ICP (Control, 12.8 ± 1.2; REBOA, 5.1 ± 0.6; PAO, 9.4 ± 1.1; p < 0.01). There were no differences in the percentage of animals with hemorrhage progression on CT (Control, 14.3%; 95% confidence interval [CI], 3.6–57.9; REBOA, 28.6%; 95% CI, 3.7–71.0; and PAO, 28.6%; 95% CI, 3.7–71.0). CONCLUSION In an animal model of TBI and shock, REBOA increased Q_carotid and pMAP, but did not exacerbate TBI progression. PAO resulted in physiology closer to baseline with smaller increases in ICP and pMAP. Rapid blood resuscitation, not REBOA, resulted in the largest increase in ICP after intervention, which occurred in Control animals. Continued studies of the cerebral hemodynamics of aortic occlusion and blood transfusion are required to determine optimal resuscitation strategies for multi-injured patients.

BACKGROUND: Peripartum hemorrhage is a significant cause of maternal death. We developed a standardized, multidisciplinary cesarean hysterectomy protocol for placenta accreta spectrum (PAS) using prophylactic resuscitative endovascular balloon occlusion of the aorta (REBOA). We initially placed the balloon in proximal zone 3, below the renal arteries. An internal review revealed more bleeding than expected, and we subsequently changed our protocol to occlude the origin of the inferior mesenteric artery (distal zone 3), to decrease blood flow through collateral circulation. We hypothesized that distal zone 3 occlusion would reduce blood loss and transfusion volume and may permit a longer duration of occlusion compared with proximal zone 3 occlusion without increasing ischemic complications. METHODS: We conducted a single-center retrospective cohort study of patients with suspected PAS who underwent REBOA-assisted cesarean hysterectomy from December 2018 to March 2022. Medical records of all patients with PAS were reviewed. Data were extracted from hospital admission through 3 months postpartum. RESULTS: Forty-four patients met the inclusion criteria. Nine never had the balloon inflated. Eighteen patients had placement in proximal zone 3, whereas twenty-six patients had placement in distal zone 3. Background and clinical characteristics were similar in both groups. Placental pathology was obtained in every case. After adjusting for relevant risk factors, multivariate analysis revealed that distal occlusion was associated with a 45.9% (95% confidence interval, 23.8–61.6%) decrease in estimated blood loss, 41.5% (13.7–60.4%) decrease in red blood cell transfusion volume, and 44.9% (13.5–64.9%) reduction in total transfusion volume. There were no vascular access or resuscitative endovascular balloon occlusion of the aorta–related complications in either group. CONCLUSION: This study highlights the safety of prophylactic REBOA in planned cesarean hysterectomy for PAS and provides a rationale for distal zone 3 positioning to reduce blood loss. Resuscitative endovascular balloon occlusion of the aorta should be considered at other institutions with placenta accreta programs, especially in patients with extensive collateral flow. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

Background Administering anti-thrombotics (AT) to the multiply injured patient with blunt cerebrovascular injury (BCVI) requires a thoughtful assessment of the risk of stroke and death associated with non-treatment. Large, multicenter analysis of outcomes stratified by injury grade and vessel injured is needed to inform future recommendations. Methods 971 BCVIs were identified from the PROspective Vascular Injury Treatment (PROOVIT) registry in this retrospective analysis. Using multivariate analysis, we identified predictors of BCVI-related stroke and death. We then stratified these risks by injury grade and vessel injured. We compared the risk of adverse outcomes in the non-treatment group to those treated with antiplatelet agents and/or anticoagulants. Results Stroke was identified in 7% of cases. Overall mortality was 12%. Both increased with increasing BCVI grade. Treatment with ATs was associated with lower mortality and was not significantly affected by the choice of agent. Withholding ATs was associated with an increased risk of stroke and/or death across all subgroups (grade I/II OR 4.66 95% CI 2.48-8.75, grade III OR 7.0 95% CI 2.01-24.5, grade IV OR 4.43 95% CI 1.76-11.1) even after controlling for covariates. Predictors of death included more severe trauma, grade IV injury, and the occurrence of stroke. Arterial occlusion, hypotension, and endovascular intervention were significant predictors of stroke. Patients that experienced a BCVI-related stroke were at a 4.2x increased risk of death. The dataset lacked the granularity necessary to evaluate AT timing or dosing regimen, which limited further analysis of stroke prevention strategies. Conclusions Stroke and death remain significant risks for all BCVI grades regardless of the vessel injured. ATs represent the only management strategy that is consistently associated with a lower incidence of stroke and death in all BCVI categories. In the multi-injured BCVI patient with a high risk of bleeding on anticoagulation, antiplatelet agents are an efficacious alternative. Given the 40% mortality rate in patients who survived their initial trauma and developed a BCVI related stroke, non-treatment may no longer be a viable option. Level of Evidence III Study Type Original Manuscript. Epidemiological

BACKGROUND: Noncompressible torso hemorrhage is a leading cause of preventable death on the battlefield. Intra-aortic balloon occlusion was first used in combat in the 1950s, but military use was rare before Operation Iraqi Freedom and Operation Enduring Freedom. During these wars, the combination of an increasing number of deployed vascular surgeons and a significant rise in deaths from hemorrhage resulted in novel adaptations of resuscitative endovascular balloon occlusion of the aorta (REBOA) technology, increasing its potential application in combat. We describe the background of REBOA development in response to a need for minimally invasive intervention for hemorrhage control and provide a detailed review of all published cases (n = 47) of REBOA use for combat casualties. The current limitations of REBOA are described, including distal ischemia and reperfusion injury, as well as ongoing research efforts to adapt REBOA for prolonged use in the austere setting. LEVEL OF EVIDENCE: Level V.

BACKGROUND: Future endovascular hemorrhage control devices will require features that mitigate the adverse effects of vessel occlusion. Permissive regional hypoperfusion (PRH) with variable aortic control (VAC) is a novel strategy to minimize hemorrhage and reduce the ischemic burden of complete aortic occlusion (AO). The objective of this study was to compare PRH with VAC to AO in a lethal model of hemorrhage. METHODS: Twenty-five swine underwent cannulation of the supraceliac aorta, with diversion of aortic flow through an automated extracorporeal circuit. After creation of uncontrolled liver hemorrhage, animals were randomized to 90 minutes of treatment: Control (full, unregulated flow; n = 5), AO (no flow; n = 10), and PRH with VAC (dynamic distal flow initiated after 20 minutes of AO; n = 10). In the PRH group, distal flow rates were regulated between 100 and 300 mL/min based on a desired, preset range of proximal mean arterial pressure (MAP). At 90 minutes, damage control surgery, resuscitation, and restoration of full flow ensued. Critical care continued for 4.5 hours or until death. Hemodynamic parameters and markers of ischemia were recorded. RESULTS: Study survival was 0%, 50%, and 90% for control, AO, and VAC, respectively ( p < 0.01). During intervention, VAC resulted in more physiologic proximal MAP (84 ± 18 mm Hg vs. 105 ± 9 mm Hg, p < 0.01) and higher renal blood flow than AO animals ( p = 0.02). During critical care, VAC resulted in higher proximal MAP (73 ± 8 mm Hg vs. 50 ± 6 mm Hg, p < 0.01), carotid and renal blood flow ( p < 0.01), lactate clearance ( p < 0.01), and urine output ( p < 0.01) than AO despite requiring half the volume of crystalloids to maintain proximal MAP ≥50 mm Hg ( p < 0.01). CONCLUSION: Permissive regional hypoperfusion with variable aortic control minimizes the adverse effects of distal ischemia, optimizes proximal pressure to the brain and heart, and prevents exsanguination in this model of lethal hemorrhage. These findings provide foundational knowledge for the continued development of this novel paradigm and inform next-generation endovascular designs.

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