Triage in major incidents: development and external validation of novel machine learning-derived primary and secondary triage tools.

BACKGROUND: Major incidents (MIs) are an important cause of death and disability. Triage tools are crucial to identifying priority 1 (P1) patients-those needing time-critical, life-saving interventions. Existing expert opinion-derived tools have limited evidence supporting their use. This study employs machine learning (ML) to develop and validate models for novel primary and secondary triage tools. METHODS: Adults (16+ years) from the UK Trauma Audit and Research Network (TARN) registry (January 2008-December 2017) served as surrogates for MI victims, with P1 patients identified using predefined criteria. The TARN database was split chronologically into model training and testing (70:30) datasets. Input variables included physiological parameters, age, mechanism and anatomical location of injury. Random forest, extreme gradient boosted tree, logistic regression and decision tree models were trained to predict P1 status, and compared with existing tools (Battlefield Casualty Drills (BCD) Triage Sieve, CareFlight, Modified Physiological Triage Tool, MPTT-24, MSTART, National Ambulance Resilience Unit Triage Sieve and RAMP). Primary and secondary candidate models were selected; the latter was externally validated on patients from the UK military's Joint Theatre Trauma Registry (JTTR). RESULTS: Models were internally tested in 57 979 TARN patients. The best existing tool was the BCD Triage Sieve (sensitivity 68.2%, area under the receiver operating curve (AUC) 0.688). Inability to breathe spontaneously, presence of chest injury and mental status were most predictive of P1 status. A decision tree model including these three variables exhibited the best test characteristics (sensitivity 73.0%, AUC 0.782), forming the candidate primary tool. The proposed secondary tool (sensitivity 77.9%, AUC 0.817), applicable via a portable device, includes a fourth variable (injury mechanism). This performed favourably on external validation (sensitivity of 97.6%, AUC 0.778) in 5956 JTTR patients. CONCLUSION: Novel triage tools developed using ML outperform existing tools in a nationally representative trauma population. The proposed primary tool requires external validation prior to consideration for practical use. The secondary tool demonstrates good external validity and may be used to support decision-making by healthcare workers responding to MIs.

Paediatric major incident triage: UK military tool offers best performance in predicting the need for time-critical major surgical and resuscitative intervention.

BACKGROUND: Children are frequently injured during major incidents (MI), including terrorist attacks, conflict and natural disasters. Triage facilitates healthcare resource allocation in order to maximise overall survival. A critical function of MI triage tools is to identify patients needing time-critical major resuscitative and surgical intervention (Priority 1 (P1) status). This study compares the performance of 11 MI triage tools in predicting P1 status in children from the UK Trauma Audit and Research Network (TARN) registry. METHODS: Patients aged <16 years within TARN (January 2008-December 2017) were included. 11 triage tools were applied to patients' first recorded pre-hospital physiology. Patients were retrospectively assigned triage categories (P1, P2, P3, Expectant or Dead) using predefined intervention-based criteria. Tools' performance in <16s were evaluated within four-yearly age subgroups, comparing tool-predicted and intervention-based priority status. FINDINGS: Amongst 4962 patients, mortality was 1.1% (n = 53); median Injury Severity Score (ISS) was 9 (IQR 9-16). Blunt injuries predominated (94.4%). 1343 (27.1%) met intervention-based criteria for P1, exhibiting greater intensive care requirement (60.2% vs. 8.5%, p < 0.01) and ISS (median 17 vs 9, p < 0.01) compared with P2 patients. The Battlefield Casualty Drills (BCD) Triage Sieve had greatest sensitivity (75.7%) in predicting P1 status in children <16 years, demonstrating a 38.4-49.8% improvement across all subgroups of children <12 years compared with the UK's current Paediatric Triage Tape (PTT). JumpSTART demonstrated low sensitivity in predicting P1 status in 4 to 8 year olds (35.5%) and 0 to 4 year olds (28.5%), and was outperformed by its adult counterpart START (60.6% and 59.6%). INTERPRETATION: The BCD Triage Sieve had greatest sensitivity in predicting P1 status in this paediatric trauma registry population: we recommend it replaces the PTT in UK practice. Users of JumpSTART may consider alternative tools. We recommend Lerner's triage category definitions when conducting MI evaluations.

The BCD Triage Sieve outperforms all existing major incident triage tools: Comparative analysis using the UK national trauma registry population.

BACKGROUND: Natural disasters, conflict, and terrorism are major global causes of death and disability. Central to the healthcare response is triage, vital to ensure the right care is provided to the right patient at the right time. The ideal triage tool has high sensitivity for the highest priority (P1) patients with acceptably low over-triage. This study compared the performance of major incident triage tools in predicting P1 casualty status in adults in the prospective UK Trauma Audit and Research Network (TARN) registry. METHODS: TARN patients aged 16+ years (January 2008-December 2017) were included. Ten existing triage tools were applied using patients' first recorded pre-hospital physiology. Patients were subsequently assigned triage categories (P1, P2, P3, Expectant or Dead) based on pre-defined, intervention-based criteria. Tool performance was assessed by comparing tool-predicted and intervention-based priority status. FINDINGS: 195,709 patients were included; mortality was 7·0% (n=13,601); median Injury Severity Score (ISS) was 9 (IQR 9-17); 97·1% sustained blunt injuries. 22,144 (11·3%) patients fulfilled intervention-based criteria for P1 status, exhibiting higher mortality (12·8% vs. 5·0%, p<0.001), increased intensive care requirement (52·4% vs 5·0%, p<0.001), and more severe injuries (median ISS 21 vs 9, p<0.001) compared with P2 patients.In 16-64 year olds, the highest performing tool was the Battlefield Casualty Drills (BCD) Triage Sieve (Prediction of P1 status: 70·4% sensitivity, over-triage 70·9%, area under the receiver operating curve (AUC) 0·068 [95%CI 0·676-0·684]). The UK National Ambulance Resilience Unit (NARU) Triage Sieve had sensitivity of 44·9%; over-triage 56·4%; AUC 0·666 (95%CI 0·662-0·670). All tools performed poorly amongst the elderly (65+ years). INTERPRETATION: The BCD Triage Sieve performed best in this nationally representative population; we recommend it supersede the NARU Triage Sieve as the UK primary major incident triage tool. Validated triage category definitions are recommended for appraising future major incidents. FUNDING: This study is funded by the National Institute for Health Research (NIHR) Surgical Reconstruction and Microbiology Research Centre. GVG also acknowledges support from the MRC Heath Data Research UK (HDRUK/CFC/01). The views expressed are those of the authors and not necessarily those of the NIHR, the Department of Health and Social Care, or the Ministry of Defence.

A Comparison of Improvised and Commercially Available Point-of-Wounding Tourniquets in Simulated Traumatic Amputation with Catastrophic Hemorrhage.

INTRODUCTION: Catastrophic hemorrhage is the leading cause of preventable trauma deaths in the military and civilian populations. The use of tourniquets by first responders (medical and nonmedically trained) is supported and has the potential to save lives if applied correctly. AIMS: We sought to examine the use of 5 tourniquets: 1 improvised and 4 commercially available tourniquets to investigate the time taken to stop simulated bleeding and to secure the device; evidence of rebleeding when the "blood pressure" was restored and to gain qualitative feedback on their application. MATERIALS AND METHODS: Four commercially available tourniquets (Combat Application Tourniquet [C-A-T], Special Operations Forces Tactical Tourniquet - Wide (SOFTT-W), stretch, wrap, and tuck tourniquet [SWAT-T], and the Tourni-key) and an improvised tourniquet (tie & wooden spoon) were tested on a complex silicone simulation model used to replicate catastrophic hemorrhage from a blast injury with above traumatic knee amputation (SAM 4.1 Trauma Simulation Ltd, UK). To limit the user variability, the same investigator applied each tourniquet and each was tested 3 times. No ethical approval was required to conduct this study. RESULTS: None of the devices took longer than 1 minute to secure. The C-A-T and SOFTT-W were quickest to occlude and secure. Although the Tourni-key took longer statistically, this was unlikely to be a clinically important difference. Compared to the others, the SOFTT-W rebled on 2 out of 3 applications. The improvised tourniquet had an obvious ligature effect because of its narrowness, followed by the Tourni-key. This effect was least evident with the SWAT-T; however, particular care was needed to ensure it was safely secured as it was slippery when wet. CONCLUSIONS: All tourniquets tested were effective and swift to apply. The Tourni-key's antipinch card seems helpful in reducing local pain under the windlass. Reinspection for rebleeding is important and should be routinely performed irrespective of the device. The width of the SWAT-T may be beneficial, thereby, reducing the risk of crush injury.

Conservation geopolitics.

We reviewed recent work concerning the impact of geopolitics on wildlife conservation (and vice versa) and identified future priorities in conservation geopolitics research. Geopolitics is understood as both an analytical focus on geopolitical practices (especially concerning the behavior) of countries with respect to territory and national security and a set of theories developed to explain and predict those behaviors. We developed a typology of core geopolitical practices of relevance to conservation: territorial practices of colonization and the management of migrations and borders, and security practices relating to military, economic, and environmental security. We identified research that considers how these practices affect conservation situations and outcomes, noting the recent emergence of conceptual developments such as "environmental geopolitics" and "geopolitical ecology" that draw on multiple fields within the social sciences to theorize the links between geopolitics and environmental management. We defined a "geopolitical perspective" as a focus on geopolitical practices combined with an explicit engagement with geopolitical theory and identified conservation situations where this perspective could contribute to analytical clarity. We suggest the most pressing questions in conservation research to which the geopolitical perspective might contribute are how political and economic differences between countries affect biodiversity outcomes, how geopolitical practices to address those differences facilitate or frustrate conservation efforts, how national borders and human and wildlife movements can be better managed for the benefit of both, and how the most effective conservation strategies can be best selected to suit existing (and future) geopolitical realities.

Geopolítica de la Conservación Resumen Revisamos el trabajo reciente relativo al impacto que tiene la geopolítica sobre la conservación de la vida silvestre (y viceversa) e identificamos prioridades futuras para la investigación de la geopolítica de la conservación. Se define a la geopolítica como un enfoque analítico en las prácticas geopolíticas (especialmente en relación con el comportamiento) de los países con respecto al territorio y a la seguridad nacional y como un conjunto de teorías desarrolladas para explicar y predecir aquellos comportamientos. Desarrollamos una tipología de prácticas nucleares de geopolítica relevantes para la conservación: prácticas territoriales de colonización y el manejo de migraciones y de las fronteras, y prácticas de seguridad relacionadas con la seguridad militar, económica y ambiental. Identificamos las investigaciones que consideran cómo estas prácticas afectan a las situaciones de conservación y sus resultados, tomando en cuenta el surgimiento reciente de desarrollos conceptuales como los de "geopolítica ambiental" y "ecología geopolítica" que parten de múltiples campos de estudio situados dentro de las ciencias sociales para teorizar las conexiones entre la geopolítica y el manejo ambiental. Definimos una perspectiva geopolítica como el enfoque en las prácticas geopolíticas combinada con una participación explícita de la teoría geopolítica e identificamos situaciones de conservación en donde esta perspectiva podría contribuir a la claridad analítica. Sugerimos que las preguntas más urgentes para la investigación en la conservación para las cuales la perspectiva geopolítica podría contribuir son cómo las diferencias políticas y económicas entre los países afectan a los resultados de la biodiversidad, cómo las prácticas geopolíticas abordan esas diferencias facilita o frustra los esfuerzos de conservación, cómo las fronteras nacionales y los movimientos humanos y faunísticos pueden manejarse de mejor manera para el beneficio de ambos, y cómo las estrategias de conservación más efectivas pueden seleccionarse de mejor forma para acoplarse a las realidades geopolíticas existentes (y futuras).

Connectivity as a multiple: In, with and as "nature".

Connectivity is a central concept in contemporary geographies of nature, but the concept is often understood and utilised in plural ways. This is problematic because of the separation, rather than the confusion, of these different approaches. While the various understandings of connectivity are rarely considered as working together, the connections between them have significant implications. This paper thus proposes re-thinking connectivity as a "multiple". It develops a taxonomy of existing connectivity concepts from the fields of biogeography and landscape ecology, conservation biology, socio-economic systems theory, political ecology and more-than-human geography. It then considers how these various understandings might be re-thought not as separate concerns, but (following Annemarie Mol) as "more than one, but less than many". The implications of using the connectivity multiple as an analytic for understanding conservation practices are demonstrated through considering the creation of wildlife corridors in conservation practice. The multiple does not just serve to highlight the practical and theoretical linkages between ecological theories, social inequities and affectual relationships in more-than-human worlds. It is also suggestive of a normative approach to environmental management that does not give temporal priority to biological theories, but considers these as always already situated in these social, often unequal, always more-than-human ecologies.

Improving the role of global conservation treaties in addressing contemporary threats to lions.

Despite their iconic status, lion (Panthera leo) populations continue to decline across the majority of their range. In the light of the recent decision (in October 2017) to add lions to the Appendices of the Convention on Migratory Species (CMS), this paper identifies the new and existing legal protections afforded to lions through five global treaties, and maps these protections against the most critical contemporary threats facing the species. It thus offers a new analysis of the CMS listing, and draws on existing legal reviews, to highlight the ways in which global treaties offer differing forms of protection for lions. It then combines multiple concordant assessments of lion populations, to highlight nine categories of threat: human-lion conflict, bushmeat poaching, human encroachment, trophy hunting, trade in lion bones, unpredictable environmental events, socio-economic factors, policy failures, and governance/institutional weakness. The paper assesses how the various treaties each address these different categories of threat. The analysis identifies two pathways for improving legal protection: expanding the application of global treaties in respect of lions and their habitats (the paper considers the CMS listing in these terms), and improving the implementation of treaty commitments through local and national-scale actions. Furthermore, it identifies local implementation challenges that include the local knowledge of rules, compliance with rules and enforcement capacity, alongside the variety in local contexts and situations, and suggests where global treaties might provide support in meeting these challenges. We suggest that this analysis has wider implications for how treaty protection can and is utilised to protect various species of large-bodied, wide-ranging animals.

Perceptions and culture of safety among helicopter emergency medical service personnel in the UK.

BACKGROUND: The use of helicopter emergency medical services (HEMS) has increased significantly in the UK since 1987. To date there has been no research that addresses HEMS pilots and medical crews' own ideas on the risks that they view as inherent in their line of work and how to mitigate these risks. The aim of this survey is to describe and compare the attitudes and perceptions towards risk in HEMS operations of these staff. METHODS: A questionnaire was administered electronically to a representative selection of HEMS doctors, paramedics and pilots in the UK. A number of questions were grouped into common themes, and presented as Likert scales and ranking where appropriate. Descriptive and comparative results were presented and statistically analysed. RESULTS: The target sample of 100 consecutive respondents was achieved. All questionnaires were entirely completed. Respondents attributed the most risk to night HEMS operations without the use of night vision goggles, commercial pressure and mechanical aircraft failure. There was no statistical difference in overall perception of safety and years of experience (p=0.58) or between professions (p=0.08). Those who had experienced a crash were more likely to believe that HEMS operations are not inherently safe (p=0.05). CONCLUSIONS: We have surveyed a cross-section of the HEMS operational community in the UK in order to describe their perceptions of safety and risk within their professional life. Two-thirds of respondents believed that HEMS operations were inherently safe. Those who did not seemed to be influenced by personal experience of a crash or serious incident. We support increased operational training for clinical crewmembers, an increased emphasis on incident reporting and a culture of safety, and careful attention to minimum training and equipment requirements for all HEMS missions.

Evaluation of role 2 (R2) medical resources in the Afghanistan combat theater: Initial review of the joint trauma system R2 registry.

BACKGROUND: A Role 2 registry (R2R) was developed in 2008 by the US Joint Trauma System (JTS). The purpose of this project was to undertake a preliminary review of the R2R to understand combat trauma epidemiology and related interventions at these facilities to guide training and optimal use of forward surgical capability in the future. METHODS: A retrospective review of available JTS R2R records; the registry is a convenience sample entered voluntarily by members of the R2 units. Patients were classified according to basic demographics, affiliation, region where treatment was provided, mechanism of injury, type of injury, time and method of transport from point of injury (POI) to R2 facility, interventions at R2, and survival. Analysis included trauma patients aged ≥18 years or older wounded in year 2008 to 2014, and treated in Afghanistan. RESULTS: A total of 15,404 patients wounded and treated in R2 were included in the R2R from February 2008 to September 2014; 12,849 patients met inclusion criteria. The predominant patient affiliations included US Forces, 4,676 (36.4%); Afghan Forces, 4,549 (35.4%); and Afghan civilians, 2,178 (17.0%). Overall, battle injuries predominated (9,792 [76.2%]). Type of injury included penetrating, 7,665 (59.7%); blunt, 4,026 (31.3%); and other, 633 (4.9%). Primary mechanism of injury included explosion, 5,320 (41.4%); gunshot wounds, 3,082 (24.0%); and crash, 1,209 (9.4%). Of 12,849 patients who arrived at R2, 167 (1.3%) were dead; of 12,682 patients who were alive upon arrival, 342 (2.7%) died at R2. CONCLUSION: This evaluation of the R2R describes the patient profiles of and common injuries treated in a sample of R2 facilities in Afghanistan. Ongoing and detailed analysis of R2R information may provide evidence-based guidance to military planners and medical leaders to best prepare teams and allocate R2 resources in future operations. Given the limitations of the data set, conclusions must be interpreted in context of other available data and analyses, not in isolation. LEVEL OF EVIDENCE: Epidemiologic study, level IV.

A torso model comparison of temperature preservation devices for use in the prehospital environment.

BACKGROUND: Hypothermia is an independent predictor of increased morbidity and mortality in patients with trauma. Several strategies and products have been developed to minimise patients' heat loss in the prehospital arena, but there is little evidence to inform the clinician concerning their effectiveness. METHODS: We used a human torso model consisting of two 5.5-litre fluid bags to simultaneously compare four passive (space blanket, bubble wrap, Blizzard blanket, ambulance blanket) and one active (Ready-Heat II blanket) temperature preservation products. A torso model without any temperature preservation device provided a control. For each test, the torso models were warmed to 37°C and left outdoors. Core temperatures were recorded every 10 min for 1 h in total; tests were repeated 10 times. RESULTS: A significant difference in temperature was detected among groups at 30 and 60 min (F (1.29, 10.30)=103.58, p<0.001 and F (1.64, 14.78)=163.28, p<0.001, respectively). Mean temperature reductions (95% CI) after 1 h of environmental exposure were the following: 11.6 (10.3 to 12.9) °C in control group, 4.5 (3.9 to 5.1) °C in space blanket group, 3.6 (3 to 4.3) °C in bubble-wrap group, 2.1 (1.7 to 2.5) °C in Blizzard blanket group, 6.1 (5.8 to 6.5) °C in ambulance blanket group and 1.1 (0.7 to 1.6) °C in Ready-Heat II blanket group. CONCLUSIONS: In this study, using a torso model based on two 5 L dialysate bags we found the Ready-Heat II heating blanket and Blizzard blanket were associated with lower rates of heat loss after 60 min environmental exposure than the other devices tested.

Survival to Discharge After Cardiac Arrest Attended by a Doctor-Paramedic Helicopter Emergency Medical Service: An Utstein-style Multiservice Review of 1085 Activations.

BACKGROUND: The presentation of outcomes after cardiac arrest presented by emergency medical service and in-hospital teams in the Utstein style allows for comparative analysis of populations and systems. Essex and Herts Air Ambulance Trust (EHAAT) and the East Anglian Air Ambulance (EAAA) are doctor-plus-paramedic prehospital care teams that respond to a large number of medical cardiac arrests. OBJECTIVE: To report the outcomes of medical cardiac arrests according to the Utstein style. METHODS: Retrospective database analysis and hospital follow-up of all cardiac arrests attended by either service over a 31-month period. Traumatic cardiac arrests were excluded. PRIMARY OUTCOME: survival and cerebral performance category at discharge from the hospital. RESULTS: There were 429 patients attended by the two services; 193 patients achieved return of spontaneous circulation, which was sustained at the time of handover to the hospital team. Of 140 patients for whom complete follow-up was available, the overall survival rate was 50.7%, 86% of whom had a Cerebral Performance Category of 1 or 2. The overall survival-to-discharge rate for all patients attended was 11.7%. CONCLUSION: Benchmarking of performance is essential to understand reasons for variability, and to allow individual systems to reflect on their own practices. We have described 31 months of data that pertain to medical cardiac arrest cases attended by our services and demonstrated a comparable survival rate to discharge with good neurological outcome.

A 26-year comparative review of United Kingdom helicopter emergency medical services crashes and serious incidents.

BACKGROUND: The use of helicopter emergency medical services (HEMS) has increased substantially in the United Kingdom since 1987. There are currently no data on the rate of crashes and serious incidents related to HEMS in the United Kingdom. The aims of this article were to present data from a 26-year period since the start of HEMS operations in the United Kingdom and to compare them with published data from Germany, Australia, and the United States. Factors identified as affecting the safety of HEMS operations will also be discussed. METHODS: A PubMed search was performed to retrieve published data on accident rates and safety discussions for international HEMS using the key words HEMS, helicopter, emergency medical services, accident, incident, and crash. The details of every helicopter crash in the United States since the beginning of HEMS operations was obtained and reviewed to identify those that involved HEMS aircraft. This novel UK information was compared with published data from three international systems. RESULTS: A total of 13 accidents or serious incidents involving HEMS aircraft were identified from Civil Aviation Authority records, only 1 of which was a fatal accident. It was estimated that approximately 230,000 HEMS missions occurred in the United Kingdom between 1987 and 2013, giving an absolute accident incidence of approximately 0.0057% and a fatal accident incidence of approximately 0.00043%. The accident and fatal accident rate per 10,000 missions in the United Kingdom was 0.57 and 0.04, respectively. This compares with published rates from Germany, Australia, and the United States with accident rate per 10,000 missions ranging between 0.57 and 0.75 and fatal accident rates per 10,000 missions ranging between 0.04 and 0.23. CONCLUSION: Accidents and serious incidents relating to HEMS operations in the United Kingdom have been comprehensively identified for the first time, allowing an estimation of overall accident and fatal accident rates and comparison with other countries' HEMS operations. Data collection and analysis were hampered by obscurity of data sources and poor availability of data. In a time of increasing HEMS use in the United Kingdom, it is essential to be mindful of safety, and standardization of data collection will improve focus in this important area.