Wartime Vascular Injury

Application of Hemostatic Tourniquet on Wounded Extremities in Modern "Trench" Warfare: The View of a Vascular Surgeon

INTRODUCTION

Blood vessel injuries in modern military conflicts account for 12% of all wounds (1), and 50%-95% of these involve arterial damage in extremities (3, 5). Furthermore, 10%-15% of all deaths on the battlefield occur due to extremity hemorrhage (2). Therefore, tourniquets and compression dressings continue to be the main methods of controlling extremity hemorrhage (4).

MATERIALS AND METHODS

The article analyzes the use of hemostatic tourniquets on wounded extremities for personnel that were provided second-level medical care by a Forward Surgical Team (FST) of one of the field hospitals of the Armed Forces of Ukraine.In these clinical cases, care was provided at the FST base in one of the district hospitals and during visits to civilian frontline hospitals by a vascular surgeon. This FST provided medical care to all severely and moderately injured or wounded in the area.The analysis included both military and civilians delivered with hemostatic tourniquets on their extremities.

RESULTS AND DISCUSSION

Assistance was provided to 69 wounded or injured, including 5 civilians. In all, 102 tourniquets were applied on 95 extremities. Tourniquets were applied on all 95 (100%) extremities including 21 (22.1%) upper extremities and 74 (77.9%) lower extremities. In 5 cases, tourniquets were applied on 3 extremities, in 16 cases on 2 extremities, and in 48 cases on 1 extremity. Combat Application Tourniquets (CAT) were used in 81 (85.3%) cases, Esmarch type in 10 (10.5%) cases, and improvised tourniquets in 4 (4.2%) cases. Duration of tourniquet application was less than 1 hour in 27 cases, 1-2 hours in 18 cases, 2-3 hours in 15 cases, and over 3 hours in 9 cases.The level of primary blood loss at the time of admission was categorized as <1 L in 44 (63.7%) cases, 1.0-1.5 L in 11 (11.5%) cases, 1.5-2.0 L in 7 (7.2%) cases, 2.0-2.5 L in 3 (3.1%) cases, and >2.5 L in 4 (4.2%) cases. Main arteries were damaged in 14 extremities in 12 (17.4%) wounded. Main veins were damaged in 4 (5.8%) cases without the involvement of the main arteries. Damage to the branches of arteries and veins was seen in 53 (76.8%) of the wounded. Surgical procedures performed included main artery reconstruction in 6, ligation of main arteries in 2, main vein ligation in 4, primary amputations of extremities in 9, and surgical debridement with ligation of arterial and/or venous branches in 37 cases. Reasons for excessive blood loss (>1.0 L) included delayed tourniquet application in 8 cases, inadequate tourniquet application in 12 cases, and bleeding secondary to injuries of the chest/abdominal cavity or head in 5 cases.

CONCLUSIONS

(1) Tourniquet application was appropriate in 24.6% of the wounded with tourniquets.(2) The success of hemostatic tourniquet use is dependent upon the experience of staff rather than the type of tourniquet used.(3) In patients with significant blood loss, the duration of ischemia should be calculated from the time of injury and not from the time tourniquet was applied.(4) During the reconstruction of the main arteries in extremities after the prolonged use of the tourniquet, a longer than usual anastomosis line is advised.(5) Injuries to upper extremities will be more common during active combat, compared to positional warfare in fortified positions.

Off-the-Shelf, Heparinized Small Diameter Vascular Graft Limits Acute Thrombogenicity in a Porcine Model

Thrombogenicity poses a challenge to the clinical translation of engineered grafts. Previously, small-diameter vascular grafts (sdVG) composed of fibrin hydrogel microfiber tubes (FMT) with an external poly(ε-caprolactone) (PCL) sheath supported long-term patency in mice. Towards the development of an sdVG with off-the-shelf availability, the FMT's shelf stability, scale-up, and successful conjugation of an antithrombotic drug to the fibrin scaffold are reported here. FMTs maintain mechanical stability and high-water retention after storage for one year in a freezer, in a refrigerator, or at room temperature. Low molecular weight heparin-conjugated fibrin scaffolds enabled local and sustained delivery during two weeks of enzymatic degradation. Upscaled fabrication of sdVGs provides natural biodegradable grafts with size and mechanics suitable for human application. Implantation in a carotid artery interposition porcine model exhibited no rupture with thrombi prevented in all heparinized sdVGs (n=4) over 4-5 weeks. Remodeling of the sdVGs is demonstrated with endothelial cells on the luminal surface and initial formation of the medial layer by 4-5 weeks. However, neointimal hyperplasia at 4-5 weeks led to the stenosis and occlusion of most of the sdVGs, which must be resolved for future long-term in vivo assessments. The off-the-shelf, biodegradable heparinized fibrin sdVG layer limits acute thrombogenicity while mediating extensive neotissue formation as the PCL sheath maintains structural integrity. STATEMENT OF SIGNIFICANCE: : To achieve clinical and commercial utility of small-diameter vascular grafts as arterial conduits, these devices must have off-the-shelf availability for emergency arterial bypass applications and be scaled to a size suitable for human applications. A serious impediment to clinical translation is thrombogenicity. Treatments have focused on long-term systemic drug therapy, which increases the patient's risk of bleeding complications, or coating grafts and stents with anti-coagulants, which minimally improves patient outcomes even when combined with dual anti-platelet therapy. We systematically modified the biomaterial properties to develop anticoagulant embedded, biodegradable grafts that maintain off-the-shelf availability, provide mechanical stability, and prevent clot formation through local drug delivery.

Upper-Extremity Vascular Exposures for Trauma: Comparative Performance Outcomes for General Surgeons and Orthopedic Surgeons

INTRODUCTION

As combat-related trauma decreases, there remains an increasing need to maintain the ability to care for trauma victims from other casualty events around the world (e.g., terrorism, natural disasters, and infrastructure failures). During these events, military surgeons often work closely with their civilian counterparts, often in austere and expeditionary contexts. In these environments, the primary aim of the surgical team is to implement damage control principles to avert blood loss, optimize oxygenation, and improve survival. Upper-extremity vascular injuries are associated with high rates of morbidity and mortality resulting from exsanguination and ischemic complications; however, fatalities may be avoided if hemorrhage is rapidly controlled. In austere contexts, deployed surgical teams typically include one general surgeon and one orthopedic surgeon, neither of which have acquired the expertise to manage these vascular injuries. The purpose of this study was to examine the baseline capabilities of general surgeons and orthopedic surgeons to surgically expose and control axillary and brachial arteries and to determine if the abilities of both groups could be increased through a focused cadaver-based training intervention.

METHODS

This study received IRB approval at our institution. Study methods included the use of cadavers for baseline assessment of procedural capabilities to expose and control axillary and brachial vessels, followed by 1:1 procedural training and posttraining re-assessment of procedural capabilities. Inferential analyses included ANOVA/MANOVA for within- and between-group effects (P < .05). Effect sizes were calculated using Cohen's d.

RESULTS

Study outcomes demonstrated significant differences between the baseline performance abilities of the two groups, with general surgeons outperforming orthopedic surgeons. Before training, neither group reached performance benchmarks for overall or critical procedural abilities in exposing axillary and brachial vessels. Training led to increased abilities for both groups. There were statistically significant gains for overall procedural abilities, as well as for critical procedural elements that are directly associated with morbidity and mortality. These outcomes were consistent for both general and orthopedic surgeons. Effect sizes ranged between medium (general surgeons) and very large (orthopedic surgeons).

CONCLUSION

There was a baseline capability gap for both general surgeons and orthopedic surgeons to surgically expose and control the axillary and brachial vessels. Outcomes from the course suggest that the methodology facilitates the acquisition of accurate and independent vascular procedural capabilities in the management of upper-extremity trauma injuries. The impact of this training for surgeons situated in expeditionary or remote contexts has direct relevance for caring for victims of extremity trauma. These outcomes underscore the need to train all surgeons serving in rural, remote, expeditionary, combat, or global health contexts to be able to competently manage extremity trauma and concurrent vascular injuries to increase the quality of care in those settings.

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

BACKGROUND

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

LEVEL OF EVIDENCE

Level V.

Annual review of Chinese Journal of Traumatology 2020

The year 2020 is an extremely unusual year. The world lost more than one million lives due to the attack of COVID-19. Economic production has been greatly reduced, and daily activities are largely restricted. Luckily the work of Chinese Journal of Traumatology (CJTEE) has not been adversely affected. 2020 is a harvest year for the journal, which (1) was included in the high-quality academic journals by China Association for Science and Technology; (2) cover of each issue is newly designed; (3) submission increased by about 60% with more countries and regions covered; (4) usage in the ScienceDirect database exceeded a million; (5) the CiteScore rises to more than 2.0 the first time. This study reviewed the articles published in the year 2020 by CJTEE.