Extremity Hemorrhage Research Articles

Laboratory Testing of Emergency Tourniquets Exposed to Prolonged Heat

Environmental exposure of tourniquets has been associated with component damage rates, but the specific type of environmental exposure, such as heat, is unknown. Emergency-tourniquet damage has been associated with malfunction and loss of hemorrhage control, which may risk loss of life during first aid. The purposes of the study are to determine the damage rate of tourniquets exposed to heat and to compare the rate to that of controls.Three tourniquet models (Combat Application Tourniquet(®); SOF(®) Tactical Tourniquet; Ratcheting Medical Tourniquet(®)) were tested using a manikin (HapMed Leg Tourniquet Trainer; www.chisystems.com) that simulates extremity hemorrhage. The study group of 15 tourniquets (five devices per model, three models) was exposed to heat (oven at 54.4° C [130° F] for 91 days), and 15 tourniquets similarly constituted the control group (unexposed to heat). Damage, hemorrhage control, distal pulse stoppage, time to effectiveness, pressure (mmHg), and blood loss volumes were measured.Three tourniquets in both groups had damage not associated with heat exposure (p = 1). Heat exposure was not associated with change in effectiveness rates (p = .32); this lack of association applied to both hemorrhage control and pulse stoppage. When adjusted for the effects of user and model, the comparisons of time to effectiveness and total blood loss were statistically significant (p < .0001), but the comparison of pressure was not (p = .0613).Heat exposure was not associated with tourniquet damage, inability to gain hemorrhage control, or inability to stop the distal pulse.

An Evidence-based Prehospital Guideline for External Hemorrhage Control: American College of Surgeons Committee on Trauma

This report describes the development of an evidence-based guideline for external hemorrhage control in the prehospital setting. This project included a systematic review of the literature regarding the use of tourniquets and hemostatic agents for management of life-threatening extremity and junctional hemorrhage. Using the GRADE methodology to define the key clinical questions, an expert panel then reviewed the results of the literature review, established the quality of the evidence and made recommendations for EMS care. A clinical care guideline is proposed for adoption by EMS systems. Key words: tourniquet; hemostatic agents; external hemorrhage

Evaluation of Contingency Telemedical Support to Improve Casualty Care at a Simulated Military Intermediate Resuscitation Facility: The EM-ANGEL Study

We sought to determine whether Contingency Telemedical Support (CTS) improves the success rate and efficiency of primary care providers performing critical actions during simulated combat trauma resuscitation. Critical actions included advanced airway, chest decompression, extremity hemorrhage control, hypothermia prevention, antibiotics and analgesics, and hypotensive resuscitation, among others.Recent studies report improved survival associated with skilled triage and treatment in the out-of-hospital/preoperative phase of combat casualty care. Historically, ground combat units are assigned primary care physicians and physician assistants as medical staff, due to resource limitations. Although they are recognized as optimal resuscitators, demand for military trauma surgeons and emergency physicians exceeds supply and is unlikely to improve in the near term.A prospective trial of telemedical mentoring during a casualty resuscitation encounter was studied using a high-fidelity patient simulator (HFPS). Subjects were randomized and formed into experimental (CTS) or control teams. CTS team leaders were equipped with a headset/microphone interface and telementored by a combat-experienced emergency physician or trauma surgeon. A standardized, scripted clinical scenario and HFPS were used with 14 critical actions. At completion, subjects were surveyed. Statistical approach included contingency table analysis, two-tailed t-test, and correlation coefficient. This study was reviewed and approved by our institutional review board (IRB).Eighteen CTS teams and 16 control teams were studied. By intention-to-treat ITT analysis, 89% of CTS teams versus 56% of controls completed all life-threatening inventions (LSIs) (p<.01); 78% versus 19% completed all critical actions (p<.01); and 89% versus 56% established advanced airways within 8 minutes (p<.06). Average time to completion in minutes (95% confidence interval [CI] 95) was 12 minutes (10?14) for CTS versus 18 (16?20) for controls, with 75% of control teams not completing all critical actions.In this model, real-time telementoring of simulated trauma resuscitation was feasible and improved accuracy and efficiency of non?emergency-trained resuscitators. Clinical validation and replicated study of these findings for guiding remote damage control resuscitation are warranted.

Prehospital Emergency Care: Evaluation of the Junctional Emergency Tourniquet Tool With a Perfused Cadaver Model

Junctional bleeding from the groin is a leading cause of potentially preventable death on the battlefield. To address this problem, a novel device called the Junctional Emergency Treatment Tool (JETT™) was developed. The JETT was designed to stabilize pelvic ring fractures while controlling lower extremity bleeding sustained during high-energy traumatic events on the battlefield and in the civilian environment. Our purpose was to assess the effectiveness of the JETT in the control of simulated life threatening hemorrhage from proximal injuries in the groin of a perfused cadaver.The JETT was compared with the standard issue combat tourniquet and a Food and Drug Administration (FDA)-cleared junctional hemorrhage control clamp (CRoC™) in a perfused human cadaver model. The JETT?s ability to stop pulsatile flow at the common femoral artery was assessed through proximal aorta and distal measurements of arterial flow rates and pressures.In three cadavers, when the JETT or the CRoC was applied in the groin, there was an immediate cessation of fluid flow from the common femoral artery while the inlet flow aortic pulsatile pressure was maintained. However, the time to bilateral application of the JETT was faster (10 seconds vs. 68 seconds) than bilateral sequential application of two CRoC devices.The JETT is a single device capable of effectively and quickly controlling bilateral lower extremity junctional hemorrhage at normal physiological blood pressures.

Abstract 203: Measurement of Cardiac Function in a Porcine Model of Cardiac Arrest Due to Massive Exsanguination

Background: While extremity hemorrhage can be stymied with a well placed tourniquet, vascular injury within the thorax and abdomen is not amenable to direct compression. Uncontrolled, noncompressible torso hemorrhage (NCTH) and the resultant cardiac arrest (CA) may account for up to 80% of preventable deaths in combat. We developed a porcine model of CA to test novel surgical interventions and are reporting measures of cardiovascular function during a simulated NCTH. Methods: Ten anesthetized Yorkshire pigs underwent tracheostomy, arterial and central line placement. Animals were awakened and sedated with midazolam titrated to a bispectral index of 75 ± 5. Spontaneously breathing, the animals were subjected to a computerized hemorrhage of 80% total blood volume (TBVH) over 20 minutes or until death, defined as mean arterial pressure (MAP)=0 mmHg and etCO2&lt;10. During hemorrhage, if minute ventilation decreased 25% from baseline (BL) for &gt;20 seconds, volume control ventilation was initiated. The Millar MPVS Ultra system continuously collected left ventricular (LV) and descending aortic pressures, as well as LV volume data via indwelling catheters. A repeated measures one-way ANOVA with Tukey’s procedure was performed on data collected at BL, 25%, 44%, 62% TBV hemorrhage, and CA, defined as a MAP&lt;20 mmHg. Data are presented as means±SEM. Results: Weight was 63.8±2.8kg. TBVH at CA was 2941±130ml (71.0±1.5%). Time to CA was 18:22±00:40min. In Table 1, * denotes a significant change (p&lt;0.05) in a variable from previous hemorrhage phase as marked by #. Conclusions: We developed a porcine model of CA secondary to exsanguination. We found that despite decreasing left ventricular volumes and pressures, cardiac contractility and conduction system function were maintained throughout hemorrhage. This suggests that lifesaving interventions (such as endovascular aortic balloon occlusion and extracorporeal life support) may be possible despite profound hypovolemia.

Identifying future ‘unexpected’ survivors: a retrospective cohort study of fatal injury patterns in victims of improvised explosive devices

ObjectivesTo identify potentially fatal injury patterns in explosive blast fatalities in order to focus research and mitigation strategies, to further improve survival rates from blast trauma.DesignRetrospective cohort study.ParticipantsUK military personnel...

Novel keratin (KeraStat™) and polyurethane (Nanosan®-Sorb) biomaterials are hemostatic in a porcine lethal extremity hemorrhage model

Traumatic injury is the leading cause of death in people aged 44 or less in the US. It is also estimated that 82% of deaths from battlefield hemorrhage may be survivable with better treatment options. In this study, two biomaterial hemostats having disparate mechanisms were evaluated in a large animal lethal hemorrhage model and compared to a commercial product and standard cotton gauze. We hypothesized that the biomaterial with a biologically active mechanism, as opposed to a mechanical mechanism, would be the most effective in this model. Using a published study protocol, the femoral artery in swine was punctured and treated. KeraStat™ (KeraNetics) and Nanosan®-Sorb (SNS Nano) hemostats were compared to a commercial chitosan dressing (second generation Hemcon®) and cotton gauze. Both KeraStat and Nanosan increased survival, significantly increased mean arterial pressure (MAP), and significantly decreased shock index compared to both controls. The Hemcon dressing was no different than gauze. Platelet adhesion assays suggested that the KeraStat mechanism of action involves β1 integrin mediated platelet adhesion while Nanosan-Sorb operates similar to one reported mechanism for Hemcon, absorbing fluid and concentrating clotting components. The Nanosan also swelled considerably and created pressure within the wound site even after direct pressure was removed.

Zones of hemorrhage

Abstract : Background Junctional extremity and noncompressible hemorrhage are difficult challenges facing the prehospital provider on the battlefield. The subset of casualties with pelvic or truncal vascular injury represents a challenge in hemorrhage control. Methods The Armed Forces Medical Examiner (AFME) System was queried for nonsurvivors with significant vascular injuries and an associated pelvic fracture. A panel of military experts in prehospital care, vascular surgery, and orthopaedic surgery reviewed all records. Zones of hemorrhage were categorized as Zone I, area of injury allowing tourniquet use; Zone II, area of injury compressible but not allowing tourniquet use; or Zone III, noncompressible. Currently available and emerging technologies for hemorrhage control were reviewed and potential applicability of each modality determined. Results An AFME database search yielded 49 nonsurvivors with pelvic fractures and associated vascular injuries. Zone I hemorrhage injuries were present in 21% of patients, Zone II in 19%, and Zone III in 60%, accounting for 115 total injuries. Thirty percent (n=15) of patients had uncontrollable hemorrhage, 39% (n=19) had hemorrhage potentially controllable by the battlefield prehospital provider, and 30% (n=15) were deemed compressible with emerging technologies not available on the battlefield. Sixty-one percent (n=30) had vascular injuries that were noncompressible using battlefield-available methods. Conclusions The majority of battlefield vascular injuries in nonsurvivors were not controllable using technology available to the prehospital responder. Classifying battlefield hemorrhage into zones of hemorrhage may allow us to focus future research and intervention development.

Deviations from evidence-based clinical management guidelines increase mortality in critically injured trauma patients*

The effect of treatment guidelines on clinical outcomes in general and specifically for trauma patients has not been well-studied. We hypothesized that better compliance with guidelines would be associated with improved clinical outcomes. Prospective, randomized, double-blinded, multicentered, placebo-controlled study of recombinant factor VII in severe trauma that utilized guidelines for damage control, transfusions, and mechanical ventilation. Vanderbilt Coordinating Center reviewed compliance in near real-time and reported deviations classified as minor, moderate, or major to investigators. Multivariate regression analysis measured the association between outcomes (30-day and 90-day mortality, development of multiple organ failure, ventilator-free days, renal failure-free days, and blood products transfused) and compliance with each guideline, as well as a composite assessment of overall compliance. One hundred hospitals in 26 countries. Blunt and/or penetrating trauma patients aged 18-70 yrs who had received 4-8 units of red blood cells for active torso and/or proximal lower extremity bleeding despite standard interventions. When assessed as composite end point, major deviations from guidelines were associated with significantly higher mortality at 30 and 90 days after injury and fewer renal failure-free days. Moderate deviations were associated with a significantly higher risk of multiple organ failure and fewer ventilator-free days. Moderate and major deviations from damage control and ventilation guidelines were also significantly associated with higher risk of death at days 30 and 90. Within the ventilation protocol, noncompliance with tidal volume and plateau pressure targets was associated with significantly higher mortality at days 30 and 90 and fewer ventilator-free days, whereas noncompliance with weaning guideline was only associated with significantly fewer ventilator-free days. : In a clinical trial of trauma patients, higher compliance with guidelines for damage control, transfusion, and ventilation management is associated with lower mortality and improved outcomes.

Incidence of Tension Pneumothorax in Police Officers Feloniously Killed in the Line of Duty: A Ten-Year Retrospective Analysis

According to US military data, tension pneumothorax (TPx) is the second leading cause of possibly preventable combat death after isolated extremity hemorrhage. The purpose of this study was to determine whether TPx similarly represents a significant cause of possibly preventable death in police officers. FBI data for the years 1998 through 2007 were reviewed. Cases were included if officers were on-duty at the time of fatal injury, and died within one hour from time of wounding from penetrating torso trauma. After case identification, letters were sent to the departments of victim officers requesting autopsy reports. One hundred and eight victim officers met inclusion criteria. Four charts were excluded due to inability to re-identify officers. Departmental response rate was 83.7%. Autopsy reports were provided for 60 officers (57.7%). All officers died from gunshot wounds. No coroner specifically identified TPx as either a direct cause of death or a contributing factor (95% CI, 0.00%-5.96%). In contrast to the military experience, TPx appears to be a rare cause of possibly preventable death in police officers. Further study of non-fatal "near miss" events will be required to determine the actual need for law enforcement-specific medical training in the recognition and management of TPx.

Tourniquets, Pressure Points, and Extremity Hemorrhage

General Albert Sydney Johnston, shot from behind unintentionally by one of his own men armed with an Enfi eld rifl e, exsanguinated and died within 30 minutes from a wound to his right popliteal artery. In the general’s uniform pocket was a fi eld tourniquet. Its use could have changed world history. The battle of Shiloh, in 1862, was a Northern victory because of Johnston’s untimely loss in the afternoon of the fi rst day of the 2-day battle. 1 Fifty years later the Boy Scouts of America, still in its infancy, described the cloth and windlass tourniquet, its indication and its application with succinct clarity 2 that fl ies in the face of apparent current confusion over control of extremity hemorrhage.

A brief history of the tourniquet

Abstract : The tourniquet is a device first used in antiquity; it has been praised or vilified throughout the ages, as it has been at times life-saving, and at other times limb-threatening.1 It interestingly has become a widely used tool in the current wars of Afghanistan and Iraq by most coalition medics, often with great success. Its current reputation is very positive among foot soldiers. Combat troops are reportedly going out on dangerous patrol missions with tourniquets already in place on extremities, as they wish to be fully ready to respond to extremity bleeding, if and when the mine or the improvised explosive device (IED) should go off. Some work has even been done on field uniforms, which have tourniquets actually sewn into sleeves, etc., in order to ensure the quickest access and application possible.2 Response times in this current conflict are so rapid and transportation by helicopter is so efficient that prolonged tourniquet times are rare. The data being collected would indicate that we are seeing few tourniquet-induced injuries because they are removed rapidly, and we are definitely saving lives because they are used liberally. The purpose of this report is to review the history of the tourniquet throughout the ages, as it has been modified and improved numerous times by a series of innovative physicians, up to the present day.

Amputation of a lower extremity after severe trauma

Serious lower extremity injuries sometimes warrant emergency amputation. The goal of amputation in polytrauma patients is to increase chances of survival, while the goal of amputation in a single limb injury is to prevent further complications, e.g., infection, septic shock. Rescue from life-threatening lower extremity bleeding in a critically injured patient. Severe injury of a lower extremity: crushed, burned, frozen, advanced infection. Patient refusal. Supine position, determination of resection border, skin incision, identification of nerves and blood vessels, osteotomy, vessel ligation, separation of blood vessels and nerves, final removal of tissue with amputation knife, disposal of amputated extremity, skin closure. Wound care, careful compression wraps beginning on postoperative day7, early prosthesis fitting, mental health care consultation. From January 2008 until October 2010, 115lower extremities were amputated at the BG Trauma Clinic in Ludwigshafen, Germany. A total of 42amputations were posttraumatic and were performed in the clinic for trauma surgery and orthopedics. There were a total of 18foot and toe amputations, 16lower leg amputations, 5knee amputations, and 3above knee amputations. Comparison of the groups is difficult due to the varying mechanisms of injury and locations of amputation. Therapeutic decisions regarding emergency amputation are made with careful consideration of the patient.

Survival after extreme left atrial hypertension and pulmonary hemorrhage in an infant supported with extracorporeal membrane oxygenation for refractory atrial flutter

We report here the survival of an infant who developed extreme left atrial hypertension and severe pulmonary hemorrhage while supported with extracorporeal membrane oxygenation for refractory atrial flutter. The patient recovered after decompression of the left heart and catheter ablation of the atrioventricular node. Lucile Packard Children's Hospital (Stanford, CA). Chart review. Recovery of lung function is possible despite systemic-level left atrial pressure resulting in pulmonary hemorrhage and complete solidification of lung parenchyma on gross inspection. Resolution of pulmonary hemorrhage despite anticoagulation while on extracorporeal membrane oxygenation can occur after relief of left atrial hypertension.

Comparison of Celox-A, ChitoFlex, WoundStat, and Combat Gauze Hemostatic Agents Versus Standard Gauze Dressing in Control of Hemorrhage in a Swine Model of Penetrating Trauma

Uncontrolled hemorrhage remains one of the leading causes of trauma deaths and one of the most challenging problems facing emergency medical professionals. Several hemostatic agents have emerged as effective adjuncts in controlling extremity hemorrhage. However, a review of the current literature indicates that none of these agents have proven superior under all conditions and in all wound types. This study compared several hemostatic agents in a lethal penetrating groin wound model where the bleeding site could not be visualized. A complex groin injury with a small penetrating wound, followed by transection of the femoral vessels and 45 seconds of uncontrolled hemorrhage, was created in 80 swine. The animals were then randomized to five treatment groups (16 animals each). Group 1 was Celox-A (CA), group 2 was combat gauze (CG), group 3 was Chitoflex (CF), group 4 was WoundStat (WS), and group 5 was standard gauze (SG) dressing. Each agent was applied with 5 minutes of manual pressure. Hetastarch (500 mL) was infused over 30 minutes. Hemodynamic parameters were recorded over 180 minutes. Primary endpoints were attainment of initial hemostasis and incidence of rebleeding. Overall, no difference was found among the agents with respect to initial hemostasis, rebleeding, and survival. Localizing effects among the granular agents, with and without delivery mechanisms, revealed that WS performed more poorly in initial hemostasis and survival when compared to CA. In this swine model of uncontrolled penetrating hemorrhage, SG dressing performed similarly to the hemostatic agents tested. This supports the concept that proper wound packing and pressure may be more important than the use of a hemostatic agent in small penetrating wounds with severe vascular trauma.

Hemostatic Dressings Reduce Tourniquet Time While Maintaining Hemorrhage Control

Tourniquet application has become first-line treatment for extremity hemorrhage on the battlefield and has seen increased use in the civilian arena. We hypothesized that an effective windlass tourniquet could be removed after application of a hemostatic dressing in a swine model of peripheral vascular injury. A tourniquet was placed proximally in 50 forelimb-injured swine after 30 seconds of hemorrhage with cessation of hemorrhage in all cases. Hemcon, ActCel, Quikclot, Celox, or standard gauze was then placed over the wound with direct pressure for three minutes. The tourniquet was then removed. Success was determined if no bleeding was identified. Standard gauze resulted in a 100 per cent failure rate with active bleeding present after each application. Celox was successful in maintaining hemostasis in 6 of 10 (60%) subjects. Quikclot succeeded in 80 per cent of subjects. ActCel maintained hemostasis in nine (90%) subjects, whereas HemCon was successful in all instances (100%). All four hemostatic dressings were superior to gauze in maintaining hemostasis after removal of an effective tourniquet. Use of hemostatic dressings in conjunction with a tourniquet may reduce tourniquet times and improve outcomes in peripheral vascular injury and warrants further study.

Part 13: First Aid

Part 13: First Aid

Comparison of Four Hemostatic Agents versus Standard Gauze Dressing in Control of Extremity Hemorrhage in a Model of Penetrating Combat Trauma

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Tactical Medical Skill Requirements for Law Enforcement Officers: A 10-Year Analysis of Line-of-Duty Deaths

In the absence of other data, military Tactical Combat Casualty Care (TCCC) precepts are increasingly being adapted to law enforcement needs. The purpose of this study is to better describe the nature of potentially preventable law enforcement Line-of-Duty Deaths (LODDs) occurring as a result of felonious assaults. A retrospective analysis was performed of open source data available through the US Federal Bureau of Investigation Uniform Crime Reporting (UCR) Law Enforcement Officers Killed and Assaulted (LEOKA) program for the years 1998-2007 inclusive. After applying exclusion criteria, 341 victim officers were included in the study. The most common cause of death was head trauma (n=198), followed by chest trauma (n=90). There were 123 victim officers that suffered potentially preventable deaths; the majority of these injuries involved the chest. Over the 10-year study period, only two officers (0.6%) died from isolated extremity hemorrhage. The current emphasis of TCCC on control of exsanguinating extremity hemorrhage may not meet the needs of law enforcement personnel in an environment with expedited access to well-developed trauma systems. Further study is needed to better examine the causes of preventable deaths in law enforcement officers, as well as the most appropriate law enforcement tactical medical skill set and treatment priorities.

Extreme lymphoproliferative disease and fatal autoimmune thrombocytopenia in FasL and TRAIL double-deficient mice

AbstractTo delineate the relative roles of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas ligand in lymphocyte biology and lymphoproliferative disease, we generated mice defective in both molecules. B6.GT mice develop severe polyclonal lymphoproliferative disease because of accumulating CD3+CD4−CD8−B220+ T cells, CD4+ and CD8+ T cells, and follicular B cells, and mice die prematurely from extreme lymphocytosis, thrombocytopenia, and hemorrhage. Accumulating lymphocytes resembled antigen-experienced lymphocytes, consistent with the maximal resistance of B6.GT CD4+ and CD8+ T cell to activation-induced cell death. More specifically, we show that TRAIL contributes to Fas ligand-mediated activation-induced cell death and controls lymphocyte apoptosis in the presence of interferon-γ once antigen stimulation is removed. Furthermore, dysregulated lymphocyte homeostasis results in the production of anti-DNA and rheumatoid factor autoantibodies, as well as antiplatelet IgM and IgG causing thrombocytopenia. Thus, B6.GT mice reveal new roles for TRAIL in lymphocyte homeostasis and autoimmune lymphoproliferative syndromes and are a model of spontaneous idiopathic thrombocytopenia purpura secondary to lymphoproliferative disease.