James Vassallo

UK triage – An improved tool for an evolving threat

INTRODUCTION A key challenge at a major incident is to quickly identify those casualties most urgently needing treatment in order to survive - triage. The UK Triage Sieve (TS) advocated by the Major Incident Medical Management (MIMMS) Course categorises casualties by ability to walk, respiratory rate (RR) and heart rate (HR) or capillary refill time. The military version (MS) includes assessment of consciousness. We tested whether the MS better predicts need for life-saving intervention in a military trauma population. Ideal HR, RR and Glasgow Coma Score (GCS) thresholds were calculated. METHODS A gold standard Priority 1 casualty was defined using resource-based criteria. Pre-hospital data from a military trauma database allowed calculation of triage category, which was compared with this standard, and presented as 2×2 tables. Sensitivity and specificity of each physiological parameter was calculated over a range of values to identify the ideal cut-offs. RESULTS A gold standard could be ascribed in 1657 cases. In 1213 both the MS and TS could ascribe a category. MS was significantly more sensitive than TS (59% vs 53%, p<0.001) with similar specificity (89 vs 88%). Varying the limits for each parameter allowed some improvements in sensitivity (70-80%) but specificity dropped rapidly. DISCUSSION Previous studies support the inclusion of GCS assessment for blunt as well as penetrating trauma. Optimising the physiological cut-offs increased sensitivity in this sample to only 71% - a Sieve based purely on physiological parameters may not be capable of an acceptable level of sensitivity. CONCLUSIONS The MS is more sensitive than the TS. Major incident planners utilising the Sieve should consider adopting the military version as their first line triage tool. If validated, altering the HR and RR thresholds may further improve the tool.

Major incident triage: Derivation and comparative analysis of the Modified Physiological Triage Tool (MPTT)

BACKGROUND Triage is a key principle in the effective management at a major incident. There are at least three different triage systems in use worldwide and previous attempts to validate them, have revealed limited sensitivity. Within a civilian adult population, there has been no work to develop an improved system. METHODS A retrospective database review of the UK Joint Theatre Trauma Registry was performed for all adult patients (>18years) presenting to a deployed Military Treatment Facility between 2006 and 2013. Patients were defined as Priority One if they had received one or more life-saving interventions from a previously defined list. Using first recorded hospital physiological data (HR/RR/GCS), binary logistic regression models were used to derive optimum physiological ranges to predict need for life-saving intervention. This allowed for the derivation of the Modified Physiological Triage Tool-MPTT (GCS≥14, HR≥100, 12<RR≥22). A comparison of the MPTT and existing triage tools was then performed using sensitivities and specificities with 95% confidence intervals. Differences in performance were assessed for statistical significance using a McNemar test with Bonferroni correction. RESULTS Of 6095 patients, 3654 (60.0%) had complete data and were included in the study, with 1738 (47.6%) identified as priority one. Existing triage tools had a maximum sensitivity of 50.9% (Modified Military Sieve) and specificity of 98.4% (Careflight). The MPTT (sensitivity 69.9%, 95% CI 0.677-0.720, specificity 65.3%, 95% CI 0.632-0.675) showed an absolute increase in sensitivity over existing tools ranging from 19.0% (Modified Military Sieve) to 45.1% (Triage Sieve). There was a statistically significant difference between the performance (p<0.001) between the MPTT and the Modified Military Sieve. DISCUSSION & CONCLUSION The performance characteristics of the MPTT exceed existing major incident triage systems, whilst maintaining an appropriate rate of over-triage and minimising under-triage within the context of predicting the need for a life-saving intervention in a military setting. Further work is required to both prospectively validate this system and to identify its performance within a civilian environment, prior to recommending its use in the major incident setting.

Major incident triage: A consensus based definition of the essential life-saving interventions during the definitive care phase of a major incident

INTRODUCTION Triage is a key principle in the effective management of major incidents. The process currently relies on algorithms assigning patients to specific triage categories; there is, however, little guidance as to what these categories represent. Previously, these algorithms were validated against injury severity scores, but it is accepted now that the need for life-saving intervention is a more important outcome. However, the definition of a life-saving intervention is unclear. The aim of this study was to define what constitutes a life-saving intervention, in order to facilitate the definition of an adult priority one patient during the definitive care phase of a major incident. METHODS We conducted a modified Delphi study, using a panel of subject matter experts drawn from the United Kingdom and Republic of South Africa with a background in Emergency Care or Major Incident Management. The study was conducted using an online survey tool, over three rounds between July and December 2013. A four point Likert scale was used to seek consensus for 50 possible interventions, with a consensus level set at 70%. RESULTS 24 participants completed all three rounds of the Delphi, with 32 life-saving interventions reaching consensus. CONCLUSIONS This study provides a consensus definition of what constitutes a life-saving intervention in the context of an adult, priority one patient during the definitive care phase of a major incident. The definition will contribute to further research into major incident triage, specifically in terms of validation of an adult major incident triage tool.

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.

Subclavian cannulation with ultrasound: a novel method.

Ultrasound-guidance is generally accepted as the safest technique for central vein cannulation. However, there are no formal guidelines for the subclavian approach. Because the subclavian vein cannot be seen or palpated, the traditional cannulation technique is ‘blind’, relying on landmarks and needle aspiration. Complications during subclavian cannulation include arterial puncture, pneumothorax and haemothorax. Ultrasound identification can also be difficult; the vein may not be easily compressible due to surrounding structures and Doppler ultrasound may be unreliable, as the transducer is perpendicular to the direction of blood flow. Ultrasound-guided subclavian vein cannulation has reduced complications [1], but there is still a high incidence of failure to cannulate the vein and of accidental arterial cannulation [2]. The subclavian vein has a hypoechoic (dark) appearance under ultrasound (Fig. 1). We noticed that a fast running intravenous infusion in the ipsilateral arm of a patient produced variable echogenicity (lighter echos) in the subclavian vein (Fig. 2). We have deliberately used this appearance to both identify the subclavian vein and differentiate it from the subclavian artery. With the intravenous infusion running with frequent drips in the drip chamber, the ultrasound beam is placed in long axis to the subclavian vessels in the subclavicular position. The angle of the ultrasound beam is adjusted to reveal both the subclavian vein and artery. The variable echogenicity, together with compression, can then be used to identify the vein. The presence of variable echogenicity in the vessel gives continuous feedback that the ultrasound beam has not drifted onto the artery. In cases where the ultrasound beam has included both artery and vein in the same image, this method has clearly identified the intended target vessel. We were unable to find similar reports of this method and as it seems simple, effective and does not increase the procedure time, we recommend it to colleagues. J. M. A. Vassallo M. J. Bennett Derriford Hospital, Plymouth, UK Email: mark.bennett@phnt.swest.nhs.uk

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.

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.

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.

54 Paediatric traumatic cardiac arrest in England and Wales a 10 year epidemiological study

Introduction Traumatic cardiac arrest (TCA) has traditionally been described as futile, with poor outcomes. Reported survival rates vary widely, with higher rates observed from mechanisms leading to a respiratory cause of traumatic cardiac arrest (e.g., drowning and hanging). Currently there is little evidence regarding outcomes following TCA in children. The primary aim of our study was to describe 30 day survival following TCA. Secondary aims were to provide an analysis of injury patterns (severe haemorrhage or traumatic brain injury), describe the functional outcome at discharge and to report the association between survival and interventions performed. Methods Using the Trauma Audit and Research Network (TARN) database, we conducted a population-based analysis of all paediatric (<18 years) trauma patients presenting to hospitals in England and Wales between 2006–2015. Patients with TCA in the pre-hospital setting and/or in the Emergency Department were included. Those without a GCS entry were excluded. Basic demographics are reported as number (%) and median (interquartile range), as appropriate. Survival odds ratios (95%CIs) and Chi Square tests were used during statistical analysis. Results During the study period, 21 710 paediatric patients were included in the database with 129 (0.6%) sustaining traumatic cardiac arrest and meeting study inclusion criteria (1.3%). The majority had a pre-hospital traumatic cardiac arrest (103 (79.8%)). Overall, 62.8% were male, aged 11.7 years (3.4–16.6), ISS 34 (25–45) and 110 (85.3%) had blunt injuries with road-traffic collision the most common mechanism (56.6%). 123 (95.3%) had severe haemorrhage and/or traumatic brain injury. Table 1 Table 2 Table 3 Overall survival was 5.4% (95% CI:2.6 to 10.8) with 7 cases surviving to 30 days. ‘Pre-hospital only’ traumatic cardiac arrest (13.0%) had a significantly higher survival than ‘pre-hospital and Emergency Department’ traumatic cardiac arrest (1.8%), (p=0.04). Those with injuries to the thorax predominated the severe haemorrhage group (67.6%). There were no survivors from ‘Emergency Department only’ traumatic cardiac arrest. Treatment at a major trauma centre was associated with a statistically significant increase in survival (p=0.02). There was no difference in survival between different times of day of presentation. Of those with Glasgow Outcome Scale recorded at discharge (n=6), four (66.7%) had either a moderate disability or good functional outcome. Conclusion Although a rare event, this study has demonstrated that resuscitation of children in traumatic cardiac arrest is not futile with overall outcomes comparable to survival rates seen in adults. Survival from pre-hospital traumatic cardiac arrest is possible and the early identification and aggressive management of these patients is advocated.