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RDF19 Poster Details

RDF19 Poster Detail

Poster Title 
Addressing the challenges of large scale out-of-hospital trials (AIRWAYS-2)

Background The “cluster randomised trial of the clinical and cost effectiveness of the i-gel supraglottic airway device versus tracheal intubation in the initial airway management of out-of-hospital cardiac arrest” (AIRWAYS-2) is a large-scale trial involving four emergency medical (ambulance) services (EMS) in England.

Objective To describe the strategies employed to overcome the challenges encountered delivering the out-of-hospital phase of AIRWAYS-2.

Methods Research Paramedics (RP) were employed to recruit and randomise EMS clinicians (paramedics). Paramedics attended trial training events, including ‘airway expert’ tuition where available. Mid-point and exit training (face-to-face and on-line) was offered to reduce the risk of skill-fade over time. In several regions, recruitment was slower than anticipated. Patients were enrolled automatically; therefore every eligible patient needed to be identified reliably. RPs identified patients and investigated apparent protocol deviations/ reporting errors by reviewing ambulance service records and raising queries with paramedics. Paramedic recruitment and screening for eligible patients and protocol deviations/ reporting errors was more labour intensive than anticipated.

Results Effective recruitment was principally enabled by the provision of sufficient convenient and accessible training opportunities. 1,523 paramedics were consented and randomised at 468 training events. Only 355 (23%) paramedics undertook mid-point or exit training. The challenges of patient screening and paramedic follow-up were resolved by the flexible allocation of resources to provide additional administrative support. Protocol deviations were limited to 870/9296 (9.4%) of eligible patients.


Conclusion Large scale cluster randomised trials are possible in out-of-hospital emergency care. However, they require resource-intensive engagement with EMS clinicians. Opt-in participation is a successful model. We have shown that automatic enrolment of eligible patients can be effective. However, this required additional investment beyond that originally planned. Successful supportive strategies included willingness by the central trials team to act on RP feedback and effective engagement with key ambulance service personnel.

  • GREEN, Jonathan (research paramedic: south western ambulance service nhs foundation trust)
  • ROBINSON, Maria (research manager: south western ambulance service nhs foundation trust)
  • REEVES, Barnaby (professional research fellow: university of bristol)
  • BENGER, Jonathan (professor of emergency care: university of the west of england)
South Western Ambulance Service NHS Foundation Trust