Distal organ inflammation and injury after resuscitative endovascular balloon occlusion of the aorta in a porcine model of severe hemorrhagic shock

Partial REBOA Zone 1 is associated with lower mortality compared to complete REBOA Zone 1 and emergency department thoracotomy: A cohort study using the AORTA registry

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) and emergency department thoracotomy (EDT) are effective methods of aortic occlusion (AO) for life-threatening bleeding; however, complete AO can lead to visceral ischemia. Partial REBOA (P-REBOA) has been proposed as an alternative to the completely occlusive REBOA (C-REBOA) to balance hemorrhage control and perfusion. Using the Aortic Occlusion for Resuscitation in Trauma (AORTA) multicenter, observational registry, we tested the hypothesis that P-REBOA resulted in better outcomes compared to EDT and C-REBOA.

STUDY DESIGN AND METHODS

We queried the 2017-2023 AORTA registry for adults who underwent EDT, C-REBOA, or P-REBOA in the emergency department (ED). Patients with chest penetrating injuries were excluded. We compared mortality, ventilator-free-days (VFD), and ICU-free-days (ICUFD) using survival analysis or generalized linear models to adjust for confounders.

RESULTS

Overall, 921 patients underwent EDT (n = 613, 66.6%), C-REBOA (n = 224, 24.3%), or P-REBOA (n = 84, 9.1%); 83.1% died. After confounder adjustment, compared to P-REBOA, both C-REBOA and EDT were associated with a lower likelihood of attaining hemodynamic improvement and stability as well as with higher mortality (adjusted hazard ratio, aHR = 1.84; 95% CI: 1.01-1.60 and aHR = 3.32; 95% CI: 1.96-2.78, respectively). EDT patients had less VFD and ICUFD than those undergoing C-REBOA and P-REBOA, but there were no differences between the two endovascular procedures. Among patients who survived >48 h, EDT was more likely to be associated with complications compared to the other two procedures.

DISCUSSION

P-REBOA was more likely to be associated with improved hemodynamic stability and reduced mortality compared to C-REBOA and EDT, suggesting this modality may be a better AO procedure for patients with no penetrating thoracic injuries.

The Efficacy of Whole Blood Resuscitation During Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) to Mitigate Post-occlusion Circulatory Collapse: A Translational Model in Large Swine

INTRODUCTION

Uncontrolled torso hemorrhage is the primary cause of potentially survivable deaths on the battlefield. Zone 1 Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA), in conjunction with damage control resuscitation, may be an effective management strategy for these patients in the prehospital or austere phase of their care. However, the effect of whole blood (WB) transfusion during REBOA on post-occlusion circulatory collapse is not fully understood.

MATERIALS AND METHODS

Yorkshire male swine (n = 6 per group, 70-90 kg) underwent a 40% volume-controlled hemorrhage. After a 10-minute hemorrhagic shock period, a REBOA balloon was inflated in Zone 1. Fifteen minutes after inflation, 0, 1, or 3 units (450 mL/unit) of autologous WB was infused through the left jugular vein. Thirty minutes after initial balloon inflation, the balloon was deflated slowly over 3 minutes. Following deflation, normal saline was administered (up to 3,000 mL) and swine were observed for 2 hours. Survival (primary outcome), hemodynamics, and blood gas values were compared among groups. Statistical significance was determined by log-rank test, one-way ANOVA, and repeated measures ANOVA.

RESULTS

Survival rates were comparable between groups (P = .345) with 66% of control, 33% of the one-unit animals, and 50% of the 3-unit animals survived until the end of the study. Following WB infusion, both the 1-unit and the 3-unit groups had significantly higher blood pressure (P < .01), pulmonary artery pressure (P < .01), and carotid artery flow (P < .01) compared to the control group.

CONCLUSIONS

WB transfusion during Zone 1 REBOA was not associated with increased short-term survival in this large animal model of severe hemorrhage. We observed no signal that WB transfusion may mitigate post-occlusion circulatory collapse. However, there was evidence of supra-normal blood pressures during WB transfusion.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) in the presence of associated severe traumatic brain injury: A propensity-score matched study

BACKGROUND

Experimental work suggested that resuscitative Endovascular Balloon Occlusion of the aorta (REBOA) preserves cerebral circulation in animal models of traumatic brain injury. No clinical work has evaluated the role of REBOA in the presence of associated severe traumatic brain injury (TBI). We investigated the impacts of REBOA on neurological and survival outcomes.

METHODS

Propensity-score matched study, using the American College of Surgeons Trauma Quality Improvement Program database. Patients with severe TBI patients (Abbreviated Injury Scale ≥3) receiving REBOA within 4 ​h from arrival were matched with similar patients not receiving REBOA. Neurological matching included head AIS, pupils, and midline shift. Clinical outcomes were compared between the two groups.

RESULTS

434 REBOA patients were matched with 859 patients without REBOA. Patients in the REBOA group had higher rates of in-hospital mortality (63.6 ​% vs 44.2 ​%, p ​< ​0.001), severe sepsis (4.4 ​% vs 2.2 ​%, p ​= ​0.029), acute kidney injury (10.1 ​% vs 6.6 ​%, p ​= ​0.029), and withdrawal of life support (25.4 ​% vs 19.6 ​%, p ​= ​0.020) despite of lower craniectomy/craniotomy rate (7.1 ​% vs 12.7 ​%, p ​< ​0.002).

CONCLUSION

In patients with severe TBI, REBOA use is associated with an increased risk of in-hospital mortality, AKI, and infectious complications.

INVESTIGATING THE RELATIONSHIP BETWEEN BLEEDING, CLOTTING, AND COAGULOPATHY DURING AUTOMATED PARTIAL REBOA STRATEGIES IN A HIGHLY LETHAL PORCINE HEMORRHAGE MODEL

ABSTRACT

Background: Death due to hemorrhagic shock, particularly, noncompressible truncal hemorrhage, remains one of the leading causes of potentially preventable deaths. Automated partial and intermittent resuscitative endovascular balloon occlusion of the aorta (i.e., pREBOA and iREBOA, respectively) are lifesaving endovascular strategies aimed to achieve quick hemostatic control while mitigating distal ischemia. In iREBOA, the balloon is titrated from full occlusion to no occlusion intermittently, whereas in pREBOA, a partial occlusion is maintained. Therefore, these two interventions impose different hemodynamic conditions, which may impact coagulation and the endothelial glycocalyx layer. In this study, we aimed to characterize the clotting kinetics and coagulopathy associated with iREBOA and pREBOA, using thromboelastography (TEG). We hypothesized that iREBOA would be associated with a more hypercoagulopathic response compared with pREBOA due to more oscillatory flow. Methods: Yorkshire swine (n = 8/group) were subjected to an uncontrolled hemorrhage by liver transection, followed by 90 min of automated pREBOA, iREBOA, or no balloon support (control). Hemodynamic parameters were continuously recorded, and blood samples were serially collected during the experiment (i.e., eight key time points: baseline (BL), T0, T10, T30, T60, T90, T120, T210 min). Citrated kaolin heparinase assays were run on a TEG 5000 (Haemonetics, Niles, IL). General linear mixed models were employed to compare differences in TEG parameters between groups and over time using STATA (v17; College Station, TX), while adjusting for sex and weight. Results: As expected, iREBOA was associated with more oscillations in proximal pressure (and greater magnitudes of peak pressure) because of the intermittent periods of full aortic occlusion and complete balloon deflation, compared to pREBOA. Despite these differences in acute hemodynamics, there were no significant differences in any of the TEG parameters between the iREBOA and pREBOA groups. However, animals in both groups experienced a significant reduction in clotting times (R time: P < 0.001; K time: P < 0.001) and clot strength (MA: P = 0.01; G: P = 0.02) over the duration of the experiment. Conclusions: Despite observing acute differences in peak proximal pressures between the iREBOA and pREBOA groups, we did not observe any significant differences in TEG parameters between iREBOA and pREBOA. The changes in TEG profiles were significant over time, indicating that a severe hemorrhage followed by both pREBOA and iREBOA can result in faster clotting reaction times (i.e., R times). Nevertheless, when considering the significant reduction in transfusion requirements and more stable hemodynamic response in the pREBOA group, there may be some evidence favoring pREBOA usage over iREBOA.

The degree of aortic occlusion in the setting of trauma alters the extent of acute kidney injury associated with mitochondrial preservation

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is used to control noncompressible hemorrhage not addressed with traditional tourniquets. However, REBOA is associated with acute kidney injury (AKI) and subsequent mortality in severely injured trauma patients. Here, we investigated how the degree of aortic occlusion altered the extent of AKI in a porcine model. Female Yorkshire-cross swine (n = 16, 68.1 ± 0.7 kg) were anesthetized and had carotid and bilateral femoral arteries accessed for REBOA insertion and distal and proximal blood pressure monitoring. Through a laparotomy, a 6-cm liver laceration was performed and balloon inflation was performed in zone 1 of the aorta for 90 min, during which animals were randomized to target distal mean arterial pressures of 25 or 45 mmHg via balloon volume adjustment. Blood draws were taken at baseline, end of occlusion, and time of death, at which point renal tissues were harvested 6 h after balloon deflation for histological and molecular analyses. Renal blood flow was lower in the 25-mmHg group (48.5 ± 18.3 mL/min) than in the 45-mmHg group (177.9 ± 27.2 mL/min) during the occlusion phase, which recovered and was not different after balloon deflation. AKI was more severe in the 25-mmHg group, as evidenced by circulating creatinine, blood urea nitrogen, and urinary neutrophil gelatinase-associated lipocalin. The 25-mmHg group had increased tubular necrosis, lower renal citrate synthase activity, increased tissue and circulating syndecan-1, and elevated systemic inflammatory cytokines. The extent of renal ischemia-induced AKI is associated with the magnitude of mitochondrial biomass and systemic inflammation, highlighting potential mechanistic targets to combine with partial REBOA strategies to prevent AKI.NEW & NOTEWORTHY Large animal models of ischemia-reperfusion acute kidney injury (IR-AKI) are lacking. This report establishes a titratable IR-AKI model in swine in which a balloon catheter can be used to alter distal pressures experienced by the kidney, thus controlling renal blood flow. Lower blood flow results in greater renal dysfunction and structural damage, as well as lower mitochondrial biomass, elevated systemic inflammation, and vascular dysfunction.

Efficacy of partial and complete resuscitative endovascular balloon occlusion of the aorta in the hemorrhagic shock model of liver injury

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) can temporarily control traumatic bleeding. However, its prolonged use potentially leads to ischemia-reperfusion injury (IRI). Partial REBOA (pREBOA) can alleviate ischemic burden; however, its security and effectiveness prior to operative hemorrhage control remains unknown. Hence, we aimed to estimate the efficacy of pREBOA in a swine model of liver injury using an experimental sliding-chamber ballistic gun.

METHODS

Twenty Landrace pigs were randomized into control (no aortic occlusion) (n=5), intervention with complete REBOA (cREBOA) (n=5), continuous pREBOA (C-pREBOA) (n=5), and sequential pREBOA (S-pREBOA) (n=5) groups. In the cREBOA and C-pREBOA groups, the balloon was inflated for 60 min. The hemodynamic and laboratory values were compared at various observation time points. Tissue samples immediately after animal euthanasia from the myocardium, liver, kidneys, and duodenum were collected for histological assessment using hematoxylin and eosin staining.

RESULTS

Compared with the control group, the survival rate of the REBOA groups was prominently improved (all P<0.05). The total volume of blood loss was markedly lower in the cREBOA group (493.14±127.31 mL) compared with other groups (P<0.01). The pH was significantly lower at 180 min in the cREBOA and S-pREBOA groups (P<0.05). At 120 min, the S-pREBOA group showed higher alanine aminotransferase (P<0.05) but lower blood urea nitrogen compared with the cREBOA group (P<0.05).

CONCLUSION

In this trauma model with liver injury, a 60-minute pREBOA resulted in improved survival rate and was effective in maintaining reliable aortic pressure, despite persistent hemorrhage. Extended tolerance time for aortic occlusion in Zone I for non-compressible torso hemorrhage was feasible with both continuous partial and sequential partial measures, and the significant improvement in the severity of acidosis and distal organ injury was observed in the sequential pREBOA.

Abdominal Aortic Occlusion and the Inflammatory Effects in Heart and Brain

Background

Abdominal aortic occlusion (AAO) occurs frequently and causes ischemia/reperfusion (I/R) injury to distant organs. In this study, we aimed to investigate whether AAO induced I/R injury and subsequent damage in cardiac and neurologic tissue. We also aimed to investigate the how length of ischemic time in AAO influences reactive oxygen species (ROS) production and inflammatory marker levels in the heart, brain, and serum.

Methods

Sixty male C57BL/6 mice were used in this study. The mice were randomly divided into either sham group or AAO group. The AAO group was further subdivided into 1-4 hr groups of aortic occlusion times. The infrarenal abdominal aorta was clamped for 1-4 hr depending on the AAO group and was then reperfused for 24 hr after clamp removal. Serum, hippocampus, and left ventricle tissue samples were then subjected to biochemical and histopathological analyses.

Results

AAO-induced I/R injury had no effect on cell necrosis, cell apoptosis, or ROS production. However, serum and hippocampus levels of malondialdehyde (MDA) and lactate dehydrogenase (LDH) increased in AAO groups when compared to sham group. Superoxide dismutase and total antioxidant capacity decreased in the serum, hippocampus, and left ventricle. In the serum, AAO increased the level of inducible nitric oxide synthase (iNOS) and decreased the levels of anti-inflammatory factors (such as arginase-1), transforming growth factor- β1 (TGF-β1), interleukin 4 (IL-4), and interleukin 10 (IL-10). In the hippocampus, AAO increased the levels of tumor necrosis factor (TNF-α), interleukin 1β (IL-1β), interleukin 6 (IL-6), IL-4, and IL-6, and decreased the level of TGF-β1. In the left ventricle, AAO increased the level of iNOS and decreased the levels of TGF-β1, IL-4, and IL-10.

Conclusions

AAO did not induce cell necrosis or apoptosis in cardiac or neurologic tissue, but it can cause inflammation in the serum, brain, and heart.

A modified chain-based sponge dressing controls junctional hemorrhage in the tactical combat casualty care simulation of pigs

BACKGROUND

Hemorrhage has always been the focus of battlefield and pre-hospitalization treatment. With the increasing fatality rates associated with junctional bleeding, treatment of bleeding at junctional sites has gradually gained attention in battlefield trauma emergency care. We designed a modified chain-based sponge dressing with a medical polyvinyl alcohol sponge that can be used to treat junctional hemorrhage and tested its hemostatic efficacy and biocompatibility.

METHODS

Twenty adult Bama miniature pigs were randomly divided into the modified chain-based sponge dressing (MCSD) and standard gauze (SG) groups. The right femoral artery of the pigs was shot at after anesthesia. The Bama miniature pigs were moved to the safety zone immediately to assess the condition according to the MARCH strategy, which evaluates massive hemorrhaging, airway obstruction, respiratory status, circulatory status, head injury & hypothermia. Hemoglobin and coagulation status were checked during the experiment.Among the pigs in which the inguinal hemorrhagic model based on bullet penetrating wounds was successfully established, those in the MCSD group received a disinfected MCSD for hemostasis, while those in the SG group received standard gauze in an imbricate manner to pack the bullet exit and entrance wounds to stop bleeding until the wound was filled, followed by compression for 3 min at sufficient pressure. CT scanning, transmission electron microscopy, and HE staining were conducted after experiment.

RESULTS

The MCSD group showed lower hemostasis time and blood loss than the gauze group. The MCSD group also showed a higher success rate of treatment,more stable vital signs and hemoglobin level. The CT scanning results showed tighter packing without large gaps in the MCSD group. The histopathological assessments and the transmission electron microscopy and HE staining findings indicated good biocompatibility of the polyvinyl alcohol sponge.

CONCLUSION

The MCSD met the battlefield's requirements of speedy hemostasis and biosafety for junctional hemorrhage in Bama miniature pigs. Moreover, in comparison with the conventional approach for hemostasis, it showed more stable performance for deep wound hemostasis. These findings provide the theoretical and experimental basis for the application of MCSD in the treatment of hemorrhage in the battlefield in the future.

MILD THERAPEUTIC HYPOTHERMIA REDUCES ISCHEMIA-REPERFUSION INJURY AFTER ZONE 1 REBOA IN A SWINE HEMORRHAGIC SHOCK MODEL

ABSTRACT

Background: Resuscitative balloon occlusion of the aorta (REBOA) is an endovascular hemostasis method used for the management of traumatic abdominal and pelvic hemorrhages. However, REBOA-associated ischemia-reperfusion injury complication limits its blocking time. We hypothesized that mild therapeutic hypothermia would relieve ischemia-reperfusion injury caused by prolonged zone 1 REBOA. Methods: Ten pigs were anesthetized, intubated, and subsequently struck with the experimental sliding-chamber ballistic gun to inflict liver damage. Animals were randomized to hypothermia (60 min of zone 1 REBOA with external cooling for 180 min, n = 5) or control (60 min of zone 1 REBOA with no external cooling, n = 5). Physiological and laboratory parameters were monitored and assessed. Distal organs were obtained for histologic analysis. Results: At 180 min, compared with the control, the hypothermia animals exhibited significantly increased pH and significantly reduced lactate, hemoglobin, and hematocrit (all P < 0.05). The change of lactate from 0 to 180 min in hypothermia animals was less than that in the control ( P = 0.02). The total bleeding in the control group was significantly less than the hypothermia ( P < 0.01). In the hypothermia group, prothrombin time at 120 and 180 min was significantly longer than that at baseline (all P < 0.05). Compared with the control, animals in the hypothermia group showed slighter pathological injury of the distal organs and significantly lower overall injury score (all P < 0.05). Conclusions: Mild therapeutic hypothermia during prolonged zone 1 REBOA offered extraordinary distal organ preservation and decreased metabolic acidosis.

CORM-3 alleviates the intestinal injury in a rodent model of hemorrhage shock and resuscitation: roles of GFAP-positive glia

Hemorrhagic shock and resuscitation (HSR) can induce severe intestinal damages, thereby leading to sepsis and long-term complications including dysbacteriosis and pulmonary injury. The NOD-like receptor protein 3 (NLRP3) inflammasome facilitates inflammation-associated cell recruitment in the gastrointestinal tract, and participates in many inflammatory bowel diseases. Previous studies have shown that exogenous carbon monoxide (CO) exerts neuroprotective effects against pyroptosis after HSR. We aimed to investigate whether carbon monoxide-releasing molecules-3 (CORM-3), an exogenous CO compound, could attenuate HSR-induced intestinal injury and the potential underlying mechanism.Rats were subjected to a HSR model by bleeding and re-infusion. Following resuscitation, 4 mg/kg of CORM-3 was administered intravenously into femoral vein. At 24 h and 7 d after HSR modeling, the pathological changes in intestinal tissues were evaluated by H&E staining. The intestinal pyroptosis, glial fibrillary acidic protein (GFAP)-positive glial pyroptosis, DAO (diamine oxidase) content, intestine tight junction proteins including zonula occludens-1 (ZO-1) and claudin-1 were further detected by immunofluorescence, western blot and chemical assays at 7 d after HSR. CORM-3 administration led to significantly mitigated HSR-induced intestinal injury, aggravation of intestinal pyroptosis indicated by cleaved caspase-1, IL-1β and IL-18, upregulation of GFAP-positive glial pyroptosis, decreased intensity of ZO-1 and claudin-1 in the jejunum, and increased of DAO in the serum. Nigericin, an agonist of NLRP3, significantly reversed the protective effects of CORM-3. CORM-3 alleviates the intestinal barrier dysfunction in a rodent model of HSR, and the potential mechanism may be associated with inhibition of NLRP3-associated pyroptosis. CORM-3 administration could be a promising therapeutic strategy for intestinal injury after hemorrhagic shock.

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

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.

REBOA for the Treatment of Blast Polytrauma: Zone 3 Provides Cerebral Perfusion, Attenuates Organ Dysfunction and Reperfusion Coagulopathy Compared to Zone 1 in a Swine Model

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a lifesaving therapy for hemorrhagic shock following pelvic/lower extremity injuries in military settings. However, Zone 1 aortic occlusion (AO; above the celiac artery), while providing brain/cardiac perfusion, may induce/worsen visceral ischemia and organ dysfunction. In contrast, AO Zone 3 (below the renal arteries) provides abdominal perfusion potentially minimizing ischemia/reperfusion injury. We hypothesized that, compared with AO Zone 1, AO Zone 3 provides neuro/cardioprotection while minimizing visceral ischemia and reperfusion coagulopathy after severe traumatic hemorrhage due to pelvic/lower extremity injuries.

METHODS

Fifty-kilogram male Yorkshire swine underwent a blast polytrauma injury followed by a resuscitation protocol with randomization to no AO (No AO, n = 6) or AO with REBOA at Zone 1 (AO Zone 1; n = 6) or Zone 3 (AO Zone 3; n = 4). Vital signs and intracranial pressure (ICP) were monitored for 240 minutes. Citrate native and tissue plasminogen activator challenge thrombelastography, prothrombin time, creatinine, lipase, total bilirubin, troponin, and enzyme-linked immunosorbent assays protein levels were measured at set intervals.

RESULTS

Both AO groups had significant increases in mean arterial pressure during aortic occlusion. All three groups had significant increases in ICP, but final ICP in the No AO group (26 ± 5.8 mm Hg) was significantly elevated compared with AO Zone 1 (17 ± 5.2 mm Hg) and AO Zone 3 (16 ± 4.2 mm Hg) ( p < 0.01). The final mean troponin in the No AO group (4.10 ± 5.67 ng/mL) was significantly higher than baseline (0.03 ± 0.02 ng/mL, p < 0.05), while the two AO groups had no significant changes ( p > 0.05). AO Zone 1 was the only group associated with hyperfibrinolysis ( p < 0.05) and significantly increased prothrombin time ( p < 0.05). Only AO Zone 1 group had significantly higher markers of organ damage.

CONCLUSION

Compared with AO Zone 1, AO Zone 3 provided similar neuro/cardioprotection but with less organ dysfunction and coagulopathy. This study suggests that Zone 3 REBOA may be preferable over Zone 1 for treating military relevant blast polytrauma with minimal intra-abdominal and chest trauma, but further clinical investigation is warranted.

OUTCOMES FOLLOWING ZONE 3 AND ZONE 1 AORTIC OCCLUSION FOR THE TREATMENT OF BLUNT PELVIC INJURIES

ABSTRACT

Background: A 2021 report of the Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery multicenter registry described the outcomes of patients treated with Zone 3 resuscitative endovascular balloon occlusion of the aorta (REBOA zone 3). Our study builds upon that report, testing the hypothesis that REBOA zone 3 is associated with better outcomes than REBOA Zone 1 in the immediate treatment of severe, blunt pelvic injuries. Methods: We included adults who underwent aortic occlusion (AO) via REBOA zone 1 or REBOA Zone 3 in the emergency department for severe, blunt pelvic injuries [Abbreviated Injury Score ≥ 3 or pelvic packing/embolization/first 24 hours] in institutions with >10 REBOAs. Adjustment for confounders was accomplished with a Cox proportional hazards model for survival, generalized estimating equations for intensive care unit (ICU)-free days (IFD) and ventilation-free days (VFD) > 0 days, and mixed linear models for continuous outcomes (Glasgow Coma Scale [GCS], Glasgow Outcome Scale [GOS]), accounting for facility clustering. Results: Of 109 eligible patients, 66 (60.6%) underwent REBOA Zone 3 and 43 (39.4%) REBOA Zone 1. There were no differences in demographics, but compared with REBOA Zone 3, REBOA Zone 1 patients were more likely to be admitted to high volume centers and be more severely injured. These patients did not differ in systolic blood pressure (SBP), cardiopulmonary resuscitation in the prehospital/hospital settings, SBP at the start of AO, time to AO start, likelihood of achieving hemodynamic stability or requirement of a second AO. After controlling for confounders, compared with REBOA Zone 3, REBOA Zone 1 was associated with a significantly higher mortality (adjusted hazard ratio, 1.51; 95% confidence interval [CI], 1.04-2.19), but there were no differences in VFD > 0 (adjusted relative risk, 0.66; 95% CI, 0.33-1.31), IFD > 0 (adjusted relative risk, 0.78; 95% CI, 0.39-1.57), discharge GCS (adjusted difference, -1.16; 95% CI, -4.2 to 1.90) or discharge GOS (adjusted difference, -0.67; 95% CI -1.9 to 0.63). Conclusions: This study suggests that compared with REBOA Zone 1, REBOA Zone 3 provides superior survival and is not inferior regarding other adverse outcomes in patients with severe blunt pelvic injuries.

Immunopathological Alterations after Blast Injury and Hemorrhage in a Swine Model of Prolonged Damage Control Resuscitation

Trauma-related hemorrhagic shock (HS) remains a leading cause of death among military and civilian trauma patients. We have previously shown that administration of complement and HMGB1 inhibitors attenuate morbidity and mortality 24 h after injury in a rat model of blast injury (BI) and HS. To further validate these results, this study aimed to develop a swine model and evaluate BI+HS-induced pathophysiology. Anesthetized Yucatan minipigs underwent combined BI and volume-controlled hemorrhage. After 30 min of shock, animals received an intravenous bolus of PlasmaLyte A and a continuous PlasmaLyte A infusion. The survival rate was 80% (4/5), and the non-survivor expired 72 min post-BI. Circulating organ-functional biomarkers, inflammatory biomarkers, histopathological evaluation, and CT scans indicated evidence of multiple-organ damage, systemic innate immunological activation, and local tissue inflammation in the injured animals. Interestingly, a rapid and dramatic increase in plasma levels of HMGB1 and C3a and markedly early myocarditis and encephalitis were associated with early death post-BI+HS. This study suggests that this model reflects the immunopathological alterations of polytrauma in humans during shock and prolonged damage control resuscitation. This experimental protocol could be helpful in the assessment of immunological damage control resuscitation approaches during the prolonged care of warfighters.

Worse outcomes with resuscitative endovascular balloon occlusion of the aorta in severe pelvic fracture: A matched cohort study

BACKGROUND

Severe pelvic fracture is the most common indication for resuscitative endovascular balloon occlusion of the aorta (REBOA). This matched cohort study investigated outcomes with or without REBOA use in isolated severe pelvic fractures.

METHODS

Trauma Quality Improvement Program database study, included patients with isolated severe pelvic fracture (AIS≥3), excluded associated injuries with AIS >3 for any region other than lower extremity. REBOA patients were propensity score matched to similar patients without REBOA. Outcomes were mortality and complications.

RESULTS

93 REBOA patients were matched with 279 without. REBOA patients had higher rates of in-hospital mortality (32.3% vs 19%, p = 0.008), higher rates of venous thromboembolism (14% vs 6.5%, p = 0.023) and DVT (11.8% vs 5.4%, p = 0.035). In multivariate analysis, REBOA use was independently associated with increased mortality and venous thromboembolism.

CONCLUSIONS

REBOA in severe pelvic fractures is associated with higher rates of mortality, venous thromboembolism.

Adenosine, lidocaine, and magnesium for attenuating ischemia reperfusion injury from resuscitative endovascular balloon occlusion of the aorta in a porcine model

BACKGROUND

Minimally invasive resuscitative endovascular balloon occlusion of the aorta (REBOA) following noncompressible hemorrhage results in significant ischemia reperfusion injury (IRI). Adverse outcomes from IRI include organ dysfunction and can result in profound hemodynamic and molecular compromise. We hypothesized that adenosine, lidocaine, and magnesium (ALM) attenuates organ injury and inflammation responses following REBOA IRI in a porcine model of hemorrhage.

METHODS

Animals underwent a 20% controlled hemorrhage followed by 45 minutes of supraceliac balloon occlusion. They were randomized into two groups: control (n = 9) and ALM intervention (n = 9) to include a posthemorrhage, pre-REBOA bolus (200 mL of 3% NaCl ALM) followed by a continuous drip (2 mL/kg per hour of 0.9% NaCl ALM) during the 4-hour resuscitative period. Primary outcomes included hemodynamic parameters, gene expression of inflammatory signaling molecules, and plasma concentrations of select cytokines and chemokines.

RESULTS

The ALM cohort demonstrated a significant reduction in cardiac output and cardiac index. Plasma concentrations of interleukin 2 and interleukin 10 were significantly lower 3 hours post-REBOA in animals treated with ALM versus vehicle. Interleukin 4 levels in plasma were also lower with ALM at 3 and 4 hours post-REBOA (p < 0.05). Liver expression of IL1RN, MTOR, and LAMP3 messenger RNA was significantly lower with ALM as compared with the vehicle. No significant difference in large bowel gene expression was observed between treatments.

CONCLUSION

In a porcine model of hemorrhage, ALM treatment mitigated inflammatory responses early during post-REBOA resuscitation. Our findings suggest that ALM use with trauma may reduce inflammatory injury and improve outcomes related to REBOA utilization.

Combatting ischemia reperfusion injury from resuscitative endovascular balloon occlusion of the aorta using adenosine, lidocaine and magnesium: A pilot study

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA), a minimally invasive alternative to resuscitative thoracotomy, has been associated with significant ischemia reperfusion injury (IRI). Resuscitation strategies using adenosine, lidocaine, and magnesium (ALM) have been shown to mitigate similar inflammatory responses in hemorrhagic and septic shock models. This study examined the effects of ALM on REBOA-associated IRI using a porcine model.

METHODS

Animals underwent a 20% controlled hemorrhage followed by 30 minutes of supraceliac balloon occlusion. They were assigned to one of four groups: control (n = 5), 4-hour ALM infusion starting at occlusion, 2-hour (n = 5) and 4-hour (n = 5) interventional ALM infusions starting at reperfusion. Adenosine, lidocaine, and magnesium cohorts received a posthemorrhage ALM bolus followed by their respective ALM infusion. Primary outcomes for the study assessed physiologic and hemodynamic parameters.

RESULTS

Adenosine, lidocaine, and magnesium infusion after reperfusion cohorts demonstrated a significant improvement in lactate, base deficit, and pH in the first hour following systemic reperfusion. At study endpoint, continuous ALM infusion initiated after reperfusion over 4 hours resulted in an overall improved lactate clearance when compared with the 2-hour and control cohorts. No differences in hemodynamic parameters were noted between ALM cohorts and controls.

CONCLUSION

Adenosine, lidocaine, and magnesium may prove beneficial in mitigating the inflammatory response seen from REBOA-associated IRI as evidenced by physiologic improvements early during resuscitation. Despite this, further refinement should be sought to optimize treatment strategies.

Resuscitative endovascular balloon occlusion of the aorta in combat casualties: The past, present, and future

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.