Bleeding Control Using Hemostatic Dressings: Lessons Learned

External Bleeding and Advanced Biomacromolecules for Hemostasis

Hemorrhage is a significant medical problem that has been an active area of research over the past few decades. The human body has a complex response to bleeding that leads to blood clot formation and hemostasis. Many biomaterials based on various biomacromolecules have been developed to either accelerate or improve the body's natural response to bleeding. This review examines the mechanisms of hemostasis, types of bleeding, and the in vitro or in vivo models and techniques used to study bleeding and hemostatic materials. It provides a detailed overview of the diverse hemostatic materials, including those that are highly absorbent, wet adhesives, and those that accelerate the biochemical cascade of blood clotting. These materials are currently marketed, under preclinical testing, or being researched. In exploring the latest advancements in hemostatic technologies, this paper highlights the potential of these materials to significantly improve bleeding control in clinical and emergency situations.

Local and Systemic Hemostatic Agents: A Comprehensive Review

Traumatic hemorrhage is the leading preventable cause of death worldwide. Systemic administration of hemostatic agents requires trained personnel and preparation, limiting their use in combat environments and prehospital settings. However, local administration of hemostatic agents may ameliorate these challenges. Currently available hemostatic products are limited by risk of infection, immunogenicity, tissue damage, limited usage and efficacy, high costs, short shelf life, and storage requirements under specific conditions. Future studies should be considered to overcome these limitations and develop effective, multifunctional hemostatic materials for widespread usage. In this review, we will provide an overview of the most commonly used systemic and local hemostatic agents in hemorrhage control.

Application of adhesives in the treatment of cartilage repair

From degeneration causing intervertebral disc issues to trauma‐induced meniscus tears, diverse factors can injure the different types of cartilage. This review highlights adhesives as a promising and rapidly implemented repair strategy. Compared to traditional techniques such as sutures and wires, adhesives offer several advantages. Importantly, they seamlessly connect with the injured tissue, deliver bioactive substances directly to the repair site, and potentially alleviate secondary problems like inflammation or degeneration. This review delves into the cutting‐edge advancements in adhesive technology, specifically focusing on their effectiveness in cartilage injury treatment and their underlying mechanisms. We begin by exploring the material characteristics of adhesives used in cartilage tissue, focusing on essential aspects like adhesion, biocompatibility, and degradability. Subsequently, we investigate the various types of adhesives currently employed in this context. Our discussion then moves to the unique role adhesives play in addressing different cartilage injuries. Finally, we acknowledge the challenges currently faced by this promising technology.

Photocurable extracellular matrix sealant for cessation of venous hemorrhage

Hemorrhage is the second leading cause of death in patients under 46 years of age in the United States. Cessation of hemorrhage prevents hemorrhagic shock and tissue hypoxia. Controlling the bleed via direct pressure or tourniquet is often the first line of defense, but long-term care requires staples, hemostatic agents, or sealants that seal the vessel and restore blood flow. Here, we compare a new photocurable extracellular matrix sealant (pcECM) with low, medium, and high crosslink density formulations to a commercially available fibrin-based sealant, TISSEEL®. pcECM has potential uses in surgical and remote settings due to room temperature storage conditions and fast preparation time. Here, we determine if pcECM sealant can stop venous hemorrhage in a murine model, adhere to the wound site in vivo throughout the wound-healing process, and has the mechanical properties necessary for stopping hemorrhage. Adjusting pcECM crosslinking density significantly affected viscosity, swelling, burst strength, tensile strength, and elasticity of the sealant. 3-Dimensional ultrasound volume segmentations showed pcECM degrades to 17 ± 8% of its initial implant volume by day 28. Initially, local hemodynamic changes were observed, but returned close to baseline levels by day 28. Acute inflammation was observed near the puncture site in pcECM implanted mice, and we observed inflammatory markers at the 14-day explant for both sealants. pcECM and fibrin sealant successfully sealed the vessel in all cases, and consistently degraded over 14-28 days. pcECM is a durable sealant with tunable mechanical properties and possible uses in hemorrhage control and other surgical procedures.

Progress of polysaccharide-based tissue adhesives

Recently, polymer-based tissue adhesives (TAs) have gained the attention of scientists and industries as alternatives to sutures for sealing and closing wounds or incisions because of their ease of use, low cost, minimal tissue damage, and short application time. However, poor mechanical properties and weak adhesion strength limit the application of TAs, although numerous studies have attempted to develop new TAs with enhanced performance. Therefore, next-generation TAs with improved multifunctional properties are required. In this review, we address the requirements of polymeric TAs, adhesive characteristics, adhesion strength assessment methods, adhesion mechanisms, applications, advantages and disadvantages, and commercial products of polysaccharide (PS)-based TAs, including chitosan (CS), alginate (AL), dextran (DE), and hyaluronic acid (HA). Additionally, future perspectives are discussed.

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.

External Hemorrhage Control Techniques for Human Space Exploration: Lessons from the Battlefield

The past few decades of military experience have brought major advances in the prehospital care of patients with trauma. A focus on early hemorrhage control with aggressive use of tourniquets and hemostatic gauze is now generally accepted. This narrative literature review aims to discuss external hemorrhage control and the applicability of military concepts in space exploration. In space, environmental hazards, spacesuit removal, and limited crew training could cause significant time delays in providing initial trauma care. Cardiovascular and hematological adaptations to the microgravity environment are likely to reduce the ability to compensate, and resources for advanced resuscitation are limited. Any unscheduled emergency evacuation requires a patient to don a spacesuit, involves exposure to high G-forces upon re-entry into Earth's atmosphere, and costs a significant amount of time until a definitive care facility is reached. As a result, early hemorrhage control in space is critical. Safe implementation of hemostatic dressings and tourniquets seems feasible, but adequate training will be essential, and tourniquets are preferably converted to other methods of hemostasis in case of a prolonged medical evacuation. Other emerging approaches such as early tranexamic acid administration and more advanced techniques have shown promising results as well. For future exploration missions to the Moon and Mars, when evacuation is not possible, we look into what training or assistance tools would be helpful in managing the bleed at the point of injury.

A Comparison of Hemostatic Activities of Zeolite-Based Formulary Finishes on Cotton Dressings

The need for affordable effective prehospital hemostatic dressings to control hemorrhage has led to an increased interest in new dressing design approaches. Here we consider the separate components of fabric, fiber, and procoagulant nonexothermic zeolite-based formulations on design approaches to accelerated hemostasis. The design of the fabric formulations was based on incorporation of zeolite Y as the principal procoagulant, with calcium and pectin to adhere and enhance the activity. Unbleached nonwoven cotton when combined with bleached cotton displays enhanced properties related to hemostasis. Here, we compare sodium zeolite with ammonium zeolite formulated on fabrics utilizing pectin with pad versus spray-dry-cure and varied fiber compositions. Notably, ammonium as a counterion resulted in shorter times to fibrin and clot formation comparable to the procoagulant standard. The time to fibrin formation as measured by thromboelastography was found to be within a range consistent with modulating severe hemorrhage control. The results indicate a correlation between fabric add-on and accelerated clotting as measured by both time to fibrin and clot formation. A comparison between the time to fibrin formation in calcium/pectin formulations and pectin alone revealed an enhanced clotting effect with calcium decreasing by one minute the time to fibrin formation. Infra-red spectra were employed to characterize and quantify the zeolite formulations on the dressings.

Chitosan-based hemostatic sponges as new generation hemostatic materials for uncontrolled bleeding emergency: Modification, composition, and applications

The choice of hemostatic technique is a curial concern for surgery and as first-aid treatment in combat. To treat uncontrolled bleeding in complex wound environments, chitosan-based hemostatic sponges have attracted significant attention in recent years because of the excellent biocompatibility, degradability, hemostasis and antibacterial properties of chitosan and their unique sponge-like morphology for high fluid absorption rate and priority aggregation of blood cells/platelets to achieve rapid hemostasis. In this review, we provide a historical perspective on the use of chitosan hemostatic sponges as the new generation of hemostatic materials for uncontrolled bleeding emergencies in complex wounds. We summarize the modification of chitosan, review the current status of preparation protocols of chitosan sponges based on various composite systems, and highlight the recent achievements on the detailed breakdown of the existing chitosan sponges to present the relationship between their composition, physical properties, and hemostatic capacity. Finally, the future opportunities and challenges of chitosan hemostatic sponges are also proposed.

Emergency first responder management of combat injuries to the torso in the military, remote and austere settings

Traumatic injuries to the torso account for almost a quarter of all injuries seen in combat and are typically secondary to blast or gunshot wounds. Injuries due to road traffic collisions or violence are also relatively common during humanitarian and disaster relief efforts. There may also be multiple injured patients in these settings, and surgical care may be limited by a lack of facilities and resources in such a non-permissive environment. The first responder in these scenarios should be prepared to manage patients with severe injuries to the torso. We aim to describe the management of these injuries in the military and austere environment, within the scope of practice of a level 5 registered prehospital practitioner.

Diatomite hemostatic particles with hierarchical porous structure for rapid and effective hemostasis

The development of fast, safe and effective hemostatic materials is crucial for pre-hospital first aid. In this study, diatomite hemostatic granules (Dhp) were developed by rotating granulation method using silica sol as binder. During rotating granulation process, the Pre-Dhp were prepared by rolling snowball effect, in which nano-silica in silica sol uniformly distributed on the surface of diatomite and polymerized through hydrogen bond to produce strong adhesion. After high-temperature calcination, the hydrogen bond transformed to silica oxygen bond and the three-dimensional gel network formed by silica sol was destroyed to exposed the pores of diatomite. Dhp retained the porous structure of diatomite with hierarchical porous structure (from nano to micro scale). Dhp could quickly adsorb the tangible components in the blood, exhibited rapid hemostatic ability (clotting time was shortened by 43 % than that of control group), and good biocompatibility (hemolysis rate < 7 %, no cytotoxicity). Dhp residue was not found in the wound of rat tail amputation model, indicating that the adhesion of silica sol and high-temperature curing treatment enhanced the stability of Dhp and reduced the hidden danger of micro thrombosis caused by residual substances entering blood vessels. Our study proved that Dhp prepared by silica sol bonding and rotary granulation was excellent hemostatic material with non-toxic side effects and rapid coagulation promotion.

Recent progress in nanocomposites of carbon dioxide fixation derived reproducible biomedical polymers

In recent years, the environmental problems accompanying the extensive application of biomedical polymer materials produced from fossil fuels have attracted more and more attentions. As many biomedical polymer products are disposable, their life cycle is relatively short. Most of the used or overdue biomedical polymer products need to be burned after destruction, which increases the emission of carbon dioxide (CO₂). Developing biomedical products based on CO₂ fixation derived polymers with reproducible sources, and gradually replacing their unsustainable fossil-based counterparts, will promote the recycling of CO₂ in this field and do good to control the greenhouse effect. Unfortunately, most of the existing polymer materials from renewable raw materials have some property shortages, which make them unable to meet the gradually improved quality and property requirements of biomedical products. In order to overcome these shortages, much time and effort has been dedicated to applying nanotechnology in this field. The present paper reviews recent advances in nanocomposites of CO₂ fixation derived reproducible polymers for biomedical applications, and several promising strategies for further research directions in this field are highlighted.

Management of Complex Upper Extremity Trauma with Associated Vascular Injury

Introduction Combined soft tissue and vascular injuries of the upper extremity pose several challenges at once to the plastic surgeon. Many decisions have to be taken urgently that will influence the salvage or amputation of the affected extremity. The aim of this article was to provide an evidence-based outline for the management of such injuries. Learning objectives of this article are as follows: (1) approach to a patient with upper extremity composite tissue and vascular injury presenting to the emergency, (2) decision-making as to when to salvage and when to go for amputation of the traumatized upper extremity, (3) role of imaging in emergency situation, (4) role of fasciotomy, (5) intraoperative sequencing of steps, and (6) options for vascular reconstruction and the flaps used for coverage. After reading this article, the reader should have a clear understanding of the management of vascular injury in a patient with composite defects of upper extremity.

Snake Venom Hydrogels as a Rapid Hemostatic Agent for Uncontrolled Bleeding

Uncontrolled bleeding from traumatic injury remains the leading cause of preventable death with loss of balance between blood clotting (coagulation) and blood clot breakdown (fibrinolysis). A major limitation of existing hemostatic agents is that they require a functioning clotting system to control the bleeding and are largely based on gauze delivery scaffolds. Herein, a novel rapid wound sealant, composed of two recombinant snake venom proteins, the procoagulant ecarin, to rapidly initiate blood clotting and the antifibrinolytic textilinin, to prevent blood clot breakdown within a synthetic thermoresponsive hydrogel scaffold is developed. In vitro, it is demonstrated that clotting is rapidly initiated with only nanomolar concentrations of venom protein and clot breakdown is effectively inhibited by textilinin. A stable clot is formed within 60 s compared to normal clot formation in 8 min. In vivo studies reveal that the snake venom hydrogel rapidly controls warfarin-induced bleeding, reducing the bleed volume from 48% to 12% and has demonstrated immune compatibility. A new class of hemostatic agents that achieve formation of rapid and stable blood clots even in the presence of blood thinners is demonstrated here.

Preparation and characterization of bifunctional edible gellan-polylysine fiber

A gellan-polylysine (GPL) fiber was prepared by wet spinning molding with gellan solution containing glucose, soybean peptide, fish collagen peptide as spinning liquid, and ε-poly-l-lysine as fixative liquid. Results showed that the material addition order affects the spinning and an acceptable material addition order was as follows: soybean peptides →glucose → fish collagen peptides. The mechanical strength of the GPL fiber decreased with the collagen peptide titer and the fiber strength can reach 0.99 cN/dtex. In addition, the GPL fiber showed comparable water absorption capacity. The GPL fiber demonstrated good antibacterial properties against Escherichia coli and Staphylococcus aureus. The GPL fiber also had no cytotoxicity on mouse embryo fibroblast L-929 cells and could effectively promote wound healing for rats. As a result, the bifunctional edible GPL fiber is potentially used as a military and rescue emergency equipment.

Automatic Hemorrhage Detection From Color Doppler Ultrasound Using a Generative Adversarial Network (GAN)-Based Anomaly Detection Method

Hemorrhage control has been identified as a priority focus area both for civilian and military populations in the United States because exsanguination is the most common cause of preventable death in hemorrhagic injury. Non-compressible torso hemorrhage (NCTH) has high mortality rate and there are currently no broadly available therapies for NCTH outside of a surgical room environment. Novel therapies, which include High Intensity Focused Ultrasound (HIFU) have emerged as promising methods for hemorrhage control as they can non-invasively cauterize bleeding tissue deep within the body without injuring uninvolved regions. A major challenge in the application of HIFU with color Doppler US guidance is the interpretation and optimization of the blood flow images in real-time to identify the hemorrhagic focus. Today, this task requires an expert sonographer, limiting the utility of this therapy in non-clinical environments. In this work, we investigated the feasibility of an automated hemorrhage detection method using a Generative Adversarial Network (GAN) for anomaly detection that learns a manifold of normal blood flow variability and subsequently identifies anomalous flow patterns that fall outside the learned manifold. As an initial feasibility study, we collected ultrasound color Doppler images of femoral arteries in an animal model of vascular injury (N = 11 pigs). Velocity information of the blood flow were extracted from the color Doppler images that were used for training and testing the anomaly detection network. Normotensive images from 8 pigs were used for training, and testing was performed on normotensive, immediately after injury, 10 minutes post-injury and 30 minutes post-injury images from 3 other pigs. The residual images or the reconstructed error maps show promise in detecting hemorrhages with an AUC of 0.90, 0.87, 0.62 immediately, 10 minutes post-injury and 30 minutes post-injury respectively with an overall AUC of 0.83.

[Management of patients with haemorrhage malignant wounds]

Patients with tumor wounds have many symptoms that impair their quality of life and their general condition. Hemorrhaging is one of them. It can be a challenge for the caregivers and the medical team and will have an impact on the patient. There is no consensus on the management of this symptom, but the literature provides some food for thought. Simple measures can be easily implemented depending on the patient's risk factors, the wound and the oncological context.

Emerging approaches to pre-hospital hemorrhage control: a narrative review

In the United States, trauma claims the lives of over 150,000 civilians each year. In military settings, trauma and exsanguination result in 50% of combat related deaths. The majority of these deaths result from uncontrolled non-compressible hemorrhage. Non-compressible hemorrhage often results from deep vascular injuries within the torso, however can also occur secondary to penetrating injuries that involve the extremities. Given the high mortality rates for non-compressible hemorrhage, rapid and effective management of patients suffering from hemorrhage is essential to good patient outcomes. Consequently, there has been increasing interest in solutions for point-of-injury hemorrhage control in trauma and military medicine. Undoubtedly there is a great need for prehospital hemostatic interventions that can be deployed by trained and untrained personnel. Since 2001, various hemostatic agents have been developed, each with its advantages based upon the type and severity of injury, wound size, wound location, accessibility to injury site, and the coagulation status of the patient. These agents are often used in the military setting as a temporizing measure prior to definitive therapy and include techniques such as resuscitative endovascular balloon occlusion of the aorta (REBOA) and bioengineered agents including ResQFoam, RevMedx’s XSTAT, Tranexamic acid (TXA), and QuikClot Combat Gauze (QCG). Here, we review the indications, composition, technique, efficacy, and outcomes of these hemostatic agents.

A composite sponge based on alkylated chitosan and diatom-biosilica for rapid hemostasis

Rapid control of bleeding is of great significance in military trauma and traffic accidents. In this study, alkylated chitosan (AC) and diatom biosilica (DB) were combined to develop a safe and effective hemostatic composite sponge (AC-DB sponge) for hemorrhage control. Due to the procoagulant chemical structure of AC-DB sponge, it exhibited rapid hemostatic ability in vitro (clotting time was shortened by 78% than that of control group), with favorable biocompatibility (hemolysis ratio < 5%, no cytotoxicity). The strong interface effect between AC-DB sponge and blood induced the erythrocyte and platelets activation, deformation and aggregation, intrinsic coagulation pathway activation, resulting in significant coagulation acceleration. AC-DB sponge had excellent performance in in vivo assessments with shortest clotting time (106.2 s) and minimal blood loss (328.5 mg). All above results proved that AC-DB sponge had great potential to be a safe and rapid hemostatic material.

Optimal approach for management of postpartum vulva hematoma: Report of three cases

OBJECTIVE

Vulvar hematomas though common in obstetrical practice can rapidly evolve into a life-threatening condition if not managed appropriately. Depending on clinical status and medical facility, conservative management, surgical debridement, or vessel-occlusion strategy can be considered.

CASE REPORT

Case 1 was a 28 year-old pregnant woman. Increasing hematoma over 12 cm in size was noted on postpartum Day 2. Debridement and arterial embolization were done. Case 2 was a referred woman at age of 30 who delivered at a local obstetric clinic. Debridement was performed successfully. Case 3 was a 23 year-old woman with postpartum bilateral hematoma. Drop in hemoglobin level prompted the medical team to transfer and airlift the patient for arterial embolization and subsequent vulva debridement.

CONCLUSION

Optimal management of hematoma is dependent on maternal hemodynamic condition, bleeding status, and availability of interventional radiology.

Polymeric Tissue Adhesives

Polymeric tissue adhesives provide versatile materials for wound management and are widely used in a variety of medical settings ranging from minor to life-threatening tissue injuries. Compared to the traditional methods of wound closure (i.e., suturing and stapling), they are relatively easy to use, enable rapid application, and introduce minimal tissue damage. Furthermore, they can act as hemostats to control bleeding and provide a tissue-healing environment at the wound site. Despite their numerous current applications, tissue adhesives still face several limitations and unresolved challenges (e.g., weak adhesion strength and poor mechanical properties) that limit their use, leaving ample room for future improvements. Successful development of next-generation adhesives will likely require a holistic understanding of the chemical and physical properties of the tissue-adhesive interface, fundamental mechanisms of tissue adhesion, and requirements for specific clinical applications. In this review, we discuss a set of rational guidelines for design of adhesives, recent progress in the field along with examples of commercially available adhesives and those under development, tissue-specific considerations, and finally potential functions for future adhesives. Advances in tissue adhesives will open new avenues for wound care and potentially provide potent therapeutics for various medical applications.

One-step fabrication of chitosan sponge and its potential for rapid hemostasis in deep trauma

In this paper, a facile and efficient preparation strategy for a porous and hydrophilic chitosan sponge is demonstrated, combining a surfactant and a pore-foaming agent. The resulting chitosan sponge possesses an interconnected pore structure and soft texture, exhibits fast water absorption rate and capacity, and the compressed sponge can achieve full shape recovery 5 s after absorbing water. Moreover, our process removes the residual acid commonly found in chitosan sponges prepared by the acid method. In addition, the results demonstrate the useful characteristics of our chitosan sponge, in terms of its contribution to improved blood coagulation, together with its compression strength and biocompatibility. It also demonstrates effective antibacterial properties in relation to both Escherichia coli and Staphylococcus aureus. Further testing via animal experimentation reveals that rapid hemostasis can be achieved within 50 s using our chitosan sponge.

Multiple trauma management in mountain environments - a scoping review : Evidence based guidelines of the International Commission for Mountain Emergency Medicine (ICAR MedCom). Intended for physicians and other advanced life support personnel

BACKGROUND

Multiple trauma in mountain environments may be associated with increased morbidity and mortality compared to urban environments.

OBJECTIVE

To provide evidence based guidance to assist rescuers in multiple trauma management in mountain environments.

ELIGIBILITY CRITERIA

All articles published on or before September 30th 2019, in all languages, were included. Articles were searched with predefined search terms.

SOURCES OF EVIDENCE

PubMed, Cochrane Database of Systematic Reviews and hand searching of relevant studies from the reference list of included articles.

CHARTING METHODS

Evidence was searched according to clinically relevant topics and PICO questions.

RESULTS

Two-hundred forty-seven articles met the inclusion criteria. Recommendations were developed and graded according to the evidence-grading system of the American College of Chest Physicians. The manuscript was initially written and discussed by the coauthors. Then it was presented to ICAR MedCom in draft and again in final form for discussion and internal peer review. Finally, in a face-to-face discussion within ICAR MedCom consensus was reached on October 11th 2019, at the ICAR fall meeting in Zakopane, Poland.

CONCLUSIONS

Multiple trauma management in mountain environments can be demanding. Safety of the rescuers and the victim has priority. A crABCDE approach, with haemorrhage control first, is central, followed by basic first aid, splinting, immobilisation, analgesia, and insulation. Time for on-site medical treatment must be balanced against the need for rapid transfer to a trauma centre and should be as short as possible. Reduced on-scene times may be achieved with helicopter rescue. Advanced diagnostics (e.g. ultrasound) may be used and treatment continued during transport.

Fast transformation of 2D nanofiber membranes into pre-molded 3D scaffolds with biomimetic and oriented porous structure for biomedical applications

The ability to transform two-dimensional (2D) structures into three-dimensional (3D) structures leads to a variety of applications in fields such as soft electronics, soft robotics, and other biomedical-related fields. Previous reports have focused on using electrospun nanofibers due to their ability to mimic the extracellular matrix. These studies often lead to poor results due to the dense structures and small poor sizes of 2D nanofiber membranes. Using a unique method of combining innovative gas-foaming and molding technologies, we report the rapid transformation of 2D nanofiber membranes into predesigned 3D scaffolds with biomimetic and oriented porous structure. By adding a surfactant (pluronic F-127) to poly(ε-caprolactone) (PCL) nanofibers, the rate of expansion is dramatically enhanced due to the increase in hydrophilicity and subsequent gas bubble stability. Using this novel method together with molding, 3D objects with cylindrical, hollow cylindrical, cuboid, spherical, and irregular shapes are created. Interestingly, these 3D shapes exhibit anisotropy and consistent pore sizes throughout entire object. Through further treatment with gelatin, the scaffolds become superelastic and shape-recoverable. Additionally, gelatin-coated, cube-shaped scaffolds were further functionalized with polypyrrole coatings and exhibited dynamic electrical conductivity during cyclic compression. Cuboid-shaped scaffolds have been demonstrated to be effective for compressible hemorrhage in a porcine liver injury model. In addition, human neural progenitor cells can be uniformly distributed and differentiated into neurons throughout the cylinder-shaped nanofiber scaffolds, forming ordered 3D neural tissue constructs. Taken together, the approach presented in this study is very promising in the production of pre-molded 3D nanofiber scaffolds for many biomedical applications.

Hemostatic agents for prehospital hemorrhage control: a narrative review

Hemorrhage is the leading cause of preventable death in combat trauma and the secondary cause of death in civilian trauma. A significant number of deaths due to hemorrhage occur before and in the first hour after hospital arrival. A literature search was performed through PubMed, Scopus, and Institute of Scientific Information databases for English language articles using terms relating to hemostatic agents, prehospital, battlefield or combat dressings, and prehospital hemostatic resuscitation, followed by cross-reference searching. Abstracts were screened to determine relevance and whether appropriate further review of the original articles was warranted. Based on these findings, this paper provides a review of a variety of hemostatic agents ranging from clinically approved products for human use to newly developed concepts with great potential for use in prehospital settings. These hemostatic agents can be administered either systemically or locally to stop bleeding through different mechanisms of action. Comparisons of current hemostatic products and further directions for prehospital hemorrhage control are also discussed.

Pre-hospital Hemorrhagic Control Effectiveness of Axiostat® Dressing Versus Conventional Method in Acute Hemorrhage Due to Trauma

Accidents and trauma are one of the leading causes of death and disability throughout the world. In developing countries like India where emergency trauma care is still emerging, it accounts for almost 10% of deaths every year. Lack of adequate pre-hospital care and uncontrolled bleeding from the wound site are stated to be the prominent reasons for such deaths. The aim of this study was to evaluate the efficacy of a novel chitosan-based haemostatic dressing, Axiostat® (Axio Biosolutions Private Ltd., Gujarat, India), as a hemorrhage control device in the ambulance setting.

A total of 104 patients with bleeding scalp wounds were randomly allocated into two treatment groups while transporting them to the hospital. Patients in Group I were treated with Axiostat® chitosan haemostatic dressing (n = 47), while a conventional cotton gauze dressing was used in Group II (n = 57). A standard procedure was followed to apply the dressing on bleeding wounds and time to achieve haemostasis, the amount of blood loss, the number of patients with haemostasis, the occurrence of rebleeding, and other side effects were noted.

The mean age of the patients was 40 years and the majority of patients were male - 73 (70%). Most of the wounds were lacerations with venous bleeding. Haemostasis time was 4.68 ± 1.04 minutes and 18.56 ± 5.04 minutes in the Axiostat® and cotton gauze groups, respectively. The use of Axiostat® significantly reduced the time to haemostasis (p < 0.0001). A significant reduction in blood loss was observed with the application of Axiostat®. Successful haemostasis was achieved in 94% of patients in the Axiostat® group and 74% patients in cotton gauze group, respectively (p < 0.05). Moreover, no side effects, such as tissue loss or rebleeding at time of removal, were seen with the use of Axiostat®, while three patients in the cotton gauze group showed some side effects.

Results show that Axiostat® enables rapid haemostasis and can prevent significant blood loss during emergency trauma and accidents. Additionally, it also allows for easier removal from the wound site without leaving any residue, which helps in rendering the wound clean. In conclusion, the study successfully demonstrates the potential of Axiostat® as a first-line intervention in controlling acute haemorrhage in emergency care.

Chitosan-Based Bioactive Hemostatic Agents with Antibacterial Properties-Synthesis and Characterization

Massive blood loss is responsible for numerous causes of death. Hemorrhage may occur on the battlefield, at home or during surgery. Commercially available biomaterials may be insufficient to deal with excessive bleeding. Therefore novel, highly efficient hemostatic agents must be developed. The aim of the following research was to obtain a new type of biocompatible chitosan-based hemostatic agents with increased hemostatic properties. The biomaterials were obtained in a quick and efficient manner under microwave radiation using l-aspartic and l-glutamic acid as crosslinking agents with no use of acetic acid. Ready products were investigated over their chemical structure by FT-IR method which confirmed a crosslinking process through the formation of amide bonds. Their high porosity above 90% and low density (below 0.08 g/cm³) were confirmed. The aerogels were also studied over their water vapor permeability and antioxidant activity. Prepared biomaterials were biodegradable in the presence of human lysozyme. All of the samples had excellent hemostatic properties in contact with human blood due to the platelet activation confirmed by blood clotting tests. The SEM microphotographs showed the adherence of blood cells to the biomaterials’ surface. Moreover, they were biocompatible with human dermal fibroblasts (HDFs). The biomaterials also had superior antibacterial properties against both Staphylococcus aureus and Escherichia coli. The obtained results showed that proposed chitosan-based hemostatic agents have great potential as a hemostatic product and may be applied under sterile, as well as contaminated conditions, by both medicals and individuals.

Prehospital haemostatic dressings for trauma: a systematic review

BACKGROUND

Haemorrhage is a major cause of mortality and morbidity following both military and civilian trauma. Haemostatic dressings may offer effective haemorrhage control as part of prehospital treatment.

AIM

To conduct a systematic review of the clinical literature to assess the prehospital use of haemostatic dressings in controlling traumatic haemorrhage, and determine whether any haemostatic dressings are clinically superior.

METHODS

MEDLINE and EMBASE databases were searched using predetermined criteria. The reference lists of all returned review articles were screened for eligible studies. Two authors independently undertook the search, performed data extraction, and risk of bias and Grading of Recommendations, Assessment, Development and Evaluation quality assessments. Meta-analysis could not be undertaken due to study and clinical heterogeneity.

RESULTS

Our search yielded 470 studies, of which 17 met eligibility criteria, and included 809 patients (469 military and 340 civilian). There were 15 observational studies, 1 case report and 1 randomised controlled trial. Indications for prehospital haemostatic dressing use, wound location, mechanism of injury, and source of bleeding were variable. Seven different haemostatic dressings were reported with QuikClot Combat Gauze being the most frequently applied (420 applications). Cessation of bleeding ranged from 67% to 100%, with a median of 90.5%. Adverse events were only reported with QuikClot granules, resulting in burns. No adverse events were reported with QuikClot Combat Gauze use in three studies. Seven of the 17 studies did not report safety data. All studies were at risk of bias and assessed of 'very low' to 'moderate' quality.

CONCLUSIONS

Haemostatic dressings offer effective prehospital treatment for traumatic haemorrhage. QuikClot Combat Gauze may be justified as the optimal agent due to the volume of clinical data and its safety profile, but there is a lack of high-quality clinical evidence, and randomised controlled trials are warranted.

LEVEL OF EVIDENCE

Systematic review, level IV.

Walter B. Cannon's World War I experience: treatment of traumatic shock then and now

Walter B. Cannon (1871-1945), perhaps America's preeminent physiologist, volunteered for service with the Army Expeditionary Force (AEF) during World War I. He initially served with Base Hospital No. 5, a unit made up of Harvard clinicians, before moving forward to the front lines to serve at a casualty clearing station run by the British. During his time there, he performed research on wounded soldiers to understand the nature and causes of traumatic shock. Subsequently, Cannon performed animal experimentation on the causes of traumatic shock in the London laboratory of Dr. William Bayliss before being assigned to the AEF Central Medical Laboratory in Dijon, France, where he continued his experimental studies. During this time, he also developed and taught a curriculum on resuscitation of wounded soldiers to medical providers. Although primarily a researcher and teacher, Cannon also performed clinical duties throughout the war, serving with distinction under fire. After the war, Cannon wrote a monograph entitled Traumatic Shock (New York: Appleton, 1923), which encapsulated the knowledge that had been gained during the war, both from direct observation of wounded soldiers, as well as laboratory experimentation on the causes and treatment of traumatic shock. In his monograph, Cannon elucidates a number of principles concerning hemorrhagic shock that were later forgotten, only to be "rediscovered" during the current conflicts in Iraq and Afghanistan. This paper summarizes Cannon's wartime experiences and the knowledge gained concerning traumatic shock during World War I, with a comparison of current combat casualty care practices and knowledge to that which Cannon and his colleagues understood a century ago.

How many patients could benefit from REBOA in prehospital care? A retrospective study of patients rescued by the doctors of the Paris fire brigade

INTRODUCTION

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a technique to control haemorrhage by placing a retrograde catheter in an artery and inflating a balloon at its tip. This retrospective study aimed to evaluate the proportion of injured people who could potentially have benefited from this technique prior to hospitalisation, including on the scene or during transport.

METHODS

A retrospective analysis was conducted of all patients with trauma registered in the Paris Fire Brigade emergency medical system between 1 January and 31 December 2014. Inclusion criteria included all patients over 18 years of age with bleeding of supposedly abdominal and/or pelvic and/or junctional origin, uncontrolled haemorrhagic shock or cardiac arrest with attempted resuscitation.

RESULTS

During this study period, a total of 1159 patients with trauma (3.2%) would have been eligible to undergo REBOA. Death on scene rate was 83.8% (n=31) and six patients had a beating heart when they arrived at the hospital. Ten out of the 37 patients had spontaneous circulatory activity. Among them, four people died on the scene or during transport. Thirty-six out of 37 patients were intubated, one benefited from the use of a haemostatic dressing and one benefited from a tourniquet.

CONCLUSIONS

REBOA can be seen as an effective non-surgical solution to ensure complete haemostasis during the prehospital setting. When comparing the high mortality rate following haemorrhage with the REBOA's rare side effects, the risk-benefit balance is positive. Given that 3% of all patients with trauma based on this study would have been eligible for REBOA, we believe that this intervention should be available in the prehospital setting. The results of this study will be used: educational models for REBOA balloon placement using training manikins, with an ultimate aim to undertake a prospective feasibility study in the prehospital setting.