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18 ‘Tell me what’s happened’: when linguistic choices affect efficiency of ambulance dispatch for cardiac arrest
  1. M Riou1,
  2. A Whiteside2,
  3. S Ball1,
  4. T Williams1,2,3,4,
  5. KL O’Halloran8,
  6. GD Perkins9,
  7. J Bray1,5,
  8. P Cameron5,
  9. K Smith3,5,7,
  10. DM Fatovich1,3,4,6,
  11. M Inoue1,
  12. D Brink1,2,
  13. P Bailey1,2,10,
  14. J Finn1,2,3,5
  1. 1Prehospital, Resuscitation and Emergency Care Research Unit (PRECRU), School of Nursing, Midwifery and Paramedicine, Curtin University, Bentley, Australia
  2. 2St John Ambulance (WA), Belmont, Australia
  3. 3Discipline of Emergency Medicine, The University of Western Australia, Crawley, Australia
  4. 4Royal Perth Hospital, Perth, Australia
  5. 5Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
  6. 6Centre for Clinical Research in Emergency Medicine, Harry Perkins Institute of Medical Research, Nedlands, Australia
  7. 7Ambulance Victoria, Blackburn North, Australia
  8. 8School of Education, Curtin University, Bentley, Australia
  9. 9Out of Hospital Cardiac Arrest Outcomes, Warwick Clinical Trials Unit, University of Warwick, UK
  10. 10St John of God Hospital Murdoch, Murdoch, Australia


Aim Clear and efficient communication between emergency caller and call-taker is crucial to timely ambulance dispatch. Within the Medical Priority Dispatch System,1 the first opportunity that callers have of describing the situation is after the scripted prompt “okay, tell me exactly what happened”. However, in 60% cases, call-takers introduce a slight linguistic variation (what’s happened v. what happened). This study analyses the effect of this change on the way callers describe the emergency.

Methods Using a mixed-methods analysis combining Conversation Analysis and Corpus Linguistics, we analysed 184 calls from paramedic-confirmed out-of-hospital cardiac arrests in Perth (Western Australia) in 2014–2015. We coded each call for its use of tense in the prompt and the format of the response as either a report (focusing on symptoms) or a narrative2 (containing irrelevant background details) and we timed the callers’ responses.

Results The use of report response was much more frequent when call-takers chose the present perfect (what’s happened) rather than the simple past (what happened) (72% v. 43%, p<0.0001). We found that the median length of caller response was significantly shorter when it was structured as a report rather than a narrative (9 v. 18 s, p<0.0001). Reports unfolded more efficiently over a median of 3 turns (v. 6 for narratives, p<0.0001).

Conclusion A change of tense can impact how efficiently callers describe a time-critical emergency. Our results suggest that a better understanding of linguistic and interactional dynamics can improve dispatch performance.


  1. Medical Priority Dispatch System (version 12.1.3). Salt Lake City, Utah, USA: Priority Dispatch Corp.

  2. Labov W, Waletzky J. Narrative analysis: Oral sessions of personal experience. In: Helm J, editor. Essays Verbal Vis. Arts, Seattle: University of Washington Press; 2003, p. 74–104.

Conflict of interest A. Whiteside and D. Brink receive full salary support, and P. Bailey, M. Inoue and J. Finn receive partial salary support from St John Ambulance.

Funding Funding for this research was received from an Australian NHMRC (National Health and Medical Research Centre) Partnership Project: #1076949 ‘Improving ambulance dispatch to time-critical emergencies’. J. Finn and J. Bray receive partial salary support from the NHMRC ‘Aus-ROC’ Centre for Research Excellence #1029983. J. Bray receives salary support from an NHMRC/NHF (National Heart Foundation) Early Career Fellowship.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: .

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