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

Prehospital Partial Resuscitative Endovascular Balloon Occlusion of the Aorta for Exsanguinating Subdiaphragmatic Hemorrhage

Importance

Hemorrhage is the most common cause of preventable death after injury. Most deaths occur early, in the prehospital phase of care.

Objective

To establish whether prehospital zone 1 (supraceliac) partial resuscitative endovascular balloon occlusion of the aorta (Z1 P-REBOA) can be achieved in the resuscitation of adult trauma patients at risk of cardiac arrest and death due to exsanguination.

Design, Setting, and Participants

This was a prospective observational cohort study (Idea, Development, Exploration, Assessment and Long-term follow-up [IDEAL] 2A design) with recruitment from June 2020 to March 2022 and follow-up until discharge from hospital, death, or 90 days evaluating a physician-led and physician-delivered, urban prehospital trauma service in the Greater London area. Trauma patients aged 16 years and older with suspected exsanguinating subdiaphragmatic hemorrhage, recent or imminent hypovolemic traumatic cardiac arrest (TCA) were included. Those with unsurvivable injuries or who were pregnant were excluded. Of 2960 individuals attended by the service during the study period, 16 were included in the study.

Exposures

ZI REBOA or P-REBOA.

Main Outcomes and Measures

The main outcome was the proportion of patients in whom Z1 REBOA and Z1 P-REBOA were achieved. Clinical end points included systolic blood pressure (SBP) response to Z1 REBOA, mortality rate (1 hour, 3 hours, 24 hours, or 30 days postinjury), and survival to hospital discharge.

Results

Femoral arterial access for Z1 REBOA was attempted in 16 patients (median [range] age, 30 [17-76] years; 14 [81%] male; median [IQR] Injury Severity Score, 50 [39-57]). In 2 patients with successful arterial access, REBOA was not attempted due to improvement in clinical condition. In the other 14 patients (8 [57%] of whom were in traumatic cardiac arrest [TCA]), 11 successfully underwent cannulation and had aortic balloons inflated in Z1. The 3 individuals in whom cannulation was unsuccessful were in TCA (failure rate = 3/14 [21%]). Median (IQR) pre-REBOA SBP in the 11 individuals for whom cannulation was successful (5 [46%] in TCA) was 47 (33-52) mm Hg. Z1 REBOA plus P-REBOA was associated with a significant improvement in BP (median [IQR] SBP at emergency department arrival, 101 [77-107] mm Hg; 0 of 10 patients were in TCA at arrival). The median group-level improvement in SBP from the pre-REBOA value was 52 (95% CI, 42-77) mm Hg (P < .004). P-REBOA was feasible in 8 individuals (8/11 [73%]) and occurred spontaneously in 4 of these. The 1- and 3-hour postinjury mortality rate was 9% (1/11), 24-hour mortality was 27% (3/11), and 30-day mortality was 82% (9/11). Survival to hospital discharge was 18% (2/11). Both survivors underwent early Z1 P-REBOA.

Conclusions and Relevance

In this study, prehospital Z1 P-REBOA is feasible and may enable early survival, but with a significant incidence of late death.

Trial Registration

ClinicalTrials.gov Identifier: NCT04145271.

Management of vascular injuries on ICU patients: KZN experience

BACKGROUND

Vascular injury management remains an extremely challenging task. The fundamental principles of management are bleeding arrest and flow restoration, to avoid death and amputation. With advances in medicine, there has been a shift from ligation to primary repair which has resulted in a fall in amputation rate from 50 % in World War II to less than 2 % in civilian injuries.

METHOD

A retrospective cross-sectional study was conducted on ICU requiring polytrauma patients with vascular trauma admitted between January 2013 and December 2021. Additional data were collected prospectively from January 2022 to December 2022. All data was from an ethics approved Trauma Registry. The injury was either confirmed by imaging or via exploration. The pre-designed data proforma acquired the following variables: age, mechanism of injury, injured vessel, associated injury, management of the vessel, and management of the associated injury. The data were analysed using Stata version 17 (StataCorp, College Station TX). Frequencies and percentages were calculated to summarise numerical data An ethical clearance was granted by the University of KwaZulu-Natal BREC (BREC 0004353/2022) and the KZN Department of Health. All data were de-identified in the data collection sheet.

RESULTS

There were 154 arterial injuries and 39 venous injuries. The majority, 77 (50 %) of arterial injuries were managed via open strategies, and 36 (23 %) were managed via endovascular intervention. The majority, 20 (51 %) of venous injuries underwent open ligation, and 12 (31 %) were managed non-surgically. The highest number of endovascular interventions was observed in aortic injuries. For a total of 25 aortic injuries, 22 (83 %) were managed endovascular (TEVAR) and 2 (8 %) were managed non-operatively.

CONCLUSION

The choice between the endovascular and open approach depends on the injured blood vessel. The majority of venous injuries were treated with open ligation in this cohort.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) successfully used in interhospital transport

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is primarily utilized in traumatic noncompressible torso hemorrhage as a temporary approach to buying time until a definite intervention could be obtained. REBOA is mostly reported in inhospital or prehospital settings. Its interhospital transfer use remains controversial. In this report, we present a case with pelvic fracture and hemorrhagic shock who underwent REBOA placement and was transferred from a local hospital to a trauma center successfully for further surgical intervention.

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.

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.

Selective aortic arch perfusion: a first-in-human observational cadaveric study

BACKGROUND

Selective aortic arch perfusion (SAAP) is a novel endovascular technique that combines thoracic aortic occlusion with extracorporeal perfusion of the brain and heart. SAAP may have a role in both haemorrhagic shock and in cardiac arrest due to coronary ischaemia. Despite promising animal studies, no data is available that describes SAAP in humans. The primary aim of this study was to assess the feasibility of selective aortic arch perfusion in humans. The secondary aim of the study was to assess the feasibility of achieving direct coronary artery access via the SAAP catheter as a potential conduit for salvage percutaneous coronary intervention.

METHODS

Using perfused human cadavers, a prototype SAAP catheter was inserted into the descending aorta under fluoroscopic guidance via a standard femoral percutaneous access device. The catheter balloon was inflated and the aortic arch perfused with radio-opaque contrast. The coronary arteries were cannulated through the SAAP catheter.

RESULTS

The procedure was conducted four times. During the first two trials the SAAP catheter was passed rapidly and without incident to the intended descending aortic landing zone and aortic arch perfusion was successfully delivered via the device. The SAAP catheter balloon failed on the third trial. On the fourth trial the left coronary system was cannulated using a 5Fr coronary guiding catheter through the central SAAP catheter lumen.

CONCLUSIONS

For the first time using a perfused cadaveric model we have demonstrated that a SAAP catheter can be easily and safely inserted and SAAP can be achieved using conventional endovascular techniques. The SAAP catheter allowed successful access to the proximal aorta and permitted retrograde perfusion of the coronary and cerebral circulation.

[Effect of a 1-day "REBOA course" on the theoretical and practical skills for the prehospital REBOA setting : Experiences from the RIBCAP-HEMS project]

Resuscitative endovascular balloon occlusion of the aorta (REBOA) represents an endovascular procedure for aortic occlusion. The procedure can be used for temporary hemorrhage control as a bridge until surgical treatment for noncompressible abdominal or pelvic bleeding and to improve coronary and cerebral perfusion pressure during cardiopulmonary resuscitation. The prehospital administration is challenging and currently hardly possible in Germany. In the REBOA in bleeding and cardiac arrest in the prehospital care by helicopter emergency medical service (RIBCAP-HEMS) project, the prehospital use of REBOA will be tested in a feasibility study. This article describes the training course on the procedure in preparation for prehospital use, which was conducted before the start of the aforementioned feasibility study for the emergency physicians and paramedics (HEMS-TC) of the DRF Air Rescue Base in Halle (Saale). The course provided the necessary theoretical and practical skills to apply REBOA in the prehospital setting to patients in extremis in a safe, indications-conform and time-critical manner. The fact that all emergency physicians of the two air ambulances Christoph 84 and Christoph 85 in Halle are specialists in anesthesiology with corresponding experience in the placement of invasive arterial catheters proved to be advantageous. The training course was able to significantly improve the theoretical and practical abilities of the participants. The results of the currently ongoing study must show whether the procedure can be usefully integrated into the prehospital care of patients in extremis.

Revisiting the promise, practice and progress of resuscitative endovascular balloon occlusion of the aorta

PURPOSE OF REVIEW

The use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) to temporarily control bleeding and improve central perfusion in critically injured trauma patients remains a controversial topic. In the last decade, select trauma services around the world have gained experience with REBOA. We discuss the recent observational data together with the initial results of the first randomized control trial and provide a view on the next steps for REBOA in trauma resuscitation.

RECENT FINDINGS

While the observational data continue to be conflicting, the first randomized control trial signals that in the UK, in-hospital REBOA is associated with harm. Likely a result of delays to haemorrhage control, views are again split on whether to abandon complex interventions in bleeding trauma patients and to only prioritize transfer to the operating room or to push REBOA earlier into the post injury phase, recognizing that some patients will not survive without intervention.

SUMMARY

Better understanding of cardiac shock physiology provides a new lens in which to evaluate REBOA through. Patient selection remains a huge challenge. Invasive blood pressure monitoring, combined with machine learning aided decision support may assist clinicians and their patients in the future. The use of REBOA should not delay definitive haemorrhage control in those patients without impending cardiac arrest.

Management of Postpartum Hemorrhage in Critical Care Transport

Postpartum hemorrhage is a relatively common and highly morbid complication of the postpartum period that often requires management by specialized providers at tertiary care facilities. Critical care transport teams may be tasked with transporting postpartum patients who are already experiencing postpartum hemorrhage, but they should also be aware that other peripartum patients may be at risk for developing postpartum hemorrhage while in the process of transport. As such, it is imperative that transport providers understand the signs, symptoms, causes, and complications of postpartum hemorrhage as well as the options for intervention and treatment. This article reviews the current clinical evidence regarding resuscitation and medical management strategies that transport teams should be familiar with as well as more advanced and invasive management techniques they may encounter and be expected to monitor during transport, such as balloon tamponade and aortic balloon occlusion.

Defence Medical Services' REBOA training course

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) enables temporary haemorrhage control and physiological stabilisation. This article describes the bespoke Defence Medical Services (DMS) training package for effectively using REBOA. The article covers how the course was designed, how the key learning objectives are taught, participant feedback and the authors' perceptions of future training challenges and opportunities. Since the inaugural training course in April 2019, the authors have delivered six courses, training over 100 clinicians. For the first time in the UK DMS, we designed and delivered a robust specialist endovascular training programme, with demonstrable, significant increases in confidence and competence. As a result of this course, the first DMS REBOA-equipped forward surgical teams deployed in June 2019. Looking to the future, there is a requirement to develop an assessment of skill retention and the potential need for revalidation.

Extracorporeal life support in thoracic emergencies-a narrative review of current evidence

BACKGROUND AND OBJECTIVE

Resuscitative therapies for respiratory and cardiac failure are lifesaving and extended by using extracorporeal life support (ECLS) as mechanical circulatory support (MSC). This review informs the debate to identify the life-threatening thoracic emergencies in which patients may be cannulated for ECLS support.

METHODS

An advanced search was performed in PubMed, Embase, Google Scholar, and references query, assessed in June 2022, identified 761 records. Among them, 74 publications in English were included in the current narrative review.

KEY CONTENT AND FINDINGS

ECLS is an additional tool for organ support in life-threatening thoracic emergencies. It provides bridging to recovery or to decision about destination as definitive therapy, intervention, or surgery. Non-traumatic emergencies include mediastinal mass, acute lung injury (ALI), aspiration, embolisms, acute and chronic heart failure. However, based on the current evidence, trauma, and especially blunt thoracic trauma, is one of the main indications for ECLS use in thoracic emergencies, among others in chest wall fractures, blunt and penetrating lung injuries. ECLS use is always individualized to patient's needs, injury pattern and kind of organ failure, circulatory arrest inclusive, depending on if respiratory or cardiac and circulatory support is needed. Further, ECLS offers the possibility for fast volume resuscitation and rewarming, thus preventing the lethal of trauma: hypothermia, hypoperfusion and acidosis. Anticoagulation may be omitted for some hours or days. Interdisciplinary cooperation between the intensivists, surgeons, anesthesiologists, emergency medical services, an appropriately organized and trained staff, equipment resources and logistical planning are essential for successful outcomes.

CONCLUSIONS

ECLS use in selected life-threatening thoracic emergencies is increasing. The summarized findings appeal to policymakers, and we hope that our summary of recommendations may impact clinical practice and research.

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.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) may also have a place outside major trauma centers - A case report from a Finnish rural hospital

The recent adoption of endovascular and hybrid methods in the management of massive bleeding following trauma to the torso and junctional areas has been a major advance in trauma care. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is one tool to tackle immediate exsanguination in such cases. To take advantage of such methods, rapid femoral artery access is crucial. In rural hospitals a trauma surgeon, vascular surgeon and interventional radiologist may not be in the hospital during on-call hours. Furthermore, gaining femoral arterial access is an infrequent procedure for a trauma surgeon working outside major trauma centers. Therefore, it might be difficult to acquire and maintain the requisite skills. However, a consultant anesthesiologist is a member of the trauma team and always on call in our hospital. An experienced anesthesiologist is a valuable asset in ultrasound guided arterial punctures and in inserting intravascular introducer sheaths, as was the case in our patient. To our knowledge, anesthesiologists do not commonly participate in the actual placement of arterial introducer sheaths for REBOA catheters in trauma teams. We wish to bring to notice this hidden asset when a team that does not routinely include a vascular surgeon or an interventional radiologist is treating a seriously injured trauma patient. We report on a patient who had sustained a shrapnel injury to the groin with massive blood loss. To stop further bleeding and to stabilize hemodynamics, we used REBOA to gain proximal control of the bleeding. As a result, the patient avoided surgical retroperitoneal exposure and a dry surgical field was created. We conclude that REBOA may also have a place in rural hospitals, and that, if necessary, trauma team members may adopt novel roles in the treatment of hemorrhage.

Resuscitative Endovascular Balloon Occlusion of the Aorta is Associated with Increased Risk of Extremity Compartment Syndrome

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been used as a temporizing procedure to control intra-abdominal or pelvic bleeding. Theoretically, occlusion of the aorta and the resulting ischemia-reperfusion of the lower extremities may increase the risk of extremity compartment syndrome (CS). To date, no study has addressed systematically the incidence and risk factors of CS following REBOA intervention. The purpose of this study was to address this knowledge gap.

METHODS

Adult trauma patients from the American College of Surgeons Trauma Quality Improvement Program (ACS-TQIP) database (2016-2019) were included. Patients who received REBOA within 4 h of admission were compared to patients without REBOA after propensity score matching for demographics, vital signs on admission, comorbidities, injury severity of different body regions, pelvic and lower extremity fractures, vascular trauma to the lower extremities, fixation for fractures, angioembolization (AE) for pelvis, preperitoneal pelvic packing (PPP), laparotomy, and venous thromboembolism (VTE) prophylaxis. The primary outcomes were rates of lower extremity CS and fasciotomy and acute kidney injury (AKI). Secondary outcomes included mortality.

RESULTS

There were 534 patients who received REBOA matched with 1043 patients without REBOA. Overall, patients in the REBOA group had significantly higher rates of CS than no REBOA patients [5.4% vs 1.1%, p < 0.001, OR: 5.39]. The risk of CS remained significantly higher in the subgroups of patients with or without pelvic or lower extremity fractures, as well as in the subgroup of patients with associated extremity vascular injury [11.2% vs 1.5%, p < 0.001, OR: 8.12].The fasciotomy and AKI rates were significantly higher in the REBOA group (5.8% vs 1.2%, p < 0.001 and 12.9% vs 7.4%, p< 0.001 respectively).

CONCLUSION

REBOA use is associated with a higher risk of lower extremity CS, fasciotomy and AKI, especially in patients with associated lower extremity vascular injuries. These complications should be taken into account when considering REBOA use, and close observation for this complication should always be part of the routine monitoring.

Do we need pre-hospital resuscitative endovascular balloon occlusion of the aorta (REBOA) in the civilian helicopter emergency medical services (HEMS)?

Pre-hospital resuscitative endovascular balloon occlusion of the aorta (REBOA) can be a life-saving procedure for patients with non-compressible torso hemorrhage. We aimed to evaluate the potential eligibility for REBOA in trauma patients of a civilian helicopter emergency medical service (HEMS) using a stepwise approach. A retrospective analysis using the electronic database (HEMSDER) of "DRF Luftrettung" HEMS covering the period from January 2015 to June 2021 was performed. Trauma patients aged ≥ 16 years and with a National Advisory Committee for Aeronautics (NACA) score of ≥ 4 were assessed for potential REBOA eligibility using two different decision trees based on assumed severe bleeding due to injuries of the abdomen, pelvis, and/or lower extremities and different vital signs on the scene and at hospital handover. Non-parametric statistical methods were used for comparison. A total of 22.426 patients met the inclusion criteria for data analysis. Of these, 0.15-2.24% were possible candidates for pre-hospital REBOA. No significant differences between groups on scene and at hospital handover regarding demographics, assumed injuries, and pre-hospital interventions were found. In the on-scene group, 21.1% of the patients remained unstable even at hospital handover despite pre-hospital care. In the handover group, 42.8% of the patients seemed initially stable but then deteriorated during the pre-hospital course. The number of potential pre-hospital REBOA in severely injured patients with a NACA score of ≥ 4 is < 3% or can be even < 1% if more strict criteria are used. There are some patients who may benefit from pre-hospital REBOA as a life-saving procedure. Further research on earlier diagnosis of life-threatening bleeding and proper indications of REBOA in trauma patients is needed.

Intermittent thoracic resuscitative endovascular balloon occlusion of the aorta improves renal function compared to 60 min continuous application after porcine class III hemorrhage

Background

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) may be considered for stabilization of patients with hemorrhage from below the diaphragm. Occluding the aorta is a powerful means of hemorrhagic control but is also associated with acute kidney injury, which increases mortality in trauma patients. Allowing for intermittent distal blood flow during REBOA application (iREBOA) could decrease this risk, but circulatory consequences have not been sufficiently elucidated. Therefore, we investigated circulatory effects and the renal artery blood flow (RBF) in iREBOA versus continuous, complete aortic occlusion (cREBOA).

Methods

In a porcine model of uncontrolled class III hemorrhage (34% estimated total blood volume, mean 1360 mL), swine (n = 12, mean weight 60.3 kg) were randomly assigned to iREBOA: 3-min full deflation every 10 min (n = 6), or cREBOA (n = 6), for 60 min of thoracic (zone I) application. The animals then underwent 60 min of reperfusion (critical care phase).

Results

Survival was 100% in iREBOA and 83% in cREBOA. The intermittent balloon deflation protocol was hemodynamically tolerable in 63% of reperfusion intervals. Systolic blood pressure decreased during the reperfusion intervals in iREBOA animals (mean 108 mm Hg versus 169 mm Hg; p < 0.005). No differences were detected in heart rate, cardiac output or stroke volume between methods. Troponin I increased in cREBOA after 60 min (mean 666–187 ng/L, p < 0.05). The norepinephrine requirement increased in cREBOA during reperfusion (mean infusion time 12.5–5.5 min; p < 0.05). Total ischemic time decreased in iREBOA (60.0–48.6 min; p < 0.001). RBF increased in iREBOA during balloon deflations and after 60 min reperfusion (61%–39% of baseline RBF; p < 0.05). Urine output increased in iREBOA (mean 135–17 mL; p < 0.001). Nephronal osteopontin, a marker of ischemic injury, increased in cREBOA (p < 0.05).

Conclusion

iREBOA was survivable, did not cause rebleeding, decreased the total ischemic time and increased the renal blood flow, urine output and decreased renal ischemic injury compared to cREBOA. Intermittent reperfusions during REBOA may be preferred to be continuous, complete occlusion in prolonged application to improve renal function.

Development of a computational fluid dynamic model to investigate the hemodynamic impact of REBOA

Background: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a lifesaving intervention for major truncal hemorrhage. Balloon-tipped arterial catheters are inserted via the femoral artery to create a temporary occlusion of the aorta, which minimizes the rate of internal bleeding until definitive surgery can be conducted. There is growing concern over the resultant hypoperfusion and potential damage to tissues and organs downstream of REBOA. To better understand the acute hemodynamic changes imposed by REBOA, we developed a three-dimensional computational fluid dynamic (CFD) model under normal, hemorrhage, and aortic occlusion conditions. The goal was to characterize the acute hemodynamic changes and identify regions within the aortic vascular tree susceptible to abnormal flow and shear stress. Methods: Hemodynamic data from established porcine hemorrhage models were used to build a CFD model. Swine underwent 20% controlled hemorrhage and were randomized to receive a full or partial aortic occlusion. Using CT scans, we generated a pig-specific aortic geometry and imposed physiologically relevant inlet flow and outlet pressure boundary conditions to match in vivo data. By assuming non-Newtonian fluid properties, pressure, velocity, and shear stresses were quantified over a cardiac cycle. Results: We observed a significant rise in blood pressure (∼147 mmHg) proximal to REBOA, which resulted in increased flow and shear stress within the ascending aorta. Specifically, we observed high levels of shear stress within the subclavian arteries (22.75 Pa). Alternatively, at the site of full REBOA, wall shear stress was low (0.04 ± 9.07E-4 Pa), but flow oscillations were high (oscillatory shear index of 0.31). Comparatively, partial REBOA elevated shear levels to 84.14 ± 19.50 Pa and reduced flow oscillations. Our numerical simulations were congruent within 5% of averaged porcine experimental data over a cardiac cycle. Conclusion: This CFD model is the first to our knowledge to quantify the acute hemodynamic changes imposed by REBOA. We identified areas of low shear stress near the site of occlusion and high shear stress in the subclavian arteries. Future studies are needed to determine the optimal design parameters of endovascular hemorrhage control devices that can minimize flow perturbations and areas of high shear.

Transsplenic Ultrasound-Guided Balloon Positioning During a Zone 1 Resuscitative Endovascular Balloon Occlusion of the Aorta: A Case Report

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an effective resuscitative modality to temporize noncompressible truncal hemorrhage. Confirming the proper position of the balloon catheter in the target aortic zone is vital. Currently, there is a need for nonradiographical methods. This would overcome the drawbacks of conventional imaging modalities, such as fluoroscopy. Several studies have suggested ultrasound-guided visualization via subxiphoid, transperitoneal, or transesophageal views as an alternative to conventional imaging methods. However, such views are easily obscured in emergency settings. Herein, we report the case of a 70-year-old patient who was successfully resuscitated by REBOA under the guidance of transsplenic ultrasound. REBOA was safely performed using transsplenic visualization without fluoroscopy.

Torso vascular trauma

Vascular injury within the chest or abdomen represents a unique challenge to the pediatric general surgeon, as these life- or limb-threatening injuries are rare and may require emergent treatment. Vascular injury may present as life-threatening hemorrhage, or with critical ischemia from intimal injury, dissection, or thrombosis. Maintaining the skillset and requisite knowledge to address these injuries is of utmost importance for pediatric surgeons that care for injured children, particularly for surgeons practicing in freestanding children's hospitals that frequently do not have adult vascular surgery coverage. The purpose of this review is to provide an overview of torso vascular trauma, with a specific emphasis in rapid recognition of torso vascular injury as well as both open and endovascular management options. Specific injuries addressed include blunt and penetrating mediastinal vascular injury, subclavian injury, abdominal aortic and visceral segment injury, inferior vena cava injury, and pelvic vascular injury. Operative exposure, vascular repair techniques, and damage control options including preperitoneal packing for pelvic hemorrhage are discussed. The role and limitations of endovascular treatment of each of these injuries is discussed, including endovascular stent graft placement, angioembolization for pelvic hemorrhage, and resuscitative endovascular balloon occlusion of the aorta (REBOA) in children.

Resuscitative Endovascular Balloon Occlusion of Aorta Versus Aortic Cross-Clamping by Thoracotomy for Noncompressible Torso Hemorrhage: A Meta-Analysis

BACKGROUND

The effect of resuscitative endovascular balloon occlusion of aorta (REBOA) in lowering mortality rate compared to resuscitative thoracotomy (RT) is inconclusive. In this updated systematic review and meta-analysis, we determined the effectiveness of the two techniques in patients with noncompressible torso hemorrhage (NCTH).

MATERIALS AND METHODS

Online databases (PubMed, Embase, and MEDLINE) were searched until April 23, 2021, for original articles investigating the effect of REBOA on relevant outcomes (e.g., mortality in ED, mortality before discharge, in-hospital mortality, length of hospital stay and length of ICU stay) among NCTH patients in contrast to open aortic occlusion by RT. Data on baseline characteristics and endpoints were extracted. Review Manager version 5.4.1 and OpenMetaAnalyst were used for analyses. Risk ratios (RR) and the weighted mean differences (WMD) with corresponding 95% confidence intervals were calculated.

RESULTS

Eight studies were included having 3241 patients in total (REBOA: 1179 and RT: 2062). The pooled analysis demonstrated that compared to RT, mortality was significantly lower in the REBOA group in all settings: In emergency department (ED) (RR 0.63 [0.45, 0.87], P = 0.006, I² = 81%), before discharge (RR= 0.86 [0.75, 0.98], P = 0.03, I^{2 =} 93%), and in-hospital mortality (RR 0.80 [0.68, 0.95], P = 0.009, I^{2 =} 85%). Similarly, the length of ICU stay was significantly lower in REBOA group (WMD = 0.50 [-0.48, 1.48], P = 0.32, I^{2 =}97%). However, no significant differences were observed in the length of hospital stay (WMD = 0.0 [-0.26, 0.26] P = 1).

CONCLUSIONS

Our pooled analysis shows REBOA to be effective in reducing mortality among NCTH patients. However, due to limited studies, the positive findings should be viewed discreetly and call for further investigation.

A survey of resuscitative endovascular balloon occlusion of the aorta (REBOA) program implementation in Canadian trauma centres

OBJECTIVE

To determine how many Level 1 and Level 2 trauma centres in Canada have implemented a resuscitative endovascular balloon occlusion of the aorta (REBOA) program, and to identify facilitators and barriers to successful implementation of REBOA programs.

METHODS

An electronic survey was developed and administered in November 2019 (updated in July 2021) via email to directors at all 32 Level 1 and Level 2 trauma centres across Canada, and to the medical director in PEI (no Level 1 or Level 2 capacity). Survey responses were supplemented by an online search in PubMed and the grey literature. Responses were analyzed using simple descriptive statistics including frequencies and proportions.

RESULTS

We received responses from directors at 22 sites (17 Level 1 trauma centres, 4 Level 2 trauma centres, PEI) for a response rate of 66.7%. There are 6 Level 1 trauma centres with REBOA programs; all were implemented between 2017 and 2019. One additional Level 1 trauma centre that did not respond was found to have a REBOA program; thus, 21.9% (7/32) of Canadian Level 1 and Level 2 trauma centres have an existing REBOA program. These programs are located in three provinces (British Columbia, Ontario, Quebec). Five other centres are planning on implementing a REBOA program in the next 2 years. The number of REBOA cases performed ranged from 0 to 30 (median 2). Factors contributing most to successful program implementation were having physician champions and patient populations with sufficient REBOA candidates, while cost and lack of expertise were the greatest barriers identified.

CONCLUSION

As of July 2021, 21.9% (7/32) of Canadian Level 1 and Level 2 trauma centres have a REBOA program. Physician champions and a patient population with sufficient numbers of REBOA candidates were the most important factors contributing to successful implementation of these programs.