Developing a national triage tool for use in NHS regional trauma networks: the MATTS mixed methods study

Background

There is currently wide variation in prehospital major trauma triage across the National Health Service, with regional ambulance services using different triage tools, varying in format, structure and variables.

Objectives To develop a national triage tool that is acceptable, usable, accurate, and optimises under- and over-triage.

Design

A three-phase research programme, comprising Phase 1: development of a new triage tool by expert consensus informed by existing evidence, a systematic review of elderly triage, document analysis of current tools, decision-analytic modelling, expert consensus definition of a major trauma reference standard, and a qualitative examination of current triage; Phase 2: case–cohort study validating triage tools identified and developed in Phase 1, with identification of an optimally performing candidate triage tool; Phase 3: evaluation of the candidate triage tool following implementation, including cohort study investigating accuracy of triage decisions, cost-effectiveness analysis, and examination of user experiences.

Setting

English regional trauma networks served by the South-Western, West Midlands, Yorkshire and London Ambulance Services. Phase 2 case–cohort study and Phase 3 cohort studies performed between 1 November 2019 and 28 February 2020, and 1 November 2021 and 15 May 2022, respectively.

Participants

Injured patients presenting to ambulance services in participating regional trauma networks.

Results

In Phase 1, document analysis identified 19 United Kingdom triage tools and 34 published international tools. The systematic review demonstrated limited diagnostic accuracy of triage tools in the elderly, with divergent real-life triage decisions. The reference standard included the need for critical trauma-related interventions, significant individual anatomical injuries, burden of multiple minor injuries and specific patient attributes. Decision-analytic modelling indicated that high-specificity triage tools were favoured. Triage tool simplicity and the option for clinical judgement were valued by stakeholders, but real-world triage was a multifaceted, nonlinear, dynamic and multiagency process. Following review of Phase 1 evidence, a three-step Major Trauma Triage Study candidate triage tool targeting relatively higher specificity was developed through expert consensus.

The Phase 2 case–cohort sample included 2757 patients, with a weighted prevalence of major trauma of 3.1% (95% confidence interval 2.3% to 4.0%). The Major Trauma Triage Study tool performed optimally compared to under- and over-triage targets (sensitivity 37.3%, specificity 95.1%).

In Phase 3, the newly implemented Major Trauma Triage Study triage tool was received favourably by stakeholders. Prehospital triage decisions using the new tool demonstrated a sensitivity of 55.3% (95% confidence interval 51.8% to 58.7%) and specificity of 94.3% (95% confidence interval 94.1% to 94.6%, n = 38,010, 2.2% prevalence of major trauma). Minimal differences were apparent between the costs (£149) and benefits (0.006 quality-adjusted life-years) of triage decisions, regardless of the triage tool used, reflecting similar real-life triage accuracy. However, the new Major Trauma Triage Study tool appeared cost-effective when theoretical triage tool performance was examined, demonstrating an incremental cost effectiveness ratio of £21,163.

Conclusions

The Major Trauma Triage Study triage tool performed optimally, targeted an appropriate under-/over-triage trade-off, and was perceived to perform well by stakeholders. National implementation could ensure evidence-based, standardised and cost-effective triage.

Limitations Significant variation in National Health Service ambulance service and trauma network configurations could limit the generalisability of results.

Future work

Paediatric triage, pre-alerting and the benefit of remote clinical support could benefit from future research.

Trial registration This trial is registered as Current Controlled Trials ISRCTN17968752.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 17/16/04) and is published in full in Health Technology Assessment; Vol. 30, No. 34. See the NIHR Funding and Awards website for further award information.