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

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.

Complications associated with the use of resuscitative endovascular balloon occlusion of the aorta (REBOA): an updated review

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has become part of the arsenal to temporize patients in shock from severe hemorrhage. REBOA is used in trauma to prevent cardiovascular collapse by preserving heart and brain perfusion and minimizing distal hemorrhage until definitive hemorrhage control can be achieved. Significant side effects, including death, ischemia and reperfusion injuries, severe renal and lung damage, limb ischemia and amputations have all been reported. The aim of this article is to provide an update on complications related to REBOA. REBOA has emerged as a critical intervention for managing severe hemorrhagic shock, aiming to temporize patients and prevent cardiovascular collapse until definitive hemorrhage control can be achieved. However, this life-saving procedure is not without its challenges, with significant reported side effects. This review provides an updated overview of complications associated with REBOA. The most prevalent procedure-related complication is distal embolization and lower limb ischemia, with an incidence of 16% (range: 4-52.6%). Vascular and access site complications are also noteworthy, documented in studies with incidence rates varying from 1.2% to 11.1%. Conversely, bleeding-related complications exhibit lower documentation, with incidence rates ranging from 1.4% to 28.6%. Pseudoaneurysms are less likely, with rates ranging from 2% to 14%. A notable incidence of complications arises from lower limb compartment syndrome and lower limb amputation associated with the REBOA procedure. Systemic complications include acute kidney failure, consistently reported across various studies, with incidence rates ranging from 5.6% to 46%, representing one of the most frequently documented systemic complications. Infection and sepsis are also described, with rates ranging from 2% to 36%. Pulmonary-related complications, including acute respiratory distress syndrome and multisystem organ failure, occur in this population at rates ranging from 7.1% to 17.5%. This comprehensive overview underscores the diverse spectrum of complications associated with REBOA.

Non-compressible truncal and junctional hemorrhage: A retrospective analysis quantifying potential indications for advanced bleeding control in Dutch trauma centers

BACKGROUND

Truncal and junctional hemorrhage is the leading cause of potentially preventable deaths in trauma patients. To reduce this mortality, the application of advanced bleeding control techniques, such as resuscitative endovascular balloon occlusion of the aorta (REBOA), junctional tourniquets, Foley catheters, or hemostatic agents should be optimized. This study aimed to identify trauma patients with non-compressible truncal and junctional hemorrhage (NCTJH) who might benefit from advanced bleeding control techniques during initial trauma care. We hypothesized that there is a substantial cohort of Dutch trauma patients that can possibly benefit from advanced bleeding control techniques.

METHODS

Adult trauma patients with an Abbreviated Injury Scale ≥3 in the torso, neck, axilla, or groin region, who were presented between January 1st, 2014 and December 31st, 2018 to two Dutch level-1 trauma centers, were identified from the Dutch Trauma Registry. Potential indications for advanced bleeding control in patients with NCTJH were assessed by an expert panel of three trauma surgeons based on injury characteristics, vital signs, response to resuscitation, and received treatment.

RESULTS

In total, 1719 patients were identified of whom 249 (14.5 %) suffered from NCTJH. In 153 patients (60.6 %), hemorrhagic shock could have been mitigated or prevented with advanced bleeding control techniques. This group was younger and more heavily injured: median age of 40 versus 48 years and median ISS 33 versus 22 as compared to the entire cohort. The mortality rate in these patients was 31.8 %. On average, each of the included level-1 trauma centers treated an NCTJH patient every 24 days in whom a form of advanced bleeding control could have been beneficial.

CONCLUSIONS

More than half of included Dutch trauma patients with NCTJH may benefit from in-hospital application of advanced bleeding control techniques, such as REBOA, during initial trauma care. Widespread implementation of these techniques in the Dutch trauma system may contribute to reduction of mortality and morbidity from non-compressible truncal and junctional hemorrhage.

Common complications and prevention strategies for resuscitative endovascular balloon occlusion of the aorta: A narrative review

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is considered a key measure of treatment due to its use in stabilizing patients in shock through temporary inflow occlusion for noncompressible torso hemorrhage as well as its supportive role in myocardial and cerebral perfusion. Although its clinical efficacy in trauma has been widely recognized, concerns over related complications, such as vascular access and ischemia-reperfusion, are on the rise. This paper aims to investigate complications associated with REBOA and identify current and emerging prevention or mitigation strategies through a literature review based on human or animal data. Common complications associated with REBOA include ischemia/reperfusion injuries, vessel injuries, venous thromboembolism, and worsening proximal bleeding. REBOA treatment outcomes can be improved substantially with the help of precise selection of patients, better visualization tools, improvement in balloon catheters, blockage strategies, and medication intervention measures. Better understanding of REBOA-related complications and further research on the strategies to mitigate the occurrence of such complications will be of vital importance for the optimization of the clinical outcomes in patients.

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.

A randomized porcine study of hemorrhagic shock comparing end-tidal carbon dioxide targeted and proximal systolic blood pressure targeted partial resuscitative endovascular balloon occlusion of the aorta in the mitigation of metabolic injury

BACKGROUND

The definition of partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) is not yet determined and clinical markers of the degree of occlusion, metabolic effects and end-organ injury that are clinically monitored in real time are lacking. The aim of the study was to test the hypothesis that end-tidal carbon dioxide (ETCO₂) targeted pREBOA causes less metabolic disturbance compared to proximal systolic blood pressure (SBP) targeted pREBOA in a porcine model of hemorrhagic shock.

MATERIALS AND METHODS

Twenty anesthetized pigs (26-35 kg) were randomized to 45 min of either ETCO₂ targeted pREBOA (pREBOA_ETCO2, ETCO₂ 90-110% of values before start of occlusion, n = 10) or proximal SBP targeted pREBOA (pREBOA_SBP, SBP 80-100 mmHg, n = 10), during controlled grade IV hemorrhagic shock. Autotransfusion and reperfusion over 3 h followed. Hemodynamic and respiratory parameters, blood samples and jejunal specimens were analyzed.

RESULTS

ETCO₂ was significantly higher in the pREBOA_ETCO2 group during the occlusion compared to the pREBOA_SBP group, whereas SBP, femoral arterial mean pressure and abdominal aortic blood flow were similar. During reperfusion, arterial and mesenteric lactate, plasma creatinine and plasma troponin concentrations were higher in the pREBOA_SBP group.

CONCLUSIONS

In a porcine model of hemorrhagic shock, ETCO₂ targeted pREBOA caused less metabolic disturbance and end-organ damage compared to proximal SBP targeted pREBOA, with no disadvantageous hemodynamic impact. End-tidal CO₂ should be investigated in clinical studies as a complementary clinical tool for mitigating ischemic-reperfusion injury when using pREBOA.

Next-Generation REBOA (Resuscitative Endovascular Balloon Occlusion of the Aorta) Device Precisely Achieves Targeted Regional Optimization in a Porcine Model of Hemorrhagic Shock

INTRODUCTION

Limitations such as time-dependent distal ischemia have slowed the adoption of resuscitative endovascular balloon occlusion of the aorta (REBOA) for noncompressible hemorrhage. Next-generation REBOA technologies may allow for controlled partial flow, known as targeted regional optimization, to reduce distal ischemia. We aimed to characterize the efficacy of one such catheter in a porcine model of lethal hemorrhagic shock.

METHODS

Noncompressible hemorrhage from an iliac injury was induced in anesthetized swine (Sus scrofa) (70-90 kg), targeting 30% total blood volume. Animals were then randomized to partial aortic occlusion (PO) with targeted distal mean arterial pressure (MAP) of 35-40 mm of mercury (mm Hg) and complete aortic occlusion (CO) (n = 8 per group) for 90 min. All groups were then resuscitated during a two-h critical care (CC) phase, with flow rate and MAP recorded continuously at the distal infrarenal aorta and proximal carotid artery, and analyzed with two-way repeated measures analysis of variance with S-N-K post-hoc test.

RESULTS

During aortic occlusion, MAP distal to the balloon was consistently maintained at 35.8 ± 0.3 mm Hg in the PO group compared to 27.1 ± 0.3 mm Hg in the CO group (P < 0.05), which also corresponded to higher flow rates (202.9 ± 4.8 mL/min PO versus 25.9 ± 0.8 mL/min CO; P < 0.05). MAP proximal to the balloon was significantly higher with CO versus PO (109.2 ± 2.3 mm Hg versus 85.2 ± 2.3 mm Hg; P < 0.05). During the CC phase, distal aortic flow and MAP were not significantly different between groups. However, creatinine returned to baseline levels by the end of the study in the PO group, but not the CO group. One animal died in the CO group, whereas none died in the PO group.

CONCLUSIONS

This is the first examination of the next-generation pREBOA-PRO in a porcine model of lethal hemorrhagic shock. We show technical feasibility of this technique to precisely achieve targeted regional optimization without device failure or complication. The ability to titrate balloon inflation and thus distal flow/pressure may extend the therapeutic window of REBOA by mitigating distal ischemia.

Zone 1 REBOA in a combat DCBI swine model does not worsen brain injury

BACKGROUND

Zone 1 resuscitative endovascular balloon occlusion of the aorta has been recommended for refractory shock after a dismounted complex blast injury for the austere combat scenario. While resuscitative endovascular balloon occlusion of the aorta should enhance coronary perfusion, there is a potential risk of secondary brain injury due to loss of cerebral autoregulation. We developed a combat casualty relevant dismounted complex blast injury swine model to evaluate the effects of resuscitative endovascular balloon occlusion of the aorta zone I on intracranial pressure and cerebral edema. We hypothesized that zone 1 aortic occlusion with resuscitative endovascular balloon occlusion of the aorta would increase mean arterial pressure transmitted in excessive intracranial pressure, thereby worsening brain injury.

METHODS

50 kg male Yorkshire swine were subjected to a combination dismounted complex blast injury model consisting of blast traumatic brain injury (50 psi, ARA Mobile Shock Laboratory), tissue injury (bilateral femur fractures), and hemorrhagic shock (controlled bleeding to a base deficit goal of 10 mEq/L). During the shock phase, pigs were randomized to no aortic occlusion (n = 8) or to 30 minutes of zone 1 resuscitative endovascular balloon occlusion of the aorta (zone 1 aortic occlusion group, n = 6). After shock, pigs in both groups received a modified Tactical Combat Casualty Care-based resuscitation and were monitored for an additional 240 minutes until euthanasia/death for a total of 6 hours. Intracranial pressure was monitored throughout, and brains were harvested for water content. Linear mixed models for repeated measures were used to compare mean arterial pressure and intracranial pressure between zone 1 aortic occlusion and no aortic occlusion groups.

RESULTS

After dismounted complex blast injury, the zone 1 group had a significantly higher mean arterial pressure during hemorrhagic shock compared to the control group (41.2 mm Hg vs 16.7 mm Hg, P = .002). During balloon occlusion, intracranial pressure was not significantly elevated in the zone 1 aortic occlusion group vs control, but intracranial pressure was significantly lower in the zone 1 group at the end of the observation period. In addition, the zone 1 aortic occlusion group did not have increased brain water content (zone 1 aortic occlusion: 3.95 ± 0.1g vs no aortic occlusion: 3.95 ± 0.3 g, P = .87). Troponin levels significantly increased in the no aortic occlusion group but did not in the zone 1 aortic occlusion group.

CONCLUSION

Zone 1 aortic occlusion using resuscitative endovascular balloon occlusion of the aorta in a large animal dismounted complex blast injury model improved proximal mean arterial pressure while not significantly increasing intracranial pressure during balloon inflation. Observation up to 240 minutes postresuscitation did not show clinical signs of worsening brain injury or cardiac injury. These data suggest that in a dismounted complex blast injury swine model, resuscitative endovascular balloon occlusion of the aorta in zone 1 may provide neuro- and cardioprotection in the setting of blast traumatic brain injury. However, longer monitoring periods may be needed to confirm that the neuroprotection is lasting.

The Underlying Cardiovascular Mechanisms of Resuscitation and Injury of REBOA and Partial REBOA

Introduction: Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is used for aortic control in hemorrhagic shock despite little quantification of its mechanism of resuscitation or cardiac injury. The goal of this study was to use pressure-volume (PV) loop analysis and direct coronary blood flow measurements to describe the physiologic changes associated with the clinical use of REBOA. Methods: Swine underwent surgical and vascular access to measure left ventricular PV loops and left coronary flow in hemorrhagic shock and subsequent placement of occlusive REBOA, partial REBOA, and no REBOA. PV loop characteristics and coronary flow are compared graphically with PV loops and coronary waveforms, and quantitatively with measures of the end systolic and end pressure volume relationship, and coronary flow parameters, with accounting for multiple comparisons. Results: Hemorrhagic shock was induced in five male swine (mean 53.6 ± 3.6 kg) as demonstrated by reduction of stroke work (baseline: 3.1 vs. shock: 1.2 L*mmHg, p < 0.01) and end systolic pressure (ESP; 109.8 vs. 59.6 mmHg, p < 0.01). ESP increased with full REBOA (178.4 mmHg; p < 0.01), but only moderately with partial REBOA (103.0 mmHg, p < 0.01 compared to shock). End systolic elastance was augmented from baseline to shock (1.01 vs. 0.39 ml/mmHg, p < 0.01) as well as shock compared to REBOA (4.50 ml/mmHg, p < 0.01) and partial REBOA (3.22 ml/mmHg, p = 0.01). Percent time in antegrade coronary flow decreased in shock (94%-71.8%, p < 0.01) but was rescued with REBOA. Peak flow increased with REBOA (271 vs. shock: 93 ml/min, p < 0.01) as did total flow (peak: 2136, baseline: 424 ml/min, p < 0.01). REBOA did not augment the end diastolic pressure volume relationship. Conclusion: REBOA increases afterload to facilitate resuscitation, but the penalty is supraphysiologic coronary flows and imposed increase in LV contractility to maintain cardiac output. Partial REBOA balances the increased afterload with improved aortic system compliance to prevent injury.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) may be superior to resuscitative thoracotomy (RT) in patients with traumatic brain injury (TBI)

Background

The effects of aortic occlusion (AO) on brain injury are not well defined. We examined the impact of AO by resuscitative endovascular balloon occlusion of the aorta (REBOA) and resuscitative thoracotomy (RT) on outcomes in the setting of traumatic brain injury (TBI).

Methods

Patients sustaining TBI who underwent RT or REBOA in zone 1 (thoracic aorta) from September 2013 to December 2018 were identified. The indication for REBOA or RT was hemodynamic collapse due to hemorrhage below the diaphragm. Primary outcomes included mortality and systemic complications.

Results

282 patients underwent REBOA or RT. Of these, 76 had mild TBI (40 REBOA, 36 RT) and 206 sustained severe TBI (107 REBOA, 99 RT). Overall, the mean (±SD) age was 42±17 years, with an Injury Severity Score (ISS) of 40±17 and mean systolic blood pressure (SBP) at the time of REBOA or RT of 81±34 mm Hg. REBOA patients had a mean SBP at the time of AO of 78.39±29.45 mm Hg, whereas RT patients had a mean SBP of 83.18±37.87 mm Hg at the time of AO (p=0.24). 55% had ongoing cardiopulmonary resuscitation (CPR) at the time of AO, and the in-hospital mortality was 86%. Binomial logistic regression controlling for TBI severity, age, ISS, SBP at the time of AO, crystalloid infusion, and CPR during AO demonstrated that the odds of mortality are 3.1 times higher for RT compared with REBOA. No significant differences were found in systemic complications between RT and REBOA.

Discussion

Patients with TBI who receive REBOA may have improved survival, but no difference in systemic complications, compared with patients who receive RT for the same indication. Although some patients are receiving RT prior to arrest for extrathoracic hemorrhagic shock, these results suggest that REBOA should be considered as an alternative to RT when RT is chosen for the sole purpose of resuscitation in the setting of TBI.

Level of evidence

4.

Advanced partial occlusion controller allows for increased precision during targeted regional optimization in a porcine model of hemorrhagic shock

BACKGROUND

Targeted regional optimization (TRO), a partial resuscitative endovascular balloon occlusion of the aorta strategy, may mitigate distal ischemia and extend the window of effectiveness for this adjunct. An automated device may allow greater control and precise regulation of flow past the balloon, while being less resource-intensive. The objective of this study was to assess the technical feasibility of the novel advanced partial occlusion controller (APOC) in achieving TRO at multiple distal pressures.

METHODS

Female swine (n = 48, 68.1 ± 0.7 kg) were randomized to a target distal mean arterial pressure (MAP) of 25 mm Hg, 35 mm Hg, or 45 mm Hg by either manual (MAN) or APOC regulation (n = 8 per group). Uncontrolled hemorrhage was generated by liver laceration. Targeted regional optimization was performed for 85 minutes, followed by surgical control and a 6-hour critical care phase. Proximal and distal MAP and flow rates were measured continuously.

RESULTS

At a target distal MAP of 25 mm Hg, there was no difference in the MAP attained (APOC: 26.2 ± 1.05 vs. MAN: 26.1 ± 1.78 mm Hg) but the APOC had significantly less deviance (10.9%) than manual titration (14.9%, p < 0.0001). Similarly, at a target distal MAP of 45 mm Hg, there was no difference in mean pressure (44.0 ± 0.900 mm Hg vs. 45.2 ± 1.31 mm Hg) but APOC had less deviance (9.34% vs. 11.9%, p < 0.0001). There was no difference between APOC and MAN in mean (34.6 mm Hg vs. 33.7 mm Hg) or deviance (9.95% vs. 10.4%) at a target distal MAP of 35 mm Hg, respectively. The APOC made on average 77 balloon volume adjustments per experiment compared with 29 by manual titrations.

CONCLUSION

The novel APOC consistently achieved and sustained precisely regulated TRO across all groups and demonstrated reduced deviance at the 25 mm Hg and 45 mm Hg groups compared with manual titration.

REBOA utility

Resuscitative endovascular balloon occlusion of the aorta is a tool that can play an important role for the modern-day Trauma Surgeon. Although the concept of aortic balloon occlusion is not new, its use as a rescue device for managing life-threatening traumatic hemorrhage has increased dramatically. The ideal role for resuscitative endovascular balloon occlusion of the aorta continues to evolve. In situations of noncompressible truncal hemorrhage, its use can temporize bleeding while other means of hemorrhage control, including those discussed elsewhere in this supplement, are used. However, it is a tool with potentially significant complications and consequences. Studies examining resuscitative endovascular balloon occlusion of the aorta are ongoing as, despite its ever-increasing adoption, quality evidence to support its clinical use is lacking.

REBOA as a bridge to brain CT in a patient with concomitant brain herniation and haemorrhagic shock - A case report

Introduction

The management of complex trauma patient with concomitant brain injury and extra-cranial lesions is challenging since the requirement of a low pressure to limit the bleeding clashes with the need to maintain an adequate cerebral perfusion and to obtain a brain CT-scan.

Here we present the use of REBOA as a bridge to CT scan in complex head and torso trauma.

Case presentation

A 59 years old male patient involved in a road traffic crash was admitted to our hospital after a car accident. He had a GCS of 3 with a left fixed pupil anisocoria. Despite right-sided chest decompression for pneumothorax and massive transfusion protocol for haemoperitoneum, blood pressure remained low; to temporally stabilize the patient and perform a brain CT scan a zone 1 REBOA was inserted and systolic blood pressure rose up from 60 mmHg to 110 mmHg. A brain CT scan highlighted a right subdural hematoma with a 8-mm midline shift. The patient went to the operating room to perform damage control surgery and, subsequently, a decompressive craniotomy. After 96 days of hospital stay, the patient was discharged at home with a complete neurological recovery.

Conclusions

The achievement of a rapid brain CT scan in traumatic brain injury is often crucial and has a deep impact in changing surgical management; moreover, duration of cerebral herniation is associated with worse outcome and increased mortality.

In the light of this, the use of REBOA in selected cases of complex head and torso trauma could allow to gain time to go to the CT room in safe conditions.

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.

Targeted Regional Optimization: Increasing the Therapeutic Window for Endovascular Aortic Occlusion In Traumatic Hemorrhage

ABSTRACT

Resuscitative endovascular balloon occlusion of the aorta (REBOA) allows for effective temporization of exsanguination from non-compressible hemorrhage (NCTH) below the diaphragm. However, the therapeutic window for aortic occlusion is time-limited given the ischemia-reperfusion injury generated. Significant effort has been put into translational research to develop new strategies to alleviate the ischemia-reperfusion injury and extend the application of endoaortic occlusion. Targeted regional optimization (TRO) is a partial REBOA strategy to augment proximal aortic and cerebral blood flow while targeting minimal threshold of distal perfusion beyond the zone of partial aortic occlusion. The objective of TRO is to reduce the degree of ischemia caused by complete aortic occlusion while providing control of distal hemorrhage. This review provides a synopsis of the concept of TRO, pre-clinical, translational experiences with TRO and early clinical outcomes. Early results from TRO strategies are promising; however, further studies are needed prior to large-scale implementation into clinical practice.

Quantifying the need for pediatric REBOA: A gap analysis

BACKGROUND

Trauma is the leading cause of death in children. Resuscitative endovascular balloon occlusion of the aorta (REBOA) provides temporary hemorrhage control, but its potential benefit has not been assessed in children. We hypothesized that there are pediatric patients who may benefit from REBOA.

METHODS

Trauma patients <18 years old at a level 1 pediatric trauma center between 2009 and 2019 were queried for deaths, pre-hospital cardiac arrest, massive transfusion protocol activation, transfusion requirement, or hemorrhage control surgery. These patients defined the cohort of severely injured patients. From this cohort, patients with intraabdominal injuries for which REBOA may provide temporary hemorrhage control were identified, including solid organ injury necessitating intervention, vascular injury, or pelvic hemorrhage.

RESULTS

There were 239 severely injured patients out of 6538 pediatric traumas. Of these, 38 had REBOA-amenable injuries (15.9%) with 34.2% mortality, accounting for 10.2% of all pediatric trauma deaths at one center. Eleven patients with REBOA-amenable injuries had TBI (28.9%). Patients with REBOA-amenable injuries represented 0.6% of all pediatric traumas.

CONCLUSION

Nearly 20% of severely injured pediatric patients could potentially benefit from REBOA. The overall proportion of pediatric patients with REBOA-amenable injuries is similar to adult studies.

TYPE OF STUDY

Retrospective comparative study.

LEVEL OF EVIDENCE

Level III.

Resuscitative endovascular occlusion of the aorta (REBOA) for refractory out of hospital cardiac arrest. An Utstein-based case series

AIMS

Out of hospital cardiac arrest (OHCA) is still a leading cause of mortality worldwide. In recent years, resuscitative endovascular balloon occlusion of the aorta (REBOA) has been progressively studied as an adjunct to standard advanced life support (ALS) in both traumatic and non-traumatic refractory OHCA. Since January 2019, the REBOA procedure has been applied to all the patients experiencing both traumatic and non-traumatic refractory OHCA (≥15 min of cardiopulmonary resuscitation) not eligible for ECPR for clinical or logistic reasons. We aimed at describing the feasibility and effects of REBOA performed both in the Emergency Department and in the pre-hospital environment served by the local HEMS for refractory OHCA.

METHODS

Twenty consecutive patients experiencing refractory OHCA and in whom REBOA was attempted in 2019 and 2020 were included in the study, Utstein data and REBOA specific variables were recorded.

RESULTS

Successful catheter placement was achieved in 18 out of 20 patients, 11 of these were non-traumatic OHCAs while 7 were traumatic OHCAs, the 2 failures were related to repeated arterial puncture failure. Median time between the EMS dispatch and REBOA catheter placing attempt was 46 min. An increase in etCO₂ over 10 mmHg was observed after balloon inflation in 12 out of 18 patients (8/11 non-traumatic and 4/7 traumatic OHCAs), a sustained ROSC was observed in 5 patients (1 traumatic and 4 non-traumatic OHCA) that were subsequently admitted to the ICU. Four out of the 5 patients reached the criteria for brain death in the subsequent 24 h while one patient experienced another episode of refractory cardiac arrest in ICU and subsequently died.

CONCLUSION

Our data confirm the feasibility of REBOA technique as an adjunct to ALS in both the ED and prehospital phase and most of the treated patients experienced a transient ROSC after balloon inflation while 5 out of 18 experienced a sustained ROSC. However, while in the trauma setting increasing evidence suggests an improved survival when REBOA is applied to refractory OHCA, in non-traumatic OHCA this has yet to be demonstrated and large studies are needed.

State-of-the-Art Review-Endovascular Resuscitation

ABSTRACT

The emerging concept of endovascular resuscitation applies catheter-based techniques in the management of patients in shock to manipulate physiology, optimize hemodynamics, and bridge to definitive care. These interventions hope to address an unmet need in the care of severely injured patients, or those with refractory non-traumatic cardiac arrest, who were previously deemed non-survivable. These evolving techniques include Resuscitative Endovascular Balloon Occlusion of Aorta, Selective Aortic Arch Perfusion, and Extracorporeal Membrane Oxygenation and there is a growing literature base behind them. This review presents the up-to-date techniques and interventions, along with their application, evidence base, and controversy within the new era of endovascular resuscitation.

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA): update and insights into current practices and future directions for research and implementation

Background

In this review, we assess the state of Resuscitative Endovascular Occlusion of the Aorta (REBOA) today with respect to out-of-hospital (OOH) vs. inhospital (H) use in blunt and penetrating trauma, as well as discuss areas of promising research that may be key in further advancement of REBOA applications.

Methods

To analyze the trends in REBOA use, we conducted a review of the literature and identified articles with human or animal data that fit the respective inclusion and exclusion criteria. In separate tables, we compiled data extracted from selected articles in categories including injury type, zone and duration of REBOA, setting in which REBOA was performed, sample size, age, sex and outcome. Based on these tables as well as more detailed review of some key cases of REBOA usage, we assessed the current state of REBOA as well as coagulation and histological disturbances associated with its usage. All statistical tests were 2-sided using an alpha=0.05 for significance. Analysis was done using SAS 9.5 (Cary, NC). Tests for significance was done with a t-test for continuous data and a Chi Square Test for categorical data.

Results

In a total of 44 cases performed outside of a hospital in both military and civilian settings, the overall survival was found to be 88.6%, significantly higher than the 50.4% survival calculated from 1,807 cases of REBOA performed within a hospital (p<.0001). We observe from human data a propensity to use Zone I in penetrating trauma and Zone III in blunt injuries. We observe lower final metabolic markers in animal studies with shorter REBOA time and longer follow-up times.

Conclusions

Further research related to human use of REBOA must be focused on earlier initiation of REBOA after injury which may depend on development of rapid vascular access devices and techniques more so than on any new improvements in REBOA. Future animal studies should provide detailed multisystem organ assessment to accurately define organ injury and metabolic burden associated with REBOA application. Overall, animal studies must involve realistic models of injury with severe clinical scenarios approximating human trauma and exsanguination, especially with long-term follow-up after injury.

Use of bilobed partial resuscitative endovascular balloon occlusion of the aorta is logistically superior in prolonged management of a highly lethal aortic injury

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a viable technique for management of noncompressible torso hemorrhage. The major limitation of the current unilobed fully occlusive REBOA catheters is below-the-balloon ischemia-reperfusion complications. We hypothesized that partial aortic occlusion with a novel bilobed partial (p)REBOA-PRO would result in the need for less intraaortic balloon adjustments to maintain a distal goal perfusion pressure as compared with currently available unilobed ER-REBOA.

METHODS

Anesthetized (40-50 kg) swine randomized to control (no intervention), ER-REBOA, or pREBOA-PRO underwent supraceliac aortic injury. The REBOA groups underwent catheter placement into zone 1 with initial balloon inflation to full occlusion for 10 minutes followed by gradual deflation to achieve and subsequently maintain half of the baseline below-the-balloon mean arterial pressure (MAP). Physiologic data and blood samples were collected at baseline and then hourly. At 4 hours, the animals were euthanized, total blood loss and urine output were recorded, and tissue samples were collected.

RESULTS

Baseline physiologic data and basic laboratories were similar between groups. Compared with control, interventions similarly prolonged survival from a median of 18 minutes to over 240 minutes with comparable mortality trends. Blood loss was similar between partial ER-REBOA (41%) and pREBOA-PRO (51%). Partial pREBOA-PRO required a significantly lower number of intraaortic balloon adjustments (10 ER-REBOA vs. 3 pREBOA-PRO, p < 0.05) to maintain the target below-the-balloon MAP. The partial ER-REBOA group developed significantly increased hypercapnia, fibrin clot formation on TEG, liver inflammation, and IL-10 expression compared with pREBOA-PRO.

CONCLUSION

In this highly lethal aortic injury model, use of bilobed pREBOA-PRO for a 4-hour partial aortic occlusion was logistically superior to unilobed ER-REBOA. It required less intraaortic balloon adjustments to maintain target MAP and resulted in less inflammation.

A feasibility study of partial REBOA data in a high-volume trauma center

PURPOSE

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is used to temporize patients with infradiaphragmatic hemorrhage. Current guidelines advise < 30 min, to avoid ischemia/ reperfusion injury, whenever possible. The technique of partial REBOA (P-REBOA) has been developed to minimize the effects of distal ischemia. This study presents our clinical experience with P-REBOA, comparing outcomes to complete occlusion (C-REBOA).

PATIENTS AND METHODS

Retrospective analysis of patients' electronic data and local REBOA registry between January 2016 and May 2019.

INCLUSION CRITERIA

adult trauma patients who received Zone I C-REBOA or P-REBOA for infradiaphragmatic hemorrhage, who underwent attempted exploration in the operating room. Comparison of outcomes based on REBOA technique (P-REBOA vs C-REBOA) and occlusion time (> 30 min, vs ≤ 30 min) RESULTS: 46 patients were included, with 14 treated with P-REBOA. There were no demographic differences between P-REBOA and C-REBOA. Prolonged (> 30 min) REBOA (regardless of type of occlusion) was associated with increased mortality (32% vs 0%, p = 0.044) and organ failure. When comparing prolonged P-REBOA with C-REBOA, there was a trend toward lower ventilator days [19 (11) vs 6 (9); p = 0.483] and dialysis (36.4% vs 16.7%; p = 0.228) with significantly less vasopressor requirement (72.7% vs 33.3%; p = 0.026).

CONCLUSION

P-REBOA can be delivered in a clinical setting, but is not currently associated with improved survival in prolonged occlusion. In survivors, there is a trend toward lower organ support needs, suggesting that the technique might help to mitigate ischemic organ injury. More clinical data are needed to clarify the benefit of partial occlusion REBOA.

Resuscitative endovascular balloon occlusion of the aorta for thoracic trauma: A translational swine study

Noncompressible torso hemorrhage in trauma is particularly lethal. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has the potential to stabilize these patients, but currently is contraindicated for major thoracic bleeding. The goal of this study was to evaluate the effect of REBOA on the hemodynamic and metabolic profile as well as its effect on early survival in a porcine model of thoracic hemorrhage and shock.

METHODS

Forty-eight male Yorkshire swine (60-80 kg) underwent 30% hemorrhage and were randomized to three thoracic injuries, with and without zone 1 REBOA occlusion: pulmonary parenchymal injury, thoracic venous injury, or subclavian artery injury. Following hemorrhage, thoracic injuries were induced (time of major thoracic injury) and allowed to bleed freely. The REBOA groups had zone 1 occlusion after the thoracic injury, with deflation at the end of prehospital. All groups had whole blood resuscitation at the end of prehospital and were euthanized at end of the hospital care phase. Survival, total blood loss, mean arterial pressure, end-tidal CO2, and arterial blood gas parameters were analyzed. Statistical significance was determined by t tests and two-way repeated-measures analysis of variance.

RESULTS

The use of REBOA improved the hemodynamics in all three injury patterns, with no differences observed in the outcomes of short-term survival and thoracic blood loss between the REBOA and non-REBOA groups. All groups showed equivalent changes in markers of shock (pH, HCO3, and base excess) prior to resuscitation.

CONCLUSION

In this animal study of hemorrhage and major thoracic bleeding, the addition of zone 1 REBOA did not significantly affect short-term survival or blood loss, while providing hemodynamic stabilization. Therefore, in noncompressible thoracic bleeding, without immediate surgical capability, long-term outcomes may be improved with REBOA, and thoracic hemorrhage should not be considered contraindications to REBOA use.

Reperfusion repercussions: A review of the metabolic derangements following resuscitative endovascular balloon occlusion of the aorta

BACKGROUND

Current resuscitative endovascular balloon occlusion of the aorta (REBOA) literature focuses on improving outcomes through careful patient selection, diligent catheter placement, and expeditious definitive hemorrhage control. However, the detection and treatment of post-REBOA ischemia-reperfusion injury (IRI) remains an area for potential improvement. Herein, we provide a review of the metabolic derangements that we have encountered while managing post-REBOA IRI in past swine experiments. We also provide data-driven clinical recommendations to facilitate resuscitation post-REBOA deflation that may be translatable to humans.

METHODS

We retrospectively reviewed the laboratory data from 25 swine across three varying hemorrhagic shock models that were subjected to complete REBOA of either 45 minutes, 60 minutes, or 90 minutes. In each model the balloon was deflated gradually following definitive hemorrhage control. Animals were then subjected to whole blood transfusion and critical care with frequent electrolyte monitoring and treatment of derangements as necessary.

RESULTS

Plasma lactate peaked and pH nadired long after balloon deflation in all swine in the 45-minute, 60-minute, and 90-minute occlusion models (onset of peak lactate, 32.9 ± 6.35 minutes, 38.8 ± 10.55 minutes, and 49.5 ± 6.5 minutes; pH nadir, 4.3 ± 0.72 minutes, 26.9 ± 12.32 minutes, and 42 ± 7.45 minutes after balloon deflation in the 45-, 60-, and 90-minute occlusion models, respectively). All models displayed persistent hypoglycemia for more than an hour following reperfusion (92.1 ± 105.5 minutes, 125 ± 114.9 minutes, and 96 ± 97.8 minutes after balloon deflation in the 45-, 60-, and 90-minute occlusion groups, respectively). Hypocalcemia and hyperkalemia occurred in all three groups, with some animals requiring treatment more than an hour after reperfusion.

CONCLUSION

Metabolic derangements resulting from REBOA use are common and may worsen long after reperfusion despite resuscitation. Vigilance is required to detect and proactively manage REBOA-associated IRI. Maintaining a readily available "deflation kit" of pharmacological agents needed to treat common post-REBOA electrolyte abnormalities may facilitate management.

LEVEL OF EVIDENCE

Level V.

Temporal Changes in REBOA Utilization Practices are Associated With Increased Survival: an Analysis of the AORTA Registry

BACKGROUND

Aortic occlusion (AO) is utilized for patients in extremis, with resuscitative endovascular balloon occlusion of the aorta (REBOA) use increasing. Our objective was to examine changes in AO practices and outcomes over time. The primary outcome was the temporal variation in AO mortality, while secondary outcomes included changes in technique, utilization, and complications.

STUDY DESIGN

This study examined the AORTA registry over a 5-year period (2014-2018). AO outcomes and utilization were analyzed using year of procedure as an independent variable. A multivariable model adjusting for year of procedure, signs of life (SOL), SBP at AO initiation, operator level, timing of AO, and hemodynamic response to AO was created to analyze AO mortality.

RESULTS

One thousand four hundred fifty-eight AO were included. Mean age (39.1 ± 16.7) and median ISS (34[25,49]) were comparable between REBOA and open AO. Open AO patients were more likely: male (84% vs. 77%, P = 0.001), s/p penetrating trauma (61% vs. 19%, P < 0.001), and arrived without SOL (60% vs. 40%, P = 0.001). REBOA use increased significantly and adjusted mortality decreased 22%/year while open AO survival was unchanged. REBOA initiation SBP increased significantly over the study period (52.2 vs. 65, P = 0.04). Compared with patients undergoing AO with CPR, each decile increase in SBP improved survival 12% (AOR 1.12, adj P = 0.001). The use of 7F REBOA (2.9%-54.8%) and Zone III deployment increased significantly (14.7% vs 40.6%), with Zone III placement having decreased associated mortality (AOR 0.33, adj P = 0.001). Overall REBOA complication rate was 4.5% and did not increase over time (P = 0.575).

CONCLUSIONS

REBOA survival has increased significantly while open AO survival remained unchanged. This may be related to lower thresholds for REBOA insertion at higher blood pressures, increased operator experience, and improved catheter technology leading to earlier deployment.

Automated Partial Versus Complete Resuscitative Endovascular Balloon Occlusion of the Aorta for the Management of Hemorrhagic Shock in a Pig Model of Polytrauma: a Randomized Controlled Pilot Study

INTRODUCTION

Endovascular variable aortic control (EVAC) is an automated partial resuscitative endovascular balloon occlusion of the aorta (REBOA) platform designed to mitigate the deleterious effects of complete REBOA. Long-term experiments are needed to assess potential benefits. The feasibility of a 24-hour experiment in a complex large animal trauma model remains unknown.

MATERIALS AND METHODS

Anesthetized swine were subjected to controlled hemorrhage, blunt thoracic trauma, and tibial fractures. Animals were then randomized (N = 3/group) to control (No balloon support), 90 minutes of complete supraceliac REBOA, or 10 minutes of supraceliac REBOA followed by 80 minutes of EVAC. One hundred ten minutes after injury, animals were resuscitated with shed blood, the REBOA catheter was removed. Automated critical care under general anesthesia was maintained for 24 hours.

RESULTS

Animals in the control and EVAC groups survived to the end of the experiment. Animals in the REBOA group survived for 120, 130, and 660 minutes, respectively. Animals in the EVAC group displayed similar mean arterial pressure and plasma lactate concentration as the control group by the end of the experiment. Histologic analysis suggested myocardial injury in the REBOA group when compared with controls.

CONCLUSIONS

This study demonstrates the feasibility of intermediate-term experiments in a complex swine model of polytrauma with 90 minutes of REBOA. EVAC may be associated with improved survival at 24 hours when compared with complete REBOA. EVAC resulted in normalized physiology after 24 hours, suggesting that prolonged partial occlusion is possible. Longer studies evaluating partial REBOA strategies are needed.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) in a swine model of hemorrhagic shock and blunt thoracic injury

PURPOSE

While resuscitative endovascular balloon occlusion of the aorta (REBOA) is contraindicated in patients with aortic injuries, this technique may benefit poly-trauma patients with less extreme thoracic injuries. The purpose of this study was to characterize the effects of thoracic injury on hemodynamics during REBOA and the changes in pulmonary contusion over time in a swine model.

METHODS

Twelve swine were anesthetized, instrumented, and randomized to receive either a thoracic injury with 5 impacts to the chest or no injury. All animals underwent controlled hemorrhage of 25% blood volume followed by 45 min of Zone 1 REBOA. Animals were then resuscitated with shed blood, observed during a critical care period, and euthanized after 6 h of total experimental time.

RESULTS

There were no differences between the groups at baseline. The only difference after 6 h was a lower hemoglobin in the thoracic trauma group (8.4 ± 0.8 versus 9.4 ± 0.6 g/dL, P = 0.04). The average proximal mean arterial pressures were significantly lower in the thoracic trauma group during aortic occlusion [103 (98-108) versus 117 (115-124) mmHg, P = 0.04]. There were no differences between the pulmonary contusion before REBOA and at the end of the experiment in size (402 ± 263 versus 356 ± 291 mL, P = 0.782) or density (- 406 ± 127 versus - 299 ± 175 HFU, P = 0.256).

CONCLUSIONS

Thoracic trauma blunted the proximal arterial pressure augmentation during REBOA but had minimal impacts on resuscitative outcomes. This initial study indicates that REBOA does not seem to exacerbate pulmonary contusion in swine, but blunt thoracic injuries may attenuate the expected rises in proximal blood pressure during REBOA.

Resuscitative endovascular balloon of the aorta is feasible in penetrating chest trauma with major hemorrhage: Proposal of a new institutional deployment algorithm

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging option for hemorrhage control, but its use is limited in scenarios such as penetrating chest trauma. The aim of this study was to describe the use of REBOA as a resuscitative adjunct in these cases with major hemorrhage and to propose a new clinical management algorithm.

METHODS

This was a prospective, observational study conducted at a single Level I trauma center in Colombia. We included all patients older than 14 years with severe trauma who underwent REBOA from January 2015 to December 2019. Patients received REBOA if they were in hemorrhagic shock and were unresponsive to resuscitation.

RESULTS

A total of 56 patients underwent REBOA placement of which 37 had penetrating trauma and 23 had chest trauma. All patients were hemodynamically unstable upon arrival to the emergency department, with a median systolic blood pressure of 69 mm Hg (interquartile range [IQR], 57-90 mm Hg) and median Injury Severity Score was 25 (IQR, 25-41). All REBOAs were deployed and inflated in zone 1, median inflation time was 40 minutes (IQR, 26-55 minutes), and no adverse neurologic outcomes were observed. Fifteen patients had REBOA and a median sternotomy. Eleven patients had concomitant abdominal wounds. Overall mortality was 28.6%, and there was no significant difference between penetrating versus blunt trauma patients (21.6% vs. 42.1%, p = 0.11). The survival rate of thoracic injured patients was similar to the predicted survival (65.2% vs. 63.3%).

CONCLUSION

Resuscitative endovascular balloon occlusion of the aorta can be used safely in penetrating chest trauma, and the implementation of a REBOA management algorithm is feasible with a well-trained multidisciplinary team.

LEVEL OF EVIDENCE

Therapeutic, level V.

Esmolol reduces myocardial injury induced by resuscitative endovascular balloon occlusion of the aorta (REBOA) in a porcine model of hemorrhagic shock

PURPOSE

Resuscitative endovascular balloon occlusion of the aorta (REBOA) causes myocardial injury from increased aortic afterload and supraphysiologic cardiac output. However, pharmacologic methods to attenuate high cardiac output and reduce myocardial injury have not been explored. We hypothesized that the use of esmolol during REBOA would reduce myocardial injury.

METHODS

Ten pigs were anesthetized and instrumented. Following 25% total blood volume hemorrhage, animals underwent 45 min of supraceliac (zone 1) REBOA with or without titration of esmolol to maintain heart rate between 80 and 100 beats per minute. Following the REBOA interventions, animals underwent 275 min of standardized critical care.

RESULTS

During REBOA, heart rate was significantly lower in the esmolol group compared to control animals (100 [88 - 112] vs 193 [172 - 203] beats/minute, respectively, p < 0.001) and the average mean arterial pressure (MAP) was lower in the esmolol group (88.0 [80.3-94.9] vs 135.1 [131.7-140.4] mmHg, respectively, p = 0.01). During the critical care phase, there were no differences in heart rate or MAP between groups. Animals in the intervention group received 237.9 [218.7-266.5] µg/kg of esmolol. There was a significant increase from baseline in serum troponins for the control group (p = 0.006) and significantly more subendocardial hemorrhage compared to animals treated with esmolol (3 [3 - 3] and 0 [0 - 0], p = 0.009, respectively).

CONCLUSION

In our porcine model of hemorrhagic shock, zone 1 REBOA was associated with myocardial injury. Pharmacologic heart rate titration with esmolol during occlusion may mitigate the deleterious effects of REBOA on the heart.

High Versus Low Volume Fluid Resuscitation Strategies in a Porcine Model (Sus scrofa) of Combined Thermal and Traumatic Brain Injury

BACKGROUND

Combined burn and traumatic brain injury (TBI) treatment priorities may not align due to opposing fluid resuscitation paradigms used in treating burns and TBI. We developed a porcine model of combined thermal injury/TBI and compared an "aggressive" fluid resuscitation strategy using the Parkland formula and a "restrictive" resuscitation strategy using the modified Brooke formula.

METHODS

Twenty-eight swine were deeply anesthetized and received a 40% total body surface area full-thickness burn injury and TBI. Swine were then randomized to receive restrictive or aggressive resuscitation for 8 h after which time animals were euthanized and necropsy was performed. Volume of brain injury was assessed after analyzing segmental slices of brain tissue.

RESULTS

There were no differences between the restrictive and aggressive resuscitation groups in blood pressure, heart rate, central venous pressure, intra-cranial pressure (ICP), or serum lactate levels after 8 h of resuscitation. Urine output was higher in the aggressive resuscitation group. The restrictive group had a significantly higher serum blood urea nitrogen (BUN) compared with baseline and compared with the aggressive group. There was no significant difference in size of brain injury between groups.

CONCLUSIONS

Both restrictive and aggressive resuscitation demonstrated adequate resuscitation at 8 h postinjury. Increased serum BUN in the restrictive group may be an indicator of early acute kidney injury, despite adequate urine output. Resuscitation strategy did not appear to affect ICP or the size of brain injury.

Mitigating Ischemia-Reperfusion Injury Using a Bilobed Partial REBOA Catheter: Controlled Lower-Body Hypotension

BACKGROUND

Non-compressible torso hemorrhage (NCTH) is the leading cause of potentially preventable death on the battlefield. Resuscitative endovascular balloon occlusion of the aorta (REBOA) aims to restore central blood pressure and control NCTH below the balloon, but risks ischemia-reperfusion injury to distal organs when prolonged. We tested a bilobed partial REBOA catheter (pREBOA), which permits some of the blood to flow past the balloon.

METHODS

Female swine (n = 37, 6 groups, n = 5-8/group), anesthetized and instrumented, were exponentially hemorrhaged 50% of estimated blood volume (all except time controls [TC]). Negative controls (NC) did not receive REBOA or resuscitation. Positive controls (PC) received retransfusion after 120 min. REBOA groups received REBOA for 120 min, then retransfusion. Balloon was fully inflated in the full REBOA group (FR), and was partially inflated in partial REBOA groups (P45 and P60) to achieve a distal systolic blood pressure of 45 mm Hg or 60 mm Hg.

RESULTS

Aortic occlusion restored baseline values of proximal mean arterial pressure, cardiac output, and carotid flow in pREBOA groups. Lactate reached high values during occlusion in all REBOA groups (9.9 ± 4.2, 8.0 ± 4.1, and 10.7 ± 2.9 for P45, P60, and FR), but normalized by 6 to 12 h post-deflation in the partial groups. All TC and P60 animals survived 24 h. The NC, PC, and P45 groups survived 18.2 ± 9.5, 19.3 ± 10.6, and 21.0 ± 8.4 h. For FR animals mean survival was 6.2 ± 5.8 h, significantly worse than all other animals (P < 0.01, logrank test).

CONCLUSIONS

In this porcine model of hemorrhagic shock, animals undergoing partial REBOA for 120 min survived longer than those undergoing full occlusion.

Endovascular Perfusion Augmentation for Critical Care: Partial Aortic Occlusion for Treatment of Severe Ischemia-Reperfusion Shock

BACKGROUND

The resuscitation of patients in shock is materially intensive and many patients are refractory to maximal therapy. We hypothesized that partial inflation of an intra-aortic balloon, termed Endovascular Perfusion Augmentation for Critical Care (EPACC), would minimize material requirements while improving physiologic metrics.

METHODS

Swine underwent a 25% controlled bleed and 45 min of complete aortic occlusion to create a severe ischemia-reperfusion shock state. Animals received either standardized critical care (SCC) composed of IV fluids and norepinephrine delivered through an algorithmically controlled platform or EPACC in addition to SCC. Physiologic parameters were collected, and blood was sampled for analysis. Primary outcomes were total IV fluids and average MAP during the critical care phase. Differences (P < 0.05) were measured with t test (continuous data) and Wilcoxon rank-sum test (ordinal data).

RESULTS

There were no differences in baseline characteristics. There were no differences in the maximum lactate; however, animals in the EPACC group had a higher average MAP (EPACC 65 mmHg, 95% confidence interval [CI], 65-66; SCC 60 mmHg, 95% CI, 57-63; P < 0.01) and remained within goal MAP for a greater period of time (EPACC 95.3%, 95% CI, 93.2-97.4; SCC 51.0%, 95% CI, 29.5-72.6; P < 0.01). EPACC animals required less IV fluids when compared with the SCC group (EPACC 21 mL/kg, 95% CI, 0-42; SCC 96 mL/kg, 95% CI, 76-117; P < 0.01). There were no differences in final lactate. Animals in the EPACC group had a higher final creatinine (EPACC 2.3 mg/dL, 95% CI, 2.1-2.5; SCC 1.7 mg/dL, 95% CI, 1.4-2.0; P < 0.01), but there were no differences in renal cellular damage on histology (P = 0.16).

CONCLUSION

Using a swine model of severe shock, the addition of EPACC to SCC significantly reduced fluid resuscitation requirements and improved blood pressure. This is the first description of a new therapy for patients in refractory shock or in resource-limited settings.

Effect of partial and complete aortic balloon occlusion on survival and shock in a swine model of uncontrolled splenic hemorrhage with delayed resuscitation

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is accepted as a resuscitation adjunct and bridge to definitive hemostasis. The ischemic burden of REBOA may be mitigated by a partial REBOA (P-REBOA) strategy permitting longer occlusion times and military use for combat trauma. We evaluated REBOA and P-REBOA in a swine multiple trauma model with uncontrolled solid organ hemorrhage and delayed resuscitation and surgical hemostasis.

METHODS

Anesthetized swine (51.9 ± 2.2 kg) had 20 mL/kg hemorrhage and closed femur fracture. Splenic transection was performed and free bleeding permitted for 10 minutes. Controls (n = 5) were hemorrhaged but had no REBOA, REBOA (n = 8) had 60 minutes complete zone 1 occlusion, P-REBOA (n = 8) had 15 minutes complete occlusion and 45 minutes 50% occlusion. Splenectomy was performed and plasma (15 mL/kg) resuscitation initiated 5 minutes prior to deflation. Resuscitation goal was 80 mm Hg systolic with epinephrine as needed. Animals were monitored for 6 hours.

RESULTS

An initial study with 120-minute occlusion had universal fatality in three REBOA (upon deflation) and three P-REBOA animals (after 60 minutes inflation). With 60-minute occlusion, mortality was 100%, 62.5%, and 12.5% in the control, REBOA, and P-REBOA groups, respectively (p < 0.05). Survival time was shorter in controls (120 ± 89 minutes) than REBOA and P-REBOA groups (241 ± 139, 336 ± 69 minutes). Complete REBOA hemorrhaged less during inflation (1.1 ± 0.5 mL/kg) than Control (5.6 ± 1.5) and P-REBOA (4.3 ± 1.4), which were similar. Lactate was higher in the REBOA group compared with the P-REBOA group after balloon deflation, remaining elevated. Potassium increased in REBOA after deflation but returned to similar levels as P-REBOA by 120 minutes.

CONCLUSION

In a military relevant model of severe uncontrolled solid organ hemorrhage 1-hour P-REBOA improved survival and mitigated hemodynamic and metabolic shock. Two hours of partial aortic occlusion was not survivable using this protocol due to ongoing hemorrhage during inflation. There is potential role for P-REBOA as part of an integrated minimally invasive field-expedient hemorrhage control and resuscitation strategy.

Aortic branch vessel flow during resuscitative endovascular balloon occlusion of the aorta

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a torso hemorrhage control adjunct. Aortic branch vessel flow (BVF) during REBOA is poorly characterized and has implications for ischemia-reperfusion injury. The aim of this study is to quantify BVF in hypovolemic shock with and without REBOA.

METHODS

Female swine (79-90 kg) underwent anesthesia, 40% controlled hemorrhage and sonographic flow monitoring of the carotid, hepatic, superior mesenteric, renal, and femoral arteries. Animals were randomized to REBOA (n = 5) or no-REBOA (n = 5) for 4 hours, followed by full resuscitation and balloon deflation for 1 hour.

RESULTS

All animals were successfully induced into hemorrhagic shock with a mean decrease of flow in all vessels of 50% from baseline (p < 0.001). Deployment of REBOA resulted in a 200% to 400% increase in carotid flow, but near complete abolition of BVF distal to the balloon. The no-REBOA group saw recovery of BVF to 100% of baseline in all measured vessels, except the hepatic at 50% to 75%. two-way analysis of variance confirmed a significant difference between the groups throughout the protocol (p < 0.001). During resuscitation, the REBOA group saw BVF restore to between 25% and 50%, but never achieving baseline values. The lactate at 4 hours was significantly higher in the REBOA versus no-REBOA group (17.2 ± 0.1 vs. 4.9 ± 1.4; p < 0.001).

CONCLUSION

REBOA not only abolishing BVF during occlusion, but appears to have a post-REBOA effect, reducing visceral perfusion. This may be a source of REBOA associated ischemia-reperfusion injury and warrants further investigation in order to mitigate this effect.

Guidelines for a system-wide multidisciplinary approach to institutional resuscitative endovascular balloon occlusion of the aorta implementation

Resuscitative endovascular occlusion of the aorta (REBOA) is a rapidly evolving technology which requires careful system-wide multidisciplinary implementation for optimal success. These guidelines developed by experienced REBOA practitioners provide a framework for a key practitioner to use in the development of a REBOA program in their institution. They detail the importance of involving doctors, nurses, and staff across departments and disciplines in the application of this technique.

Hate to Burst Your Balloon: Successful REBOA Use Takes More Than a Course

Background

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is emerging as a viable intervention for hemorrhagic shock. Training surgeons to place the device is only part of the process. We hypothesize that implementation challenges extend beyond surgical skills training and initial REBOA use should not be expected to mirror published success.

Methods

All REBOA placements from January 2016 to February 2017 at a level 1 trauma center were reviewed for opportunities for improvement. From September 2016 to February 2017, all patients meeting highest trauma activation criteria were reviewed against our REBOA algorithm to identify patients meeting criteria for REBOA placement but not undergoing the procedure.

Results

REBOA was introduced at our institution in September 2015, with the first placement in January 2016. Trauma surgery, emergency department, and operating room staff underwent training. Nine patients had REBOA placed with six survivors. One patient underwent an unsuccessful REBOA attempt and died. Four patients had complications from REBOA. Eight additional patients met indications but did not undergo REBOA.

Conclusions

Successful REBOA use requires more than teaching surgeons indications and techniques. For a successful REBOA program, system factors must be addressed. System processes must ensure equipment and procedures are standardized and familiar to all involved. Complications should be expected.

Resuscitative endovascular balloon occlusion of the aorta induced myocardial injury is mitigated by endovascular variable aortic control

BACKGROUND

The cardiac effects of resuscitative endovascular balloon occlusion of the aorta (REBOA) are largely unknown. We hypothesized that increased afterload from REBOA would lead to cardiac injury, and that partial flow using endovascular variable aortic control (EVAC) would mitigate this injury.

METHODS

Eighteen anesthetized swine underwent controlled 25% blood volume hemorrhage. Animals were randomized to either Zone 1 REBOA, Zone 1 EVAC, or no intervention (control) for 45 minutes. Animals were then resuscitated with shed blood, observed during critical care, and euthanized after a 6-hour total experimental time. Left ventricular function was measured with a pressure-volume catheter, and blood samples were drawn at routine intervals.

RESULTS

The average cardiac output during the intervention period was higher in the REBOA group (9.3 [8.6-15.4] L/min) compared with the EVAC group (7.2 [5.8-8.0] L/min, p = 0.01) and the control group (6.8 [5.8-7.7] L/min, p < 0.01). At the end of the intervention, the preload recruitable stroke work was significantly higher in both the REBOA and EVAC groups compared with the control group (111.2 [102.5-148.6] and 116.7 [116.6-141.4] vs. 67.1 [62.7-87.9], p = 0.02 and p < 0.01, respectively). The higher preload recruitable stroke work was maintained throughout the experiment in the EVAC group, but not in the REBOA group. Serum troponin concentrations after 6 hours were higher in the REBOA group compared with both the EVAC and control groups (6.26 ± 5.35 ng/mL vs 0.92 ± 0.61 ng/mL and 0.65 ± 0.38 ng/mL, p = 0.05 and p = 0.03, respectively). Cardiac intramural hemorrhage was higher in the REBOA group compared with the control group (1.67 ± 0.46 vs. 0.17 ± 0.18, p = 0.03), but not between the EVAC and control groups.

CONCLUSION

In a swine model of hemorrhagic shock, complete aortic occlusion resulted in cardiac injury, although there was no direct decrease in cardiac function. EVAC mitigated the cardiac injury and improved cardiac performance during resuscitation and critical care.

Efficacy of intermittent versus standard resuscitative endovascular balloon occlusion of the aorta in a lethal solid organ injury model

BACKGROUND

High-grade solid organ injury is a major cause of mortality in trauma. Use of resuscitative endovascular balloon occlusion of the aorta (REBOA) can be effective but is limited by ischemia-reperfusion injury. Intermittent balloon inflation/deflation has been proposed as an alternative, but the safety and efficacy prior to operative hemorrhage control is unknown.

METHODS

Twenty male swine underwent standardized high-grade liver injury, then randomization to controls (N = 5), 60-min continuous REBOA (cR, n = 5), and either a time-based (10-minute inflation/3-minute deflation, iRT = 5) or pressure-based (mean arterial pressure<40 during deflation, iRP = 5) intermittent schedule. Experiments were concluded after 120 minutes or death.

RESULTS

Improved overall survival was seen in the iRT group when compared to cR (p < 0.01). Bleeding rate in iRT (5.9 mL/min) was significantly lower versus cR and iRP (p = 0.02). Both iR groups had higher final hematocrit (26% vs. 21%) compared to cR (p = 0.03). Although overall survival was lower in the iRP group, animals surviving to 120 minutes with iRP had decreased end organ injury (Alanine aminotransferase [ALT] 33 vs. 40 in the iRT group, p = 0.03) and lower lactate levels (13 vs. 17) compared with the iRT group (p = 0.03). No differences were seen between groups in terms of coagulopathy based on rotational thromboelastometry.

CONCLUSION

Intermittent REBOA is a potential viable adjunct to improve survival in lethal solid organ injury while minimizing the ischemia-reperfusion seen with full REBOA. The time-based intermittent schedule had the best survival and prolonged duration of tolerable zone 1 placement. Although the pressure-based schedule was less reliable in terms of survival, when effective, it was associated with decreased acidosis and end-organ injury.

The Effects of Balloon Occlusion of the Aorta on Cerebral Blood Flow, Intracranial Pressure, and Brain Tissue Oxygen Tension in a Rodent Model of Penetrating Ballistic-Like Brain Injury

Trauma is among the leading causes of death in the United States. Technological advancements have led to the development of resuscitative endovascular balloon occlusion of the aorta (REBOA) which offers a pre-hospital option to non-compressible hemorrhage control. Due to the prevalence of concomitant traumatic brain injury (TBI), an understanding of the effects of REBOA on cerebral physiology is critical. To further this understanding, we employed a rat model of penetrating ballistic-like brain injury (PBBI). PBBI produced an injury pattern within the right frontal cortex and striatum that replicates the pathology from a penetrating ballistic round. Aortic occlusion was initiated 30 min post-PBBI and maintained continuously (cAO) or intermittently (iAO) for 30 min. Continuous measurements of mean arterial pressure (MAP), intracranial pressure (ICP), cerebral blood flow (CBF), and brain tissue oxygen tension (PbtO₂) were recorded during, and for 60 min following occlusion. PBBI increased ICP and decreased CBF and PbtO₂. The arterial balloon catheter effectively occluded the descending aorta which augmented MAP in the carotid artery. Despite this, CBF levels were not changed by aortic occlusion. iAO caused sustained adverse effects to ICP and PbtO₂ while cAO demonstrated no adverse effects on either. Temporary increases in PbtO₂ were observed during occlusion, along with restoration of sham levels of ICP for the remainder of the recordings. These results suggest that iAO may lead to prolonged cerebral hypertension following PBBI. Following cAO, ICP, and PbtO₂ levels were temporarily improved. This information warrants further investigation using TBI-polytrauma model and provides foundational knowledge surrounding the non-hemorrhage applications of REBOA including neurogenic shock and stroke.

Use of Resuscitative Endovascular Balloon Occlusion of the Aorta for Proximal Aortic Control in Patients With Severe Hemorrhage and Arrest

Importance

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a percutaneous transfemoral balloon technique used in select centers for resuscitation and temporary hemostasis, often instead of emergency department thoracotomy. The ability to perform aortic occlusion (AO) with an intravascular device allows focused occlusion at the most distal level to perfuse proximal regions while slowing hemorrhage to injured areas.

Objective

To describe what is to date the largest single-institution experience with REBOA in the United States.

Design, Setting, and Participants

Use of REBOA at an urban tertiary care facility for severe traumatic hemorrhage, traumatic arrest (AR), or nontraumatic hemorrhage (NTH) was investigated from February 1, 2013, to January 31, 2017, among 90 patients who were not responsive or were transiently responsive to resuscitation measures, or were in arrest, from presumed hemorrhage below the diaphragm. Possible causes were trauma or nontrauma-related hemorrhage. Patients with ruptured aortic aneurysms were excluded.

Main Outcomes and Measures

In-hospital mortality.

Results

Of the 90 patients in the study (15 women and 75 men; mean [SD] age, 41.5 [17.4] years), 29 underwent REBOA for severe traumatic hemorrhage, 50 for AR, and 11 for NTH. For the patients with severe traumatic hemorrhage and AR, the median age was 36.2 years (interquartile range, 25.3-55.5 years), mean (SD) admission Glasgow Coma Scale score was 6 (5), and median Injury Severity Score was 39 (interquartile range, 10-75). The distal thoracic aorta was occluded in 73 patients (81%), and in all patients with AR. A total of 17 patients (19%) had distal abdominal AO. Mean (SD) systolic blood pressure improved in patients with severe traumatic hemorrhage, from 68 (28) mm Hg prior to AO, to 131 (12) mm Hg after AO (P < .001). Percutaneous access was used in 30 patients (33%), including 13 patients with AR (26%), and groin cutdown in 60 patients (67%), including 37 patients with AR (74%). Overall 30-day mortality was 62% (n = 56): 11 (39%) in patients with severe traumatic hemorrhage and 45 (90%) in patients with AR. Of the patients with AR, 29 (58%) had return of spontaneous circulation and 11 of those patients (38%) survived to the operating room. All patients who survived AR gained full neurologic recovery. No aortoiliac injury or limb loss occurred from REBOA use. Eleven patients underwent REBOA for NTH; 7 (64%) were in arrest. Overall in-hospital mortality for patients with NTH was 36% (n = 4). No procedural complications occurred in this group.

Conclusions and Relevance

REBOA is a minimally invasive alternative to emergency department thoracotomy with aortic cross-clamp to temporize noncompressible torso hemorrhage and obtain proximal control in both traumatic and nontraumatic causes of hemorrhage. REBOA can also be used for more targeted AO in the distal aorta for pelvic, junctional, or extremity hemorrhage.

[Resuscitative endovascular balloon occlusion of the aorta : Bridge to surgery]

BACKGROUND

Severe hemorrhage remains the leading cause of death among trauma patients. Resuscitative balloon occlusion of the aorta (REBOA) is an endovascular alternative to the established emergency room thoracotomy with cross-clamping of the aorta in patients with severe abdominal or pelvic bleeding.

OBJECTIVE

The article reports on initial experiences with REBOA.

METHODS

Based on the literature and own experiences the pathophysiology, indications, contraindications, technical details and first results with REBOA are presented.

RESULTS

The REBOA procedure is indicated in patients with treatment-refractive hemorrhagic shock with severe abdominal or pelvic bleeding. Via a transfemoral approach a balloon catheter is placed in the aorta and inflated. Depending on the indication the aortic occlusion is located in a supradiaphragmatic (zone 1) or infrarenal (zone 3) position. Experimental results proved a significant increase in central perfusion pressure after performance of REBOA. Furthermore, first clinical data indicate an improved patient survival rate after trauma. Improvements of the devices and minimizing the access trauma using small 7 Fr sheaths decreased the perioperative complication rate.

CONCLUSION

The REBOA procedure is a promising endovascular technique for temporary stabilization of the circulation in patients with hemorrhagic shock. Further clinical studies and registries have yet to prove its superiority over emergency room thoracotomy.

A systematic review of large animal models of combined traumatic brain injury and hemorrhagic shock

Traumatic brain injury (TBI) and severe blood loss (SBL) frequently co-occur in human trauma, resulting in high levels of mortality and morbidity. Importantly, each of the individual post-injury cascades is characterized by complex and potentially opposing pathophysiological responses, complicating optimal resuscitation and therapeutic approaches. Large animal models of poly-neurotrauma closely mimic human physiology, but a systematic literature review of published models has been lacking. The current review suggests a relative paucity of large animal poly-neurotrauma studies (N = 52), with meta-statistics revealing trends for animal species (exclusively swine), characteristics (use of single biological sex, use of juveniles) and TBI models. Although most studies have targeted blood loss volumes of 35-45%, the associated mortality rates are much lower relative to Class III/IV human trauma. This discrepancy may result from potentially mitigating experimental factors (e.g., mechanical ventilation prior to or during injury, pausing/resuming blood loss based on physiological parameters, administration of small volume fluid resuscitation) that are rarely associated with human trauma, highlighting the need for additional work in this area.

Resuscitative Endovascular Balloon Occlusion of the Aorta: Review of the Literature and Applications to Veterinary Emergency and Critical Care

While hemorrhagic shock might be the result of various conditions, hemorrhage control and resuscitation are the corner stone of patient management. Hemorrhage control can prove challenging in both the acute care and surgical settings, especially in the abdomen, where no direct pressure can be applied onto the source of bleeding. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as a promising replacement to resuscitative thoracotomy (RT) for the management of non-compressible torso hemorrhage in human trauma patients. By inflating a balloon at specific levels (or zones) of the aorta to interrupt blood flow, hemorrhage below the level of the balloon can be controlled. While REBOA allows for hemorrhage control and augmentation of blood pressure cranial to the balloon, it also exposes caudal tissue beds to ischemia and the whole body to reperfusion injury. We aim to introduce the advantages of REBOA while reviewing known limitations. This review outlines a step-by-step approach to REBOA implementation, and discusses common challenges observed both in human patients and during translational large animal studies. Currently accepted and debated indications for REBOA in humans are discussed. Finally, we review possible applications for veterinary patients and how REBOA has the potential to be translated into clinical veterinary practice.

Examination of hemodynamics in patients in hemorrhagic shock undergoing Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA)

BACKGROUND

The objective of this study was to investigate the hemodynamic effects of aortic occlusion (AO) during Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) using a sophisticated continuous vital sign (CVS) monitoring tool.

METHODS

Patients admitted between February 2013 and May 2017 at a tertiary center that received REBOA were included. Patients in cardiac arrest before or at the time of REBOA were excluded. Time of AO was documented by time-stamped videography and correlated with CVS data.

RESULTS

28 patients were included, mean (standard deviation) ISS was 38 (11). 18 received Zone 1 (distal thoracic aorta) and 10 received Zone 3 (distal abdominal aorta) AO. Among Zone 1 patients the pre-AO systolic blood pressure (SBP) nadir was 64 (19) mmHg, which increased to a mean of 124 (29) mmHg within 5 min after AO (p < 0.01). Among Zone 3 patients the pre-AO SBP nadir was 75 (19) mmHg, which increased to a mean of 98 (14) mmHg within 5 min after AO (p < 0.01). 72% of Zone 1 patients had episodes during AO where SBP was less than 90 mmHg as compared to 80% of Zone 3 patients (p = 0.51). 100% of Zone 1 patients had periods during AO where SBP was greater than 140 mmHg as compared to 70% Zone 3 patients (p = 0.04). The overall mean decrease in SBP after balloon deflation was 13 (20) mmHg (p < 0.01), with similar decreases among groups (14 (21) mmHg vs 12 (18) mmHg for Zone 1 and 3 patients, respectively (p = 0.85)). Patients undergoing Zone 1 AO were more likely to have an acute change (increase or decrease) in their heart rate immediately after AO as compared to Zone 3 AO (p = 0.048).

CONCLUSIONS

Significant hemodynamic alterations occur before, during, and after AO. The effects of Zone 1 AO on blood pressure and heart rate appear different than Zone 3 AO. This may have important implications for cardiac or cerebral function and perfusion goals, particularly with concomitant injuries such as cardiac contusion or traumatic brain injury.

Extending the golden hour for Zone 1 resuscitative endovascular balloon occlusion of the aorta: Improved survival and reperfusion injury with intermittent versus continuous resuscitative endovascular balloon occlusion of the aorta of the aorta in a porcine severe truncal hemorrhage model

BACKGROUND

Noncompressible hemorrhage can be controlled using resuscitative endovascular balloon occlusion of the aorta (REBOA). Prolonged ischemia limits REBOA application during Zone 1 deployment. Intermittent inflation/deflation may effectively mitigate this problem.

METHODS

A lethal abdominal vascular injury was created in 28 swines. Animals were randomized to controls (n = 7), 60 minutes full REBOA (FR, n = 5), time-based intermittent REBOA (iRT, n = 7), and pressure-based REBOA (iRP, n = 9). Intermittent groups had an initial inflation for 15 minutes, followed by 10-minute inflation: 3-minute deflation cycles (iRT), or an inflate/deflate schedule based on mean arterial pressure (MAP) less than 40 mm Hg (iRP). Experiments were concluded after 120 minutes or death (MAP < 20 mm Hg).

RESULTS

Intermittent REBOA animals all survived to 120 minutes versus 15 minutes for controls and 63 minutes for FR (p < 0.001). After 60 minutes, FR animals were more hypotensive (MAP 20 mm Hg vs. 80 mm Hg [iRP] and 100 mm Hg [iRT]; p < 0.001), had lower cardiac output (1.06 mL/min vs. 5.1 L/min [iRP] and 8.2 L/min [iRT]; p < 0.001), higher lactate (12.5 mg/dL vs. 8.5 mg/dL [iRP], p = 0.02), and decreased clot firmness on rotational thromboelastometry than iRP/T (64 mm vs. 69 mm [iRP] and 69 mm [iRT], p = 0.04). Acidosis was worse in iRT versus iRP at 120 minutes (pH 7.28 vs. pH 7.12; p = 0.02), improved lactate (11.9 mg/dL vs. 16.3 mg/dL; p = 0.04), and decreased whole blood resuscitation (452 mL vs. 646 mL, p = 0.05). Blood loss (clot weight) was higher in controls (2.0 kg) versus iRT and iRP (1.16 kg and 1.23 kg; p < 0.01) and not different from FR (0.87 kg; p = 0.10).

CONCLUSION

Intermittent REBOA can maintain supraceliac hemorrhage control while decreasing distal ischemia in a swine model. Prolonged survival times, decreased acidosis, and lower resuscitation requirements indicate that this technique could potentially extend Zone 1 REBOA deployment times. Schedules based on MAP may be superior to time-based regimens.

Traumatic brain injury may worsen clinical outcomes after prolonged partial resuscitative endovascular balloon occlusion of the aorta in severe hemorrhagic shock model

BACKGROUND

The use of partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) in combined hemorrhagic shock (HS) and traumatic brain injury (TBI) has not been well studied. We hypothesized that the use of pREBOA in the setting of TBI would be associated with worse clinical outcomes.

METHODS

Female Yorkshire swine were randomized to the following groups: HS-TBI, HS-TBI-pREBOA, and HS-pREBOA (n = 5/cohort). Animals in the HS-TBI group were left in shock for a total of 2 hours, whereas animals assigned to pREBOA groups were treated with supraceliac pREBOA deployment (60 minutes) 1 hour into the shock period. All animals were then resuscitated, and physiologic parameters were monitored for 6 hours. Further fluid resuscitation and vasopressors were administered as needed. At the end of the observation period, brain hemispheric swelling (%) and lesion size (mm) were assessed.

RESULTS

Mortality was highest in the HS-TBI-pREBOA group (40% [2/5] vs. 0% [0/5] in the other groups, p = 0.1). Severity of shock was greatest in the HS-TBI-pREBOA group, as defined by peak lactate levels and pH nadir (p < 0.05). Fluid resuscitation and norepinephrine requirements were significantly higher in the HS-TBI-pREBOA group (p < 0.05). No significant differences were noted in brain hemispheric swelling and lesion size between the groups.

CONCLUSION

Prolonged application of pREBOA in the setting of TBI does not contribute to early worsening of brain lesion size and edema. However, the addition of TBI to HS-pREBOA may worsen the severity of shock. Providers should be aware of the potential physiologic sequelae induced by TBI.

Extended resuscitative endovascular balloon occlusion of the aorta (REBOA)-induced type 2 myocardial ischemia: a time-dependent penalty

Background

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) increases cardiac-afterload and is used for patients in hemorrhagic shock. The cardiac tolerance of prolonged afterload augmentation in this context is unknown. The aim of this study is to quantify cardiac injury, if any, following 2, 3 and 4 hours of REBOA.

Methods

Anesthetized swine (70-90 kg) underwent a 40% controlled hemorrhage, followed by supraceliac resuscitative endovascular balloon occlusion of the aorta (REBOA) for 2 (n=5), 3 (n=5), and 4 hours (n=5). High-fidelity arterial wave form data were collected, and signal processing techniques were used to extract key inflection points. The adjusted augmentation index (AIx@75; augmentation pressure/pulse pressure, normalized for heart rate) was derived for use as a measure of aortic compliance (higher ratio = less compliance). Endpoints consisted of electrocardiographic, biochemical, and histologic markers of myocardial injury/ischemia. Regression modeling was used to assess the trend against time.

Results

All animals tolerated instrumentation, hemorrhage, and REBOA. The mean (±SD) systolic blood pressure (mm Hg) increased from 65±11 to 212±39 (p<0.001) during REBOA. The AIx@75 was significantly higher during REBOA than baseline, hemorrhage, and resuscitation phases (p<0.05). A time-dependent rise in troponin (R²=0.95; p<0.001) and T-wave deflection (R²=0.64; p<0.001) was observed. The maximum mean troponin (ng/mL) occurred at 4 hours (14.6±15.4) and maximum T-wave deflection (mm) at 65 minutes (3.0±1.8). All animals demonstrated histologic evidence of acute injury with increasing degrees of cellular myocardial injury.

Discussion

Prolonged REBOA may result in type 2 myocardial ischemia, which is time-dependent. This has important implications for patients where prolonged REBOA may be considered beneficial, and strategies to mitigate this effect require further investigation.

Level of evidence

II.

Resuscitative endovascular balloon occlusion of the aorta: current evidence

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has recently gained popularity as a minimally invasive alternative to open aortic cross-clamping in the management of patients with non-compressible hemorrhage arising below the diaphragm. The purpose of this review is to provide a description of the technical aspects of REBOA use along with an overview of the current animal and clinical data regarding its use.