Improving ambulance dispatch triage to trauma: A scoping review using the framework of development and evaluation of clinical prediction rules.

OBJECTIVE: Ambulance dispatch algorithms should function as clinical prediction rules, identifying high acuity patients for advanced life support, and low acuity patients for non-urgent transport. Systematic reviews of dispatch algorithms are rare and focus on study types specific to the final phases of rule development, such as impact studies, and may miss the complete value-added evidence chain. We sought to summarise the literature for studies seeking to improve dispatch in trauma by performing a scoping review according to standard frameworks for developing and evaluating clinical prediction rules. METHODS: We performed a scoping review searching MEDLINE, EMBASE, CINAHL, the CENTRAL trials registry, and grey literature from January 2005 to October 2021. We included all study types investigating dispatch triage to injured patients in the English language. We reported the clinical prediction rule phase (derivation, validation, impact analysis, or user acceptance) and the performance and outcomes measured for high and low acuity trauma patients. RESULTS: Of 2067 papers screened, we identified 12 low and 30 high acuity studies. Derivation studies were most common (52%) and rule-based computer-aided dispatch was the most frequently investigated (23 studies). Impact studies rarely reported a prior validation phase, and few validation studies had their impact investigated. Common outcome measures in each phase were infrequent (0 to 27%), making a comparison between protocols difficult. A series of papers for low acuity patients and another for pediatric trauma followed clinical prediction rule development. Some low acuity Medical Priority Dispatch System codes are associated with the infrequent requirement for advanced life support and clinician review of computer-aided dispatch may enhance dispatch triage accuracy in studies of helicopter emergency medical services. CONCLUSIONS: Few derivation and validation studies were followed by an impact study, indicating important gaps in the value-added evidence chain. While impact studies suggest clinician oversight may enhance dispatch, the opportunity exists to standardize outcomes, identify trauma-specific low acuity codes, and develop intelligent dispatch systems.

Diagnostic performance of prehospital ultrasound diagnosis for traumatic pneumothorax by a UK Helicopter Emergency Medical Service.

OBJECTIVE: Up to 20% of major trauma patients may sustain a pneumothorax. Traumatic pneumothoraces can be difficult to diagnose on scene. Although the use of handheld ultrasound (HHUS) is becoming increasingly widespread, there remains uncertainty about its efficacy as a diagnostic tool in the prehospital setting. The aim of this study was to determine the diagnostic performance of prehospital chest HHUS in trauma patients. METHOD: Retrospective review of trauma patients who received a prehospital chest HHUS and subsequently conveyed to the Royal Sussex County Hospital (RSCH) between 1 July 2013 and 24 September 2018. Data including patient age, sex, mechanism of injury and clinical interventions were obtained. Prehospital ultrasound findings were compared with the computer tomography (CT) scan performed on arrival at the hospital. RESULTS: Four hundred eleven patients were conveyed to RSCH, the single largest group being following road traffic collisions. The majority of HHUS (66%) were performed by doctors. Three hundred sixty-one patients (88%) subsequently had a CT scan. Of these, 98 patients (27%) were found to have pneumothoraces. For pneumothorax diagnosis, prehospital HHUS had a sensitivity of 28% [95% confidence interval (CI): 19-37%] and specificity of 98% [95% CI: 97-99%]. CONCLUSION: In this retrospective study, sensitivity of prehospital HHUS for diagnosing a pneumothorax was lower than is often reported in in-hospital studies. This suggests that caution should be exercised in using HHUS for the exclusion of pneumothorax in the prehospital setting.

Pre-hospital anaesthesia and assessment of head injured patients presenting to a UK Helicopter Emergency Medical Service with a high Glasgow Coma Scale: a cohort study.

OBJECTIVES: Patients who sustain a head injury but maintain a Glasgow Coma Scale (GCS) of 13-15 may still be suffering from a significant brain injury. We aimed to assess the appropriateness of triage and decision to perform prehospital rapid sequence induction (RSI) in patients attended by a UK Helicopter Emergency Medical Service (HEMS) following head injury. DESIGN: A retrospective cohort study of patients attended by Kent Surrey & Sussex Air Ambulance Trust (KSSAAT) HEMS. SETTING: A mixed urban and rural area of 4.5 million people in South East England. PARTICIPANTS: GCS score of 13, 14 or 15 on arrival of the HEMS team and clinical findings suggesting head injury. Patients accompanied by the HEMS team to hospital ('Escorted'), and those that were 'Assisted' but conveyed by the ambulance service were reviewed. No age restrictions to inclusion were set. PRIMARY OUTCOME MEASURE: Significant brain injury. SECONDARY OUTCOME MEASURE: Recognition of patients requiring prehospital anaesthesia for head injury. RESULTS: Of 517 patients, 321 had adequate follow-up, 69% of these were Escorted, 31% Assisted. There was evidence of intracranial injury in 13.7% of patients and clinically important brain injury in 7.8%. There was no difference in the rate of clinically important brain injury between Escorted and Assisted patients (p=0.46). Nineteen patients required an RSI by the HEMS team and this patient group was significantly more likely to have clinically important brain injury (p=0.04). CONCLUSION: In patients attended by a UK HEMS service with a head injury and a GCS of 13-15, a small but significant proportion had a clinically important brain injury and a proportion were appropriately recognised as requiring prehospital RSI. For patients deemed not to need a HEMS intervention, differentiating between those with and without clinically important brain injury appears challenging. LEVEL OF EVIDENCE: V.

Managing accidental hypothermia: a UK-wide survey of prehospital and search and rescue providers.

AIM: The management of hypothermic casualties is a challenge faced by all prehospital and search and rescue (SAR) teams. It is not known how the practice of these diverse teams compare. The aim of this study was to review prehospital hypothermia management across a wide range of SAR providers in the UK. METHODS: A survey of ground ambulances (GAs), air ambulances (AAs), mountain rescue teams (MRTs, including Ministry of Defence), lowland rescue teams (LRTs), cave rescue teams (CRTs), and lifeboats and lifeguard organisations (LLOs) across the UK was conducted between May and November 2017. In total, 189 teams were contacted. Questions investigated packaging methods, temperature measurement and protocols for managing hypothermic casualties. RESULTS: Response rate was 59%, comprising 112 teams from a wide range of organisations. Heavyweight (>3 kg) casualty bags were used by all CRTs, 81% of MRTs, 29% of LRTs, 18% of AAs and 8% of LLOs. Specially designed lightweight (<0.5 kg) blankets or wraps were used by 93% of LRTs, 85% of LLOs, 82% of GAs, 71% of AAs and 50% of MRTs. Bubble wrap was used mainly by AAs, with 35% of AAs reporting its use. Overall, 94% of packaging methods incorporated both insulating and vapour-tight layers. Active warming by heated pads or blankets was used by 65% of AAs, 60% of CRTs, 54% of MRTs, 29% of LRTs and 9% of GAs, with no LLO use. Temperature measurement was reported by all AAs and GAs, 93% of LRTs, 80% of CRTs, 75% of MRTs and 31% of LLOs. The favoured anatomical site for temperature measurement was tympanic. Protocols for packaging hypothermic casualties were reported by 73% of services. CONCLUSIONS: This survey describes current practice in prehospital hypothermia management, comparing the various methods used by different teams, and provides a basis to direct further education and research.