Measuring Cardiac Output in a Swine Model

Swine are frequently used in medical research given their similar cardiac physiology to that of humans. Measuring cardiac parameters such as stroke volume and cardiac output are essential in this type of research. Contrast ventriculography, thermodilution, and pressure-volume loop (PV-loop) catheters can be used to accurately obtain cardiac performance data depending on which resources and expertise are available. For this study,five Yorkshire swine were anesthetized and intubated. Central venous and arterial access was obtained to place the necessary measurement instruments.A temperature probe was placed in the aortic root. A cold saline bolus was delivered to the right atrium and temperature deflection curve was recorded. Integration of the area under the curve allowed for the calculation of the current cardiac output.A pigtail catheter was percutaneously placed in the left ventricle and 30 mL of iodinated contrast was power injected over 2 seconds. Digital subtraction angiography images were uploaded to volumetric analysis software to calculate the stroke volume and cardiac output. A pressure volume-loop catheter was placed into the left ventricle (LV) and provided continuous pressure and volume data of the LV, which allowed the calculation of both stroke volume and cardiac output.All three methods demonstrated good correlation with each other. The PV-loop catheter and thermodilution exhibited the best correlation with a 3% error and a Pearson coefficient of 0.99, with 95% CI=0.97 to 1.1, (p=0.002). The PV-loop catheter against ventriculography also showed good correlation with a 6% error and a Pearson coefficient of 0.95, 95% CI=0.96 to 1.1 (p=0.01). Finally, thermodilution against ventriculography had a 2% error with r=0.95, 95% CI=0.93 to 1.11, (p=0.01). In conclusion, we state that the PV-loop catheter, contrast ventriculography, and thermodilution each offer certain advantages depending on the researcher's requirements. Each method is reliable and accurate for measuring various cardiac parameters in swine such as the stroke volume and cardiac output.

Selective aortic arch perfusion versus open cardiac massage in exsanguination cardiac arrest: A comparison of coronary pressure dynamics in swine

AIM

To evaluate the mean aortic-right atrial pressure (AoP-RAP) gradients and mean coronary perfusion pressures (CPPs) observed during open cardiac massage (OCM) versus those obtained with selective aortic arch perfusion (SAAP) in post-mortem hypovolemic swine.

METHODS

Post-mortum, male swine, utilized in prior studies of hemorrhage, were included in the study. Animals were bled ∼25-50% of circulating volume prior to death. Animals either underwent clamshell thoracotomy and OCM immediately after death was confirmed (n = 6) or underwent SAAP within 5-15 min of death (n = 6). Aortic root and right atrial pressures were recorded continuously during each method of resuscitation using solid state blood pressure catheters. Representative five beat samples were extracted; short, similarly timed segments of SAAP were also extracted. Mean AoP-RAP gradient and CPPs were calculated and compared.

RESULTS

Mean AoP-RAP gradient and CPP were significantly higher in SAAP animals compared to OCM animals (mean ± SD; 29.1 ± 8.4 vs. 24.5 ± 5.0, p < 0.001; 28.9 ± 8.5 vs. 9.9 ± 6.0, p < 0.001). Mean CPP was not significantly different from mean AoP-RAP gradient in SAAP animals (p = 0.92); mean CPP was significantly lower than mean AoP-RAP gradient in OCM animals (p < 0.001). While 97% of SAAP segments had a CPP > 15 mmHg, only 17% of OCM segments had a CPP > 15 mmHg (p < 0.001).

CONCLUSION

SAAP appears to create a more favorable and efficient hemodynamic profile for obtaining ROSC when compared to OCM in this preclinical porcine study.

The polytrauma patient: Current concepts and evolving care

Principles of care in the polytraumatized patient have continued to evolve with advancements in technology. Although hemorrhage has remained a primary cause of morbidity and mortality in acute trauma, emerging strategies that can be applied pre-medical facility as well as in-hospital have continued to improve care. Exo-vascular modalities, including the use of devices to address torso hemorrhage and areas not amenable to traditional tourniquets, have revolutionized prehospital treatment. Endovascular advancements including the resuscitative endovascular balloon occlusion of the aorta (REBOA), have led to dramatic improvements in systolic blood pressure, although not without their own unique complications. Although novel treatment options have continued to emerge, so too have concepts regarding optimal time frames for intervention. Though prior care has focused on Injury Severity Score (ISS) as a marker to determine timing of intervention, current consensus contends that unnecessary delays in fracture care should be avoided, while respecting the complex physiology of certain patient groups that may remain at increased risk for complications. Thromboelastography (TEG) has been one technique that focuses on the unique pathophysiology of each patient, providing guidance for resuscitation in addition to providing information in recognizing the at-risk patient for venous thromboembolism. Negative pressure wound therapy (NPWT) has emerged as a therapeutic adjuvant for select trauma patients with significant soft tissue defects and open wounds. With significant advancements in medical technology and improved understanding of patient physiology, the optimal approach to the polytrauma patient continues to evolve.

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.

Potentially survivable fatal vascular access hemorrhage with tourniquet use: A post-mortem analysis

BACKGROUND

The US military has prioritized battlefield hemorrhage control. Researchers credit tourniquet use, and a novel trauma care training program, with saving 1000-2000 lives in Iraq and Afghanistan. The Stop the Bleed campaign translates these lessons learned to the public. This is the first analysis of the potential impact of this newfound knowledge about tourniquet use for extremity fatal vascular access hemorrhage in a civilian population. Fatal vascular access hemorrhage includes bleeding from arteriovenous fistulas and grafts used for hemodialysis and central venous catheters.

METHODS

This is a retrospective study of decedent records. We selected Maryland death records from 2002-2017 using the following search terms: "graft," "shunt," "fistula," "dialysis," and "central venous catheter." The records were analyzed for potential survivability with a checklist of military criteria modified for a civilian population. Suicides were excluded. Two reviewers independently classified the deaths as either potentially survivable or non-survivable, and a third reviewer broke ties.

RESULTS

There were 111 deaths included in the final analysis. Ninety-two of the 111 decedents had potentially survivable extremity fatal vascular access hemorrhage. The remaining 19 records were excluded, because they did not have extremity hemorrhage. Zero decedents had hemorrhage deemed to be non-survivable with prompt tourniquet application.

CONCLUSION

This study identified 92 Maryland extremity fatal vascular access hemorrhage decedents who potentially could have survived with tourniquet use-an average of 6 per year. These results suggest the need for further epidemiology investigation, as well as exploration of the risks and benefits of teaching and equipping vascular access patients and their caregivers to use tourniquets for life-threatening bleeding.

A Primer on the Military Health System's Approach to Medical Research and Development

The Military Health System (MHS) has a medical research program aimed at a wide range of health-, disease-, and injury-related topic areas that works with civilian academic institutions and the biomedical industry to accomplish its goals. There are many opportunities for civilian academic institutions and the biomedical industry to engage with this program, but its unique features are important to understand to optimize the chances for successful partnerships. Unlike the National Institutes of Health, which uses an "investigator-initiated" approach, the Department of Defense (DoD) aligns its funding with specific needs, also referred to as requirements; thus, DoD research is often described as "requirements-driven" research. At the highest level, requirements are aligned with the National Security Strategy and National Defense Strategy, though requirements documents list specific areas in medicine with unmet needs. Military labs and the Uniformed Services University of the Health Sciences, which can also receive DoD appropriations to conduct medical research, serve as hubs that interface with civilian academic institutions and the biomedical industry and organize and track the overall progress of DoD investments. As a mechanism to propel findings from "bench to bedside," the military budgets funds for the various phases of research and development for a given topic area. Research programs are most effective when they are integrated into the MHS learning health system, which allows MHS clinical communities to inform and track research investments and evaluate the utility of research products in real clinical practice settings. This Perspective provides introductory information and a basic framework for those interested in performing DoD-funded medical research or collaborating with researchers in military labs. It is hoped that as academic institutions and the biomedical industry look to increase efficiency in medical research, they will find ways to engage with DoD research opportunities and consider elements of the military's approach useful.

Prehospital Detection of Life-Threatening Intracranial Pathology: An Unmet Need for Severe TBI in Austere, Rural, and Remote Areas

Severe traumatic brain injury (TBI) is a leading cause of death and disability worldwide, especially in low- and middle-income countries, and in austere, rural, and remote settings. The purpose of this Perspective is to challenge the notion that accurate and actionable diagnosis of the most severe brain injuries should be limited to physicians and other highly-trained specialists located at hospitals. Further, we aim to demonstrate that the great opportunity to improve severe TBI care is in the prehospital setting. Here, we discuss potential applications of prehospital diagnostics, including ultrasound and near-infrared spectroscopy (NIRS) for detection of life-threatening subdural and epidural hemorrhage, as well as monitoring of cerebral hemodynamics following severe TBI. Ultrasound-based methods for assessment of cerebrovascular hemodynamics, vasospasm, and intracranial pressure have substantial promise, but have been mainly used in hospital settings; substantial development will be required for prehospital optimization. Compared to ultrasound, NIRS is better suited to assess certain aspects of intracranial pathology and has a smaller form factor. Thus, NIRS is potentially closer to becoming a reliable method for non-invasive intracranial assessment and cerebral monitoring in the prehospital setting. While one current continuous wave NIRS-based device has been FDA-approved for detection of subdural and epidural hemorrhage, NIRS methods using frequency domain technology have greater potential to improve diagnosis and monitoring in the prehospital setting. In addition to better technology, advances in large animal models, provider training, and implementation science represent opportunities to accelerate progress in prehospital care for severe TBI in austere, rural, and remote areas.

Temporary intravascular shunt use improves early limb salvage after extremity vascular injury

OBJECTIVE

The use of temporary intravascular shunts (TIVSs) allow for restoration of distal perfusion and reduce ischemic time in the setting of arterial injury. As a damage control method, adjunct shunts restore perfusion during treatment of life-threatening injuries, or when patients require evacuation to a higher level of care. Single-center reports and case series have demonstrate that TIVS use can extend the opportunity for limb salvage. However, few multi-institutional studies on the topic have been reported. The objective of the present study was to characterize TIVS use through a multi-institutional registry and define its effects on early limb salvage.

METHODS

Data from the Prospective Observation Vascular Injury Treatment registry was analyzed. Civilian patients aged ≥18 years who had sustained an extremity vascular injury from September 2012 to November 2018 were included. Patients who had a TIVS used in the management of vascular injury were included in the TIVS group and those who had received treatment without a TIVS served as the control group. An unadjusted comparison of the groups was conducted to evaluate the differences in the baseline and outcome characteristics. Double robust estimation combining logistic regression with propensity score matching was used to evaluate the effect of TIVS usage on the primary end point of limb salvage.

RESULTS

TIVS use was identified in 78 patients from 24 trauma centers. The control group included 613 patients. Unmatched analysis demonstrated that the TIVS group was more severely injured (mean ± standard deviation injury severity score, 18.83 ± 11.76 for TIVS vs 14.93 ± 10.46 for control; P = .002) and had more severely mangled extremities (mean ± standard deviation abbreviated injury scale, extremity, score 3.23 ± 0.80 for TIVS vs 2.95 ± 0.87 for control; P = .008). Logistic regression demonstrated that propensity-matched control patients had a three times greater likelihood of amputation compared with the TIVS patients (odds ratio, 3.6; 95% confidence interval, 1.2-11.1; P = .026). Concomitant nerve injury and orthopedic fracture were associated with a greater risk of amputation. The median follow-up for the TIVS group was 12 days (interquartile range, 4-25 days) compared with 9 days (interquartile range, 4-18 days) for the control group.

CONCLUSIONS

To the best of our knowledge, the present study is the first multicenter, matched-cohort study to characterize early limb salvage as a function of TIVS use in the setting of extremity vascular injury. Shunts expedite limb perfusion and resulted in lower rates of amputation during the early phase of care. The use of TIVS should be one part of a more aggressive approach to restore perfusion in the most injured patients and ischemic limbs.

Development of a Selective Aortic Arch Perfusion System in a Porcine Model of Exsanguination Cardiac Arrest

Hemorrhage constitutes the majority of potentially preventable deaths from trauma. There is growing interest in endovascular resuscitation techniques such as selective aortic arch perfusion (SAAP) for patients in cardiac arrest. This involves active perfusion of the coronary circulation via a thoracic aortic balloon catheter and is approaching clinical application. However, the technique is complex and requires refinement in animal models before human use can be considered. This paper describes a large animal model of exsanguination cardiac arrest treated with a bespoke SAAP system. Swine were anesthetized, instrumented and a splenectomy was performed before a controlled, logarithmic exsanguination was initiated. Animals were heparinized and the shed blood collected in a reservoir. Once cardiac arrest was observed, the blood was pumped through an extra-corporeal circuit into an oxygenator and then delivered through a 10 Fr balloon catheter placed in the thoracic aorta. This resulted in the return of a spontaneous circulation (ROSC) as demonstrated by ECG and aortic root pressure waveform. This model and accompanying SAAP system allow for standardized and reproducible recovery from exsanguination cardiac arrest.

Timing of repair of blunt thoracic aortic injuries in the thoracic endovascular aortic repair era

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) is the preferred operative treatment of blunt thoracic aortic injuries (BTAIs). Its use is associated with improved outcomes compared with open surgical repair and nonoperative management. However, the optimal time from injury to repair is unknown and remains a subject of debate across different societal practice guidelines. The purpose of this study was to evaluate national trends in the management of BTAI, with a specific focus on the impact of timing of repair on outcomes.

METHODS

Using the National Trauma Data Bank, we identified adult patients with BTAI between 2012 and 2017. Patients with prehospital or emergency department cardiac arrest or incomplete data sets were excluded from analysis. Patients were classified according to timing of repair: group 1, <24 hours; and group 2, ≥24 hours. The primary outcome evaluated was in-hospital mortality; secondary outcomes included overall hospital and intensive care unit length of stay. Multivariable logistic regression was performed to identify independent predictors of mortality.

RESULTS

The analysis was completed for 2821 patients who underwent TEVAR for BTAI with known operative times. The overall mortality in the patient cohort was 8.4% (238/2821); 75% of patients undergoing TEVAR were repaired within 24 hours. Mortality was more than twofold greater in group 1 compared with group 2 (9.8% [207/2118] vs 4.4% [31/703]; P = .001). This mortality benefit persisted across injury severity groups and was independent of the presence of serious extrathoracic injuries. Logistic regression analysis, adjusting for age ≥65 years, Glasgow Coma Scale score ≤8, systolic blood pressure ≤90 mm Hg at admission, and serious extrathoracic injuries, showed a higher adjusted mortality in group 1 (odds ratio, 2.54; 95% confidence interval, 1.66-3.91; P = .001).

CONCLUSIONS

The majority of patients with BTAI undergo endovascular repair within 24 hours of injury. Patients undergoing delayed repair have improved survival compared with those repaired within the first 24 hours of injury in spite of similar injury patterns and severity. In patients with BTAIs without signs of imminent rupture, delaying endovascular repair beyond 24 hours after injury should be considered.

Defining a Research Agenda for Layperson Prehospital Hemorrhage Control: A Consensus Statement

IMPORTANCE

Trauma is the leading cause of death for US individuals younger than 45 years, and uncontrolled hemorrhage is a major cause of trauma mortality. The US military's medical advancements in the field of prehospital hemorrhage control have reduced battlefield mortality by 44%. However, despite support from many national health care organizations, no integrated approach to research has been made regarding implementation, epidemiology, education, and logistics of prehospital hemorrhage control by layperson immediate responders in the civilian sector.

OBJECTIVE

To create a national research agenda to help guide future work for prehospital hemorrhage control by laypersons.

EVIDENCE REVIEW

The 2-day, in-person, National Stop the Bleed (STB) Research Consensus Conference was conducted on February 27 to 28, 2019, to identify and achieve consensus on research gaps. Participants included (1) subject matter experts, (2) professional society-designated leaders, (3) representatives from the federal government, and (4) representatives from private foundations. Before the conference, participants were provided a scoping review on layperson prehospital hemorrhage control. A 3-round modified Delphi consensus process was conducted to determine high-priority research questions. The top items, with median rating of 8 or more on a Likert scale of 1 to 9 points, were identified and became part of the national STB research agenda.

FINDINGS

Forty-five participants attended the conference. In round 1, participants submitted 487 research questions. After deduplication and sorting, 162 questions remained across 5 a priori-defined themes. Two subsequent rounds of rating generated consensus on 113 high-priority, 27 uncertain-priority, and 22 low-priority questions. The final prioritized research agenda included the top 24 questions, including 8 for epidemiology and effectiveness, 4 for materials, 9 for education, 2 for global health, and 1 for health policy.

CONCLUSIONS AND RELEVANCE

The National STB Research Consensus Conference identified and prioritized a national research agenda to support laypersons in reducing preventable deaths due to life-threatening hemorrhage. Investigators and funding agencies can use this agenda to guide their future work and funding priorities.

Delta Systolic Blood Pressure (SBP) Can be a Stronger Predictor of Mortality Than Pre-Aortic Occlusion SBP in Non-Compressible Torso Hemorrhage; an Abotrauma and AORTA Analysis

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is becoming a standardized adjunct for the management in patients with severe non-compressible torso hemorrhage (NCTH). Although guidelines have been developed to help with the best indications for REBOA utilization, no studies have addressed the significance of change in systolic blood pressure (ΔSBP) after REBOA insufflation. We hypothesized that ΔSBP would predict mortality in patients with NCTH and have utility as a surrogate marker for hemorrhage status.

STUDY DESIGN

This was an international, multicenter retrospective review of all patients managed with REBOA from the ABOTrauma Registry and the AORTA database. ΔSBP was defined as the difference between pre- and post-REBOA insertion SBP. Based on post-insertion SBP, patient hemorrhage status was categorized as responder or non-responder. A non-responder was defined as a hypotensive patient with systolic blood pressure (SBP) < 90 mmHg after REBOA placement with full aortic occlusion. Significance was set at P < 0.05.

RESULTS

A total of 524 patients with NCTH were included. Most (74%) were male, 77% blunt injured with a median (IQR) age of 40 (27 - 58) years and ISS 34 (25 - 45). Overall mortality was 51.0%. 20% of patients were classified as non-responders. Demographic and injury descriptors did not differ between groups. Mortality was significantly higher in non-responders vs responders (64% vs 46%, respectively; P = 0.001). Non-responders had lower median pre-insertion SBP (50mmHg vs 67mmHg; P < 0.001) and lower ΔSBP (20mmHg vs 48mmHg; P < 0.001).

CONCLUSION

REBOA non-responders present and remain persistently hypotensive and are more likely to die than responders, indicating a potential direct correlation between ΔSBP as a surrogate marker of hemorrhage volume status and mortality. Future prospective studies will need to further elucidate the impact of Damage Control Resuscitation efforts on ΔSBP and mortality.

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.

Infraclavicular Thoracic Outlet Decompression Compared to Supraclavicular Thoracic Outlet Decompression for the Management of Venous Thoracic Outlet Syndrome

BACKGROUND

The treatment of venous thoracic outlet syndrome (VTOS) requires surgical decompression often combined with catheter-directed thrombolysis and venoplasty. Surgical options include transaxillary, supraclavicular, or infraclavicular approaches to first rib resection. The optimal method, however, has yet to be defined. The purpose of this study is to compare the outcomes of patients who underwent infraclavicular versus supraclavicular surgical decompression for VTOS.

METHODS

A retrospective review of patients who underwent surgical management for VTOS from December 2010 to November 2017 was performed. During the study period, supraclavicular and infraclavicular approaches were chosen according to surgeon preference. Patient demographics, pre- and postdecompression interventions, perioperative outcomes for each group of patients were analyzed.

RESULTS

Thirty patients underwent surgical management of VTOS, of which 15 (50%) underwent infraclavicular decompression and 15 (50%) supraclavicular decompression. The mean age of patients was 32.1 ± 13.6 years and 80% were male. Twenty-six patients (86.7%) presented with thrombotic VTOS. Acute axillosubclavian vein thrombosis was present in 20 (76.9%) of these patients, 10 patients in each group. Subacute or chronic thrombosis was encountered in the remaining 6 (23%) patients, 2 patients in the infraclavicular group and 4 patients in the supraclavicular group. Preoperative thrombolysis was utilized in 7 (46.7%) and 6 (40%) patients in the infraclavicular and supraclavicular groups, respectively (P = 1.00). Patients without postdecompression venography were removed from analysis and included 1 patient in the infraclavicular group and 5 patients in the supraclavicular group. Initial postdecompression venogram, prior to any endovascular intervention, demonstrated a residual axillosubclavian vein stenosis of greater than 50% in 6 (42.9%) patients in the infraclavicular decompression group and 7 (70%) patients in the supraclavicular decompression group (P = 0.24). Crossing the stenosis after surgical decompression was more easily accomplished in the infraclavicular group, 14 (100%) versus 5 (50%), (P = 0.01). Following endovascular venoplasty, calculated residual stenosis greater than 50% was found in 0 (0%) and 3 (30%) patients in the infraclavicular and supraclavicular approaches, respectively (P = 0.047). Infraclavicular thoracic outlet decompression was associated with fewer patients with postoperative symptoms, 0 of 15 (0%) versus 8 of 15 (53.3%), (P = 0.0022), and infraclavicular thoracic outlet decompression demonstrated improved patency, 15 of 15 (100%) versus 8 of 15 (53.3%), (P = 0.028) at a mean combined follow-up of 8.47 ± 10.8 months.

CONCLUSIONS

Infraclavicular thoracic outlet decompression for the surgical management of VTOS was associated with fewer postoperative symptoms and improved axillosubclavian vein patency compared to the supraclavicular approach. Prospective analysis is warranted to determine long-term outcomes following infraclavicular decompression.

Epidemiology of Upper Extremity Vascular Injury in Contemporary Combat

BACKGROUND

The incidence of wartime upper-extremity vascular injury (UEVI) has been stable for the past century. The objective of this study is to provide a contemporary review of wartime UEVI, including epidemiologic characterization and description of early limb loss.

METHODS

The Department of Defense Trauma Registry (DoDTR) was queried to identify US service members who sustained a battle-related UEVI in Afghanistan between January 2009 and December 2015. Anatomic distribution of injury, mechanism of injury (MOI), associated injuries, early management, and early limb loss were analyzed.

RESULTS

Analysis identified 247 casualties who sustained 308 UEVIs. The most common injury was to the vessels distal to the brachial bifurcation (63.3%, n = 195), followed by the brachial vessels (27.3%, n = 84) and the axillary vessels (9.4%, n = 29). The predominant MOIs were penetrating explosive fragments (74.1%, n = 183) and gunshot wounds (25.9%, n = 64). Associated fractures were identified in 151 (61.1%) casualties and nerve injuries in 133 (53.8%). Angiography was performed in 91 (36.8%) casualties, and endovascular treatment was performed 10 (4%) times. Temporary vascular shunts were placed in 39 (15.8%) casualties. Data on surgical management were available for 171 injuries and included repair (48%, n = 82) and ligation (52%, n = 89). The early limb loss rate was 12.1% (n = 30). For all casualties sustaining early limb loss, the MOI was penetrating fragments from an explosion; the average injury severity score (ISS) was 32.3, and the mortality was 6.7% (n = 2). In those without amputation, the ISS and mortality were low at 20 and 4.6% (n = 10), respectively. Overall mortality was 4.9% (n = 12).

CONCLUSIONS

The early limb loss rate was increased compared with initial descriptions from Operation Iraqi Freedom. Amputations are associated with a higher ISS. Improved data capture and fidelity, or differing MOIs, may account for this trend. Proficiency with open and endovascular therapy remains a critical focus for combat casualty care.

Clinical implementation of the Humacyte human acellular vessel: Implications for military and civilian trauma care

The incidence of wartime vascular injury has increased and is a leading cause of mortality and morbidity. While ligation remains an option, current resuscitation and damage control techniques have resulted in vascular repair being pursued in more than half of wartime injuries. Options for vascular reconstruction are currently limited to autologous vein or synthetic conduits, choices which have not changed in decades, both of which have problems. Autologous vein is preferable but requires time to harvest and may not be available. Synthetic grafts are poorly resistant to infection and associated with thrombotic complications. Recognizing this capability gap, the US Combat Casualty Care Research Program has partnered with academia and industry to support the development and clinical introduction of a bioengineered human acellular vessel. This human acellular vessel has the potential to be an off-the-shelf conduit that is resistant to infection and incorporates well into native tissues. This report reviews the rationale of this military-civilian partnership in medical innovation and provides an update on the clinical use and ongoing study of this new vascular technology. LEVEL OF EVIDENCE: Therapeutic, level III.

Advanced Resuscitative Care in Tactical Combat Casualty Care: TCCC Guidelines Change 18-01:14 October 2018

TCCC has previously recommended interventions that can effectively prevent 4 of the top 5 causes of prehospital preventable death in combat casualties-extremity hemorrhage, junctional hemorrhage, airway obstruction, and tension pneumothorax- and deaths from these causes have been markedly reduced in US combat casualties. Noncompressible torso hemorrhage (NCTH) is the last remaining major cause of preventable death on the battlefield and often causes death within 30 minutes of wounding. Increased use of whole blood, including the capability for massive transfusion, if indicated, has the potential to increase survival in casualties with either thoracic and/or abdominopelvic hemorrhage. Additionally, Zone 1 Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) can provide temporary control of bleeding in the abdomen and pelvis and improve hemodynamics in casualties who may be approaching traumatic cardiac arrest as a result of hemorrhagic shock. Together, these two interventions are designated Advanced Resuscitative Care (ARC) and may enable casualties with severe NCTH to survive long enough to reach the care of a surgeon. Although Special Operations units are now using whole blood far-forward, this capability is not routinely present in other US combat units at this point in time. REBOA is not envisioned as care that could be accomplished by a unit medic working out of his or her aid bag. This intervention should be undertaken only by designated teams of advanced combat medical personnel with special training and equipment.