Abstract
IntroductionWhen triaging an emergency phone call for ambulance assistance, one of the key areas of questions asked in internationally used triage decision support systems is around the patient’s level of consciousness. A patient with a reduced level of consciousness can be indicative of a requirement for a high level of urgency of ambulance response. However, the value of this as a triage criterion is dependent on how accurately it can be determined by the call-taker. We sought to identify and summarise the results from published studies which determine the accuracy of call-taker assessment of conscious state during an emergency phone call.
MethodsWe searched MEDLINE, EMBASE, CINAHL and Scopus databases for studies relating to concepts of emergency medical services, conscious state, triage and/or accuracy. Studies were screened and included if they dealt with emergency calls in the community, reported call-taker determination and on-scene determination of conscious state, and included sufficient data for at least one measure of diagnostic accuracy to be calculated.
ResultsOut of 5753 articles initially identified, only two were found that matched the inclusion criteria. Both reported accuracy of a binary determination of consciousness versus unconsciousness, and found that it is common for the reported consciousness to differ from actual findings at scene. There were no studies identified that measured accuracy of determination of altered conscious states among conscious patients.
ConclusionThere is a notable gap in the literature regarding accuracy of determination of the patient’s conscious state in an emergency call, which needs to be addressed.
References
Ball SJ, Williams TA, Smith K, et al. Association between ambulance dispatch priority and patient condition. Emerg Med Australas 2016;28:716-24.
Feldmen M, Verbeek P, Lyons D, et al. Comparison of the medical priority dispatch system to an out-of-hospital patient acuity score. Acad Emerg Med 2006;13:954-60.
Neely KW, Eldurkar JA, Drake MER. Do emergency medical services dispatch nature and severity codes agree with paramedic field findings? ibid. 2000;7:174-80.
Sporer KA, Craig AM, Johnson NJ, Yeh CC. Does emergency medical dispatch priority predict delphi process-derived levels of prehospital intervention? Prehosp Disaster Med 2010;25:309-17.
Hodell EM, Sporer KA, Brown JF. Which emergency medical dispatch codes predict high prehospital nontransport rates in an urban community? Prehosp Emerg Care 2014;18:28-34.
Hoikka M, Länkimäki S, Silfvast T, Ala-Kokko TI. Medical priority dispatch codes: comparison with National Early Warning Score. Scand J Trauma Resusc Emerg Med 2016;24:142.
Sporer KA, Youngblood GM, Rodriguez RM. The ability of emergency medical dispatch codes of medical complaints to predict ALS prehospital interventions. Prehosp Emerg Care 2007;11:192-8.
Eastwood K, Morgans A, Smith K, et al. A novel approach for managing the growing demand for ambulance services by low-acuity patients. Aust Health Rev 2016;40:378-84.
Andrew E, Jones C, Stephenson M, et al. Aligning ambulance dispatch priority to patient acuity: a methodology. Emerg Med Australas 2019;31:405-10.
International Academy of Emergency Medical Dispatch. Medical Priority Dispatch System QA Guide v12. Salt Lake City: Priority Dispatch Corporation; 2010.
King County Emergency Medical Services Division. Criteria Based Dispatch: Emergency Medical Dispatch Guidelines 2010. Available at: www.emsonline.net/assets/CriteriaBasedDispatchGuidelines-Rev2010.pdf.
Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ 2009;339:b2535.
Centre for Reviews and Dissemination. PROSPERO: International Prospective Register of Systematic Reviews. York, UK: University of York. Available at: www.crd.york.ac.uk/prospero/
Akobeng AK. Principles of evidence based medicine. Arch Dis Child 2005;90:837-40.
Hoffmann T, Bennett S, Mar CD. Evidence-based practice across the health professions. Chatswood, Australia: Elsevier; 2017, p. 470.
Clopper C, Pearson E. The use of confidence or fiducial limits illustrated in the case of the binomial. Biometrika 1934;26:404-13.
Whiting PF, Rutjes AW, Westwood ME, et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med 2011;155:529-36.
Whiting PF. QUADAS-2 Worksheet: University of Bristol; 2011. Available at: www.bristol.ac.uk/media-library/sites/quadas/migrated/documents/quadas2.pdf
Bach A, Christensen EF. Accuracy in identifying patients with loss of consciousness in a police-operated emergency call centre – first step in the chain of survival. Acta Anaesthesiol Scand 2007;51:742-6.
Clawson J, Olola C, Scott G, et al. Association between patient unconscious or not alert conditions and cardiac arrest or high-acuity outcomes within the medical priority dispatch system “falls” protocol. Prehosp Disaster Med 2010;25:302-8.
Gibson JME, Bullock M, Ford GA, et al. ‘Is he awake?’: dialogues between callers and call handlers about consciousness during emergency calls for suspected acute stroke. Emerg Med J 2013;30:414-8.
Jones SP, McAdam JJ, McLoughlin ASR, Gibson JME, Leathley MJ, Watkins CL. Understanding of the term conscious when used during emergency calls for suspected stroke. 20th European Stroke Conference; Hamburg, Germany, 2011. p. 234.
Ohshige K, Kawakami C, Mizushima S, Moriwaki Y, Suzuki N. Evaluation of an algorithm for estimating a patient's life threat risk from an ambulance call. BMC Emerg Med 2009;9:21.
Radonić J, Gnjidić M, Matijanec M, Hochstädter D, Jasprica-Hrelec V. [What is not revealed in the telephone call reporting "unconsciousness"]. Lijec Vjesn 1995;117(Suppl 2):68-70.
Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet 1974;2:81-4.
Kelly C, Upex A, Bateman D. Comparison of consciousness level assessment in the poisoned patient using the alert/verbal/painful/unresponsive scale and the Glasgow Coma Scale. Ann Emerg Med 2004;44:108-13.
Queensland Ambulance Service. Neurological assessment. Clinical Practice Manual; 2016, p. 431-3.
Australian Government Department of Health and Ageing. Emergency Triage Education Kit. Canberra, Australia: DoHA; 2009. Available at: https://acem.org.au/getmedia/c9ba86b7-c2ba-4701-9b4f-86a12ab91152/Triage-Education-Kit.aspx
Canadian Association of Emergency Physicians, CTAS National Working Group. Canadian Triage and Acuity Scale Combined Adult/Paediatric Educational Program Participants Manual. 2.5b, edn 2013.