Defence Medical Services' REBOA training course.

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) enables temporary haemorrhage control and physiological stabilisation. This article describes the bespoke Defence Medical Services (DMS) training package for effectively using REBOA. The article covers how the course was designed, how the key learning objectives are taught, participant feedback and the authors' perceptions of future training challenges and opportunities. Since the inaugural training course in April 2019, the authors have delivered six courses, training over 100 clinicians. For the first time in the UK DMS, we designed and delivered a robust specialist endovascular training programme, with demonstrable, significant increases in confidence and competence. As a result of this course, the first DMS REBOA-equipped forward surgical teams deployed in June 2019. Looking to the future, there is a requirement to develop an assessment of skill retention and the potential need for revalidation.

Balloons on the battlefield: REBOA implementation in the UK Defence Medical Services.

Established in 2018, the Defence Endovascular Resuscitation (DefER) group recognised that resuscitative endovascular balloon occlusion of the aorta (REBOA) offered an option to improve survival in battle casualties dying from haemorrhage, particularly in remote and austere surgical settings. Following a successful jHub opportunity assessment, DefER purchased training and operational kit at pace. By 1 April 2019, the first forward surgical group undertook a bespoke endovascular training and assessment package. Results of the pilot were presented back to a jHub 4* Innovation Board, which initially awarded £500 000 to fund the project to full implementation. Med Op Cap provided a solution to establish REBOA as a core capability on to the 370 modules. REBOA catheters and arterial access kit are now available to deployed Role 2 facilities across defence as an adjunct to damage control resuscitation in specific circumstances. REBOA has, from a standing start, gained pan-Defence Medical Services (DMS) endorsement and has been integrated into deployed damage control resuscitation. To establish a new resuscitation capability across all Role 2 platforms within 15 months of inception represents implementation at pace. This agility was unlocked by empowering clinicians to develop the platform in conjunction with commercial procurement. This article describes how this innovative pathway facilitated the rapid introduction of a lifesaving haemorrhage control technique to equip DMS clinicians.

Effects of Angular Resolution and b Value on Diffusion Tensor Imaging in Knee Joint.

OBJECTIVE: To investigate the influences of the diffusion gradient directions (angular resolution) and the strength of the diffusion gradient (b value) on diffusion tensor imaging (DTI) metrics and tractography of various connective tissues in knee joint. DESIGN: Two rat knee joints were scanned on a preclinical 9.4-T system using a 3-dimensional diffusion-weighted spin echo pulse sequence. One protocol with b value of 500, 1500, and 2500 s/mm2 were acquired separately using 43 diffusion gradient directions. The other protocol with b value of 1000 s/mm2 was performed using 147 diffusion gradient directions. The in-plane resolution was 45 µm isotropic. Fractional anisotropy (FA) and mean diffusivity (MD) were compared at different angular resolution. Tractography was quantitatively evaluated at different b values and angular resolutions in cartilage, ligament, meniscus, and growth plate. RESULTS: The ligament showed higher FA value compared with growth plate and cartilage. The FA values were largely overestimated at the angular resolution of 6. Compared with FA, MD showed less sensitivity to the angular resolution. The fiber tracking was failed at low angular resolution (6 diffusion gradient directions) or high b value (2500 s/mm2). The quantitative measurements of tract length and track volume were strongly dependent on angular resolution and b value. CONCLUSIONS: To obtain consistent DTI outputs and tractography in knee joint, the scan may require a proper b value (ranging from 500 to 1500 s/mm2) and sufficient angular resolution (>14) with signal-to-noise ratio >10.

The REBOA window: a cadaveric study delineating the optimum site for austere cannulation of the femoral artery for resuscitative endovascular balloon occlusion of the aorta.

INTRODUCTION: Haemorrhage is the major cause of early mortality following traumatic injury. Patients suffering from non-compressible torso haemorrhage are more likely to suffer early death. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) can be effective in initial resuscitation; however, establishing swift arterial access is challenging, particularly in a severe shock. This is made more difficult by anatomical variability of the femoral vessels. METHODS: The femoral vessels were characterised in 81 cadaveric lower limbs, measuring specifically the distance from the inferior border of the inguinal ligament to the distal part of the origin of the profunda femoris artery (PFA), and from the distal part of the origin of the PFA to where the femoral vein lies posterior to and is completely overlapped by the femoral artery. RESULTS: The femoral vein lay deep to the femoral artery at a mean distance of 105 mm from the inferior border of the inguinal ligament. The PFA arose from the femoral artery at a mean distance of 51.1 mm from the inguinal ligament. From the results, it is predicted that the PFA originates from the common femoral artery approximately 24 mm from the inguinal ligament, and the femoral vein is completely overlapped by the femoral artery by 67.7 mm distal from the inguinal ligament, in 95% of subjects. CONCLUSIONS: Based on the results, proposed is an 'optimal access window' of up to 24 mm inferior to the inguinal ligament for common femoral arterial catheterisation for pre-hospital REBOA, or more simply within one finger breadth.

Application of automated electron microscopy imaging and machine learning to characterise and quantify nanoparticle dispersion in aqueous media.

For many nanoparticle applications it is important to understand dispersion in liquids. For nanomedicinal and nanotoxicological research this is complicated by the often complex nature of the biological dispersant and ultimately this leads to severe limitations in the analysis of the nanoparticle dispersion by light scattering techniques. Here we present an alternative analysis and associated workflow which utilises electron microscopy. The need to collect large, statistically relevant datasets by imaging vacuum dried, plunge frozen aliquots of suspension was accomplished by developing an automated STEM imaging protocol implemented in an SEM fitted with a transmission detector. Automated analysis of images of agglomerates was achieved by machine learning using two free open-source software tools: CellProfiler and ilastik. The specific results and overall workflow described enable accurate nanoparticle agglomerate analysis of particles suspended in aqueous media containing other potential confounding components such as salts, vitamins and proteins. LAY DESCRIPTION: In order to further advance studies in both nanomedicine and nanotoxicology, we need to continue to understand the dispersion of nanoparticles in biological fluids. These biological environments often contain a number of components such as salts, vitamins and proteins which can lead to difficulties when using traditional techniques to monitor dispersion. Here we present an alternative analysis which utilises electron microscopy. In order to use this approach statistically relevant large image datasets were collected from appropriately prepared samples of nanoparticle suspensions by implementing an automated imaging protocol. Automated analysis of these images was achieved through machine learning using two readily accessible freeware; CellProfiler and ilastik. The workflow presented enables accurate nanoparticle dispersion analysis of particles suspended in more complex biological media.

Military application of mechanical CPR devices: a pressing requirement?

Maintaining high-quality chest compressions during cardiopulmonary resuscitation following cardiac arrest presents a challenge. The currently available mechanical CPR (mCPR) devices are described in this review, coupled with an analysis of the evidence pertaining to their efficacy. Overall, mCPR appears to be at least equivalent to high-quality manual CPR in large trials. There is potential utility for mCPR devices in the military context to ensure uninterrupted quality CPR following a medical cardiac arrest. Particular utility may be in a prohibitive operational environment, where manpower is limited or where timelines to definitive care are stretched resulting in a requirement for prolonged resuscitation. mCPR can also act as a bridge to advanced endovascular resuscitation techniques should they become more mainstream therapy.

Colorectal cancer and thrombosis.

SIGNIFICANCE: Colorectal cancer (CRC), results in a hypercoagulable state which manifests clinically as venous thromboembolism (VTE), often presenting as a deep vein thrombosis (DVT) or pulmonary embolism (PE). The consequences of VTE in CRC can be devastating, resulting in long-term morbidity and are a frequent cause of death, even amongst those who would have otherwise had a favourable cancer prognosis. The incidence of VTE in all cancers is increasing, whilst the exact incidence of VTE in CRC is likely to be underestimated. All cancer treatments increase the risk of VTE in an already at risk population. CRITICAL ISSUES: CRC-associated VTE is a challenging entity to manage with recurrences occurring more frequently in cancer patients, despite anticoagulation. Anticoagulation, whether treatment or prophylactic, increases the risk of bleeding, especially in patients with cancer. Although strong evidence underpins the initial management of cancer-associated VTE, there is uncertainty with regard optimum treatment duration. For VTE prevention, extended (28 days), pharmacological thromboprophylaxis post CRC surgery is internationally recommended. Pharmacological thromboprophylaxis is not routinely recommended for nonhospitalised patients receiving chemotherapy. FUTURE DIRECTIONS: There is growing evidence of a symbiotic relationship between cancer biology and the clotting system. Tissue factor (TF), the initiator of the clotting pathway, promotes cancer via clotting dependent and independent mechanisms. Clotting pathway factors, including TF, may have utility as biomarkers in CRC, for assessment of VTE risk in addition to cancer prognosis. The clotting system may also be a target for potential anti-cancer therapies, either via existing anticoagulants or experimental direct TF inhibitors.

Shocking the system: AEDs in military resuscitation.

Automated external defibrillator (AED) devices have been in routine clinical use since the early 1990s to deliver life-saving shocks to appropriate patients in non-clinical environments. As expectations of survival from out-of-hospital cardiac arrest increase, and evidence incontrovertibly points to reduced timelines as the most crucial factor in achieving return of spontaneous circulation, questions regarding the availability and location of AEDs in the UK military need to be readdressed. This article explores the background of AEDs and reviews their history, life-saving potential and defines current and best practice. It goes on to review the evidence surrounding training and looks to identify knowledge gaps that might be addressed effectively by future research. Finally, it makes recommendations regarding training, availability of AEDs on military bases and locations most likely to deliver good outcomes for military personnel in the future.

Enhanced case management can be delivered for patients with EVD in Africa: Experience from a UK military Ebola treatment centre in Sierra Leone.

BACKGROUND: Limited data exist describing supportive care management, laboratory abnormalities and outcomes in patients with Ebola virus disease (EVD) in West Africa. We report data which constitute the first description of the provision of enhanced EVD case management protocols in a West African setting. METHODS: Demographic, clinical and laboratory data were collected by retrospective review of clinical and laboratory records of patients with confirmed EVD admitted between 5 November 2014 and 30 June 2015. RESULTS: A total of 44 EVD patients were admitted (median age 37 years (range 17-63), 32/44 healthcare workers), and excluding those evacuated, the case fatality rate was 49% (95% CI 33%-65%). No pregnant women were admitted. At admission 9/44 had stage 1 disease (fever and constitutional symptoms only), 12/44 had stage 2 disease (presence of diarrhoea and/or vomiting) and 23/44 had stage 3 disease (presence of diarrhoea and/or vomiting with organ failure), with case fatality rates of 11% (95% CI 1%-58%), 27% (95% CI 6%-61%), and 70% (95% CI 47%-87%) respectively (p = 0.009). Haemorrhage occurred in 17/41 (41%) patients. The majority (21/40) of patients had hypokalaemia with hyperkalaemia occurring in 12/40 patients. Acute kidney injury (AKI) occurred in 20/40 patients, with 14/20 (70%, 95% CI 46%-88%) dying, compared to 5/20 (25%, 95% CI 9%-49%) dying who did not have AKI (p = 0.01). Ebola virus (EBOV) PCR cycle threshold value at baseline was mean 20.3 (SD 4.3) in fatal cases and 24.8 (SD 5.5) in survivors (p = 0.007). Mean national early warning score (NEWS) at admission was 5.5 (SD 4.4) in fatal cases and 3.0 (SD 1.9) in survivors (p = 0.02). Central venous catheters were placed in 37/41 patients and intravenous fluid administered to 40/41 patients (median duration of 5 days). Faecal management systems were inserted in 21/41 patients, urinary catheters placed in 27/41 and blood component therapy administered to 20/41 patients. CONCLUSIONS: EVD is commonly associated life-threatening electrolyte imbalance and organ dysfunction. We believe that the enhanced levels of protocolized care, scale and range of medical interventions we report, offer a blueprint for the future management of EVD in resource-limited settings.

Organic matter identifies the nano-mechanical properties of native soil aggregates.

Localized variations at the nanoscale in soil aggregates and in the spatial organisation of soil organic matter (SOM) are critical to understanding the factors involved in soil composition and turnover. However soil nanoscience has been hampered by the lack of suitable methods to determine soil biophysical properties at nanometre spatial resolution with minimal sample preparation. Here we introduce for the first time an Atomic Force Microscopy (AFM)-based Quantitative Nano-Mechanical mapping (QNM) approach that allows the characterisation of the role of SOM in controlling surface nano-mechanical properties of soil aggregates. SOM coverage resulted in an increased roughness and surface variability of soil, as well as in decreased stiffness and adhesive properties. The latter also correlates with nano- to macro-wettability features as determined by contact angle measurements and Water Drop Penetration Time (WDPT) testing. AFM thus represents an ideal quantitative tool to complement existing techniques within the emerging field of soil nanoscience.

Spatially-resolved profiling of carbon nanotube uptake across cell lines.

The internalisation and intra-cellular distribution of carbon nanotubes (CNT) has been quantitatively assessed using imaging flow cytometry. Spatial analysis of the bright field images indicates the presence of a small sub-population (5% of cells) in which the internalised CNTs are packed into pronounced clusters, visible as dark spots due to strong optical scattering by the nanotubes. The area of these spots can be used as a label-free metric of CNT dose and we assess the relative uptake of charge-neutral CNTs, over a 24 hours exposure period across four cell types: J774 mouse macrophage cells, A549 and Calu-6 human lung cancer cells, and MCF-7 human breast cells. The relative dose as indicated by the spot-area metric closely correlates to results using the same CNT preparation, conjugated to a FITC-label and shows pronounced uptake by the J774 cells leading to a mean dose that is >60% higher than for the other cell types. Spatial evaluation of dosing clusters is also used to quantify differences in uptake by J774 cells of CNTs with different surface functionalisation. While the percentage of CNT-cluster positive cells increases from 5% to 19% when switching from charge-neutral CNTs to poly-cationic, dendron functionalised CNTs, the single cell level analysis of internalised clusters indicates a lower dose per cell of poly-cationic CNTs relative to the charge-neutral CNTs. We concluded that there is dose homeostasis i.e., the population-averaged cellular dose of CNTs remained unchanged.

Child abuse and fabricated or induced illness in the ENT setting: a systematic review.

BACKGROUND: Child maltreatment is persistently under-recognised. Given that a third of maltreated children may return with serious or fatal injuries, it is imperative that otolaryngologists who are in frequent contact with children are able to detect maltreatment at first presentation. OBJECTIVE OF REVIEW: This review aims to identify ENT injuries, signs or symptoms that are indicative of physical abuse or fabricated or induced illness (child maltreatment). TYPE OF REVIEW: Systematic review. SEARCH STRATEGY: An all-language search, developed in Medline Ovid and consisting of 76 key words, was conducted of published and grey literature across 10 databases from inception to July 2015, for primary observational studies involving children aged <18 years. EVALUATION METHOD: Each relevant article underwent two independent reviews with full critical appraisal, applying strict quality standards. RESULTS: Of the 2448 studies identified and screened, 371 underwent full review, resulting in 38 included studies that detailed 122 maltreated children. Pharyngeal perforations (n = 20) were the most frequent abusive ENT injury, predominantly affecting neonates and infants, presenting with dysphagia, drooling, haemoptysis and surgical emphysema. At least 52% of children with abusive pharyngeal injuries had additional co-existent injuries. The majority of ear injuries were inflicted to the external ear (n = 11) and included auricular deformity, abrasions, petechiae, lacerations and burns. Fabricated or induced illness cases presented most commonly with recurrent, unexplained otorrhoea or ENT lesions that failed to heal despite appropriate therapy. CONCLUSIONS: All clinicians should be familiar with the signs of child maltreatment. Pharyngeal injuries, or injuries to the external ear, presenting in young children without an explicit history of witnessed injury should prompt a child protection referral for full evaluation. Likewise, children who present with recurrent, or apparently intractable symptoms and signs despite appropriate treatment, should raise the possibility of fabricated or induced illness, and discussion with a child protection specialist is advised. Early recognition of possible child maltreatment and instigation of appropriate safeguarding measures are essential to prevent repetition and escalation of injury. This is of paramount importance to otolaryngologists, who have the potential to identify these children in their practice.

PO-32 - Patient, tumour and operative factors influencing perioperative hypercoagulability in colorectal cancer.

INTRODUCTION: Up to 6% of patients develop venous thromboembolism (VTE) following elective colorectal cancer surgery despite thromboprophylaxis. Clinical practices for perioperative thromboprophylaxis remains variable, particularly the use and duration of extended thromboprophylaxis. Identification of factors associated with a prolonged postoperative hypercoagulable state may allow the development of algorithms that allow more targeted thromboprophylaxis. AIM: To identify patient, tumour and surgical risk factors for prolonged (two and six weeks) hypercoagulability in colorectal cancer patients undergoing surgical resection. MATERIALS AND METHODS: In a prospective cohort study (Cancer-induced Hypercoagulability As a Marker of Prognosis [CHAMPion]), plasma d-dimer was measured at 2 and 6weeks post-operatively in patients undergoing elective, curative resection for colorectal cancer. Hypercoagulability (raised D-dimer) at 2 and 6weeks was correlated with patient, tumour and operative factors. RESULTS: Of the 62 patients recruited (median age 69years [range 39-90]), 37 were male. D-dimer was increased in females compared to males at six weeks (geometric mean (GM) 1,287ng/ml [95% CI 944 - 1,755 vs. 821ng/ml (95% CI 633 - 1064) p=0.03]. Age, smoking, hypertension, use of antiplatelet medication, BMI and WHO performance status were not associated with a prolonged hypercoagulable state. There were no tumour factors (including size/T stage/lymph node involvement/differentiation) associated with a prolonged hypercoagulable state. D-dimer was increased in patients undergoing open surgery (n=39) compared to laparoscopic surgery (n=23) at 2weeks (GM 2,337ng/ml [95% CI 1,806-3,023] vs. 1,212ng/ml [95% CI 898-1,629], p=0.001) and 6weeks (GM 1,162ng/ml [95% CI 818-1647] vs. 723ng/ml [95% CI 533-982]p=0.04). Operative time was not associated with prolonged hypercoagulability. D-dimer had a trend to be increased at 2weeks in patients receiving perioperative blood transfusions (n=8) compared to those that did not (n=54) (GM 2,618ng/ml [95% CI 1,525-4,536] vs. 1613ng/ml [95% CI 1,236 - 2,100] p=0.08). CONCLUSIONS: Even in this relatively small cohort of patients female gender, open surgery and receiving a blood transfusion are associated with on-going hypercoagulability up to six weeks post operation. This may represent a group where thromboprophylaxis should be targeted.

The athletic ECG.

The electrocardiogram (ECG) is the most frequently performed basic cardiology investigation. Correct interpretation of the ECG is vital, both to confirm acute diagnoses such as myocardial infarction, and in the elective setting to diagnose previous or underlying cardiac abnormalities. Normal electrocardiographic parameters for the multiple components of the ECG have been identified and are applied to the general population, but it is acknowledged that cardiac conditioning occurs with frequent and sustained aerobic exercise, in turn leading to physiological changes in the ECG. Service personnel may perform exercise at a level that leads to cardiac conditioning with associated ECG changes. This clinical review will briefly address the normal ECG and consider changes associated with aerobic cardiac conditioning. By identifying what constitutes physiological non-pathological changes in the athletic ECG, this clinical review aims to assist those who interpret ECGs in Service personnel.

Acute chest pain in contingency operations at a Role 1 facility.

Acute chest pain is a common medical presenting complaint which can be difficult to diagnose and treat outside of a fully equipped emergency department. In future contingency operations the number of personnel deployed is likely be smaller, with the medical cover appropriate for the population at risk, such that the deployed medical facilities will be smaller than the Role 3 unit with which we have become familiar over the last 10 years of operations in Afghanistan. Physician involvement in these smaller medical facilities is crucial to maintain clinical effect when dealing with patients presenting with disease and non-battle injury, which can often make up the majority of deployed healthcare work. Patients presenting with chest pain require rapid assessment and stabilisation prior to medical evacuation to a suitable definitive care unit. This article focuses on emergency acute chest pain presentations, non-cardiac causes of chest pain, risk reduction and how contingency will affect patient care.

Coronary artery disease in the military patient.

Ischaemic heart disease is the most common cause of sudden death in the UK, and the most common cardiac cause of medical discharge from the Armed Forces. This paper reviews current evidence pertaining to the diagnosis and management of coronary artery disease from a military perspective, encompassing stable angina and acute coronary syndromes. Emphasis is placed on the limitations inherent in the management of acute coronary syndromes in the deployed environment. Occupational issues affecting patients with coronary artery disease are reviewed. Consideration is also given to the potential for coronary artery disease screening in the military, and the management of modifiable cardiovascular disease risk factors, to help decrease the prevalence of coronary artery disease in the military population.

Safety and feasibility of a strategy of early central venous catheter insertion in a deployed UK military Ebola virus disease treatment unit.

PURPOSE: Early central venous catheter (CVC) insertion in Ebola virus disease (EVD) is a novel approach and has not previously been described. This report delineates the safety, feasibility and clinical implications of early CVC insertion as the optimum means of vascular access in patients with EVD, in the setting of a deployed military Ebola virus disease treatment unit in Sierra Leone. METHODS: In the gastrointestinal phase of EVD, a 7-French 20-cm triple-lumen CVC was inserted using aseptic technique. Data were collected prospectively on all cases to include baseline and subsequent blood test variables, insertion site and technique, and complications associated with CVC placement. RESULTS: Twenty-three patients underwent CVC insertion as follows: subclavian, 21 (88 %); internal jugular, 2 (8 %); axillary, 1 (4 %). The mean duration of CVC placement was 5 days. There were no significant procedure-related adverse events. Despite coagulopathy being present in 75 % of cases, CVC insertion was safe, and there was only 1 case of significant catheter site bleeding. A total of 152 needle venepunctures were avoided owing to the presence of a CVC, a mean of 7 (±3.8) per case over the average stay. CONCLUSION: The early use of CVCs in Ebola virus disease is safe, effective and facilitates patient care. It should be considered a feasible additional route of venous access, where physician expertise and resources allow.

Nurse-delivered focused echocardiography to determine intravascular volume status in a deployed maritime critical care unit.

Focused echocardiography is increasingly used by clinicians to guide fluid resuscitation. The UK Defence Medical Services (DMS) have adopted focused echocardiography as a tool to guide flow assessment and resuscitation in deployed critical care. We aimed to explore whether two focused echo techniques, namely Inferior Vena Cava (IVC) and Left Ventricular Outflow Tract Velocity Time integer (LVOT VTi) respiratory variability could be taught to a group of critical care nurses without previous exposure to ultrasound imaging. After a five-week program of training, validation was carried out on healthy volunteers. The mentor, an accredited focused echo trainer, and six nurses performed a total of forty-eight scans on eleven volunteers. The mentor and students acquired subcostal long axis views of the IVC and apical five chamber views using a high frequency linear ultrasound probe. Mean values from three measurements were obtained for IVC diameter and LVOT VTi. Minimum and maximum values were recorded for both variables across a full respiratory cycle. Echo images were saved and at least two images for each student were reviewed offline by an accredited echo-training supervisor. In all cases students were able to obtain adequate echo windows. There was good correlation between values recorded by the mentor and students for both IVC diameter (r = 0.90, p < 0.001) and LVOT VTi (r = 0.77, p < 0.001). Bland Altman analysis showed good correlation with minimal bias for VTi measurements. There was some increase in bias for IVC measurements below 1.2 cm. In summary, we found that these skills for assessing intravascular volume status could be acquired in a relatively short time by specialist nurses without previous experience, and that results were comparable to those produced by an experienced practitioner.