Pre-hospital haemostatic dressings: a systematic review

Use of local pro-coagulant haemostatic agents for intra-cavity control of haemorrhage after trauma

INTRODUCTION

Uncontrolled haemorrhage as a result of trauma remains a significant surgical challenge, accounting for approximately 25-40% of trauma-related mortality. A wide range of local internal haemostatic agents have been developed to help achieve intra-cavity control of bleeding, with choice of agent influenced by the circumstances and nature of the haemorrhage. Trauma patients are frequently coagulopathic, so products that incorporate pro-coagulant technology and thereby act independently of the clotting cascade may be more effective in these settings. A range of products that utilise thrombin and fibrinogen to promote local haemostasis at intra-cavity bleeding points are available or in development, including fibrin glues (e.g. Tisseel®/Tissucol® and Evicel®/Crosseal®/Quixil®), fibrin sealant patches (e.g. TachoSil®) and products based on a gelatin-thrombin haemostatic matrix (e.g. FloSeal®).

MATERIALS AND METHODS

This systematic review was performed to assess all peer-reviewed evidence of product efficacy.

RESULTS

Fibrin sealant patches have shown haemostatic efficacy in a variety of surgical procedures and appear to offer practical advantages over liquid fibrin glues. Existing evidence suggests that patch products enable delivery of pro-coagulants to defined areas with less chance of dilution and/or displacement by blood flow, but they require a pressure buttress for a suitable amount of time to achieve good results after trauma.

CONCLUSIONS

Our experience, supported by other reports in the literature, suggests the use of such fibrin patches may provide an effective option in helping to control haemorrhage after trauma. However, there is a general paucity of clinical data for intra-cavity haemostatic agent use, with the majority of data being based on animal models and case reports. Further clinical evidence, ideally including comparative studies between different agents, would be beneficial in helping guide surgeon choice to the most appropriate products to use in trauma settings.

Hemostatic strategies for traumatic and surgical bleeding

Wide interest in new hemostatic approaches has stemmed from unmet needs in the hospital and on the battlefield. Many current commercial hemostatic agents fail to fulfill the design requirements of safety, efficacy, cost, and storage. Academic focus has led to the improvement of existing strategies as well as new developments. This review will identify and discuss the three major classes of hemostatic approaches: biologically derived materials, synthetically derived materials, and intravenously administered hemostatic agents. The general class is first discussed, then specific approaches discussed in detail, including the hemostatic mechanisms and the advancement of the method. As hemostatic strategies evolve and synthetic-biologic interactions are more fully understood, current clinical methodologies will be replaced.

Fibrin patch in a pig model with blunt liver injury under severe hypothermia

BACKGROUND

Rapid control of hemorrhage is one of the key aspects in trauma handling. To cope with bleeding, local hemostatic approaches are useful, along with surgical and systemic homostatic therapy. In this experimental study, we investigated the efficacy of a fibrinogen/thrombin containing collagen patch (TachoSil) in a coagulopathic pig model with blunt liver trauma under severe hypothermia.

METHODS

Eighteen anesthetized pigs underwent hemodilution by exchanging 70% of the blood volume with Ringer Lactate solution and hydroxyethyl starch 130/0.4 (1:1). Ten minutes after induction of a grade III blunt liver trauma, the animals randomly received treatment with TachoSil (FT-patch, n = 9) or a collagen patch (Tachotop, control group, n = 9). Blood loss, hemodynamics, and coagulation parameters were observed for 2 h. To confirm the consistency of liver trauma, pathologic examination of the liver tissue was performed.

RESULTS

Hypothermia (33.5°C ± 0.5°C) and hemodilution led to severe coagulopathy as measured by thromboelastometry and coagulation parameters. After trauma and patch application, thromboelastometry and coagulation parameters in the control group showed further deterioration compared with the stable parameters in the FT-patch group. The total blood loss was significantly reduced in the FT-patch group (FT-patch: 1195 mL; control group: 2495 mL; P < 0.001). Concordantly, the control animals were hemodynamically jeopardized to a higher degree. Microscopy confirmed a similar degree of liver injury.

CONCLUSIONS

Despite severe hypothermia and coagulopathy, TachoSil provided effective hemorrhage control in pigs with blunt liver injury. Therefore, TachoSil demonstrated usefulness as an additional early therapy in cases of uncontrolled bleeding following severe trauma.

Comparison of novel hemostatic dressings with QuikClot combat gauze in a standardized swine model of uncontrolled hemorrhage

BACKGROUND

Uncontrolled hemorrhage is the leading cause of preventable death on the battlefield. The development, testing, and application of novel hemostatic dressings may lead to a reduction of prehospital mortality through enhanced point-of-injury hemostatic control. This study aimed to determine the efficacy of currently available hemostatic dressings as compared with the current Committee for Tactical Combat Casualty Care Guidelines standard of treatment for hemorrhage control (QuikClot Combat Gauze [QCG]).

METHODS

The femoral artery of anesthetized Yorkshire pigs was isolated and punctured. Free bleeding was allowed to proceed for 45 seconds before packing of QCG, QuikClot Combat Gauze XL (QCX), Celox Trauma Gauze (CTG), Celox Gauze (CEL), or HemCon ChitoGauze (HCG), into the wound. After 3 minutes of applied, direct pressure, fluid resuscitation was administered to elevate and maintain a mean arterial pressure of 60 mm Hg or greater during the 150-minute observation time. Animal survival, hemostasis, and blood loss were measured as primary end points. Hemodynamic and physiologic parameters, along with markers of coagulation, were recorded and analyzed.

RESULTS

Sixty percent of QCG-treated animals (controls) survived through the 150-minute observation period. QCX, CEL, and HCG were observed to have higher rates of survival in comparison to QCG (70%, 90%, and 70% respectively), although these results were not found to be of statistical significance in pairwise comparison to QCG. Immediate hemostasis was achieved in 30% of QCG applications, 80% of QCX, 70% of CEL, 60% of HCG, and 30% of CTG-treated animals. Posttreatment blood loss varied from an average of 64 mL/kg with CTG to 29 mL/kg with CEL, but no significant difference among groups was observed.

CONCLUSION

These results suggest that the novel hemostatic devices perform at least as well as the current Committee on Tactical Combat Casualty Care standard for point-of-injury hemorrhage control. Despite their different compositions and sizes, the lack of clear superiority of any agent suggests that contemporary hemostatic dressing technology has potentially reached a plateau for efficacy.

Minimising blood loss in early trauma resuscitation

Worldwide, trauma is responsible for more than 10,000 deaths each day with hundreds of thousands seriously injured. Current trauma resuscitation strategies are based on supporting haemostasis, maintaining circulating volume and rapidly identifying sites of blood loss. Approaches include hypotensive/hypovolaemic resuscitation, avoidance of colloids and crystalloids, early blood product based resuscitation, early imaging to identify sites of blood loss and damage control surgery. In this paper, we focus on ways to minimise blood loss and preserve the circulating volume. These include minimal movement of the patient, splinting fractures, use of tourniquets, application of local haemostatic dressings/agents, keeping the patient warm and giving tranexamic acid to improve clot strength. The recent CRASH-2 trial provided unequivocal evidence that tranexamic acid reduces mortality in bleeding trauma patients. This will be discussed in detail. When employed as part of a package of care in a well-rehearsed trauma system, these interventions to preserve the remaining circulating volume have the potential to save lives and allow patients to survive until timely definitive haemostasis can occur.

Successful use of a military-grade haemostatic agent for a major head and neck bleed

Background:

Major haemorrhage is a catastrophic complication occurring in 3–4 per cent of head and neck cancer patients. Massive haemorrhage also causes 50 per cent of preventable deaths in combat situations. There has been a surge of interest in the development of effective haemostatic products in the military, with chitosan being one such product.

Case report:

A 48-year-old lady presented with a life-threatening head and neck bleed. She was known to have a malignant peripheral nerve sheath sarcoma originating from the left parapharyngeal space. Bleeding was successfully controlled with the application of Celox™ granules, a chitosan-based product currently used in the military.

Conclusion:

This paper describes the first known use of a military haemostatic agent to control a malignant head and neck bleed. Celox granules can be poured directly onto a wound to enhance haemorrhage control. The suggested mechanism of action and reports of current uses of haemostatic agents are described.

Modelling for conflict: the legacy of ballistic research and current extremity in vivo modelling

Extremity ballistic injury is unique and the literature intended to guide its management is commonly misinterpreted. In order to care for those injured in conflict and conduct appropriate research, clinicians must be able to identify key in vivo studies, understand their weaknesses and desist the propagation of miscited and misunderstood ballistic dogma. This review provides the only inclusive critical overview of key studies of relevance to military extremity injury. In addition, the non-ballistic studies of limb injury, stabilisation and contamination that will form the basis from which future small animal extremity studies are constructed are presented. With an awareness of the legacy of military wound models and an insight into available generic models of extremity injury and contamination, research teams are well placed to optimise future military extremity injury management.

Haemorrhagic shock, therapeutic management

The management of a patient in post-traumatic haemorrhagic shock will meet different logics that will apply from the prehospital setting. This implies that the patient has beneficiated from a "Play and Run" prehospital strategy and was sent to a centre adapted to his clinical condition capable of treating all haemorrhagic lesions. The therapeutic goals will be to control the bleeding by early use of tourniquet, pelvic girdle, haemostatic dressing, and after admission to the hospital, the implementation of surgical and/or radiological techniques, but also to address all the factors that will exacerbate bleeding. These factors include hypothermia, acidosis and coagulopathy. The treatment of these contributing factors will be associated to concepts of low-volume resuscitation and permissive hypotension into a strategy called "Damage Control Resuscitation". Thus, the objective in situation of haemorrhagic shock will be to not exceed a systolic blood pressure of 90 mmHg (in the absence of severe head trauma) until haemostasis is achieved.

[Evolution of US military transfusion support for resuscitation of trauma and hemorrhagic shock]

Military conflicts create a dynamic medical environment in which the number of severe trauma cases is compressed in both time and space. In consequence, lessons are learned at a rapid pace. Because the military has an effective organizational structure at its disposal and the logistical capacity to rapidly disseminate new ideas, adoption of novel therapies and protective equipment occurs quickly. The recent conflicts in Iraq and Afghanistan are no exception: more than three dozen new clinical practice guidelines were implemented by the US Armed Forces, with attendant survival benefits, in response to observation and research by military physicians. Here we review the lessons learned by coalition medical personnel regarding resuscitation of severe trauma, integrating knowledge gained from massive transfusion, autopsies, and extensive review of medical records contained in the Joint Theater Trauma Registry. Changes in clinical care included the shift to resuscitation with 1:1:1 component therapy, use of fresh whole blood, and the application of both medical devices and pharmaceutical adjuncts to reduce bleeding. Future research will focus on emerging concepts regarding coagulopathy of trauma and evaluation of promising new blood products for far-forward resuscitation. New strategies aimed at reducing mortality on the battlefield will focus on resuscitation in the pre-hospital setting where hemorrhagic death continues to be a major challenge.

The use of Celox gauze as an adjunct to pelvic Packing in otherwise uncontrollable pelvic haemorrhage secondary to penetrating trauma

Haemorrhage from severe pelvic fractures can be associated with significant mortality. Modern civilian trauma centres may manage these injuries with a combination of external pelvic fixation, extra-peritoneal packing and/or selective angiography; however, military patterns of wounding are different and deployed medical facilities may be resource constrained. We report two successful instances of pelvic packing using chitosan impregnated gauze (Celox) when conventional surgical attempts at vascular control had failed. We conclude that pelvic packing should be considered early in patients with military pelvic trauma and major haemorrhage, as part of damage control surgery and that Celox gauze may be a useful adjunct. In our cases, the Celox gauze was easily removed after 24-48 hours without significant bowel adhesions and did not leave a residual phelgmon (of exudate or gel) that may predispose to infection.

Prehospital emergency trauma care and management

Prehospital care of the trauma patient is continuing to evolve; however, the principles of airway maintenance, hemorrhage control, and appropriate resuscitative maneuvers remain central to the role of the emergency medical care provider. Recent changes in the regulations for research in emergency settings will allow randomized trials to proceed to test new devices, drugs, and resuscitative strategies in the prehospital environment. The creation of prehospital research networks will provide the appropriate infrastructure to greatly facilitate the development of new protocols and the execution of large-scale randomized trials with the potential to change current prehospital practice.

Haemorrhage control in severely injured patients

Most surgeons have adopted damage control surgery for severely injured patients, in which the initial operation is abbreviated after control of bleeding and contamination to allow ongoing resuscitation in the intensive-care unit. Developments in early resuscitation that emphasise rapid control of bleeding, restrictive volume replacement, and prevention or early management of coagulopathy are making definitive surgery during the first operation possible for many patients. Improved topical haemostatic agents and interventional radiology are becoming increasingly useful adjuncts to surgical control of bleeding. Better understanding of trauma-induced coagulopathy is paving the way for the replacement of blind, unguided protocols for blood component therapy with systemic treatments targeting specific deficiencies in coagulation. Similarly, treatments targeting dysregulated inflammatory responses to severe injury are under investigation. As point-of-care diagnostics become more suited to emergency environments, timely targeted intervention for haemorrhage control will result in better patient outcomes and reduced demand for blood products. Our Series paper describes how our understanding of the roles of the microcirculation, inflammation, and coagulation has shaped new and emerging treatment strategies.

The early management of patients with multiple injuries: an evidence-based, practical guide for the orthopaedic surgeon

There have been many advances in the resuscitation and early management of patients with severe injuries during the last decade. These have come about as a result of the reorganisation of civilian trauma services in countries such as Germany, Australia and the United States, where the development of trauma systems has allowed a concentration of expertise and research. The continuing conflicts in the Middle East have also generated a significant increase in expertise in the management of severe injuries, and soldiers now survive injuries that would have been fatal in previous wars. This military experience is being translated into civilian practice. The aim of this paper is to give orthopaedic surgeons a practical, evidence-based guide to the current management of patients with severe, multiple injuries. It must be emphasised that this depends upon the expertise, experience and facilities available within the local health-care system, and that the proposed guidelines will inevitably have to be adapted to suit the local resources.

Life or death? A physiogenomic approach to understand individual variation in responses to hemorrhagic shock

Severe hemorrhage due to trauma is a major cause of death throughout the world. It has often been observed that some victims are able to withstand hemorrhage better than others. For decades investigators have attempted to identify physiological mechanisms that distinguish survivors from nonsurvivors for the purpose of providing more informed therapies. As an alternative approach to address this issue, we have initiated a research program to identify genes and genetic mechanisms that contribute to this phenotype of survival time after controlled hemorrhage. From physiogenomic studies using inbred rat strains, we have demonstrated that this phenotype is a heritable quantitative trait, and is therefore a complex trait regulated by multiple genes. Our work continues to identify quantitative trait loci as well as potential epigenetic mechanisms that might influence survival time after severe hemorrhage. Our ultimate goal is to improve survival to traumatic hemorrhage and attendant shock via regulation of genetic mechanisms and to provide knowledge that will lead to genetically-informed personalized treatments.