The accuracy of prehospital triage decisions in English trauma networks - a case-cohort study.

BACKGROUND: Care for injured patients in England is provided by inclusive regional trauma networks. Ambulance services use triage tools to identify patients with major trauma who would benefit from expedited Major Trauma Centre (MTC) care. However, there has been no investigation of triage performance, despite its role in ensuring effective and efficient MTC care. This study aimed to investigate the accuracy of prehospital major trauma triage in representative English trauma networks. METHODS: A diagnostic case-cohort study was performed between November 2019 and February 2020 in 4 English regional trauma networks as part of the Major Trauma Triage Study (MATTS). Consecutive patients with acute injury presenting to participating ambulance services were included, together with all reference standard positive cases, and matched to data from the English national major trauma database. The index test was prehospital provider triage decision making, with a positive result defined as patient transport with a pre-alert call to the MTC. The primary reference standard was a consensus definition of serious injury that would benefit from expedited major trauma centre care. Secondary analyses explored different reference standards and compared theoretical triage tool accuracy to real-life triage decisions. RESULTS: The complete-case case-cohort sample consisted of 2,757 patients, including 959 primary reference standard positive patients. The prevalence of major trauma meeting the primary reference standard definition was 3.1% (n=54/1,722, 95% CI 2.3 - 4.0). Observed prehospital provider triage decisions demonstrated overall sensitivity of 46.7% (n=446/959, 95% CI 43.5-49.9) and specificity of 94.5% (n=1,703/1,798, 95% CI 93.4-95.6) for the primary reference standard. There was a clear trend of decreasing sensitivity and increasing specificity from younger to older age groups. Prehospital provider triage decisions commonly differed from the theoretical triage tool result, with ambulance service clinician judgement resulting in higher specificity. CONCLUSIONS: Prehospital decision making for injured patients in English trauma networks demonstrated high specificity and low sensitivity, consistent with the targets for cost-effective triage defined in previous economic evaluations. Actual triage decisions differed from theoretical triage tool results, with a decreasing sensitivity and increasing specificity from younger to older ages.

Electrophysiology and 3D-imaging reveal properties of human intracardiac neurons and increased excitability with atrial fibrillation.

Altered autonomic input to the heart plays a major role in atrial fibrillation (AF). Autonomic neurons termed ganglionated plexi (GP) are clustered on the heart surface to provide the last point of neural control of cardiac function. To date the properties of GP neurons in humans are unknown. Here we have addressed this knowledge gap in human GP neuron structure and physiology in patients with and without AF. Human right atrial GP neurons embedded in epicardial adipose tissue were excised during open heart surgery performed on both non-AF and AF patients and then characterised physiologically by whole cell patch clamp techniques. Structural analysis was also performed after fixation at both the single cell and at the entire GP levels via three-dimensional confocal imaging. Human GP neurons were found to exhibit unique properties and structural complexity with branched neurite outgrowth. Significant differences in excitability were revealed between AF and non-AF GP neurons as measured by lower current to induce action potential firing, a reduced occurrence of low action potential firing rates, decreased accommodation and increased synaptic density. Visualisation of entire GPs showed almost all neurons are cholinergic with a small proportion of noradrenergic and dual phenotype neurons. Phenotypic distribution differences occurred with AF including decreased cholinergic and dual phenotype neurons, and increased noradrenergic neurons. These data show both functional and structural differences occur between GP neurons from patients with and without AF, highlighting that cellular plasticity occurs in neural input to the heart that could alter autonomic influence on atrial function. KEY POINTS: The autonomic nervous system plays a critical role in regulating heart rhythm and the initiation of AF; however, the structural and functional properties of human autonomic neurons in the autonomic ganglionated plexi (GP) remain unknown. Here we perform the first whole cell patch clamp electrophysiological and large tissue confocal imaging analysis of these neurons from patients with and without AF. Our data show human GP neurons are functionally and structurally complex. Measurements of action potential kinetics show higher excitability in GP neurons from AF patients as measured by lower current to induce action potential firing, reduced low firing action potential rates, and decreased action potential accommodation. Confocal imaging shows increased synaptic density and noradrenergic phenotypes in patients with AF. Both functional and structural differences occur in GP neurons from patients with AF that could alter autonomic influence on atrial rhythm.

Fine-scale spatiotemporal variations in bacterial community diversity in agricultural pond water.

Microbial communities in surface waters are affected by environmental conditions and can influence changes in water quality. To explore the hypothesis that the microbiome in agricultural waters associates with spatiotemporal variations in overall water quality and, in turn, has implications for resource monitoring and management, we characterized the relationships between the microbiota and physicochemical properties in a model irrigation pond as a factor of sampling time (i.e., 9:00, 12:00, 15:00) and location within the pond (i.e., bank vs. interior sites and cross-sectional depths at 0, 1, and 2 m). The microbial communities, which were defined by 16S rRNA gene sequencing analysis, significantly varied based on all sampling factors (PERMANOVA P < 0.05 for each). While the relative abundances of dominant phyla (e.g., Proteobacteria and Bacteroidetes) were relatively stable throughout the pond, subtle yet significant increases in α-diversity were observed as the day progressed (ANOVA P < 0.001). Key water quality properties that also increased between the morning and afternoon (i.e., pH, dissolved oxygen, and temperature) positively associated with relative abundances of Cyanobacteria, though were inversely proportional to Verrucomicrobia. These properties, among additional parameters such as bioavailable nutrients (e.g., NH3, NO3, PO4), chlorophyll, phycocyanin, conductivity, and colored dissolved organic matter, exhibited significant relationships with relative abundances of various bacterial genera as well. Further investigation of the microbiota in underlying sediments revealed significant differences between the bank and interior sites of the pond (P < 0.05 for α- and ß-diversity). Overall, our findings emphasize the importance of accounting for time of day and water sampling location and depth when surveying the microbiomes of irrigation ponds and other small freshwater sources.

Optimisation of mitochondrial function as a novel target for resuscitation in haemorrhagic shock: a systematic review.

INTRODUCTION: Traumatic injury is one of the leading causes of death worldwide, and despite significant improvements in patient care, survival in the most severely injured patients remains unchanged. There is a crucial need for innovative approaches to improve trauma patient outcomes; this is particularly pertinent in remote or austere environments with prolonged evacuation times to definitive care. Studies suggest that maintenance of cellular homeostasis is a critical component of optimal trauma patient management, and as the cell powerhouse, it is likely that mitochondria play a pivotal role. As a result, therapies that optimise mitochondrial function could be an important future target for the treatment of critically ill trauma patients. METHODS: A systematic review of the literature was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol to determine the potential role of mitochondria in traumatic injury and haemorrhagic shock (HS) and to identify current evidence for mitochondrial optimisation therapies in trauma. Articles were included if they assessed a mitochondrial targeted therapy in comparison to a control group, used a model of traumatic injury and HS and reported a method to assess mitochondrial function. RESULTS: The search returned 918 articles with 37 relevant studies relating to mitochondrial optimisation identified. Included studies exploring a range of therapies with potential utility in traumatic injury and HS. Therapies were categorised into the key mitochondrial pathways impacted following traumatic injury and HS: ATP levels, cell death, oxidative stress and reactive oxygen species. CONCLUSION: This systematic review provides an overview of the key cellular functions of the mitochondria following traumatic injury and HS and identifies why mitochondrial optimisation could be a viable and valuable target in optimising outcome in severely injured patients in the future.

Haemostatic resuscitation in practice: a descriptive analysis of blood products administered during Operation HERRICK, Afghanistan.

INTRODUCTION: Life-threatening haemorrhage is the leading cause of potentially survivable injury in battlefield casualties. During Operation HERRICK (Afghanistan), mortality rates improved year on year due to a number of advances in trauma care, including haemostatic resuscitation. Blood transfusion practice has not previously been reported in detail during this period. METHODS: A retrospective analysis of blood transfusion at the UK role 3 medical treatment facility (MTF) at Camp Bastion between March 2006 and September 2014 was performed. Data were extracted from two sources: the UK Joint Theatre Trauma Registry (JTTR) and the newly established Deployed Blood Transfusion Database (DBTD). RESULTS: 3840 casualties were transfused 72 138 units of blood and blood products. 2709 adult casualties (71%) were fully linked with JTTR data and were transfused a total of 59 842 units. Casualties received between 1 unit and 264 units of blood product with a median of 13 units per patient. Casualties wounded by explosion required almost twice the volume of blood product transfusion as those wounded by small arms fire or in a motor vehicle collision (18 units, 9 units, and 10 units, respectively). More than half of blood products were transfused within the first 2 hours following arrival at the MTF. There was a trend towards balanced resuscitation with more equal ratios of blood and blood products being used over time. CONCLUSION: This study has defined the epidemiology of blood transfusion practice during Operation HERRICK. The DBTD is the largest combined trauma database of its kind. It will ensure that lessons learnt during this period are defined and not forgotten; it should also allow further research questions to be answered in this important area of resuscitation practice.

Outcomes of UK military personnel treated with ice cold water immersion for exertional heat stroke.

INTRODUCTION: Despite mitigation efforts, exertional heat stroke (EHS) is known to occur in military personnel during training and operations. It has significant potential to cause preventable morbidity and mortality. International consensus from sports medicine organisations supports treating EHS with early rapid cooling by immersing the casualty in cold water. However, evidence remains sparse and the practice is not yet widespread in the UK. METHODS: Following changes to enable on-site ice cold water immersion (ICWI) at the Royal Marines Commando Training Centre, Lympstone, UK, we prospectively gathered data on 35 patients treated with ICWI over a 3-year period. These data included the incidence of adverse events (e.g. death, cardiac arrest or critical care admission) as the primary outcome. Basic anthropometric data, cooling rates achieved and biochemical and haematological test results on days 0-5 were also gathered and analysed. RESULTS: Despite being a cohort of patients in whom we might expect significant morbidity and mortality based on the severity of EHS at presentation, none experienced a serious adverse event. In this cohort with rapid initiation of effective cooling, biochemical derangement appeared less severe than that reported in previous studies. Higher body mass index (BMI) was associated with a lower cooling rate across a range of values previously reported as potentially of clinical significance. CONCLUSIONS: This case series supports recent updates to UK military guidance that ICWI should be more widely adopted for the treatment of EHS. Clinicians should be aware of likely patterns of blood test abnormalities in the days following EHS. Further work should seek to establish the impact of lower rates of cooling and develop strategies to optimise cooling in patients with higher BMI.

Intra-Areal Visual Topography in Primate Brains Mapped with Probabilistic Tractography of Diffusion-Weighted Imaging.

Noninvasive diffusion-weighted magnetic resonance imaging (dMRI) can be used to map the neural connectivity between distinct areas in the intact brain, but the standard resolution achieved fundamentally limits the sensitivity of such maps. We investigated the sensitivity and specificity of high-resolution postmortem dMRI and probabilistic tractography in rhesus macaque brains to produce retinotopic maps of the lateral geniculate nucleus (LGN) and extrastriate cortical visual area V5/MT based on their topographic connections with the previously established functional retinotopic map of primary visual cortex (V1). We also replicated the differential connectivity of magnocellular and parvocellular LGN compartments with V1 across visual field positions. Predicted topographic maps based on dMRI data largely matched the established retinotopy of both LGN and V5/MT. Furthermore, tractography based on in vivo dMRI data from the same macaque brains acquired at standard field strength (3T) yielded comparable topographic maps in many cases. We conclude that tractography based on dMRI is sensitive enough to reveal the intrinsic organization of ordered connections between topographically organized neural structures and their resultant functional organization.

Evolution of the deployed medical director role in an era of contingency operations: reflections from a United Nations operation.

This paper examines the development and evolution of the deployed medical director (DMD) role and argues for the re-establishment of a formal selection process and training pathway. Recent deployments into new areas of operations, deployment of smaller medical treatment facilities (MTFs), the reduced numbers of deployments for clinicians, working with various multinational partners and both military and civilian organisations all pose specific problems for DMDs. The initial and then continued deployment of a secondary care role 2 MTF as part of the United Nations Mission in South Sudan illustrated some of these challenges. Although a novel operation, the broad categories of these new challenges were similar to the historical challenges facing the first DMDs in Afghanistan. Corporate memory loss may be unavoidable to some degree due to rapid turnover in appointments, particularly in single service and joint headquarters. However, individual memory and experience remains extant within the military medical deployable workforce. After the cessation of UK military deployed hospital care involvement in Afghanistan, the UK DMD formal training pathway ended. This paper argues for the re-establishment of a more formal DMD selection process and training pathway to ensure that organisational learning is optimised.

Killed in action (KIA): an analysis of military personnel who died of their injuries before reaching a definitive medical treatment facility in Afghanistan (2004-2014).

INTRODUCTION: The majority of combat deaths occur before arrival at a medical treatment facility but no previous studies have comprehensively examined this phase of care. METHODS: The UK Joint Theatre Trauma Registry was used to identify all UK military personnel who died in Afghanistan (2004-2014). These data were linked to non-medical tactical and operational records to provide an accurate timeline of events. Cause of death was determined from records taken at postmortem review. The primary objective was to report time between injury and death in those killed in action (KIA); secondary objectives included: reporting mortality at key North Atlantic Treaty Organisation timelines (0, 10, 60, 120 min), comparison of temporal lethality for different anatomical injuries and analysing trends in the case fatality rate (CFR). RESULTS: 2413 UK personnel were injured in Afghanistan from 2004 to 2014; 448 died, with a CFR of 18.6%. 390 (87.1%) of these died prehospital (n=348 KIA, n=42 killed non-enemy action). Complete data were available for n=303 (87.1%) KIA: median Injury Severity Score 75.0 (IQR 55.5-75.0). The predominant mechanisms were improvised explosive device (n=166, 54.8%) and gunshot wound (n=96, 31.7%).In the KIA cohort, the median time to death was 0.0 (IQR 0.0-21.8) min; 173 (57.1%) died immediately (0 min). At 10, 60 and 120 min post injury, 205 (67.7%), 277 (91.4%) and 300 (99.0%) casualties were dead, respectively. Whole body primary injury had the fastest mortality. Overall prehospital CFR improved throughout the period while in-hospital CFR remained constant. CONCLUSION: Over two-thirds of KIA deaths occurred within 10 min of injury. Improvement in the CFR in Afghanistan was predominantly in the prehospital phase.

Civil-military cooperation on operational deployment: the Bentiu State Hospital medical training programme.

The United Nations Mission in South Sudan has a mandate to protect civilians and support the delivery of humanitarian assistance. Recognising this during Operation TRENTON, UK staff of the UN level 2 hospital were able to support the people of Bentiu through initiatives to develop local health services with on-the-ground civil-military cooperation. The Bentiu State Hospital Medical Training Programme was developed to train and mentor staff associated with healthcare in Bentiu, to help improve service delivery, support local health services with on-the-ground non-governmental organisation/military coordination and to create a platform to facilitate the sharing of information to support local health services with the overall humanitarian response. It was recognised how important it was to deliver a programme that carefully understood the unique challenging limitations, circumstances and environment. Hence careful tailoring of the programme was essential to ensure that the training was valuable, implementable and durable, long beyond the operational deployment of TRENTON. Despite the logistical and practical complexities, the programme was very positively received, and the training team believed that the development and progress made would build a small part of the future infrastructure of healthcare delivery in the region. Future contingency operations are likely to take place in the resource- limited austere environment. As reflected in this deployed initiative, local health training activity providing key knowledge to build resilience for the current and immediate future is a precious and important defence engagement utility.

Intensive care medicine on military operations in the resource-limited environment: a case series.

This paper describes a series of critically ill patients who were cared for at a UK military field hospital during Op TRENTON 4, in support of the United Nations Mission in South Sudan. These cases highlight the potential challenges in managing the critically ill patient during contingency operations that take place in an austere resource-limited environment.

UK Defence Medical Services' support to the development of a multiagency major incident plan in South Sudan.

UK Defence Medical Services personnel deployed in support of the United Nations Mission in South Sudan as part of Operation TRENTON in 2017-2018. One key contribution was the development of a multiagency major incident plan in collaboration with key stakeholders within the region, including our UN partners, other troop-contributing countries and non-governmental organisations. This paper describes the process and contribution made, with some transferable lessons for future similar operations, such as adaptation of our courses. Major incident management is one of several technical areas ripe for a proactive Defence Healthcare Engagement strategy, seeking to offer capacity building in areas where Defence is rich in expertise that is highly sought after by other sectors.

Intraseasonal variation of phycocyanin concentrations and environmental covariates in two agricultural irrigation ponds in Maryland, USA.

Recently, cyanobacteria blooms have become a concern for agricultural irrigation water quality. Numerous studies have shown that cyanotoxins from these harmful algal blooms (HABs) can be transported to and assimilated into crops when present in irrigation waters. Phycocyanin is a pigment known only to occur in cyanobacteria and is often used to indicate cyanobacteria presence in waters. The objective of this work was to identify the most influential environmental covariates affecting the phycocyanin concentrations in agricultural irrigation ponds that experience cyanobacteria blooms of the potentially toxigenic species Microcystis and Aphanizomenon using machine learning methodology. The study was performed at two agricultural irrigation ponds over a 5-month period in the summer of 2018. Phycocyanin concentrations, along with sensor-based and fluorometer-based water quality parameters including turbidity (NTU), pH, dissolved oxygen (DO), fluorescent dissolved organic matter (fDOM), conductivity, chlorophyll, color dissolved organic matter (CDOM), and extracted chlorophyll were measured. Regression tree analyses were used to determine the most influential water quality parameters on phycocyanin concentrations. Nearshore sampling locations had higher phycocyanin concentrations than interior sampling locations and "zones" of consistently higher concentrations of phycocyanin were found in both ponds. The regression tree analyses indicated extracted chlorophyll, CDOM, and NTU were the three most influential parameters on phycocyanin concentrations. This study indicates that sensor-based and fluorometer-based water quality parameters could be useful to identify spatial patterns of phycocyanin concentrations and therefore, cyanobacteria blooms, in agricultural irrigation ponds and potentially other water bodies.

Medical Civil-Military Relationships: A Feasibility Study of a United Kingdom Deployment in South Sudan.

OBJECTIVES: Civil-military relationships are necessary in humanitarian emergencies but, if poorly managed, may be detrimental to the efforts of humanitarian organizations. Awareness of guidelines and understanding of risks relating to the relationship among deployed military personnel have not been evaluated. METHODS: Fifty-five military and 12 humanitarian healthcare workers in South Sudan completed questionnaires covering experience, training and role, agreement with statements about the deployment, and free text comments. RESULTS: Both cohorts were equally aware of current guidance. Eight themes defined the relationship. There was disagreement about the benefit to the South Sudanese people of the military deployment, and whether military service was compatible with beneficial health impacts. Two key obstacles to the relationship and 3 areas the relationship could be developed were identified. CONCLUSION: This study shows that United Kingdom military personnel are effectively trained and understand the constraints on the civil-military relationship. Seven themes in common between the groups describe the relationship. Current guidance could be adapted to allow a different relationship for healthcare workers.

Triage and the Modified Physiological Triage Tool-24 (MPTT-24).

Major incidents occur on a regular basis. So far in 2017, England has witnessed five terrorism-related major incidents, resulting in approximately 40 fatalities and 400 injured. Triage is a key principle in the effective management of a major incident and involves prioritising patients on the basis of their clinical acuity. This paper describes the limitations associated with existing methods of primary major incident triage and the process of developing a new and improved triage tool-the Modified Physiological Triage Tool-24 (MPTT-24). Whilst the MPTT-24 is likely to be the optimum physiological method for primary major incident triage, it needs to be accompanied by an appropriate secondary triage process. The existing UK military and civilian secondary triage tool, the Triage Sort, is described, which offers little advantage over primary methods for identifying patients who require life-saving intervention. Further research is required to identify the optimum method of secondary triage.

The impact of emergency department patient-controlled analgesia (PCA) on the incidence of chronic pain following trauma and non-traumatic abdominal pain.

The effect of patient-controlled analgesia during the emergency phase of care on the prevalence of persistent pain is unkown. We studied individuals with traumatic injuries or abdominal pain 6 months after hospital admission via the emergency department using an opportunistic observational study design. This was conducted using postal questionnaires that were sent to participants recruited to the multi-centre pain solutions in the emergency setting study. Patients with prior chronic pain states or opioid use were not studied. Questionnaires included the EQ5D, the Brief Pain Inventory and the Hospital Anxiety and Depression scale. Overall, 141 out of 286 (49% 95%CI 44-56%) patients were included in this follow-up study. Participants presenting with trauma were more likely to develop persistent pain than those presenting with abdominal pain, 45 out of 64 (70%) vs. 24 out of 77 (31%); 95%CI 24-54%, p < 0.001. There were no statistically significant associations between persistent pain and analgesic modality during hospital admission, age or sex. Across both abdominal pain and traumatic injury groups, participants with persistent pain had lower EQ5D mobility scores, worse overall health and higher anxiety and depression scores (p < 0.05). In the abdominal pain group, 13 out of 50 (26%) patients using patient-controlled analgesia developed persistent pain vs. 11 out of 27 (41%) of those with usual treatment; 95%CI for difference (control - patient-controlled analgesia) -8 to 39%, p = 0.183. Acute pain scores at the time of hospital admission were higher in participants who developed persistent pain; 95%CI 0.7-23.6, p = 0.039. For traumatic pain, 25 out of 35 (71%) patients given patient-controlled analgesia developed persistent pain vs. 20 out of 29 (69%) patients with usual treatment; 95%CI -30 to 24%, p = 0.830. Persistent pain is common 6 months after hospital admission, particularly following trauma. The study findings suggest that it may be possible to reduce persistent pain (at least in patients with abdominal pain) by delivering better acute pain management. Further research is needed to confirm this hypothesis.

Catastrophic haemorrhage in military major trauma patients: a retrospective database analysis of haemostatic agents used on the battlefield.

OBJECTIVES: Catastrophic haemorrhage is a leading cause of morbidity and mortality in trauma, in both military and civilian settings. There are numerous studies looking at the effectiveness of different haemostatic agents in the laboratory but few in a clinical setting. This study analyses the use of haemostatic dressings used in patients injured on the battlefield and their association with survival. METHOD: A retrospective database review was undertaken using the UK Joint Theatre Trauma Registry from 2003 to 2014, during combat operations in Iraq and Afghanistan. Data included patient demographics, the use of haemostatic dressings, New Injury Severity Score (NISS) and patient outcome. RESULTS: Of 3792 cases, a haemostatic dressing was applied in 317 (either Celox, Hemcon or Quickclot). When comparing patients who had a haemostatic dressing applied versus no haemostatic agent, there was a 7% improvement in survival. Celox was the only individual haemostatic dressing that was associated with a statistically significant improvement in survival, which was most apparent in the more severely injured (NISS 36-75). CONCLUSION: We have shown an association between use of haemostatic agents and improved survival, mostly in those with more severe injuries, which is particularly evident in those administered Celox. This supports the continued use of haemostatic agents as part of initial haemorrhage control for patients injured in conflict and suggests that civilian organisations that may need to deal with patients with similar injury patterns should consider their use and implementation.

Use of supplemental oxygen in emergency patients: a systematic review and recommendations for military clinical practice.

INTRODUCTION: Supplemental oxygen is a key element of emergency treatment algorithms. However, in the operational environment, oxygen supply poses a challenge. The lack of high-quality evidence alongside emerging technologies provides the opportunity to challenge current guidelines. The aim of this review was to appraise the evidence for the administration of oxygen in emergency patients and give recommendations for its use in clinical practice. METHODS: A critical review of the literature was undertaken to determine the evidence for emergency supplemental oxygen use. RESULTS: Based on interpretation of the limited available evidence, five key recommendations are made: pulse oximetry should be continuous and initiated as early as possible; oxygen should be available to all trauma and medical patients in the forward operating environment; if peripheral oxygen saturations (SpO2) are greater than or equal to 92%, supplemental oxygen is not routinely required; if SpO2 is less than 92%, supplemental oxygen should be titrated to achieve an SpO2 of greater than 92%; and if flow rates of greater than 5 L/min are required, then urgent evacuation and critical care support should be requested. CONCLUSION: Oxygen is not universally required for all patients. Current guidelines aim to prevent hypoxia but with potentially conservative limits. Oxygen should be administered to maintain SpO2 at 92% or above. New areas for research, highlighted in this review, may provide a future approach for oxygen use from point of injury to definitive care.