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: A Delphi process to determine clinicians' attitudes and beliefs within the United Kingdom and Ireland.

AIM: Triage is key to effective management of major incidents, yet there is scarce evidence surrounding the optimal method of paediatric major incident triage (MIT). This study aimed to derive consensus on key components of paediatric MIT among healthcare professionals responsible for triage during paediatric major incidents. METHODS: Two-round online Delphi consensus study delivered July 2021-October 2021, including participants from pre-hospital and hospital specialities responsible for triage during paediatric major incidents. A 5-point Likert scale was used to determine consensus, set a priori at 70%. RESULTS: 111 clinicians completed both rounds; 13 of 17 statements reached consensus. Positive consensus was reached on rescue breaths in mechanisms associated with hypoxia or asphyxiation, mobility assessment as a crude discriminator and use of adult physiology for older children. Whilst positive consensus was reached on the benefits of a single MIT tool across all adult and paediatric age ranges, there was negative consensus in relation to clinical implementation. CONCLUSIONS: This Delphi study has established consensus among a large group of clinicians involved in the management of major incidents on several key elements of paediatric major incident triage. Further work is required to develop a triage tool that can be implemented based on emerging and ongoing research and which is acceptable to clinicians.

New NHS Prehospital Major Incident Triage Tool: from MIMMS to MITT.

Triage is a key principle in the effective management of major incidents and is the process by which patients are prioritised on the basis of their clinical acuity. However, work published over the last decade has demonstrated that existing methods of triage perform poorly when trying to identify patients in need of life-saving interventions. As a result, a review of major incident triage was initiated by NHS England with the remit to determine the optimum way in which to triage patients of all ages in a major incident for the UK. This article describes the output from this review, the changes being undertaken to UK major incident triage and the introduction of the new NHS Major Incident Triage Tool from the Spring of 2023.

Comparative analysis of major incident triage tools in children: a UK population-based analysis.

INTRODUCTION: Triage is a key principle in the effective management of major incidents. There is currently a paucity of evidence to guide the triage of children. The aim of this study was to perform a comparative analysis of nine adult and paediatric triage tools, including the novel 'Sheffield Paediatric Triage Tool' (SPTT), assessing their ability in identifying patients needing life-saving interventions (LSIs). METHODS: A 10-year (2008-2017) retrospective database review of the Trauma Audit Research Network (TARN) Database for paediatric patients (<16 years) was performed. Primary outcome was identification of patients receiving one or more LSIs from a previously defined list. Secondary outcomes included mortality and prediction of Injury Severity Score (ISS) >15. Primary analysis was conducted on patients with complete prehospital physiological data with planned secondary analyses using first recorded data. Performance characteristics were evaluated using sensitivity, specificity, undertriage and overtriage. RESULTS: 15 133 patients met TARN inclusion criteria. 4962 (32.8%) had complete prehospital physiological data and 8255 (54.5%) had complete first recorded physiological data. The majority of patients were male (69.5%), with a median age of 11.9 years. The overwhelming majority of patients (95.4%) sustained blunt trauma, yielding a median ISS of 9 and overall, 875 patients (17.6%) received at least one LSI. The SPTT demonstrated the greatest sensitivity of all triage tools at identifying need for LSI (92.2%) but was associated with the highest rate of overtriage (75.0%). Both the Paediatric Triage Tape (sensitivity 34.1%) and JumpSTART (sensitivity 45.0%) performed less well at identifying LSI. By contrast, the adult Modified Physiological Triage Tool-24 (MPTT-24) triage tool had the second highest sensitivity (80.8%) with tolerable rates of overtriage (70.2%). CONCLUSION: The SPTT and MPTT-24 outperform existing paediatric triage tools at identifying those patients requiring LSIs. This may necessitate a change in recommended practice. Further work is needed to determine the optimum method of paediatric major incident triage, but consideration should be given to simplifying major incident triage by the use of one generic tool (the MPTT-24) for adults and children.

Relationship between the Injury Severity Score and the need for life-saving interventions in trauma patients in the UK.

INTRODUCTION: Major trauma is the third leading cause of avoidable mortality in the UK. Defining which patients require care in a major trauma centre is a critical component of developing, evaluating and enhancing regional major trauma systems. Traditionally, trauma patients have been classified using the Injury Severity Score (ISS), but resource-based criteria have been proposed as an alternative. The aim of this study was to investigate the relationship between ISS and the use of life-saving interventions (LSI). METHODS: Retrospective cohort study using the Trauma Audit Research Network database for all adult patients (aged ≥18 years) between 2006 and 2014. Patients were categorised as needing an LSI if they received one or more interventions from a previously defined list determined by expert consensus. RESULTS: 193 290 patients met study inclusion criteria: 56.9% male, median age 60.0 years (IQR 41.2-78.8) and median ISS 9 (IQR 9-16). The most common mechanism of injury was falls <2 m (52.1%), followed by road traffic collisions (22.2%). 15.1% received one or more LSIs. The probability of a receiving an LSI increased with increasing ISS, but only a low to moderate correlation was evident (0.334, p<0.001). A clinically significant number of cases (5.3% and 7.6%) received an LSI despite having an ISS ≤8 or <15, respectively. CONCLUSIONS: A clinically significant number of adult trauma patients requiring LSIs have an ISS below the traditional definition of major trauma. The traditional definition should be reconsidered and either lowered, or an alternative metric should be used.

Major incident triage and the evaluation of the Triage Sort as a secondary triage method.

INTRODUCTION: A key principle in the effective management of major incidents is triage, the process of prioritising patients on the basis of their clinical acuity. In many countries including the UK, a two-stage approach to triage is practised, with primary triage at the scene followed by a more detailed assessment using a secondary triage process, the Triage Sort. To date, no studies have analysed the performance of the Triage Sort in the civilian setting. The primary aim of this study was to determine the performance of the Triage Sort at predicting the need for life-saving intervention (LSI). METHODS: Using the Trauma Audit Research Network (TARN) database for all adult patients (>18 years) between 2006 and 2014, we determined which patients received one or more LSIs using a previously defined list. The first recorded hospital physiology was used to categorise patient priority using the Triage Sort, National Ambulance Resilience Unit (NARU) Sieve and the Modified Physiological Triage Tool-24 (MPTT-24). Performance characteristics were evaluated using sensitivity and specificity with statistical analysis using a McNemar's test. RESULTS: 127 233patients (58.1%) had complete data and were included: 55.6% men, aged 61.4 (IQR 43.1-80.0 years), ISS 9 (IQR 9-16), with 24 791 (19.5%) receiving at least one LSI (priority 1). The Triage Sort demonstrated the lowest accuracy of all triage tools at identifying the need for LSI (sensitivity 15.7% (95% CI 15.2 to 16.2) correlating with the highest rate of under-triage (84.3% (95% CI 83.8 to 84.8), but it had the greatest specificity (98.7% (95% CI 98.6 to 98.8). CONCLUSION: Within a civilian trauma registry population, the Triage Sort demonstrated the poorest performance at identifying patients in need of LSI. Its use as a secondary triage tool should be reviewed, with an urgent need for further research to determine the optimum method of secondary triage.

Paediatric traumatic cardiac arrest: the development of an algorithm to guide recognition, management and decisions to terminate resuscitation.

INTRODUCTION: Paediatric traumatic cardiac arrest (TCA) is a high acuity, low frequency event. Traditionally, survival from TCA has been reported as low, with some believing resuscitation is futile. Within the adult population, there is growing evidence to suggest that with early and aggressive correction of reversible causes, survival from TCA may be comparable with that seen from medical out-of-hospital cardiac arrests. Key to this survival has been the adoption of a standardised approach to resuscitation. The aim of this study was, by a process of consensus, to develop an algorithm for the management of paediatric TCA for adoption in the UK. METHODS: A modified consensus development meeting of UK experts involved in the management of paediatric TCA was held. Statements discussed at the meeting were drawn from those that did not reach consensus (positive/negative) from a linked three-round online Delphi study. 19 statements relating to the diagnosis, management and futility of paediatric TCA were initially discussed in small groups before each participant anonymously recorded their agreement with the statement using 'yes', 'no' or 'don't know'. In keeping with our Delphi study, consensus was set a priori at 70%. Statements reaching consensus were included in the proposed algorithm. RESULTS: 41 participants attended the meeting. Of the 19 statements discussed, 13 reached positive consensus and were included in the algorithm. A single statement regarding initial rescue breaths reached negative consensus and was excluded. Consensus was not reached for five statements, including the use of vasopressors and thoracotomy for haemorrhage control in blunt trauma. CONCLUSION: In attempt to standardise our approach to the management of paediatric TCA and to improve outcomes, we present the first consensus-based algorithm specific to the paediatric population. While this algorithm was developed for adoption in the UK, it may be applicable to similar healthcare systems internationally.

Paediatric traumatic cardiac arrest: a Delphi study to establish consensus on definition and management.

AIMS: Paediatric traumatic cardiac arrest (TCA) is associated with low survival and poor outcomes. The mechanisms that underlie TCA are different from medical cardiac arrest; the approach to treatment of TCA may therefore also need to differ to optimise outcomes. The aim of this study was to explore the opinion of subject matter experts regarding the diagnosis and treatment of paediatric TCA, and to reach consensus on how best to manage this group of patients. METHODS: An online Delphi study was conducted over three rounds, with the aim of achieving consensus (defined as 70% agreement) on statements related to the diagnosis and management of paediatric TCA. Participants were invited from paediatric and adult emergency medicine, paediatric anaesthetics, paediatric ICU and paediatric surgery, as well as Paediatric Major Trauma Centre leads and representatives from the Resuscitation Council UK. Statements were informed by literature reviews and were based on elements of APLS resuscitation algorithms as well as some concepts used in the management of adult TCA; they ranged from confirmation of cardiac arrest to the indications for thoracotomy. RESULTS: 73 experts completed all three rounds between June and November 2016. Consensus was reached on 14 statements regarding the diagnosis and management of paediatric TCA; oxygenation and ventilatory support, along with rapid volume replacement with warmed blood, improve survival. The duration of cardiac arrest and the lack of a response to intervention, along with cardiac standstill on ultrasound, help to guide the decision to terminate resuscitation. CONCLUSION: This study has given a consensus-based framework to guide protocol development in the management of paediatric TCA, though further work is required in other key areas including its acceptability to clinicians.

Major incident triage and the implementation of a new triage tool, the MPTT-24.

INTRODUCTION: The Modified Physiological Triage Tool (MPTT) is a recently developed primary triage tool and in comparison with existing tools demonstrates the greatest sensitivity at predicting need for life-saving intervention (LSI) within both military and civilian populations. To improve its applicability, we proposed to increase the upper respiratory rate (RR) threshold to 24 breaths per minute (bpm) to produce the MPTT-24. Our aim was to conduct a feasibility analysis of the proposed MPTT-24, comparing its performance with the existing UK Military Sieve. METHOD: A retrospective review of the Joint Theatre Trauma Registry (JTTR) and Trauma Audit Research Network (TARN) databases was performed for all adult (>18 years) patients presenting between 2006-2013 (JTTR) and 2014 (TARN). Patients were defined as priority one (P1) if they received one or more LSIs. Using first recorded hospital RR in isolation, sensitivity and specificity of the ≥24 bpm threshold was compared with the existing threshold (≥22 bpm) at predicting P1 status. Patients were then categorised as P1 or not-P1 by the MPTT, MPTT-24 and the UK Military Sieve. RESULTS: The MPTT and MPTT-24 outperformed existing UK methods of triage with a statistically significant (p<0.001) increase in sensitivity of between 25.5% and 29.5%. In both populations, the MPTT-24 demonstrated an absolute reduction in sensitivity with an increase in specificity when compared with the MPTT. A statistically significant difference was observed between the MPTT and MPTT-24 in the way they categorised TARN and JTTR cases as P1 (p<0.001). CONCLUSIONS: When compared with the existing MPTT, the MPTT-24 allows for a more rapid triage assessment. Both continue to outperform existing methods of primary major incident triage and within the military setting, the slight increase in undertriage is offset by a reduction in overtriage. We recommend that the MPTT-24 be considered as a replacement to the existing UK Military Sieve.

The civilian validation of the Modified Physiological Triage Tool (MPTT): an evidence-based approach to primary major incident triage.

INTRODUCTION: Triage is a key principle in the effective management of a major incident. Existing triage tools have demonstrated limited performance at predicting need for life-saving intervention (LSI). Derived on a military cohort, the Modified Physiological Triage Tool (MPTT) has demonstrated improved performance. Using a civilian trauma registry, this study aimed to validate the MPTT in a civilian environment. METHODS: Retrospective database review of the Trauma Audit and Research Network (TARN) database for all adult patients (>18 years) between 2006 and 2014. Patients were defined as Priority One if they received one or more LSIs from a previously defined list. Only patients with complete physiological data were included. Patients were categorised by the MPTT and existing triage tools using first recorded hospital physiology. Performance characteristics were evaluated using sensitivity, specificity and area under receiver operating characteristic (AUROC). RESULTS: During the study period, 218 985 adult patients were included in the TARN database. 127 233 (58.1%) had complete data: 55.6% male, aged 61.4 (IQR 43.1-80.0) years, Injury Severity Score 9 (IQR 9-16), 96.5% suffered blunt trauma and 24 791 (19.5%) were Priority One. The MPTT (sensitivity 57.6%, specificity 71.5%) outperformed all existing triage methods with a 44.7% absolute reduction in undertriage compared with existing UK civilian methods. AUROC comparison supported the use of the MPTT over other tools (P<0.001.) CONCLUSION: Within a civilian trauma registry population, the MPTT demonstrates improved performance at predicting need for LSI, with the lowest rates of undertriage and an appropriate level of overtriage. We suggest the MPTT be considered as an alternative to existing triage tools.

The prospective validation of the Modified Physiological Triage Tool (MPTT): an evidence-based approach to major incident triage.

INTRODUCTION: Triage is a key principle in the effective management of major incidents. There is limited evidence to support existing triage tools, with a number of studies demonstrating poor performance at predicting the need for a life-saving intervention. The Modified Physiological Triage Tool (MPTT) is a novel triage tool derived using logistic regression, and in retrospective data sets has shown optimum performance at predicting the need for life-saving intervention. MATERIALS AND METHODS: Physiological data and interventions were prospectively collected for consecutive adult patients with trauma (>18 years) presenting to the emergency department at Camp Bastion, Afghanistan, between March and September 2011. Patients were considered priority 1 (P1) if they received one or more interventions from a previously defined list. Patients were triaged using existing triage tools and the MPTT. Performance was measured using sensitivity and specificity, and a McNemar test with Bonferroni calculation was applied for tools with similar performance. RESULTS: The study population comprised 357 patients, of whom 214 (59.9%) were classed as P1. The MPTT (sensitivity: 83.6%, 95% CI 78.0% to 88.3%; specificity: 51.0%, 95% CI 42.6% to 59.5%) outperformed all existing triage tools at predicting the need for life-saving intervention, with a 19.6% absolute reduction in undertriage compared with the existing Military Sieve. The improvement in undertriage comes at the expense of overtriage; rates of overtriage were 11.6% higher with the MPTT than the Military Sieve. Using a McNemar test, a statistically significant (p<0.001) improvement in overall performance was demonstrated, supporting the use of the MPTT over the Military Sieve. DISCUSSION AND CONCLUSIONS: The MPTT outperforms all existing triage tools at predicting the need for life-saving intervention, with the lowest rates of undertriage while maintaining acceptable levels of overtriage. Having now been validated on both military and civilian cohorts, we recommend that the major incident community consider adopting the MPTT for the purposes of primary triage.

Usefulness of the Shock Index as a secondary triage tool.

INTRODUCTION: Secondary triage at a major incident allows for a more detailed assessment of the patient. In the UK, the Triage Sort (TSO) is the preferred method, combining GCS, systolic BP (SBP) and RR to categorise Priority 1 casualties. The Shock Index (SI) is calculated by dividing HR by SBP (HR/SBP). This study examines whether SI is better at predicting need for life-saving intervention (LSI) following trauma than TSO. METHODS: A prospective observational study was undertaken. Physiological data and interventions performed in the Emergency Department and operating theatre were prospectively collected for 482 consecutive adult trauma patients presenting to Camp Bastion, Afghanistan, over a 6-month period. A patient was deemed to have required LSI if they received any intervention from a set described previously. RESULTS: Complete data were available for 345 patients (71.6%). Of these, 203 (58.8%) were gold standard P1, and 142 (41.2%) were non-P1. The TSO predicted need for LSI with a sensitivity of 58.6% (95% CI 51.8% to 65.4%) and specificity of 88.7% (95% CI 83.5% to 93.9%). Using an SI cut-off >0.75 provided greater sensitivity of 70.0% (95% CI 63.6% to 76.3%) while maintaining an acceptably high (although lower than TSO) specificity of 74.7% (95% CI 67.5% to 81.8%). At this SI cut-off, there was evidence of a difference between TSO and SI in terms of the way in which patients were triaged (p<0.0001). DISCUSSION: Our study showed that a SI >0.75 more accurately predicted the need for LSI, while maintaining acceptable specificity. SI may be more useful than TSO for secondary triage in a mass-casualty situation; this relationship in civilian trauma should be examined to clarify whether these results can be more widely translated into civilian practice. PROJECT REGISTRATION NUMBER: RCDM/Res/Audit/1036/12/0050.

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.

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.

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.