Extending existing recommended military casualty evacuation timelines will likely increase morbidity and mortality: a UK consensus statement.

INTRODUCTION: Future conflicts may have limited use of aviation-based prehospital emergency care for evacuation. This will increase the likelihood of extended evacuation timelines and an extended hold at a forward hospital care facility following the completion of damage control surgery or acute medical interventions. METHODS: A three-round Delphi Study was undertaken using a panel comprising 44 experts from the UK armed forces including clinicians, logisticians, medical planners and commanders. The panel was asked to consider the effect of an extended hold at Deployed Hospital Care (Forward) from the current 2-hour timeline to +4, +8, +12 and +24 hours on a broad range of clinical and logistical issues. Where 75% of respondents had the same opinion, consensus was accepted. Areas where consensus could not be achieved were used to identify future research priorities. RESULTS: Consensus was reached that increasing timelines would increase the personnel, logistics and equipment support required to provide clinical care. There is a tipping point with a prolonged hold over 8 hours, after which the greatest number of clinical concerns emerge. Additional specialties of surgeons other than general and orthopaedic surgeons will likely be required with holds over 24 hours, and robust telemedicine would not negate this requirement. CONCLUSIONS: Retaining acute medical emergencies at 4 hours, and head injuries was considered a particular risk. This could potentially be mitigated by an increased forward capacity of some elements of medical care and availability of a CT scanner and intracranial pressure monitoring at over 12 hours. Any efforts to mitigate the effects of prolonged timelines will come at the expense of an increased logistical burden and a reduction in mobility. Ultimately the true effect of prolonged timelines can only be answered by close audit and analysis of clinical outcomes during future operations with an extended hold.

Minimum depths to essential structures in a UK military population using computed tomography: application to stab-resistant body armour.

INTRODUCTION: Edged weapons are a known domestic threat to the police forces of the UK. This threat is mitigated by wearing stab-resistant body armour that is either worn overtly or covertly depending on role. Although the UK military have traditionally focused their body armour design upon ballistic and fragmentation threats, future roles may require protection against an edged weapon threat. Since 2017, UK police body armour requirements for anatomical coverage for both edged weapon and ballistic threats are now based upon the requirements of UK military. This revised coverage may need additional research to determine minimum distances to essential structures. METHOD: Three entry locations and penetration vectors were chosen using the limited available information in the literature, in combination with a specialist in edged weapons defence. One hundred twenty CT trauma scans of male military service personnel were subsequently analysed to ascertain minimum distances from skin surface to the first structure encountered that is included in essential coverage (heart, aorta, vena cava, liver and spleen) at 3 specific entry points. RESULTS: Individuals ranged between 18 and 46 years, with a mean body mass index of 24.8. The absolute minimum depth from skin surface to a structure within the auspice of essential coverage was 17 mm to the liver in entry point 3 and 19 mm to the heart in entry point 2. CONCLUSIONS: Minimum distances to critical structures were significantly larger than those described in previous studies on civilians. This study will be used to supplement existing evidence to support existing UK police requirements for stab-resistant body armour. Using the weapon entry sites and vectors described in this study, overmatching to a behind armour depth of 17 mm would cover all of this population in this study.

UK military helmet design and test methods.

The aim of this paper was to provide the military medical community with an expert summary of military helmets used by HM Armed Forces. The design of military helmets and test methods used to determine the fragmentation and non-ballistic impact protection are discussed. The helmets considered are Parachutist, Combat Vehicle Crewman, Mk6, Mk6A, Mk7 and VIRTUS. The helmets considered provide different levels of fragmentation and non-ballistic impact protection dictated by the materials available at the time of the helmet design and the end-user requirement. The UK Ministry of Defence defines the area of coverage of military helmets by considering external anatomical features to provide protection to the brain and the majority of the brainstem. Established test methods exist to assess the performance of the helmet with respect to the threats; however, these test methods do not typically consider anatomical vulnerability.

Edged weapons awareness.

Edged weapons (sometimes referred to as sharp weapons or blades) are an increasing threat to military personnel, the blue light community (police, ambulance, firefighters, other first responders) and the general public worldwide. The use of edged weapons in criminal and terrorist incidents internationally means the forensic community needs an awareness of the technology of edged weapons, how they are used, the damage (clothing and wounding) that might be caused and any other forensic implications. In this paper, the magnitude of the problem is presented, prior research summarised and implications for forensic investigations discussed.

The use of gelatine in wound ballistics research.

Blocks of gelatine are used in both lethality and survivability studies for broadly the same reason, i.e. comparison of ammunition effects using a material that it is assumed represents (some part of) the human body. The gelatine is used to visualise the temporary and permanent wound profiles; elements of which are recognised as providing a reasonable approximation to wounding in humans. One set of researchers aim to improve the lethality of the projectile, and the other to understand the effects of the projectile on the body to improve survivability. Research areas that use gelatine blocks are diverse and include ammunition designers, the medical and forensics communities and designers of ballistic protective equipment (including body armour). This paper aims to provide an overarching review of the use of gelatine for wound ballistics studies; it is not intended to provide an extensive review of wound ballistics as that already exists, e.g. Legal Med 23:21-29, 2016. Key messages are that test variables, projectile type (bullet, fragmentation), impact site on the body and intermediate layers (e.g. clothing, personal protective equipment (PPE)) can affect the resulting wound profiles.

Does preliminary optimisation of an anatomically correct skull-brain model using simple simulants produce clinically realistic ballistic injury fracture patterns?

Ballistic head injury remains a significant threat to military personnel. Studying such injuries requires a model that can be used with a military helmet. This paper describes further work on a skull-brain model using skulls made from three different polyurethane plastics and a series of skull 'fills' to simulate brain (3, 5, 7 and 10% gelatine by mass and PermaGel™). The models were subjected to ballistic impact from 7.62 × 39 mm mild steel core bullets. The first part of the work compares the different polyurethanes (mean bullet muzzle velocity of 708 m/s), and the second part compares the different fills (mean bullet muzzle velocity of 680 m/s). The impact events were filmed using high speed cameras. The resulting fracture patterns in the skulls were reviewed and scored by five clinicians experienced in assessing penetrating head injury. In over half of the models, one or more assessors felt aspects of the fracture pattern were close to real injury. Limitations of the model include the skull being manufactured in two parts and the lack of a realistic skin layer. Further work is ongoing to address these.

AAGBI: Safer pre-hospital anaesthesia 2017: Association of Anaesthetists of Great Britain and Ireland.

Pre-hospital emergency anaesthesia with oral tracheal intubation is the technique of choice for trauma patients who cannot maintain their airway or achieve adequate ventilation. It should be carried out as soon as safely possible, and performed to the same standards as in-hospital emergency anaesthesia. It should only be conducted within organisations with comprehensive clinical governance arrangements. Techniques should be straightforward, reproducible, as simple as possible and supported by the use of checklists. Monitoring and equipment should meet in-hospital anaesthesia standards. Practitioners need to be competent in the provision of in-hospital emergency anaesthesia and have supervised pre-hospital experience before carrying out pre-hospital emergency anaesthesia. Training programmes allowing the safe delivery of pre-hospital emergency anaesthesia by non-physicians do not currently exist in the UK. Where pre-hospital emergency anaesthesia skills are not available, oxygenation and ventilation should be maintained with the use of second-generation supraglottic airways in patients without airway reflexes, or basic airway manoeuvres and basic airway adjuncts in patients with intact airway reflexes.

Laboratory evaluation of a novel anaesthesia delivery device.

Here, we describe proof of concept of a novel method for delivering volatile anaesthetics, where the liquid anaesthetic (sevoflurane or isoflurane) is formulated into an emulsion that is contained in a compact, lightweight device through which carrier gas flows. Release of anaesthetic is achieved by stirring of the formulation, allowing controlled and responsive release of anaesthetic at a variety of fixed flow rates between 0.5 l.min-1 and 5 l.min-1 , with ventilated, non-ventilated and draw-over breathing systems. Anaesthetic release was evaluated using target anaesthetic concentrations ranging from 0.5% v/v to 8% v/v to mimic those typically required for induction and maintenance of anaesthesia, and lower concentrations suitable for sedation. Under all conditions, output could be maintained within 0.1% v/v of the intended setting, and the device could deliver a controlled level of anaesthetic for at least 60 min, with compensation for different ambient temperatures (10-30 °C) and carrier gas flow rates. This device offers a simple, inexpensive method of delivering safe concentrations of volatile anaesthetics for a wide range of applications.

Died of wounds: a mortality review.

OBJECTIVES: Combat casualty care is a complex system involving multiple clinicians, medical interventions and casualty transfers. Improving the performance of this system requires examination of potential weaknesses. This study reviewed the cause and timing of death of casualties deemed to have died from their injuries after arriving at a medical treatment facility during the recent conflicts in Iraq and Afghanistan, in order to identify potential areas for improving outcomes. METHODS: This was a retrospective review of all casualties who reached medical treatment facilities alive, but subsequently died from injuries sustained during combat operations in Afghanistan and Iraq. It included all deaths from start to completion of combat operations. The UK military joint theatre trauma registry was used to identify cases, and further data were collected from clinical notes, postmortem records and coroner's reports. RESULTS: There were 71 combat-related fatalities who survived to a medical treatment facility; 17 (24%) in Iraq and 54 (76%) in Afghanistan. Thirty eight (54%) died within the first 24 h. Thirty-three (47%) casualties died from isolated head injuries, a further 13 (18%) had unsurvivable head injuries but not in isolation. Haemorrhage following severe lower limb trauma, often in conjunction with abdominal and pelvic injuries, was the cause of a further 15 (21%) deaths. CONCLUSIONS: Severe head injury was the most common cause of death. Irrespective of available medical treatment, none of this group had salvageable injuries. Future emphasis should be placed in preventative strategies to protect the head against battlefield trauma.

Modelling the blast environment and relating this to clinical injury: experience from the 7/7 inquest.

This paper addresses the computational modelling of a series of specific blast-related incidents and the relationships of clinical and engineering interpretations. The Royal Centre for Defence Medicine and the Defence Science and Technology Laboratory were tasked in 2010 by the UK Ministry of Defence to assist the Coroner's inquests into the 7 July 2005 London bombings. A three phase approach was taken. The first phase included an engineering expert in blast effects on structures reviewing photographs of the damaged carriages and bus to give a view on the likely physical effects on people close to the explosions. The second phase was a clinical review of the evidence by military clinicians to assess blast injury in the casualties. The third phase was to model the blast environment by structural dynamics experts to assess likely blast loading on victims to evaluate the potential blast loading on individuals. This loading information was then assessed by physiology experts. Once all teams (engineering, clinical and modelling/physiological) had separately arrived at their conclusions, the information streams were integrated to arrive at a consensus. The aim of this paper is to describe the methodology used as a potential model for others to consider if faced with a similar investigation, and to show the benefit of the transition of military knowledge to a civilian environment.

Primary blast lung injury at a NATO Role 3 hospital.

BACKGROUND: Primary blast lung injury (PBLI) is defined as lung contusion from barotrauma following an explosive mechanism of injury (MOI). Military data have focused on PBLI characteristics following evacuation from the combat theatre; less is known about its immediate management and epidemiology in the deployed setting. We conducted a quality improvement project to describe the prevalence, clinical characteristics, management strategies and evacuation techniques for PBLI patients prior to evacuation. METHODS: Patients admitted to a Role 3 hospital in southwest, Afghanistan, from January 2008 to March 2013 with a blast MOI were identified through the Department of Defense Trauma Registry; International Classification of Diseases 9 codes and patient record review were used to identify the PBLI cohort from radiology reports. Descriptive statistics and Fishers exact test were used to report findings. RESULTS: Prevalence of PBLI among blast injured patients with radiology reports was 11.2% (73/648). The population exhibited high Injury Severity Scores median 25 (IQR 14-34) and most received a massive blood transfusion (mean 33.4±38.3 total blood products/24 h). The mean positive end expiratory pressure (PEEP) requirement was 6.2±3.7 (range 5-15) cm H2O and PaO2 to FiO2 ratio was 297±175.2 (66-796) mm Hg. However, 16.6% of patients had a PaO2 to FiO2 ratio <200, 13.3% required PEEP ≥10 cm H2O and one patient required specialised evacuation for respiratory failure. A dismounted MOI (72.8%) and evacuation from point of injury by the Medical Emergency Response Team (62.3%) appeared to be associated with worse lung injury. Only eight of the 73 PBLI patients died and of the five with retrievable records, none died from respiratory failure. CONCLUSIONS: PBLI has a low prevalence and conventional lung protective ventilator management is generally appropriate immediately after injury; application of advanced modes of ventilation and specialised evacuation assistance may be required. PBLI may be a marker of underlying injury severity since all deaths were not due to respiratory failure. Further work is needed to determine exact MOI in mounted and dismounted casualties.

Haemorrhage and coagulopathy in the Defence Medical Services.

Over the past 12 years, the United Kingdom Defence Medical Services have evolved an integrated 'damage control resuscitation - damage control surgery' sequence for the management of patients sustaining complex injuries. During 2009, over 3200 units of blood products were administered as massive transfusions to severely injured UK personnel. An important part of the approach to traumatic bleeding is the early, empirical use of predefined ratios of blood and clotting products. As soon as control of bleeding is achieved, current practice is to switch towards a tailored transfusion, based on clinical and laboratory assessments, including point-of-care coagulation testing. A key goal is to provide resuscitation seamlessly throughout surgery, so that patients leave the operating room with their normal physiology restored. This article outlines the current management of haemorrhage and coagulation employed in Afghanistan from the point of wounding to transfer back to the National Health Service.

The pattern of paediatric trauma on operations.

OBJECTIVES: Recent military campaigns in Iraq and Afghanistan have resulted in the treatment of children in British Medical facilities. In order to determine how care for children may develop in the future, it is necessary to understand the current situation. The aim of this article is to examine the pattern of paediatric trauma on recent operations in Iraq and Afghanistan. METHODS: Data was requested from the Joint Theatre Trauma Registry, held at the Royal Centre for Defence Medicine in Birmingham, on all trauma calls for patients aged under 16 between the dates 21/3/03 and 31/8/09. Data included age, gender, theatre of operation, injury mechanism and type, trauma scores and destination of the child. RESULTS: 176 children were identified with 16.5% from Iraq and 83.5% from Afghanistan. The overall survival rate was 88.6% with survival rates in Iraq of 89.7% and in Afghanistan of 88.4%. Males accounted for 66.5% of admissions and the commonest age group was age 6-8 years. In 59.1% of total admissions the mechanism of injury was related to explosives. This differed between theatres with explosive injury causing 27.6% of admissions in Iraq and 63.5% in Afghanistan. Injury Severity Scores (ISS) showed equal numbers of minor and severe injuries with fewer moderately injured patients. The median ISS of all data was nine. The median ISS from Iraq was 16 and the median ISS from Afghanistan was nine. CONCLUSIONS: The treatment of children in British medical facilities whilst deployed on operations is likely to continue. An assessment of the injury patterns of paediatric patients on current deployments allows development of training and an understanding of logistic requirements. Data collection will also need to be adapted to meet the needs of paediatric patients. These remain issues that are being addressed by the Defence Medical Services.

The deployed medical director: managing the challenges of a complex trauma system.

Contemporary combat casualty care has never been more sophisticated or effective, which is matched by an unprecedented level of clinical complexity. The management of this complexity has demanded the evolution of a more direct clinical leadership model in the field hospital: the Deployed Medical Director (DMD). The DMD has a central co-ordinating role in reducing the friction generated by individuals' unfamiliarity in a rapidly developing clinical environment that has diverged from the NHS; in cementing interoperability within a multinational medical treatment facility working at high intensity; and in maintaining and developing the highest clinical standards within the deployed trauma system. This article describes the evolution of the DMD role and illustrates the challenges through a series of vignettes. Particular emphasis is given to the organisational risk that the role carries through necessary ethical choices, the requirement to integrate multi-national cultural differences and the challenge of dealing with interpersonal frictions amongst senior staff.

Is pre-hospital thoracotomy necessary in the military environment?

INTRODUCTION: Exsanguination from penetrating torso injury is a major source of mortality on the battlefield. Advanced Life Support guidelines suggest 'on-scene' thoracotomy for patients in cardiac arrest following penetrating chest trauma. This requires significant resourcing and training. Experience from published series (31 pre-hospital thoracotomies with 3 survivors) suggests that when this manoeuvre is applied to a well selected group it is a significant and life-saving procedure. Can this be applied to military injuries? METHODS: Over a 12 month period on Operation Herrick all patients who sustained significant thoracic trauma were retrospectively reviewed. Parameters were recorded to allow detailed analysis of injury pattern and operative management. Our main objective was to determine if an early (pre-hospital) thoracotomy would have influenced the outcome. RESULTS: Over the period, 81 patients required operative intervention following thoracic trauma: 8 patients underwent emergency thoracotomy (performed as part of the resuscitation) and 14 underwent urgent thoracotomy (performed after physiology partly restored). There were 9 fatalities--7 undergoing emergency thoracotomy and 2 post-operatively from multi-organ failure. Of the 7 intra-operative deaths 4/7 patients had thoracic injury and 6/7 had additional abdominal injuries. The median predicted survival of fatalities was 2.0% using Trauma Injury Severity Scoring. DISCUSSION: Emergency thoracotomy should be performed in cardiac arrest following penetrating trauma as soon as possible. Highest survival rates in both in-hospital and pre-hospital thoracotomy are found in isolated cardiac stab wounds (19.4%). Poorest survival is found in multiply, ballistic injured patients (0.7%). The latter best reflects the injury pattern of military patients who have cardiac arrest following penetrating torso injury. CONCLUSION: As our injury pattern suggests, any pre-hospital thoracotomy on military patients is likely to require complex intervention in very challenging environments. Our evidence does not support the notion that earlier thoracotomy could improve survival.

The clinical outcome of UK military personnel who received a massive transfusion in Afghanistan during 2009.

OBJECTIVES: The UK Defence Medical Services has developed a Massive Transfusion Protocol (MTP) that forms part of the initial Damage Control Resuscitation process for severely injured combat casualties. The key objectives of this retrospective review of MTP recipients are to document the survival rates, level of critical care support required and the blood components transfused as part of the Massive Transfusion Protocol in Afghanistan during 2009. In addition to providing a measure of our current effectiveness it should also provide a reference point for future reviews as the MTP continues to evolve. METHODS: This was a collaborative project involving the Royal Centre for Defence Medicine and the Critical Care Department, University Hospitals Birmingham. It was limited to UK military personnel who were injured in 2009 and received massive transfusions (defined as the transfusion of 10 or more units of packed red blood cells over a 24-hour period) at Camp Bastion Role 3 Medical Facility, Afghanistan. RESULTS: During the 12-month period, 59 personnel received massive transfusions. 51 (86%) personnel survived to be discharged from hospital in the UK. 48 (92%) personnel required ventilatory support for a median of 3 (2-8) days. The longest period of ventilation was 40 days; 29 (55%) personnel required vasopressor support and eight personnel (15%) required renal replacement therapy. The median total transfusion of blood components was 45 (28.5-62) units. There were seven transfusions of more than 100 units. Five of the personnel in this group (including the recipient of a 237-unit transfusion) survived to be discharged from University Hospitals Birmingham. On average, 1.21 (SD 0.28) units of packed red blood cells were transfused for every unit of fresh frozen plasma. CONCLUSIONS: The use of the current MTP was associated with a high rate of survival. Survivors require a continuity of critical care with a median demand for 3 days. The early use of plasma and platelets can be successfully delivered in the battlefield despite operational and logistic constraints.