External validation of the Manchester Acute Coronary Syndromes ECG risk model within a pre-hospital setting.

OBJECTIVES: The Manchester Acute Coronary Syndromes ECG (MACS-ECG) prediction model calculates a score based on objective ECG measurements to give the probability of a non-ST elevation myocardial infarction (NSTEMI). The model showed good performance in the emergency department (ED), but its accuracy in the pre-hospital setting is unknown. We aimed to externally validate MACS-ECG in the pre-hospital environment. METHODS: We undertook a secondary analysis from the Pre-hospital Evaluation of Sensitive Troponin (PRESTO) study, a multi-centre prospective study to validate decision aids in the pre-hospital setting (26 February 2019 to 23 March 2020). Patients with chest pain where the treating paramedic suspected acute coronary syndrome were included. Paramedics collected demographic and historical data and interpreted ECGs contemporaneously (as 'normal' or 'abnormal'). After completing recruitment, we analysed ECGs to calculate the MACS-ECG score, using both a pre-defined threshold and a novel threshold that optimises sensitivity to differentiate AMI from non-AMI. This was compared with subjective ECG interpretation by paramedics. The diagnosis of AMI was adjudicated by two investigators based on serial troponin testing in hospital. RESULTS: Of 691 participants, 87 had type 1 AMI and 687 had complete data for paramedic ECG interpretation. The MACS-ECG model had a C-index of 0.68 (95% CI: 0.61 to 0.75). At the pre-determined cut-off, MACS-ECG had 2.3% (95% CI: 0.3% to 8.1%) sensitivity, 99.5% (95% CI: 98.6% to 99.9%) specificity, 40.0% (95% CI: 10.2% to 79.3%) positive predictive value (PPV) and 87.6% (87.3% to 88.0%) negative predictive value (NPV). At the optimal threshold for sensitivity, MACS-ECG had 50.6% sensitivity (39.6% to 61.5%), 83.1% specificity (79.9% to 86.0%), 30.1% PPV (24.7% to 36.2%) and 92.1% NPV (90.4% to 93.5%). In comparison, paramedics had a sensitivity of 71.3% (95% CI: 60.8% to 80.5%) with 53.8% (95% CI: 53.8% to 61.8%) specificity, 19.7% (17.2% to 22.45%) PPV and 93.3% (90.8% to 95.1%) NPV. CONCLUSION: Neither MACS-ECG nor paramedic ECG interpretation had a sufficiently high PPV or NPV to 'rule in' or 'rule out' NSTEMI alone.

Should video laryngoscopy or direct laryngoscopy be used for adults undergoing endotracheal intubation in the pre-hospital setting? A critical appraisal of a systematic review.

The safety and utility of endotracheal intubation by paramedics in the United Kingdom is a matter of debate. Considering the controversy surrounding the safety of paramedic-performed endotracheal intubation, any interventions that enhance patient safety should be evaluated for implementation based on solid evidence of their effectiveness. A systematic review performed by Hansel and colleagues (2022) sought to assess compare video laryngoscopes against direct laryngoscopes in clinical practice. This commentary aims to critically appraise the methods used within the review by Hansel et al (2022) and expand upon the findings in the context of clinical practice.

Towards enhanced telephone triage for chest pain: a Delphi study to define life-threatening conditions that must be identified.

BACKGROUND: Improving telephone triage for patients with chest pain has been identified as a national research priority. However, there is a lack of strong evidence to define the life-threatening conditions (LTCs) that telephone triage ought to identify. Therefore, we aimed to build consensus for the LTCs associated with chest pain that ought to be identified during telephone triage for emergency calls. METHODS: We conducted a Delphi study in three rounds. Twenty experts in pre-hospital care and emergency medicine experience from the UK were invited to participate. In round I, experts were asked to list all LTCs that would require priority 1, 2, and 4 ambulance responses. Round II was a ranking evaluation, and round III was a consensus round. Consensus level was predefined at > = 70%. RESULTS: A total of 15 participants responded to round one and 10 to rounds two and three. Of 185 conditions initially identified by the experts, 26 reached consensus in the final round. Ten conditions met consensus for requiring priority 1 response: oesophageal perforation/rupture; ST elevation myocardial infarction; non-ST elevation myocardial infarction with clinical compromise (defined, also by consensus, as oxygen saturation < 90%, heart rate < 40/min or systolic blood pressure < 90 mmHg); acute heart failure; cardiac tamponade; life-threatening asthma; cardiac arrest; tension pneumothorax and massive pulmonary embolism. An additional six conditions met consensus for priority 2 response, and three for priority 4 response. CONCLUSION: Using expert consensus, we have defined the LTCs that may present with chest pain, which ought to receive a high-priority ambulance response. This list of conditions can now form a composite primary outcome for future studies to derive and validate clinical prediction models that will optimise telephone triage for patients with a primary complaint of chest pain.

Alternatives to direct emergency department conveyance of ambulance patients: a scoping review of the evidence.

BACKGROUND: The role of ambulance services is shifting, due in part to more intermediate, non-urgent patients who do not require direct emergency department conveyance, yet who cannot be safely left at home alone. Evidence surrounding the safety, effectiveness and efficiency of alternate care routes is not well known. METHODS: This scoping review sought to identify all studies that examined alternate routes of care for the non-urgent "intermediate" patient, as triaged on scene. Search terms for the sample (ambulances, paramedics, etc.) and intervention (e.g. referrals, alternate care route, non-conveyance) were combined. Articles were systematically searched using four databases and grey literature sources (February 2020). Independent researchers screened title-abstract and full text stages. RESULTS: Of 16,037 records, 41 examined alternate routes of care after triage by the on-scene paramedic. Eighteen articles considered quantitative patient data, 12 studies provided qualitative perspectives while 11 were consensus or opinion-based articles. The benefits of alternative schemes are well-recognised by patients, paramedics and stakeholders and there is supporting evidence for a positive impact on patient-centered care and operational efficiency. Challenges to successful use of schemes included: patient safety resulting from incorrect triage decisions, inadequate training, lack of formal partnerships between ambulance and supporting services, and insufficient evidence to support safe implementation or continued use. Studies often inaccurately defined success using proxies for patient safety (e.g. decision comparisons, rates of secondary contact). Finally, patients expressed willingness for such schemes but their preference must be better understood. CONCLUSIONS: This broad summary offers initial support for alternate routes of care for intermediate, non-urgent patients. Even so, most studies lacked methodologically rigorous evidence and failed to evaluate safe patient outcomes. Some remedies appear to be available such as formal triage pathways, targeted training and organisational support, however there is an urgent need for more research and dissemination in this area.

Bypassing nearest hospital for more distant neuroscience care in head-injured adults with suspected traumatic brain injury: findings of the head injury transportation straight to neurosurgery (HITS-NS) pilot cluster randomised trial.

OBJECTIVE: Reconfiguration of trauma services, with direct transport of patients with traumatic brain injury (TBI) to specialist neuroscience centres (SNCs)-bypassing non-specialist acute hospitals (NSAHs), could improve outcomes. However, delays in stabilisation of airway, breathing and circulation (ABC) may worsen outcomes when compared with selective secondary transfer from nearest NSAH to SNC. We conducted a pilot cluster randomised controlled trial to determine the feasibility and plausibility of bypassing suspected patients with TBI -directly into SNCs-producing a measurable effect. SETTING: Two English Ambulance Services. PARTICIPANTS: 74 clusters (ambulance stations) were randomised within pairs after matching for important characteristics. Clusters enrolled head-injured adults-injured nearest to an NSAH-with internationally accepted TBI risk factors and stable ABC. We excluded participants attended by Helicopter Emergency Medical Services or who were injured more than 1 hour by road from nearest SNC. INTERVENTIONS: Intervention cluster participants were transported directly to an SNC bypassing nearest NSAH; control cluster participants were transported to nearest NSAH with selective secondary transfer to SNC. OUTCOMES: Trial recruitment rate (target n=700 per annum) and percentage with TBI on CT scan (target 80%) were the primary feasibility outcomes. 30-day mortality, 6-month Extended Glasgow Outcome Scale and quality of life were secondary outcomes. RESULTS: 56 ambulance station clusters recruited 293 patients in 12 months. The trial arms were similar in terms of age, conscious level and injury severity. Less than 25% of recruited patients had TBI on CT (n=70) with 7% (n=20) requiring neurosurgery. Complete case analysis showed similar 30-day mortality in the two trial arms (control=8.8 (2.7-14.0)% vs intervention=9.4(2.3-14.0)%). CONCLUSION: Bypassing patients with suspected TBI to SNCs gives an overtriage (false positive) ratio of 13:1 for neurosurgical intervention and 4:1 for TBI. A measurable effect from a full trial of early neuroscience care following bypass is therefore unlikely. TRIAL REGISTRATION NUMBER: ISRCTN68087745.

The Head Injury Transportation Straight to Neurosurgery (HITS-NS) randomised trial: a feasibility study.

BACKGROUND: Reconfiguration of trauma services, with direct transport of traumatic brain injury (TBI) patients to neuroscience centres (NCs), bypassing non-specialist acute hospitals (NSAHs), could potentially improve outcomes. However, delays in stabilisation of airway, breathing and circulation (ABC) and the difficulties in reliably identifying TBI at scene may make this practice deleterious compared with selective secondary transfer from nearest NSAH to NC. National Institute for Health and Care Excellence guidance and systematic reviews suggested equipoise and poor-quality evidence - with regard to 'early neurosurgery' in this cohort - which we sought to address. METHODS: Pilot cluster randomised controlled trial of bypass to NC conducted in two ambulance services with the ambulance station (n = 74) as unit of cluster [Lancashire/Cumbria in the North West Ambulance Service (NWAS) and the North East Ambulance Service (NEAS)]. Adult patients with signs of isolated TBI [Glasgow Coma Scale (GCS) score of < 13 in NWAS, GCS score of < 14 in NEAS] and stable ABC, injured nearest to a NSAH were transported either to that hospital (control clusters) or bypassed to the nearest NC (intervention clusters). PRIMARY OUTCOMES: recruitment rate, protocol compliance, selection bias as a result of non-compliance, accuracy of paramedic TBI identification (overtriage of study inclusion criteria) and pathway acceptability to patients, families and staff. 'Open-label' secondary outcomes: 30-day mortality, 6-month Extended Glasgow Outcome Scale (GOSE) and European Quality of Life-5 Dimensions. RESULTS: Overall, 56 clusters recruited 293 (169 intervention, 124 control) patients in 12 months, demonstrating cluster randomised pre-hospital trials as viable for heath service evaluations. Overall compliance was 62%, but 90% was achieved in the control arm and when face-to-face paramedic training was possible. Non-compliance appeared to be driven by proximity of the nearest hospital and perceptions of injury severity and so occurred more frequently in the intervention arm, in which the perceived time to the NC was greater and severity of injury was lower. Fewer than 25% of recruited patients had TBI on computed tomography scan (n = 70), with 7% (n = 20) requiring neurosurgery (craniotomy, craniectomy or intracranial pressure monitoring) but a further 18 requiring admission to an intensive care unit. An intention-to-treat analysis revealed the two trial arms to be equivalent in terms of age, GCS and severity of injury. No significant 30-day mortality differences were found (8.8% vs. 9.1/%; p > 0.05) in the 273 (159/113) patients with data available. There were no apparent differences in staff and patient preferences for either pathway, with satisfaction high with both. Very low responses to invitations to consent for follow-up in the large number of mild head injury-enrolled patients meant that only 20% of patients had 6-month outcomes. The trial-based economic evaluation could not focus on early neurosurgery because of these low numbers but instead investigated the comparative cost-effectiveness of bypass compared with selective secondary transfer for eligible patients at the scene of injury. CONCLUSIONS: Current NHS England practice of bypassing patients with suspected TBI to neuroscience centres gives overtriage ratios of 13 : 1 for neurosurgery and 4 : 1 for TBI. This important finding makes studying the impact of bypass to facilitate early neurosurgery not plausible using this study design. Future research should explore an efficient comparative effectiveness design for evaluating 'early neurosurgery through bypass' and address the challenge of reliable TBI diagnosis at the scene of injury. TRIAL REGISTRATION: Current Controlled Trials ISRCTN68087745. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 1. See the NIHR Journals Library website for further project information.

The challenges of conducting prehospital research: successes and lessons learnt from the Head Injury Transportation Straight to Neurosurgery (HITS-NS) trial.

Head Injury Transportation Straight to Neurosurgery was a cluster randomised trial studying suspected severe head injury treatment pathways conducted in the North East Ambulance Service NHS Foundation Trust and North West Ambulance Service NHS Trust between January 2012 and March 2013. This was the world's first large scale trial of any trauma bypass and was conducted as a feasibility study. This short report will describe some of the lessons learnt during this ground breaking and complex trial.