Bleeding to death in a big city: An analysis of all trauma deaths from hemorrhage in a metropolitan area during 1 year

Alginate based hemostatic materials for bleeding management: A review

Severe bleeding has caused significant financial losses as well as a major risk to the lives and health of military and civilian populations. Under some situations, the natural coagulation mechanism of the body is unable to achieve fast hemostasis without the use of hemostatic drugs. Thus, the development of hemostatic materials and techniques is essential. Improving the quality of life and survival rate of patients and minimizing bodily damage requires fast, efficient hemostasis and prevention of bleeding. Alginate is regarded as an outstanding hemostatic polymer because of its non-immunogenicity, biodegradability, good biocompatibility, simple gelation, non-toxicity, and easy availability. This review summarizes the basics of hemostasis and emphasizes the recent developments regarding alginate-based hemostatic systems. Structural modifications and mixing with other materials have widely been used for the improvement of hemostatic characteristics of alginate and for making multifunctional medical devices that not only prevent uncontrolled bleeding but also have antibacterial characteristics, drug delivery abilities, and curing effects. This review is hoped to prepare critical insights into alginate modifications for better hemostatic properties.

Engineering Low Volume Resuscitants for the Prehospital Care of Severe Hemorrhagic Shock

Globally, traumatic injury is a leading cause of suffering and death. The ability to curtail damage and ensure survival after major injury requires a time-sensitive response balancing organ perfusion, blood loss, and portability, underscoring the need for novel therapies for the prehospital environment. Currently, there are few options available for damage control resuscitation (DCR) of trauma victims. We hypothesize that synthetic polymers, which are tunable, portable, and stable under austere conditions, can be developed as effective injectable therapies for trauma medicine. In this work, we design injectable polymers for use as low volume resuscitants (LVRs). Using RAFT polymerization, we evaluate the effect of polymer size, architecture, and chemical composition upon both blood coagulation and resuscitation in a rat hemorrhagic shock model. Our therapy is evaluated against a clinically used colloid resuscitant, Hextend. We demonstrate that a radiant star poly(glycerol monomethacrylate) polymer did not interfere with coagulation while successfully correcting metabolic deficit and resuscitating animals from hemorrhagic shock to the desired mean arterial pressure range for DCR - correcting a 60 % total blood volume (TBV) loss when given at only 10 % TBV. This highly portable and non-coagulopathic resuscitant has profound potential for application in trauma medicine.

Polydopamine-Coated Silk Fiber with Controllable Length for Enhanced Hemostatic Application

The development of highly effective hemostatic materials with high biocompatibility and outstanding performance is vital to the field of biomaterials. In this study, we develop a hemostatic fiber material that exhibits high biocompatibility and excellent performance. By incorporating polydopamine (PDA) into the alkaline treatment of silk fibroin (SF), we achieve PDA-coated SF fibers with lengths that can be controlled by the alkaline concentration. The PDA coating significantly enhances the hemostatic ability of the silk fibers and exhibits superior performance in both in vitro and ex vivo experiments. By performing animal studies involving a mouse liver puncture model and a femoral vein incision model, we demonstrate the remarkable hemostatic capability of the PDA-coated SF fibers, as evidenced by the lower blood loss compared to that of a commercial hemostat powder. These findings highlight the potential of applying a PDA-assisted alkaline treatment to SF fibers to efficiently create hemostatic fibers with controllable lengths, which would be promising candidates for clinical hemostatic applications.

Progressive Reduction in Preventable Mortality in a State Trauma System Using Continuous Preventable Mortality Review to Drive Provider Education: Results of Analyzing 1,979 Trauma Deaths from 2015 to 2022

BACKGROUND

The state legislature codified and funded the Arkansas Trauma System (ATS) in 2009. Quarterly preventable mortality reviews (PMRs) by the ATS began in 2015 and were used to guide state-wide targeted education to reduce preventable or potentially preventable (P/PP) deaths. We present the results of this PMR-education initiative from 2015 to 2022.

STUDY DESIGN

The ATS uses a statistical sampling model of the Arkansas Trauma Registry to select ~40% of the deaths for quarterly review, reflecting the overall the Arkansas Trauma Registry mortality population. A multispecialty PMR committee reviews the medical records from prehospital care to death, and hospital and regional advisory council reviews for each death. The PMR committee assigns opportunities for improvement (OFIs), cause(s) of death, and the likelihood of preventability for each case. Education to improve trauma care includes annual state-wide trauma meetings, novel classes targeted at level III/IV trauma center hospital providers, trauma evidence-based guidelines, and PMR "pearls."

RESULTS

We reviewed 1,979 deaths with 211 (10.6%) deaths judged to be P/PP deaths. There was a progressive decrease in P/PP deaths and OFIs for P/PP deaths. Five OFI types targeted by education accounted for 72% of the 24 possible OFI types in the P/PP cases, and 94% of the "contributory OFIs." Reductions in "delay in treatment" resulted in the most rapid decrease in P/PP deaths.

CONCLUSIONS

Using ongoing PMR studies to target provider education led to a reduction in P/PP deaths and OFIs for P/PP deaths. Focusing on education designed to improve preventable mortality can result in a substantial decrease in P/PP deaths by 43% (14% to 8%) for trauma systems.

Characteristics of traumatic major haemorrhage in a tertiary trauma center

BACKGROUND

Major traumatic haemorrhage is potentially preventable with rapid haemorrhage control and improved resuscitation techniques. Although advances in prehospital trauma management, haemorrhage is still associated with high mortality. The aim of this study was to use a recent pragmatic transfusion-based definition of major bleeding to characterize patients at risk of major bleeding and associated outcomes in this cohort after trauma.

METHODS

This was a retrospective cohort study including all trauma patients (n = 7020) admitted to a tertiary trauma center from January 2015 to June 2020. The major bleeding cohort (n = 145) was defined as transfusion of 4 units of any blood components (red blood cells, plasma, or platelets) within 2 h of injury. Univariate and multivariable logistic regression analyses were performed to identify risk factors for 24-hour and 30-day mortality post trauma admission.

RESULTS

In the major bleeding cohort (n = 145; 145/7020, 2.1% of the trauma population), there were 77% men (n = 112) and 23% women (n = 33), median age 39 years [IQR 26-53] and median Injury Severity Score (ISS) was 22 [IQR 13-34]. Blunt trauma dominated over penetrating trauma (58% vs. 42%) where high-energy fall was the most common blunt mechanism and knife injury was the most common penetrating mechanism. The major bleeding cohort was younger (OR 0.99; 95% CI 0.98 to 0.998, P = 0.012), less female gender (OR 0.66; 95% CI 0.45 to 0.98, P = 0.04), and had more penetrating trauma (OR 4.54; 95% CI 3.24 to 6.36, P = 0.001) than the rest of the trauma cohort. A prehospital (OR 2.39; 95% CI 1.34 to 4.28; P = 0.003) and emergency department (ED) (OR 6.91; 95% CI 4.49 to 10.66, P = 0.001) systolic blood pressure < 90 mmHg was associated with the major bleeding cohort as well as ED blood gas base excess < -3 (OR 7.72; 95% CI 5.37 to 11.11; P < 0.001) and INR > 1.2 (OR 3.09; 95% CI 2.16 to 4.43; P = 0.001). Emergency damage control laparotomy was performed more frequently in the major bleeding cohort (21.4% [n = 31] vs. 1.5% [n = 106]; OR 3.90; 95% CI 2.50 to 6.08; P < 0.001). There was no difference in transportation time from alarm to hospital arrival between the major bleeding cohort and the rest of the trauma cohort (47 [IQR 38;59] vs. 49 [IQR 40;62] minutes; P = 0.17). However, the major bleeding cohort had a shorter time from ED to first emergency procedure (71.5 [IQR 10.0;129.0] vs. 109.00 [IQR 54.0; 259.0] minutes, P < 0.001). In the major bleeding cohort, patients with penetrating trauma, compared to blunt trauma, had a shorter alarm to hospital arrival time (44.0 [IQR 35.5;54.0] vs. 50.0 [IQR 41.5;61.0], P = 0.013). The 24-hour mortality in the major bleeding cohort was 6.9% (10/145). All fatalities were due to blunt trauma; 40% (4/10) high energy fall, 20% (2/10) motor vehicle accident, 10% (1/10) motorcycle accident, 10% (1/10) traffic pedestrian, 10% (1/10) traffic other, and 10% (1/10) struck/hit by blunt object. In the logistic regression model, prehospital cardiac arrest (OR 83.4; 95% CI 3.37 to 2063; P = 0.007) and transportation time (OR 0.95, 95% CI 0.91 to 0.99, P = 0.02) were associated with 24-hour mortality.

RESULTS

Early identification of patients at high risk of major bleeding is challenging but essential for rapid definitive haemorrhage control. The major bleeding trauma cohort is a small part of the entire trauma population, and is characterized of being younger, male gender, higher ISS, and exposed to more penetrating trauma. Early identification of patients at high risk of major bleeding is challenging but essential for rapid definitive haemorrhage control.

Platelets in Hemostasis, Thrombosis, and Inflammation After Major Trauma

Trauma currently accounts for 10% of the total global burden of disease and over 5 million deaths per year, making it a leading cause of morbidity and mortality worldwide. Although recent advances in early resuscitation have improved early survival from critical injury, the mortality rate in patients with major hemorrhage approaches 50% even in mature trauma systems. A major determinant of clinical outcomes from a major injury is a complex, dynamic hemostatic landscape. Critically injured patients frequently present to the emergency department with an acute traumatic coagulopathy that increases mortality from bleeding, yet, within 48 to 72 hours after injury will switch from a hypocoagulable to a hypercoagulable state with increased risk of venous thromboembolism and multiple organ dysfunction. This review will focus on the role of platelets in these processes. As effectors of hemostasis and thrombosis, they are central to each phase of recovery from injury, and our understanding of postinjury platelet biology has dramatically advanced over the past decade. This review describes our current knowledge of the changes in platelet behavior that occur following major trauma, the mechanisms by which these changes develop, and the implications for clinical outcomes. Importantly, supported by research in other disease settings, this review also reflects the emerging role of thromboinflammation in trauma including cross talk between platelets, innate immune cells, and coagulation. We also address the unresolved questions and significant knowledge gaps that remain, and finally highlight areas that with the further study will help deliver further improvements in trauma care.

When to use tranexamic acid for the treatment of major bleeding?

Tranexamic acid (TXA) is an antifibrinolytic agent originally developed for the management of bleeding in the setting of postpartum hemorrhage (PPH). Over the last 15 years, there has been accumulating evidence on the use of TXA for the treatment of active bleeding in a variety of clinical contexts. Clinical trials have shown that the efficacy and safety of TXA for the treatment of bleeding differ according to the clinical context in which it is being administered, timing of administration, and dose. Early administration is important for efficacy, particularly in trauma and PPH. Further studies are needed to understand the mechanisms by which TXA provides benefit, optimal modes of administration and dosing, and its effect in some clinical settings, such as spontaneous intracerebral hemorrhage. There is no evidence that TXA increases the risk of thrombotic events in patients with major bleeding overall. However, there is evidence of increased risk of venous thrombosis in patients with gastrointestinal bleeding. There is also evidence of increased risk of seizures with the use of higher doses. This review summarizes the current evidence for the use of TXA for patients with active bleeding and highlights the importance of generating evidence of efficacy and safety of hemostatic interventions specific to the bleeding contexts-as findings from 1 clinical setting may not be generalizable to other contexts-and that of individual patient assessment for bleeding, thrombotic, and other risks, as well as important logistical and other practical considerations, to optimize care and outcomes in these settings.

TiME OUT: Time-specific machine-learning evaluation to optimize ultramassive transfusion

BACKGROUND

Ultramassive transfusion (UMT) is a resource-demanding intervention for trauma patients in hemorrhagic shock, and associated mortality rates remains high. Current research has been unable to identify a transfusion ceiling or point where UMT transitions from lifesaving to futility. Furthermore, little consideration has been given to how time-specific patient data points impact decisions with ongoing high-volume resuscitation. Therefore, this study sought to use time-specific machine learning modeling to predict mortality and identify parameters associated with survivability in trauma patients undergoing UMT.

METHODS

A retrospective review was conducted at a Level I trauma (2018-2021) and included trauma patients meeting criteria for UMT, defined as ≥20 red blood cell products within 24 hours of admission. Cross-sectional data were obtained from the blood bank and trauma registries, and time-specific data were obtained from the electronic medical record. Time-specific decision-tree models predicating mortality were generated and evaluated using area under the curve.

RESULTS

In the 180 patients included, mortality rate was 40.5% at 48 hours and 52.2% overall. The deceased received significantly more blood products with a median of 71.5 total units compared with 55.5 in the survivors ( p < 0.001) and significantly greater rates of packed red blood cells and fresh frozen plasma at each time interval. Time-specific decision-tree models predicted mortality with an accuracy as high as 81%. In the early time intervals, hemodynamic stability, undergoing an emergency department thoracotomy, and injury severity were most predictive of survival, while, in the later intervals, markers of adequate resuscitation such as arterial pH and lactate level became more prominent.

CONCLUSION

This study supports that the decision of "when to stop" in UMT resuscitation is not based exclusively on the number of units transfused but rather the complex integration of patient and time-specific data. Machine learning is an effective tool to investigate this concept, and further research is needed to refine and validate these time-specific decision-tree models.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Advanced Non-compressible Torso Hemorrhage Management is Combat Casualty Care's Moon Shot

Non-compressible torso hemorrhage continues to cause considerable preventable mortality on the battlefield. In this editorial, we highlight the burden of deaths, the most at-risk torso structures, current interventions, and their limitations and recommendations for future research and device development.

Functional hemostatic hydrogels: design based on procoagulant principles

Uncontrolled hemorrhage results in various complications and is currently the leading cause of death in the general population. Traditional hemostatic methods have drawbacks that may lead to ineffective hemostasis and even the risk of secondary injury. Therefore, there is an urgent need for more effective hemostatic techniques. Polymeric hemostatic materials, particularly hydrogels, are ideal due to their biocompatibility, flexibility, absorption, and versatility. Functional hemostatic hydrogels can enhance hemostasis by creating physical circumstances conducive to hemostasis or by directly interfering with the physiological processes of hemostasis. The procoagulant principles include increasing the concentration of localized hemostatic substances or establishing a physical barrier at the physical level and intervention in blood cells or the coagulation cascade at the physiological level. Moreover, synergistic hemostasis can combine these functions. However, some hydrogels are ineffective in promoting hemostasis or have a limited application scope. These defects have impeded the advancement of hemostatic hydrogels. To provide inspiration and resources for new designs, this review provides an overview of the procoagulant principles of hemostatic hydrogels. We also discuss the challenges in developing effective hemostatic hydrogels and provide viewpoints.

Epidemiology of Trauma-Related Hemorrhage and Time to Definitive Care Across North America: Making the Case for Bleeding Control Education

INTRODUCTION

Uncontrolled trauma-related hemorrhage remains the primary preventable cause of death among those with critical injury.

STUDY OBJECTIVE

The purpose of this investigation was to evaluate the types of trauma associated with critical injury and trauma-related hemorrhage, and to determine the time to definitive care among patients treated at major trauma centers who were predicted to require massive transfusion.

METHODS

A secondary analysis was performed of the Pragmatic, Randomized, Optimal Platelet and Plasma Ratios (PROPPR) trial data (N = 680). All patients included were predicted to require massive transfusion and admitted to one of 12 North American trauma centers. Descriptive statistics were used to characterize patients, including demographics, type and mechanism of injury, source of bleeding, and receipt of prehospital interventions. Patient time to definitive care was determined using the time from activation of emergency services to responder arrival on scene, and time from scene departure to emergency department (ED) arrival. Each interval was calculated and then summed for a total time to definitive care.

RESULTS

Patients were primarily white (63.8%), male (80.3%), with a median age of 34 (IQR 24-51) years. Roughly one-half of patients experienced blunt (49.0%) versus penetrating (48.2%) injury. The most common types of blunt trauma were motor vehicle injuries (83.5%), followed by falls (9.3%), other (3.6%), assaults (1.8%), and incidents due to machinery (1.8%). The most common types of penetrating injuries were gunshot wounds (72.3%), stabbings (24.1%), other (2.1%), and impalements (1.5%). One-third of patients (34.5%) required some prehospital intervention, including intubation (77.4%), chest or needle decompression (18.8%), tourniquet (18.4%), and cardiopulmonary resuscitation (CPR; 5.6%). Sources of bleeding included the abdomen (44.3%), chest (20.4%), limb/extremity (18.2%), pelvis (11.4%), and other (5.7%). Patients waited for a median of six (IQR4-10) minutes for emergency responders to arrive at the scene of injury and traveled a median of 27 (IQR 19-42) minutes to an ED. Time to definitive care was a median of 57 (IQR 44-77) minutes, with a range of 12-232 minutes. Twenty-four-hour mortality was 15% (n = 100) with 81 patients dying due to exsanguination or hemorrhage.

CONCLUSION

Patients who experience critical injury may experience lengthy times to receipt of definitive care and may benefit from bystander action for hemorrhage control to improve patient outcomes.

Progress and future prospects of hemostatic materials based on nanostructured clay minerals

The occurrence of uncontrolled hemorrhage is a significant threat to human life and health. Although hemostatic materials have made remarkable advances in the biomaterials field, it remains a challenge to develop safe and effective hemostatic materials for global medical use. Natural clay minerals (CMs) have long been used as traditional inorganic hemostatic agents due to their good hemostatic capability, biocompatibility and easy availability. With the advancement of science, technology and ideology, CM-based hemostatic materials have undergone continuous innovations by integrating new inspirations with conventional concepts. This review systematically summarizes the hemostatic mechanisms of different natural CMs based on their nanostructures. Moreover, it also comprehensively reviews the latest research progress for CM-based hemostatic hybrid and nanocomposite materials, and discusses the challenges and developments in this field.

Lyophilized apoptotic vesicle-encapsulated adhesive hydrogel sponge as a rapid hemostat for traumatic hemorrhage in coagulopathy

Rapid hemostasis of uncontrolled bleeding following traumatic injuries, especially accompanied by coagulopathies, remains a significant clinical challenge. Extracellular vesicles (EVs) show therapeutic effects for fast clotting. However, low yield, specific storage conditions, and lack of proper carriers have hindered EVs' clinical application. Herein, we establish an optimized procedure method to generate lyophilized mesenchymal stem cell-derived apoptotic vesicles (apoVs) with adhesive hydrogel sponge to show superior procoagulant activity for traumatic hemorrhage. Mechanistically, apoVs' procoagulant ability stems from their high tissue factor (TF) and phosphatidylserine (PS) expression independent of hemocytes and circulating procoagulant microparticles (cMPs). Their stable hemostatic capability was maintained after 2-month room temperature storage. Subsequently, we mixed apoVs with both phenylboronic acid grafted oxidized hyaluronic acid (PBA-HA) and poly(vinyl alcohol) (PVA) simultaneously, followed by lyophilization to construct a novel apoV-encapsulated hydrogel sponge (apoV-HS). Compared to commercial hemostats, apoV-HS exhibits rapid procoagulant ability in liver-laceration and femoral artery hemorrhage in rat and rabbit models of coagulopathies. The combination of high productivity, physiological stability, injectability, plasticity, excellent adhesivity, biocompatibility, and rapid coagulant property indicates that apoV-HS is a promising therapeutic approach for heavy hemorrhage in civilian and military populations.

A Systematic Review of Live Animal Use as a Simulation Modality ("Live Tissue Training") in the Emergency Management of Trauma

INTRODUCTION

Live anaesthetized animals are used as simulation models to teach techniques in the emergency management of trauma. We aimed to explore how "live tissue training" (LTT) is designed, delivered and evaluated in order to better understand and characterize aspects of educational merit.

METHODS

A systematic review was performed using PRISMA guidance. A combined approach, involving a 3-stage modified narrative synthesis process and reflexive thematic analysis was used to identify key concepts across the published literature.

FINDINGS

Qualitative synthesis of 48 selected articles suggests that LTT is mainly used to teach military and civilian physicians and military medical technicians. The procedures trained vary with the learner population, from simple pre-hospital trauma tasks to advanced operative surgical skills. Many courses use a combination of didactic and practical training, with an animal model used to train practical application of knowledge and procedural skills. Descriptions of the learning interventions are limited, and explicit use of educational theory or pedagogic frameworks were absent within the literature. Four themes were identified regarding aspects of LTT that are valued by learners: "recreating the experience," relating to fidelity and realism; "tick tock" "dynamics of hemorrhage", encompassing the impact of bleeding and urgent pressure to act; "emotional impact" of conducting the training, and "self-efficacy: I believe I can do it."

CONCLUSION

Thematic analysis of published literature suggests that there may be educational benefit in the use of live tissue models due to time criticality and bleeding, which creates a real-life event. LTT also invokes an emotional response, and learners experience an increase in self-efficacy from participation. We consider that these aspects and associated pedagogy should be addressed when researching and developing alternative simulation modalities, in order to intelligently replace, reduce and refine the use of animals in training practitioners in the emergency management of trauma.

Retrospective value assessment of a dedicated, trauma hybrid operating room

BACKGROUND

In traumatic hemorrhage, hybrid operating rooms offer near simultaneous performance of endovascular and open techniques, with correlations to earlier hemorrhage control, fewer transfusions, and possible decreased mortality. However, hybrid operating rooms are resource intensive. This study quantifies and describes a single-center experience with the complications, cost-utility, and value of a dedicated trauma hybrid operating room.

METHODS

This retrospective cohort study evaluated 292 consecutive adult trauma patients who underwent immediate (<4 hours) operative intervention at a Level I trauma center. A total of 106 patients treated before the construction of a hybrid operating room served as historical controls to the 186 patients treated thereafter. Demographics, hemorrhage-control procedures, and financial data as well as postoperative complications and outcomes were collected via electronic medical records. Value and incremental cost-utility ratio were calculated.

RESULTS

Demographics and severity of illness were similar between cohorts. Resuscitative endovascular occlusion of the aorta was more frequently used in the hybrid operating room. Hemorrhage control occurred faster (60 vs. 49 minutes, p = 0.005) and, in the 4- to 24-hour postadmission period, required less red blood cell (mean, 1.0 vs. 0 U, p = 0.001) and plasma (mean, 1.0 vs. 0 U, p < 0.001) transfusions. Complications were similar except for a significant decrease in pneumonia (7% vs. 4%, p = 0.008). Severe complications (Clavien-Dindo classification, ≥3) were similar. Across the patient admission, costs were not significantly different ($50,023 vs. $54,740, p = 0.637). There was no change in overall value (1.00 vs. 1.07, p = 0.778).

CONCLUSION

The conversion of our standard trauma operating room to an endovascular hybrid operating room provided measurable improvements in hemorrhage control, red blood cell and plasma transfusions, and postoperative pneumonia without significant increase in cost. Value was unchanged.

LEVEL OF EVIDENCE

Economic/Value-Based Evaluations; Level III.

A Cautionary Tale: The Use of Propensity Matching to Evaluate Hemorrhage-Related Trauma Mortality in the American College of Surgeons TQIP Database

BACKGROUND

Propensity-matched methods are increasingly being applied to the American College of Surgeons TQIP database to evaluate hemorrhage control interventions. We used variation in systolic blood pressure (SBP) to demonstrate flaws in this approach.

STUDY DESIGN

Patients were divided into groups based on initial SBP (iSBP) and SBP at 1 hour (2017 to 2019). Groups were defined as follows: iSBP 90 mmHg or less who decompensated to 60 mmHg or less (immediate decompensation [ID]), iSBP 90 mmHg or less who remained greater than 60 mmHg (stable hypotension [SH]), and iSBP greater than 90 mmHg who decompensated to 60 mmHg or less (delayed decompensation [DD]). Individuals with Head or Spine Abbreviated Injury Scale score 3 or greater were excluded. Propensity score was assigned using demographic and clinical variables. Outcomes of interest were in-hospital mortality, emergency department death, and overall length of stay.

RESULTS

Propensity matching yielded 4,640 patients per group in analysis #1 (SH vs DD) and 5,250 patients per group in analysis #2 (SH vs ID). The DD and ID groups had 2-fold higher in-hospital mortality than the SH group (DD 30% vs 15%, p < 0.001; ID 41% vs 18%, p < 0.001). Emergency department death rate was 3 times higher in the DD group and 5 times higher in the ID group (p < 0.001), and length of stay was 4 days shorter in the DD group and 1 day shorter in the ID group (p < 0.001). Odds of death were 2.6 times higher for the DD vs SH group and 3.2 times higher for the ID vs SH group (p < 0.001).

CONCLUSIONS

Differences in mortality rate by SBP variation underscore the difficulty of identifying individuals with a similar degree of hemorrhagic shock using the American College of Surgeons TQIP database despite propensity matching. Large databases lack the detailed data needed to rigorously evaluate hemorrhage control interventions.

Hemorrhagic shock and tissue injury provoke distinct components of trauma-induced coagulopathy in a swine model

INTRODUCTION

Tissue injury (TI) and hemorrhagic shock (HS) are the major contributors to trauma-induced coagulopathy (TIC). However, the individual contributions of these insults are difficult to discern clinically because they typically coexist. TI has been reported to release procoagulants, while HS has been associated with bleeding. We developed a large animal model to isolate TI and HS and characterize their individual mechanistic pathways. We hypothesized that while TI and HS are both drivers of TIC, they provoke different pathways; specifically, TI reduces time to clotting, whereas, HS decreases clot strength stimulates hyperfibrinolysis.

METHODS

After induction of general anesthesia, 50 kg male, Yorkshire swine underwent isolated TI (bilateral muscle cutdown of quadriceps, bilateral femur fractures) or isolated HS (controlled bleeding to a base excess target of - 5 mmol/l) and observed for 240 min. Thrombelastography (TEG), calcium levels, thrombin activatable fibrinolysis inhibitor (TAFI), protein C, plasminogen activator inhibitor 1 (PAI-1), and plasminogen activator inhibitor 1/tissue-type plasminogen activator complex (PAI-1-tPA) were analyzed at pre-selected timepoints. Linear mixed models for repeated measures were used to compare results throughout the model.

RESULTS

TI resulted in elevated histone release which peaked at 120 min (p = 0.02), and this was associated with reduced time to clot formation (R time) by 240 min (p = 0.006). HS decreased clot strength at time 30 min (p = 0.003), with a significant decline in calcium (p = 0.001). At study completion, HS animals had elevated PAI-1 (p = 0.01) and PAI-1-tPA (p = 0.04), showing a trend toward hyperfibrinolysis, while TI animals had suppressed fibrinolysis. Protein C, TAFI and skeletal myosin were not different among the groups.

CONCLUSION

Isolated injury in animal models can help elucidate the mechanistic pathways leading to TIC. Our results suggest that isolated TI leads to early histone release and a hypercoagulable state, with suppressed fibrinolysis. In contrast, HS promotes poor clot strength and hyperfibrinolysis resulting in hypocoagulability.

Survival and neurologic outcomes following aortic occlusion for trauma and hemorrhagic shock in a hybrid operating room

BACKGROUND

Outcomes following aortic occlusion for trauma and hemorrhagic shock are poor, leading some to question the clinical utility of aortic occlusion in this setting. This study evaluates neurologically intact survival following resuscitative endovascular balloon occlusion of the aorta (REBOA) versus resuscitative thoracotomy at a center with a dedicated trauma hybrid operating room with angiographic capabilities.

METHODS

This retrospective cohort analysis compared patients who underwent zone 1 aortic occlusion via resuscitative thoracotomy (n = 13) versus REBOA (n = 13) for blunt or non-thoracic, penetrating trauma and refractory hemorrhagic shock (systolic blood pressure less than 90 mmHg despite volume resuscitation) at a level 1 trauma center with a dedicated trauma hybrid operating room. The primary outcome was survival to hospital discharge. The secondary outcome was neurologic status at hospital discharge, assessed by Glasgow Coma Scale (GCS) scores.

RESULTS

Overall median age was 40 years, 27% had penetrating injuries, and 23% had pre-hospital closed-chest cardiopulmonary resuscitation. In both cohorts, median injury severity scores and head-abbreviated injury scores were 26 and 2, respectively. The resuscitative thoracotomy cohort had lower systolic blood pressure on arrival (0 [0-75] vs. 76 [65-99], p = 0.009). Hemorrhage control (systolic blood pressure 100 mmHg without ongoing vasopressor or transfusion requirements) was obtained in 77% of all REBOA cases and 8% of all resuscitative thoracotomy cases (p = 0.001). Survival to hospital discharge was greater in the REBOA cohort (54% vs. 8%, p = 0.030), as was discharge with GCS 15 (46% vs. 0%, p = 0.015).

CONCLUSIONS

Among patients undergoing aortic occlusion for blunt or non-thoracic, penetrating trauma and refractory hemorrhagic shock at a center with a dedicated, trauma hybrid operating room, nearly half of all patients managed with REBOA had neurologically intact survival. The high death rate in resuscitative thoracotomy and differences in patient cohorts limit direct comparison.

Access to Immediately Available Balanced Blood Products in a Rural State's Trauma System

INTRODUCTION

The Arkansas Trauma System was established by law more than a dozen years ago, and all participating trauma centers are required to maintain red blood cells. Since then, there has been a paradigm shift in resuscitating exsanguinating trauma patients. Damage Control Resuscitation with balanced blood products (or whole blood) and minimal crystalloid is now the standard of care. This project aimed to determine access to balanced blood products in our state's Trauma System (TS).

METHODS

A survey of all trauma centers in the Arkansas TS was conducted, and geospatial analysis was performed. Immediately Available Balanced Blood (IABB) was defined as at least 2 units (U) of thawed plasma (TP) or never frozen plasma (NFP), 4 units of red blood cells (RBCs), 2 units of fresh frozen plasma (FFP), and 1 unit of platelets or 2 units of whole blood (WB).

RESULTS

All 64 trauma centers in the state TS completed the survey. All level I, II, and III Trauma Centers (TCs) maintain RBC, plasma, and platelets, but only half of the level II and 16% of the level III TCs have thawed or never frozen plasma. A third of level IV TCs maintain only RBCs, while only 1 had platelets, and none had thawed plasma. 85% of people in our state are within 30 min of RBCs, almost two-thirds are within 30 min of plasma (TP, NFP, or FFP) and platelets, while only a third are within 30 min of IABB. More than 90% are within an hour of plasma and platelets, while only 60% are within that time from an IABB. The median drive times for Arkansas from RBC, plasma (TP, NFP, or FFP), platelets, and an immediately available and balanced blood bank are 19, 21, 32, and 59 minutes, respectively. A lack of thawed or non-frozen plasma and platelets are the most common limitations of IABB. One level III TC in the state maintains WB, which would alleviate the limited access to IABB.

CONCLUSION

Only 16% of the trauma centers in Arkansas can provide IABB, and only 61% of the population can reach IABB within 60 minutes. Opportunities exist to reduce the time to balanced blood products by selectively distributing WB, TP, or NFP to hospitals in our state trauma system.

The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition

BACKGROUND

Severe trauma represents a major global public health burden and the management of post-traumatic bleeding continues to challenge healthcare systems around the world. Post-traumatic bleeding and associated traumatic coagulopathy remain leading causes of potentially preventable multiorgan failure and death if not diagnosed and managed in an appropriate and timely manner. This sixth edition of the European guideline on the management of major bleeding and coagulopathy following traumatic injury aims to advise clinicians who care for the bleeding trauma patient during the initial diagnostic and therapeutic phases of patient management.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma included representatives from six European professional societies and convened to assess and update the previous version of this guideline using a structured, evidence-based consensus approach. Structured literature searches covered the period since the last edition of the guideline, but considered evidence cited previously. The format of this edition has been adjusted to reflect the trend towards concise guideline documents that cite only the highest-quality studies and most relevant literature rather than attempting to provide a comprehensive literature review to accompany each recommendation.

RESULTS

This guideline comprises 39 clinical practice recommendations that follow an approximate temporal path for management of the bleeding trauma patient, with recommendations grouped behind key decision points. While approximately one-third of patients who have experienced severe trauma arrive in hospital in a coagulopathic state, a systematic diagnostic and therapeutic approach has been shown to reduce the number of preventable deaths attributable to traumatic injury.

CONCLUSION

A multidisciplinary approach and adherence to evidence-based guidelines are pillars of best practice in the management of severely injured trauma patients. Further improvement in outcomes will be achieved by optimising and standardising trauma care in line with the available evidence across Europe and beyond.

Mechanistic considerations for adenosine-lidocaine-magnesium (ALM) in controlling coagulopathy

Adenosine-lidocaine-magnesium (ALM) mixture is a cardioplegic agent that improves survivability in rodent, but not swine, models of noncompressible torso hemorrhage (NCTH). However, despite protection from comorbid coagulopathy being the one common effect reported in both NCTH models, the underlying prothrombotic mechanism for ALM has not been elucidated in either. Here, we undertook a component-based approach focusing on individual drugs in the mixture to elaborate on the protective mechanism against coagulopathy within the frames of adenosine signaling and metabolic pathways. Additionally, the translational potential of small and large animal models of NCTH for human survival is critically appraised, owing to substantial quantitative/qualitative differences between humans and rodents, particularly regarding the genetics of G protein-coupled receptors (GPCRs) interacting with ALM's constituents.

Geospatial Analysis of Prehospital Triage and Early Potential Preventable Traumatic Deaths

Severely injured patients often depend on prompt prehospital triage for survival. This study aimed to examine the under-triage of preventable or potentially preventable traumatic deaths. A retrospective review of Harris County, TX, revealed 1848 deaths within 24 hours of injury, with 186 being preventable or potentially preventable (P/PP). The analysis evaluated the geospatial relationship between each death and the receiving hospital. Out of the 186 P/PP deaths, these were more commonly male, minority, and penetrating mechanisms when compared with NP deaths. Of the 186 PP/P, 97 patients were transported to hospital care, 35 (36%) were transported to Level III, IV, or non-designated hospitals. Geospatial analysis revealed an association between the location of initial injury and proximity to receiving Level III, IV, and non-designated centers. Geospatial analysis supports proximity to the nearest hospital as one of the primary reasons for under-triage.

Characteristics and Outcomes of Prehospital Tourniquet Use for Trauma in the United States

INTRODUCTION

The use of the extremity tourniquet in military environments has reduced preventable deaths due to exsanguinating hemorrhage, leading to increased use in civilian settings. However, the outcomes of contemporary prehospital tourniquet use in civilian settings are not well-described nationally. The objective of this study was to describe the characteristics and outcomes following prehospital tourniquet use by emergency medical services (EMS) in the United States.

METHODS

All trauma activations reported to the National EMS Information System 2019 (NEMSIS) were included. Patients who had ≥1 tourniquet applied were identified. Descriptive analyses were used to compare characteristics between tourniquet and no-tourniquet cohorts. Coarsened exact matching was performed to generate a k2k match (on age, sex, lowest-systolic blood pressure, initial patient acuity, provider's initial impression, injury mechanism, and presence of upper/lower extremity injuries) and used to compare outcomes. Trauma patients who may have potentially benefited from tourniquet application (extremity injury, shock index ≥1 and no documented tourniquet application) were identified.

RESULTS

A total of 7,161 tourniquets were applied among 4,571,379 trauma activations (1.6/1000 activations). Patients in the tourniquet cohort were younger (40 ± 18 vs 52 ± 26 mean ± SD years), more hypotensive (16.1% vs. 2.5%) and had higher initial acuity (65.0% critical/emergent vs. 20.6%) [p < 0.01 for all]. A total of 7,074 patients in the tourniquet cohort were matched with 7,074 patients in the non-tourniquet cohort. Post-match analysis revealed that the patients in tourniquet cohort had a higher final acuity (80.8% vs. 75.0%, p < 0.01), lower scene-time (15.4 ± 13.6 vs. 17.0 ± 14.2 mean ± SD minutes, p < 0.01), and higher survival-to-hospital (83.6% vs. 75.1%, p < 0.01). A total of 141,471 trauma patients who may have potentially benefited from tourniquet application were identified.

CONCLUSION

Prehospital tourniquet use by EMS in the United States is associated with lower scene-time and improved survivability to hospital. Results indicate that patients might benefit from wider tourniquet use in the civilian prehospital setting.

Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.

Pressure Points Technique for Traumatic Proximal Axillary Artery Hemorrhage: A Case Report

INTRODUCTION

While the pressure points technique for proximal hemorrhage control is long known, it is not recommended in standard prehospital guidelines based on a study showing the inability to maintain occlusion for over two minutes.

MAIN SYMPTOM

This report details a gunshot wound to the left axillary area with complete transection of the axillary artery, leading to profuse junctional hemorrhage and profound hemorrhagic shock.

THERAPEUTIC INTERVENTION

Proximal pressure of the subclavian artery was applied against the first rib (the pressure points technique) and maintained for 28 minutes.

OUTCOMES

Cessation of apparent bleeding and excellent, enduring physiologic response to blood transfusion were observed.

CONCLUSION

The pressure points technique can be life-saving in junctional arterial hemorrhage and should be reconsidered in prehospital guidelines.

Manual Pressure Points Technique for Massive Hemorrhage Control - A Prospective Human Volunteer Study

BACKGROUND

While commonly thought to be effective for management of limb and junctional hemorrhage, the manual pressure points technique was excluded from leading prehospital guidelines over a decade ago following the publication of a single human-volunteers study presenting unfavorable results. This work aimed to re-assess the efficacy and feasibility of the femoral and supraclavicular pressure points technique for temporary hemorrhage control distal to the pressure point.

METHODS

A prospective, non-randomized, human volunteer, controlled environment study. In the study 35 healthy male combat medics (age 21.1 ± 1.3 years) received brief training after which they were requested to apply pressure in the femoral and supraclavicular points in attempts to stop regional blood flow, measured distally by Doppler ultrasound. Success rates in achieving flow cessation in under 2 minutes, time required for achievement of flow cessation, and cumulative flow cessation duration within a 3-minute follow-up after initial success were measured.

RESULTS

For the supraclavicular point, success rates were 97.1% with a mean time to success of 12.5 (±20.9) seconds, lasting for 76.2% (±23.7) of the follow-up time. For the femoral point, success rates were 100% with a mean time to success of 5.5 (±4.3) seconds, lasting for 98.7% (±3.8) of the follow-up time.

CONCLUSIONS

Manual pressure on the femoral and supraclavicular points is an applicable and efficient method for temporary hemorrhage control distal to the pressure point. As such, with additional study, this method may be considered for re-introduction to prehospital care guidelines and training programs.

Pathophysiology in patients with polytrauma

The pathophysiology after polytrauma represents a complex network of interactions. While it was thought for a long time that the direct and indirect effects of hypoperfusion are most relevant due to the endothelial permeability changes, it was discovered that the innate immune response to trauma is equally important in modifying the organ response. Recent multi center studies provided a "genetic storm" theory, according to which certain neutrophil changes are activated at the time of injury. However, a second hit phenomenon can be induced by activation of certain molecules by direct organ injury, or pathogens (damage associated molecular patterns, DAMPS - pathogen associated molecular patterns, PAMPS). The interactions between the four pathogenetic cycles (of shock, coagulopathy, temperature loss and soft tissue injuries) and cross-talk between coagulation and inflammation have also been identified as important modifiers of the clinical status. In a similar fashion, overzealous surgeries and their associated soft tissue injury and blood loss can induce secondary worsening of the patient condition. Therefore, staged surgeries in certain indications represent an important alternative, to allow for performing a "safe definitive surgery" strategy for major fractures. The current review summarizes all these situations in a detailed fashion.

Nationwide estimates of the need for prehospital blood products after injury

INTRODUCTION

Prehospital blood product resuscitation after injury significantly decreases risk of mortality. However, the number of patients who may potentially benefit from this life-saving intervention is currently unknown. The primary objective of this study was to estimate the number of patients who may potentially benefit from prehospital blood product resuscitation after injury in the United States. The secondary objective was to estimate the amount of blood products needed for prehospital resuscitation of injured patients.

METHODS

Patients ≥16 years with blunt/penetrating injuries included in National Emergency Medical Services Information System 2019 were identified and classified into four separate cohorts of hemodynamic instability: Cohort 1 (systolic blood pressure [SBP] <90 mmHg), Cohort 2 (SBP <90 and/or heart rate [HR] >120), Cohort 3 (SBP <90 and HR >108 or SBP <70), and Cohort 4 (shock index ≥1). The need for prehospital blood was estimated by multiplying number of patients in each cohort with average number of blood products used for prehospital resuscitation.

RESULTS

After exclusions, 3.7 million adult trauma patients were included. The number of patients who may potentially benefit from prehospital blood products was estimated as 89,391 (Cohort 1), 901,346 (Cohort 2), 54,160 (Cohort 3), and 300,475 (Cohort 4). Assuming 1 unit of whole blood is needed per patient, a lower-bound estimate of 54,160 additional whole blood units (0.6% of current collections) will be need for prehospital resuscitation of the injured.

CONCLUSIONS

Annually, between 54,000 and 900,000 patients may potentially benefit from prehospital blood product resuscitation after injury in the United States. Prehospital blood utilization and collection of blood products will need to be increased to scale-up this life-saving intervention nationwide.

Percutaneous delivery of self-propelling thrombin-containing powder increases survival from non-compressible truncal hemorrhage in a swine model of coagulopathy and hypothermia

BACKGROUND

Non-compressible truncal hemorrhage (NCTH) remains a leading cause of preventable death on the battlefield. Definitively managing severe NCTH requires surgery within the first hour after injury, which is difficult when evacuating casualties from remote and austere environments. During delays to surgery, hemostatic interventions that are performed prehospital can prevent coagulopathy and hemorrhagic shock and increase the likelihood that casualties survive to receive definitive care. We previously reported that a self-propelling thrombin-containing powder (SPTP) can be delivered percutaneously into the abdomen as a minimally invasive intervention and can self-disperse through pooled blood to deliver the hemostatic agents thrombin and tranexamic acid (TXA) locally to noncompressible intracavitary wounds. We hypothesized that in swine with massive NCTH, dilutional coagulopathy and hypothermia, delivering SPTP could extend survival times.

METHODS

Ten swine (n = 5 per group) underwent NCTH from a Grade V liver injury following a midline laparotomy. The laparotomy was closed with sutures afterwards, creating a hemoperitoneum, and animals were managed with crystalloid fluid resuscitation, or crystalloid resuscitation and SPTP. SPTP was delivered into the closed abdomen using a CO2-powered spray device and a catheter placed into the hemoperitoneum, entering through the upper right quadrant using the Seldinger technique. Survival to one and three hours was recorded. In an additional animal, hemorrhage was created laparoscopically and SPTP was imaged in-situ within the abdomen to visually track dispersion of the particles.

RESULTS

SPTP dispersed as far as 35 +/- 5.0 cm within the abdomen. SPTP increased survival to one and three hours (Kaplan-Meier p = 0.007 for both). The median survival time was 61 minutes with SPTP and 31 minutes without (p = 0.016).

CONCLUSION

SPTP effectively disperses medications throughout a hemoperitoneum and increases survival in a model of NCTH. SPTP is a promising strategy for nonsurgical management of NCTH, warranting further testing of its safety and efficacy.

LEVEL OF EVIDENCE

Basic Science, N/A.

It is time to look in the mirror: Individual surgeon outcomes after emergent trauma laparotomy

BACKGROUND

Multiple quality indicators are used by trauma programs to decrease variation and improve outcomes. However, little if any provider level outcomes related to surgical procedures are reviewed. Emergent trauma laparotomy (ETL) is arguably the signature case that trauma surgeons perform on a regular basis, but few data exist to facilitate benchmarking of individual surgeon outcomes. As part of our comprehensive performance improvement program, we examined outcomes by surgeon for those who routinely perform ETL.

METHODS

A retrospective cohort study of patients undergoing ETL directly from the trauma bay by trauma faculty from December 2019 to February 2021 was conducted. Patients were excluded from mortality analysis if they required resuscitative thoracotomy for arrest before ETL. Surgeons were compared by rates of damage control and mortality at multiple time points.

RESULTS

There were 242 ETL (7-32 ETLs per surgeon) performed by 14 faculties. Resuscitative thoracotomy was performed in 7.0% (n = 17) before ETL. Six patients without resuscitative thoracotomy died intraoperatively and damage-control laparotomy was performed on 31.9% (n = 72 of 226 patients). Mortality was 4.0% (n = 9) at 24 hours and 7.1% (n = 16) overall. Median Injury Severity Score (p = 0.21), new injury severity score (p = 0.21), and time in emergency department were similar overall among surgeons (p = 0.15), while operative time varied significantly (40-469 minutes; p = 0.005). There were significant differences between rates of individual surgeon's mortality (range [hospital mortality], 0-25%) and damage-control laparotomy (range, 14-63%) in ETL.

CONCLUSION

Significant differences exist in outcomes by surgeon after ETL. Benchmarking surgeon level performance is a necessary natural progression of quality assurance programs for individual trauma centers. Additional data from multiple centers will be vital to allow for development of more granular quality metrics to foster introspective case review and quality improvement.

LEVEL OF EVIDENCE

Therapeutic/care management, level III.

Impact of time to surgery on mortality in hypotensive patients with noncompressible torso hemorrhage: An AAST multicenter, prospective study

BACKGROUND

Death from noncompressible torso hemorrhage (NCTH) may be preventable with improved prehospital care and shorter in-hospital times to hemorrhage control. We hypothesized that shorter times to surgical intervention for hemorrhage control would decrease mortality in hypotensive patients with NCTH.

METHODS

This was an AAST-sponsored multicenter, prospective analysis of hypotensive patients aged 15+ years who presented with NCTH from May 2018 to December 2020. Hypotension was defined as an initial systolic blood pressure (SBP) ≤ 90 mm Hg. Primary outcomes of interest were time to surgical intervention and in-hospital mortality.

RESULTS

There were 242 hypotensive patients, of which 48 died (19.8%). Nonsurvivors had higher mean age (47.3 vs. 38.8; p = 0.02), higher mean New Injury Severity Score (38 vs. 29; p < 0.001), lower admit systolic blood pressure (68 vs. 79 mm Hg; p < 0.01), higher incidence of vascular injury (41.7% vs. 21.1%; p = 0.02), and shorter median (interquartile range, 25-75) time from injury to operating room start (74 minutes [48-98 minutes] vs. 88 minutes [61-128 minutes]; p = 0.03) than did survivors. Multivariable Cox regression showed shorter time from emergency department arrival to operating room start was not associated with improved survival (p = 0.04).

CONCLUSION

Patients who died arrived to a trauma center in a similar time frame as did survivors but presented in greater physiological distress and had significantly shorter times to surgical hemorrhage intervention than did survivors. This suggests that even expediting a critically ill patient through the current trauma system is not sufficient time to save lives from NCTH. Civilian prehospital advance resuscitative care starting from the patient first contact needs special consideration.

LEVEL OF EVIDENCE

Prognostic/Epidemiologic, Level III.

Percutaneous delivery of self-propelling hemostatic powder for managing non-compressible abdominal hemorrhage: a proof-of-concept study in swine

INTRODUCTION

Non-compressible intra-abdominal hemorrhage (NCIAH) is a major cause of preventable death on the battlefield and in civilian trauma. Currently, it can only be definitively managed with surgery, as there are limited strategies for controlling ongoing NCIAH in the prehospital environment. We hypothesized that a self-propelling thrombin-containing powder (SPTP) could increase survival in a swine model of NCIAH when delivered percutaneously into the closed abdomen using an engineered spray system.

MATERIALS AND METHODS

Nineteen swine underwent surgical laparotomy followed by a Grade V liver injury that created massive hemorrhage, before closing the abdomen with sutures. Animals either received treatment with standard of care fluid resuscitation (n=9) or the SPTP spray system (n=10), which consisted of a spray device and a 14 Fr catheter. Using the spray system, SPTP was delivered into a hemoperitoneum identified using a focused assessment with sonography in trauma (FAST) exam. Lactated Ringer's solution was administered to all animals to maintain a mean arterial pressure (MAP) of >50 mmHg. The primary outcome was percentage of animals surviving at three hours following injury.

RESULTS

In the swine model of NCIAH, a greater percentage of animals receiving SPTP survived to three hours, although differences were not significant. The SPTP spray system increased the median survival of animals from 1.6 hr in the fluid resuscitation group to 4.3 hr. The SPTP spray system delivered a total mass of 18.5 ± 1.0 g of SPTP. The mean change in intra-abdominal pressure following SPTP delivery was 5.2 ± 1.8 mmHg (mean ± SEM). The intervention time was 6.7 ± 1.7 min. No adverse effects related to the SPTP formulation or the spray system were observed. SPTP was especially beneficial in animals that had either severely elevated lactate concentrations or low mean arterial pressure of <35 mmHg shortly after injury.

CONCLUSIONS

This demonstrates proof-of-concept for use of a new minimally invasive procedure for managing NCIAH, which could extend survival time to enable patients to reach definitive surgical care.

Application of Alginate-Based Hydrogels in Hemostasis

Hemorrhage, as a common trauma injury and clinical postoperative complication, may cause serious damage to the body, especially for patients with huge blood loss and coagulation dysfunction. Timely and effective hemostasis and avoidance of bleeding are of great significance for reducing body damage and improving the survival rate and quality of life of patients. Alginate is considered to be an excellent hemostatic polymer-based biomaterial due to its excellent biocompatibility, biodegradability, non-toxicity, non-immunogenicity, easy gelation and easy availability. In recent years, alginate hydrogels have been more and more widely used in the medical field, and a series of hemostatic related products have been developed such as medical dressings, hemostatic needles, transcatheter interventional embolization preparations, microneedles, injectable hydrogels, and hemostatic powders. The development and application prospects are extremely broad. This manuscript reviews the structure, properties and history of alginate, as well as the research progress of alginate hydrogels in clinical applications related to hemostasis. This review also discusses the current limitations and possible future development prospects of alginate hydrogels in hemostatic applications.

Development and Internal Validation of a Nomogram to Predict Mortality During the ICU Stay of Thoracic Fracture Patients Without Neurological Compromise: An Analysis of the MIMIC-III Clinical Database

Background: This study aimed to develop and validate a nomogram for predicting mortality in patients with thoracic fractures without neurological compromise and hospitalized in the intensive care unit. Methods: A total of 298 patients from the Medical Information Mart for Intensive Care III (MIMIC-III) database were included in the study, and 35 clinical indicators were collected within 24 h of patient admission. Risk factors were identified using the least absolute shrinkage and selection operator (LASSO) regression. A multivariate logistic regression model was established, and a nomogram was constructed. Internal validation was performed by the 1,000 bootstrap samples; a receiver operating curve (ROC) was plotted, and the area under the curve (AUC), sensitivity, and specificity were calculated. In addition, the calibration of our model was evaluated by the calibration curve and Hosmer-Lemeshow goodness-of-fit test (HL test). A decision curve analysis (DCA) was performed, and the nomogram was compared with scoring systems commonly used during clinical practice to assess the net clinical benefit. Results: Indicators included in the nomogram were age, OASIS score, SAPS II score, respiratory rate, partial thromboplastin time (PTT), cardiac arrhythmias, and fluid-electrolyte disorders. The results showed that our model yielded satisfied diagnostic performance with an AUC value of 0.902 and 0.883 using the training set and on internal validation. The calibration curve and the Hosmer-Lemeshow goodness-of-fit (HL). The HL tests exhibited satisfactory concordance between predicted and actual outcomes (P = 0.648). The DCA showed a superior net clinical benefit of our model over previously reported scoring systems. Conclusion: In summary, we explored the incidence of mortality during the ICU stay of thoracic fracture patients without neurological compromise and developed a prediction model that facilitates clinical decision making. However, external validation will be needed in the future.

Selective Prehospital Advanced Resuscitative Care - Developing a Strategy to Prevent Prehospital Deaths From Noncompressible Torso Hemorrhage

Hemorrhage, and particularly noncompressible torso hemorrhage remains a leading cause of potentially preventable prehospital death from trauma in the United States and globally. A subset of severely injured patients either die in the field or develop irreversible hemorrhagic shock before they can receive hospital definitive care, resulting in poor outcomes. The focus of this opinion paper is to delineate (a) the need for existing trauma systems to adapt so that potentially life-saving advanced resuscitation and truncal hemorrhage control interventions can be delivered closer to the point-of-injury in select patients, and (b) a possible mechanism through which some trauma systems can train and incorporate select prehospital advanced resuscitative care teams to deliver those interventions.

THOR-AABB Working Party Recommendations for a Prehospital Blood Product Transfusion Program

The evidence for the lifesaving benefits of prehospital transfusions is increasing. As such, emergency medical services (EMS) might increasingly become interested in providing this important intervention. While a few EMS and air medical agencies have been providing exclusively red blood cell (RBC) transfusions to their patients for many years, transfusing plasma in addition to the RBCs, or simply using low titer group O whole blood (LTOWB) in place of two separate components, will be a novel experience for many services. The recommendations presented in this document were created by the Trauma, Hemostasis and Oxygenation Research (THOR)-AABB (formerly known as the American Association of Blood Banks) Working Party, and they are intended to provide a framework for implementing prehospital blood transfusion programs in line with the best available evidence. These recommendations cover all aspects of such a program including storing, transporting, and transfusing blood products in the prehospital phase of hemorrhagic resuscitation.

Massive Transfusion in trauma: an evolving paradigm

A considerable amount of literature has nurtured the idea that massive transfusion is an independent trauma disease and therapeutic tool. In this opinion paper, the authors expose the evolution and challenge the classic paradigm and historic definition of massive transfusion. Based on current evidence the elements of an evolving strategy in transfusion management and bleeding control are exposed such as use of tranexamic acid, combination and ratios of blood products, use of fluids and viscoelastic testing. The synergy of these elements provides the basis to develop updated strategies and perspectives for transfusion management after trauma and to consider a classic definition of massive transfusion as outdated or the need for massive transfusion as failure. An alternative concept, Time Critical Transfusion may be better placed to take into account modern transfusion management after trauma.

Preventable death in trauma: A systematic review on definition and classification

PURPOSE

Trauma-related preventable death (TRPD) has been used to assess the management and quality of trauma care worldwide. However, due to differences in terminology and application, the definition of TRPD lacks validity. The aim of this systematic review is to present an overview of current literature and establish a designated definition of TRPD to improve the assessment of quality of trauma care.

METHODS

A search was conducted in PubMed, Embase, the Cochrane Library and the Web of Science Core Collection. Including studies regarding TRPD, published between January 1, 1990, and April 6, 2021. Studies were assessed on the use of a definition of TRPD, injury severity scoring tool and panel review.

RESULTS

In total, 3,614 articles were identified, 68 were selected for analysis. The definition of TRPD was divided in four categories: I. Clinical definition based on panel review or expert opinion (TRPD, trauma-related potentially preventable death, trauma-related non-preventable death), II. An algorithm (injury severity score (ISS), trauma and injury severity score (TRISS), probability of survival (Ps)), III. Clinical definition completed with an algorithm, IV. Other. Almost 85% of the articles used a clinical definition in some extend; solely clinical up to an additional algorithm. A total of 27 studies used injury severity scoring tools of which the ISS and TRISS were the most frequently reported algorithms. Over 77% of the panels included trauma surgeons, 90% included other specialist; 61% emergency medicine physicians, 46% forensic pathologists and 43% nurses.

CONCLUSION

The definition of TRPD is not unambiguous in literature and should be based on a clinical definition completed with a trauma prediction algorithm such as the TRISS. TRPD panels should include a trauma surgeon, anesthesiologist, emergency physician, neurologist, and forensic pathologist.

Advanced prehospital resuscitative care: Can we identify trauma patients who might benefit?

BACKGROUND

Uncontrolled truncal hemorrhage remains the most common cause of potentially preventable death after injury. The notion of earlier hemorrhage control and blood product resuscitation is therefore attractive. Some systems have successfully implemented prehospital advanced resuscitative care (ARC) teams. Early identification of patients is key and is reliant on rapid decision making and communication. The purpose of this simulation study was to explore the feasibility of early identification of patients who might benefit from ARC in a typical US setting.

METHODS

We conducted a prospective observational/simulation study at a level I trauma center and two associated emergency medical service (EMS) agencies over a 9-month period. The participating EMS agencies were asked to identify actual patients who might benefit from the activation of a hypothetical trauma center-based ARC team. This decision was then communicated in real time to the study team.

RESULTS

Sixty-three patients were determined to require activation. The number of activations per month ranged from 2 to 15. The highest incidence of calls occurred between 4 pm to midnight. Of the 63 patients, 33 were transported to the trauma center. The most common presentation was with penetrating trauma. The median age was 27 years (interquartile range, 24-45 years), 75% were male, and the median Injury Severity Score was 11 (interquartile range, 7-20). Based on injury patterns, treatment received, and outcomes, it was determined that 6 (18%) of 33 patients might have benefited from ARC. Three of the patients died en-route to or soon after arrival at the trauma center.

CONCLUSION

The prehospital identification of patients who might benefit from ARC is possible but faces challenges. Identifying strategies to adapt existing processes may allow better utilization of the existing infrastructure and should be a focus of future efforts.

LEVEL OF EVIDENCE

Prognostic/Epidemiologic, level III.

A new definition for massive transfusion in the modern era of whole blood resuscitation

BACKGROUND

Multiple thresholds are defined to identify patients at risk of death from hemorrhage, including massive transfusion (MT), critical administration threshold (CAT), and resuscitation intensity (RI). All fail to account for the use of whole blood (WB). We hypothesized that a definition including WB transfusion would better predict early mortality following trauma.

METHODS

This is a retrospective review of all trauma patients with activation of the MT protocol from December 2018 to February 2020. Combinations of WB, RBCs, and fresh frozen plasma (FFP) units transfused during the initial hour of resuscitation were compared using receiver operating characteristic and area under the receiver curve (AUC) for 3- and 6-h mortality. WB massive transfusion (WB MT) score was defined as the sum of each unit RBC plus three times each unit of WB transfused within the first hour of resuscitation.

RESULTS

There were 235 patients eligible for analysis with 60 resuscitated using ≥1 unit of WB. Overall, 27 and 29 patients died in the first 3 and 6 h, respectively. WB MT ≥7 had the greatest 3-h and 6-h mortality AUC values (0.78 and 0.79, respectively) when compared to MT, CAT, RI4+, and other attempted definitions using units of WB, RBC, and FFP. Compared to WB MT-, WB MT+ patients died at significantly higher rates at 3 h (28.9% vs. 3.1%, p < .001), 24 h (35.5% vs. 5.7%, p < .001), and 28 days (42.1% vs. 11.9%, p < .001).

CONCLUSION

WB MT is the first measure of massive resuscitation to incorporate WB and better identifies early mortality than other definitions.

Physician-staffed ambulance and increased in-hospital mortality of hypotensive trauma patients following prolonged prehospital stay: A nationwide study

BACKGROUND

The benefits of physician-staffed emergency medical services (EMS) for trauma patients remain unclear because of the conflicting results on survival. Some studies suggested potential delays in definitive hemostasis due to prolonged prehospital stay when physicians are dispatched to the scene. We examined hypotensive trauma patients who were transported by ambulance, with the hypothesis that physician-staffed ambulances would be associated with increased in-hospital mortality, compared with EMS personnel-staffed ambulances.

METHODS

A retrospective cohort study that included hypotensive trauma patients (systolic blood pressure ≤ 90 mm Hg at the scene) transported by ambulance was conducted using the Japan Trauma Data Bank (2004-2019). Physician-staffed ambulances are capable of resuscitative procedures, such as thoracotomy and surgical airway management, while EMS personnel-staffed ambulances could only provide advanced life support. In-hospital mortality and prehospital time until the hospital arrival were compared between patients who were classified based on the type of ambulance. Inverse probability weighting was conducted to adjust baseline characteristics including age, sex, comorbidities, mechanism of injury, vital signs at the scene, injury severity, and ambulance dispatch time.

RESULTS

Among 14,652 patients eligible for the study, 738 were transported by a physician-staffed ambulance. In-hospital mortality was higher in the physician-staffed ambulance than in the EMS personnel-staffed ambulance (201/699 [28.8%] vs. 2287/13,090 [17.5%]; odds ratio, 1.90 [1.61-2.26]; adjusted odds ratio, 1.22 [1.14-1.30]; p < 0.01), and the physician-staffed ambulance showed longer prehospital time (50 [36-66] vs. 37 [29-48] min, difference = 12 [11-12] min, p < 0.01). Such potential harm of the physician-staffed ambulance was only observed among patients who arrived at the hospital with persistent hypotension (systolic blood pressure < 90 mm Hg on hospital arrival) in subgroup analyses.

CONCLUSION

Physician-staffed ambulances were associated with prolonged prehospital stay and increased in-hospital mortality among hypotensive trauma patients compared with EMS personnel-staffed ambulance.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Vorbereitung auf eine differenzierte Hämotherapie nach Trauma – Ergebnisse einer Befragung deutscher Kliniken

Hintergrund

Die unkontrollierte Blutung ist weiterhin eine führende potenziell vermeidbare Todesursache im Rahmen schwerer Verletzungen.

Ziel der Arbeit

Die vorliegende Arbeit hat zum Ziel, die Vorbereitung für eine differenzierte Hämotherapie im Rahmen der Schwerstverletztenbehandlung in Kliniken verschiedener Versorgungsstufen innerhalb der Struktur des TraumaNetzwerks der Deutschen Gesellschaft für Unfallchirurgie (DGU)® zu evaluieren.

Material und Methoden

Anhand einer Online-Umfrage wurden gezielt Diagnose- und Therapiestrategien sowie vorhandene Ressourcen innerhalb der Kliniken erfragt. Im Rahmen einer Subgruppenanalyse sollte festgestellt werden, ob es Unterschiede in Bezug auf infrastrukturelle Voraussetzungen und diagnostisches bzw. therapeutisches Vorgehen innerhalb der Versorgungsstufen des TraumaNetzwerks DGU® gibt.

Ergebnisse

Massivtransfusionsprotokolle (MTP) bestehen in 75 % der Kliniken. Die Aktivierung erfolgt i. d. R. durch den Trauma-Leader (62 %). In 63 % erfolgt die Aktivierung aufgrund einer Anforderung aus der Präklinik. Als Transfusionstrigger werden ein positives FAST (80 %) und ein Pulsdruck < 45 mm Hg (60 %) angegeben. In 50 % der Kliniken existiert kein starres Transfusionsverhältnis der einzelnen Blutkomponenten. Überregionale Traumazentren (ÜTZ) bekommen im Vergleich zu regionalen Traumazentren (RTZ) und lokalen Traumazentren (LTZ) angeforderte Blutprodukte frühzeitiger (p 0,025).

Diskussion

Der massive Blutverlust ist ein seltenes Ereignis, welches mit einer hohen Letalität vergesellschaftet sein kann. MTP bilden die Grundlage für eine frühe Therapie der traumainduzierten Koagulopathie und tragen zur Verbesserung der Überlebenschancen der Patienten bei. Es existiert ein deutlicher Unterschied in den diagnostischen und therapeutischen Möglichkeiten in den einzelnen Versorgungsebenen. ÜTZ verfügen mehrheitlich über die umfangreichsten Optionen, gefolgt von RTZ und LTZ.

Fatal and Nonfatal Injury Patterns of Stranded Motorists

Because nonfatal and fatal incidents for stranded motorists are not separated from vehicular accidents, little data are available on incident characteristics. To close this gap, data fields were inserted into databases at a medical examiner's office and two trauma centers to collect injury-related information. Forensic nurses and pathologists aided in forming a collaboration among the agencies involved and supported data collection efforts. Data collected over a 5-year period were examined for injury patterns to determine risk factors affecting these patterns. Of the total sample (N = 219), 24.7% had spinal injuries resulting in fatal injuries for 46 of 54 individuals. The odds were stranded motorists with spine-related injuries (C1-C7) had 9.13 times higher risk for a fatal outcome compared with those without spine-related injuries. Severe injuries (Abbreviated Injury Scale scores ≥ 4) noted for head/neck (29.7%) and chest (24.2%) were significantly associated with fatality. Of the 219 cases, 22.8% were inside of a stopped vehicle, and 77.2% were outside a vehicle at the time of injury. Outcomes illustrated the success of the interprofessional collaboration between trauma centers and a medicolegal death investigation agency that resulted in data useful for forensic nurses and pathologists documenting evidence, emergency and trauma responding personnel in patient priority stabilization, and injury prevention specialists for highway safety programs.

Whole truths but half the blood: Addressing the gap between the evidence and practice of pre-hospital and in-hospital blood product use for trauma resuscitation

BACKGROUND

In recent years, several studies have demonstrated the efficacy of using pre-hospital blood product and in-hospital whole blood for trauma resuscitation. While some observations suggest an encouraging uptake of this evidence by emergency medical service (EMS) agencies and trauma centers, a nationwide characterization of blood product utilization for bleeding trauma patients remains unknown. The objective of this study is to determine nationwide estimates of pre-hospital blood product and in-hospital whole blood utilization for trauma resuscitation.

STUDY DESIGN AND METHODS

All adult trauma patients reported to the National Emergency Medical Services Information System (NEMSIS) dataset 2019 were included. Proportions of patients who received any pre-hospital blood product were calculated. The American College of Surgeons (ACS) Trauma Quality Programs (TQP) databases 2015-2017 and first quarter of 2020 were used to calculate the proportion of ACS-verified trauma centers that transfused whole blood.

RESULTS

Among a total of 3,058,804 pre-hospital trauma patients, only 313 (0.01%) received any blood transfusion; 208 (0.21%) patients with systolic blood pressure (SBP) ≤90 mmHg and 121 (0.67%) patients with SBP ≤90 mmHg and heart rate ≥120 beats per minute received any blood product. The proportion of ACS-verified trauma centers transfusing whole blood increased from 16.7% (45/269) in 2015 to 24.5% (123/502) in first quarter of 2020.

DISCUSSION

Despite strong evidence and recommendations, pre-hospital utilization of blood products for trauma resuscitation remains low. Additionally, while the overall in-hospital whole blood use also remains low, its use has increased at ACS-verified trauma centers over the past 5 years.

The impact of prehospital TXA on mortality among bleeding trauma patients: A systematic review and meta-analysis

BACKGROUND

Tranexamic acid (TXA) is an antifibrinolytic drug associated with improved survival among trauma patients with hemorrhage. Tranexamic acid is considered a primary hemostatic intervention in prehospital for treatment of bleeding alongside blood product transfusion.

METHODS

A systematic review and meta-analysis was conducted to investigate the impact of prehospital TXA on mortality among trauma patients with bleeding. A systematic search was conducted using the National Institute for Health and Care Excellence Healthcare Databases Advanced Search library which contain the following of databases: EMBASE, Medline, PubMed, BNI, EMCARE, and HMIC. Other databases searched included SCOPUS and the Cochrane Central Register for Clinical Trials Library. Quality assessment tools were applied among included studies; Cochrane Risk of Bias for randomized control trials and Newcastle-Ottawa Scale for cohort observational studies.

RESULTS

A total of 797 publications were identified from the initial database search. After removing duplicates and applying inclusion/exclusion criteria, four studies were included in the review and meta-analysis which identified a significant survival benefit in patients who received prehospital TXA versus no TXA. Three observational cohort and one randomized control trial were included into the review with a total of 2,347 patients (TXA, 1,169 vs. no TXA, 1,178). There was a significant reduction in 24 hours mortality; odds ratio (OR) of 0.60 (95% confidence interval [CI], 0.37-0.99). No statistical significant differences in 28 days to 30 days mortality; OR of 0.69 (95% CI, 0.47-1.02), or venous thromboembolism OR of 1.49 (95% CI, 0.90-2.46) were found.

CONCLUSION

This review demonstrates that prehospital TXA is associated with significant reductions in the early (24 hour) mortality of trauma patients with suspected or confirmed hemorrhage but no increase in the incidence of venous thromboembolism.

LEVEL OF EVIDENCE

Systematic review and meta-analysis. Level I.

Trauma-induced coagulopathy

Uncontrolled haemorrhage is a major preventable cause of death in patients with traumatic injury. Trauma-induced coagulopathy (TIC) describes abnormal coagulation processes that are attributable to trauma. In the early hours of TIC development, hypocoagulability is typically present, resulting in bleeding, whereas later TIC is characterized by a hypercoagulable state associated with venous thromboembolism and multiple organ failure. Several pathophysiological mechanisms underlie TIC; tissue injury and shock synergistically provoke endothelial, immune system, platelet and clotting activation, which are accentuated by the 'lethal triad' (coagulopathy, hypothermia and acidosis). Traumatic brain injury also has a distinct role in TIC. Haemostatic abnormalities include fibrinogen depletion, inadequate thrombin generation, impaired platelet function and dysregulated fibrinolysis. Laboratory diagnosis is based on coagulation abnormalities detected by conventional or viscoelastic haemostatic assays; however, it does not always match the clinical condition. Management priorities are stopping blood loss and reversing shock by restoring circulating blood volume, to prevent or reduce the risk of worsening TIC. Various blood products can be used in resuscitation; however, there is no international agreement on the optimal composition of transfusion components. Tranexamic acid is used in pre-hospital settings selectively in the USA and more widely in Europe and other locations. Survivors of TIC experience high rates of morbidity, which affects short-term and long-term quality of life and functional outcome.

Prehospital ABC Score Accurately Forecasts Patients Who Will Require Immediate Resource Utilization

OBJECTIVES

Scoring systems, such as the Assessment of Blood Consumption (ABC) Score, are used to identify patients at risk for massive transfusion (MT, ≥10 U red blood cells in 24 hours). Our aeromedical transport helicopter uses ultrasound to perform the Focused Assessment with Sonography for Trauma (FAST) examination. Our objective was to evaluate the ability of the Prehospital ABC (PhABC) Score to predict blood transfusions and the need for emergent laparotomy.

METHODS

Post hoc analysis of a prospective observational study of trauma patients who underwent an in-flight FAST during aeromedical transport during a 7-month period. PhABC Score was positive if ≥2 of the following were present in flight: penetrating trauma, heart rate >120 bpm, systolic blood pressure <90 mm Hg, or a positive abdominal FAST. The PhABC Score was evaluated by area under the receiver operating characteristic (AUROC) curves and logistic regression.

RESULTS

A total of 291 trauma patients met inclusion criteria, 23 underwent emergent laparotomy, and 12 received an MT. A positive PhABC Score predicted emergent laparotomy, with a positive predictive value of 48% and a negative predictive value of 95% (sensitivity 46%, specificity 96%, AUROC curve 0.83). A positive PhABC Score also predicted receipt of an MT with a positive predictive value of 28% and a negative predictive value of 94% (sensitivity 33%, specificity 93%, AUROC curve 0.77). Multiple logistic regression identified FAST as the most powerful contributor of the PhABC Score to the prediction of both emergent laparotomy (odds ratio 8.5, P < 0.001) and MT (odds ratio 5.9, P < 0.001).

CONCLUSIONS

The PhABC Score effectively predicts in-hospital resource utilization. It provides an outstanding undertriage rate from the prehospital setting, and it is helpful to improve trauma team activation, mobilize blood products, and prepare the operating room.

Appropriate Tourniquet Types in the Pediatric Population: A Systematic Review

Trauma is the leading cause of mortality in those aged 1-19, with hemorrhage accounting for up to 40% of all trauma deaths. Manufactured tourniquets are recommended for the control of life-threatening extremity hemorrhage in adults but their use in the pediatric population requires further investigation. We performed a systematic review to evaluate the most appropriate tourniquet design for use in the pediatric population. A literature search of Embase and the Cochran databases of trials and systematic reviews on October 1, 2020 identified 454 unique references, of which 15 were included for full-text screening. Two single-arm observational studies with a high risk of bias evaluated the use of windlass tourniquets in the pediatric population (73 patients, age 2-16 years). The certainty of the evidence was very low. In both studies, conducted on uninjured extremities, the use of a manufactured windlass tourniquet, specifically the Combat Application Tourniquet (C-A-T®) Generation 7, led to the cessation of Doppler detected pulses in 71/71 (100%) of upper extremities and 69/73 (94.5%) of lower extremities. Of the four failures, one participant withdrew due to pain and three tourniquet applications failed to occlude pulses after three turns of the windlass. No controls were used for comparison. In conclusion, two observational studies demonstrated that windlass tourniquets were able to abolish distal pulses in children as young as two years of age and with a minimum limb circumference of 13 cm. These preliminary findings may be helpful for organizations in the creation of guidelines for the management of life-threatening extremity bleeding in children.