Journal of Clinical Monitoring and Computing

, Volume 21, Issue 6, pp 353–363 | Cite as

A New Paradigm for the Design of Audible Alarms that Convey Urgency Information

  • Richard R. McNeer
  • Jorge Bohórquez
  • Özcan Özdamar
  • Albert J. Varon
  • Paul Barach



The current international standard (IEC 60601-1-8) stipulates that medical device audible alarms should be priority-encoded and validated for efficacy. Evidence suggests that the melodic alarms described in the standard are not functioning as originally intended. We present a multi-disciplinary, human factors paradigm for audible alarm development whereby urgency information is encoded via modulation of the physical characteristics of sounds. We also test the feasibility of this approach using information measures.


We designed series of experimental sounds that varied along controlled physical and acoustical dimensions. Subjects rated these sound series for perceived urgency. Based on these ratings, selected sounds from each series were assigned a␣priority category from ‹low’ to ‹high’ – we call these resulting sets of sounds ‹urgency-codecs’. The method of categorical judgments (based on information theory) was used to compare each urgency-codec for ability to convey urgency information.


Subjects were consistent in their ratings of the three series of experimental sounds for perceived urgency. The urgency data pertaining to one of the series (harmonic interval) was successfully fit to a psychophysical empirical law. The urgency-codec derived from another sound series (melodic interval) was found to have the highest signal (correct interpretation of urgency level by subjects) transmission rate.


The proposed paradigm is feasible, and it offers an evidence-based strategy for alarm sound design and testing. This approach would be performed before implementation of new alarm sounds in clinical settings, and should result in development of alarm sounds that satisfy the requirements of priority-encoding and validation.


alarm sounds alarms urgency urgency matching urgency mismatch anesthesia monitoring medical monitoring medical device human factors standardization 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Stanton NA, Edworthy J Auditory warnings, displays: an overview. In: Stanton NA, Edworthy J, eds Human factors in auditory warnings. Aldershot: Ashgate Publishing Limited, 1999: 3–30Google Scholar
  2. 2.
    Patterson RD Auditory warning systems for high-workload environments. Ergonom Internat 1985; 85: 163–165Google Scholar
  3. 3.
    Edworthy J Urgency mapping in auditory warning signals. In: Stanton NA ed Human factors in alarm design. London: Taylor and Francis, 1994, 15–31Google Scholar
  4. 4.
    Williams S, Beatty PCW Measuring the performance of audible alarms for anaesthesia. Physiol Meas 2005;26:571–581PubMedCrossRefGoogle Scholar
  5. 5.
    Loeb RG, Jones BR, Leonard RA, Behrman K Recognition accuracy of current operating room alarms. Anesth Analg 1992;75:499–505PubMedCrossRefGoogle Scholar
  6. 6.
    Meredith C, Edworthy J Sources of confusion in intensive therapy unit alarms. In: Stanton N, ed Human factors in alarm design. London: Taylor and Francis, 1994, 207–219Google Scholar
  7. 7.
    Momtahan KL, Hetu R, Tansley BW Audibility and identification of auditory alarms in the operating room and intensive care unit. Ergonomics 1993;36:1159–1176PubMedCrossRefGoogle Scholar
  8. 8.
    Seagull FJ, Sanderson PM Anesthesia alarms in context: an observational study. Hum Fact 2001;43:66–78CrossRefGoogle Scholar
  9. 9.
    Tsien CL, Fackler JC Poor prognosis for existing monitors in the intensive care unit. Crit Care Med 1997;25:614–619PubMedCrossRefGoogle Scholar
  10. 10.
    Sorkin RD Why are people turning off our alarms? J Acoust Soc Am 1988;84(3):1107–1108CrossRefGoogle Scholar
  11. 11.
    Medical electrical equipment-Part 1-8: General requirements, tests and guidance for alarm systems in medical electrical equipment and medical electrical systems. International Electrotechnical Committee 60601-1-8:2003(E)Google Scholar
  12. 12.
    Stanton NA, Booth RT The psychology of alarms. In: Lovesey EJ, ed Contemporary ergonomics. London: Taylor and Francis, 1990, pp 378–383Google Scholar
  13. 13.
    Gaba DM, Howard SK, Small SD Situation awareness in anesthesiology. Hum Fact 1995;37(1):20–31CrossRefGoogle Scholar
  14. 14.
    Bye A, Berg O, Owre F Operator support systems for status identification and alarm processing at the OECD Halden Reactor Project – experiences and perspective for future development. In: Stanton NA, ed Human factors in alarm design. London: Taylor & Francis, 1994Google Scholar
  15. 15.
    Mackenzie CF, Martin P, Xiao Y, LOTAS group Video analysis of prolonged uncorrected esophageal intubation. Anesthesiology 1996;84:1494–1503PubMedCrossRefGoogle Scholar
  16. 16.
    Marshall E, Baker S Alarms in nuclear power plant control rooms: current approaches and future design. In: Stanton NA, ed Human factors in alarm design. London: Taylor & Francis, 1994Google Scholar
  17. 17.
    Stanton NA Alarm initiated activities. In: Stanton NA, ed Human factors in alarm design. London: Taylor & Francis, 1994Google Scholar
  18. 18.
    Woods DD The alarm problem and directed attention in dynamic fault management. Ergonomics 1994;38(11):2371–2394CrossRefGoogle Scholar
  19. 19.
    Xiao Y, Mackenzie CF, Jaberi M, Harper B, LOTAS group Alarms: silenced, ignored and missed. Anesthesiology 1996;73:995–1021Google Scholar
  20. 20.
    Meredith C, Edworthy J Are there too many alarms in the intensive care unit? An overview of the problems. J Adv Nurs 1995;21(1):15–20PubMedCrossRefGoogle Scholar
  21. 21.
    Kestin IG, Miller BR, Lockhart CH Auditory alarms during anesthesia monitoring. Anesthesiology 1988;69(1):106–109PubMedCrossRefGoogle Scholar
  22. 22.
    Watson M, Sanderson P, Russell WJ Tailoring reveals information requirements: the case of anaesthesia alarms. Interact Comput 2004;16:271–293CrossRefGoogle Scholar
  23. 23.
    Finley GA, Cohen AJ Perceived urgency and the anaesthetist: responses to common operating room monitor alarms. Can J Anaesth 1991;38(8):958–964PubMedCrossRefGoogle Scholar
  24. 24.
    Mondor TA, Finley GA The perceived urgency of auditory warning alarms used in the hospital operating room is inappropriate. Can J Anesth 2003;50(3):221–228PubMedGoogle Scholar
  25. 25.
    Watt R, Maslana E, Mylrea C Alarms and anesthesia: challenges in the design of intelligent systems for patient monitoring. IEEE Eng Med Biol 1993;12(4):34–41CrossRefGoogle Scholar
  26. 26.
    Hudson DL, Cohen ME Fuzzy logic in medical expert systems. IEEE Eng Med Biol 1994;13(5):693–698CrossRefGoogle Scholar
  27. 27.
    Becker K, Rau G, Kasmacher H, Petermeyer M, Kalff G, Zimmermann HJ Fuzzy logic approach to intelligent alarms. IEEE Eng Med Biol 1994;13(5):710–716CrossRefGoogle Scholar
  28. 28.
    Wolf M, Keel M, von Siebenthal K, Bucher HU, Geering K, Lehareinger Y, Niederer P Improved monitoring preterm infants by fuzzy logic. Technol Health Care 1996;4(2):193–201PubMedGoogle Scholar
  29. 29.
    Block FE, Rouse JD, Hakala M, Thompson CL A proposed new set of alarm sounds which satisfy standards and rationale to encode source information. J Clin Monit 2000;16(7):541–546CrossRefGoogle Scholar
  30. 30.
    Sanderson PM, Wee A, Lacherez P Learnability and discriminability of melodic medical equipment alarms. Anaesthesia 2006;61:142–147PubMedCrossRefGoogle Scholar
  31. 31.
    Sanderson P, Wee A, Seah E, Lacherez P. Auditory alarms, medical standards, and urgency. In: Stockman T, Nickerson LV, Frauenberger C, Edwards ADN, Brock D, eds, Proceedings of the 12th International Conference on Auditory Display. London: International Conference on Auditory Display, 2006Google Scholar
  32. 32.
    Annett J Subjective rating scales: science or art? Ergonomics 2002;45:966–987PubMedCrossRefGoogle Scholar
  33. 33.
    Norwich KH. Information of events with discrete outcomes: methods of communication theory and psychology. In: Information, sensation and perception. San Diego: Academic Press, Inc., 2003: 34–49Google Scholar
  34. 34.
    Stevens SS On the psychophysical law. Psychol Rev 1957;64:153–181PubMedCrossRefGoogle Scholar
  35. 35.
    Miller GA The magical number seven, plus or minus two: some limits on our capacity for processing information. Psychol Rev 1956;63:81–97PubMedCrossRefGoogle Scholar
  36. 36.
    Pollack I The information of elementary auditory displays. J Acoust Soc Am 1952;24:745–749CrossRefGoogle Scholar
  37. 37.
    Pollack I The information of elementary auditory displays II. J Acoust Soc Am 1953;25:765–769CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Richard R. McNeer
    • 1
  • Jorge Bohórquez
    • 2
  • Özcan Özdamar
    • 2
  • Albert J. Varon
    • 1
  • Paul Barach
    • 3
    • 4
  1. 1.Division of Trauma Anesthesia & Critical Care, Department of Anesthesiology, School of MedicineUniversity of MiamiMiamiUSA
  2. 2.Department of Biomedical Engineering, College of EngineeringUniversity of MiamiCoral GablesUSA
  3. 3.Department of AnesthesiologyUniversity of South FloridaTampaUSA
  4. 4.University of UtrechtUtrechtNetherlands

Personalised recommendations