title: Ambulance smartphone tool for field triage of ruptured aortic aneurysms (FILTR): study protocol for a prospective observational validation of diagnostic accuracy.
abstract: Rupture of an abdominal aortic aneurysm (rAAA) carries a considerable mortality rate and is often fatal. rAAA can be treated through open or endovascular surgical intervention and it is possible that more rapid access to definitive intervention might be a key aspect of improving mortality for rAAA. Diagnosis is not always straightforward with up to 42% of rAAA initially misdiagnosed, introducing potentially harmful delay. There is a need for an effective clinical decision support tool for accurate prehospital diagnosis and triage to enable transfer to an appropriate centre.
  
  
  
  Prospective multicentre observational study assessing the diagnostic accuracy of a prehospital smartphone triage tool for detection of rAAA. The study will be conducted across London in conjunction with London Ambulance Service (LAS). A logistic score predicting the risk of rAAA by assessing ten key parameters was developed and retrospectively validated through logistic regression analysis of ambulance records and Hospital Episode Statistics data for 2200 patients from 2005 to 2010. The triage tool is integrated into a secure mobile app for major smartphone platforms. Key parameters collected from the app will be retrospectively matched with final hospital discharge diagnosis for each patient encounter. The primary outcome is to assess the sensitivity, specificity and positive predictive value of the rAAA triage tool logistic score in prospective use as a mob app for prehospital ambulance clinicians. Data collection started in November 2014 and the study will recruit a minimum of 1150 non-consecutive patients over a time period of 2 years.
  
  
  
  Full ethical approval has been gained for this study. The results of this study will be disseminated in peer-reviewed publications, and international/national presentations.
  
  
  
  CPMS 16459; pre-results.
authors: St George's Vascular Institute, St George's University of London, London, UK.
authors: Thomas L
authors: TL
authors: Lewis
authors: Clinical Audit & Research Unit, London Ambulance Service NHS Trust, 8-20 Pocock Street, London, UK.
authors: Rachael T
authors: RT
authors: Fothergill
authors: St George's Vascular Institute, St George's University of London, London, UK.|Cardiovascular and Cell Sciences Institute, St George's University of London, London, UK.
authors: Alan
authors: A
authors: Karthikesalingam
mesh_terms: D000328:Adult; D000552:Ambulances; D001011:Aorta / Q000473:pathology; D017544:Aortic Aneurysm, Abdominal / Q000175:diagnosis* / Q000601:surgery; D001019:Aortic Rupture / Q000175:diagnosis* / Q000601:surgery; D000066491:Clinical Decision-Making / Q000379:methods*; D057210:Delayed Diagnosis; D005260:Female; D017052:Hospital Mortality; D006761:Hospitals; D006801:Humans; D008131:London; D008297:Male; D063731:Mobile Applications / Q000592:standards; D018579:Patient Selection; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012107:Research Design; D012680:Sensitivity and Specificity; D000068997:Smartphone; D014218:Triage
keywords: VASCULAR SURGERY; mobile app; pre-hospital; ruptured abdominal aortic aneurysm; smartphone