Applying Human Factors to the Design of Medical Equipment: Patient-Controlled Analgesia

  • Laura Lin
  • Racquel Isla
  • Karine Doniz
  • Heather Harkness
  • Kim J. Vicente
  • D. John Doyle


Objective. Medical instruments commonly have poorly designed user interfaces that promote human errors with life-threatening consequences. The primary hypothesis of this study was that a specific user interface could be made safer and more efficient if redesigned using human factors techniques and principles. Methods. The user interface of a commercially available patient-controlled analgesia (PCA) pump, the Abbott Lifecare 4100 PCA Plus II infuser, was evaluated using a cognitive task analysis of bench tests and field observations. Based on this analysis, the user interface was redesigned. Important elements of the new design include a dialog structure with fewer steps, a dialog overview showing the user's location in the programming sequence, better command feedback, easier error recovery, and clearer labels and messages. The changes were evaluated by comparing a computer prototype of the new interface with a computer simulation of the old one. Twelve student nurses performed six programming tasks with each interface. Task completion time, number of errors, and subjective mental workload were collected for each trial. Results. The results showed significantly faster programming times (F(1,11) = 6.85, P < 0.025), lower mental workload ratings (χ2(1) = 4.45, p < 0.025, one-tailed), and fewer errors (χ2(1) = 3.33, p < 0.05, one-tailed) with the new interface. Conclusion. Adopting a human factors approach to redesigning the PCA interface led to significantly faster, easier, and more reliable performance. These findings have important implications for improving the design of other computer-based medical equipment.

Medical equipment interface design human factors task analysis patient-controlled analgesia human-computer interaction 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Bogner MS. Medical devices and human error. In: Mouloua M, Parasuraman R, eds. Human performance in automated systems: Current research and trends. Hillsdale, NJ: Erlbaum, 1994: 64–67Google Scholar
  2. 2.
    Perrow C. Normal accidents: Living with high-risk technologies. New York: Basic Books, 1984Google Scholar
  3. 3.
    Leape LL. Error in medicine. J Am Med Assoc 1994; 272(23): 1851–1857Google Scholar
  4. 4.
    White PF. Mishaps with patient-controlled analgesia. Anesthesiology 1987; 66: 81Google Scholar
  5. 5.
    Smythe M. Patient-controlled analgesia: A review. Pharmacotherapy 1992; 12: 132–143Google Scholar
  6. 6.
    Cohen MR. Preventing errors associated with P.C.A. pumps. Nursing 1993; 23: 17Google Scholar
  7. 7.
    Vicente KJ, Rasmussen J. Ecological interface design: Theoretical foundations. IEEE Transactions on Systems, Man, and Cybernetics 1992; SMC-22: 589–606Google Scholar
  8. 8.
    Sawaki Y, Parker RK, White PF. Patient and nurse evaluation of patient-controlled analgesia delivery systems for postoperative pain management. J Pain Symptom Management 1992; 7: 443–453Google Scholar
  9. 9.
    Rouse WB. Computer-generated display system guidelines, volume 2: Developing an evaluation plan (EPRI NP-3701). PaloAlto, CA: EPRI, 1984Google Scholar
  10. 10.
    Owen H, Glavin RJ, Reekie RM, Trew AS. Patient-controlled analgesia: Experience of two new machines. Anaesthesia 1986; 41: 1230–1235Google Scholar
  11. 11.
    Ilsley AH, Owen H, Plummer JL, Mackey NA, Roberts DRD. A system for standardized evaluation of patient-controlled analgesia devices: Design, construction, and engineering aspects. J Clin Monit 1994; 10: 194–200Google Scholar
  12. 12.
    Charante EM, Cook RI, Woods DD, Lue Y, Howie MB. Human-computer interaction in context: Physician interaction with automated intravenous controllers in the heart room. In: Stassen HG, ed. Analysis, design, and evaluation of man-machine systems 1992. London: Pergamon Press, 1992: 263–274Google Scholar
  13. 13.
    Yue L, Woods DD, Cook RI. Cognitive engineering of the human-computer interface: Re-design of an infusion controller in cardiac anesthesiology (CSEL Report TR–01–92). Columbus, OH: Cognitive Systems Engineering Laboratory, Ohio State University, 1992Google Scholar
  14. 14.
    Cook RI, Potter SS, Woods DD, McDonald JS. Evaluating the human engineering of microprocessor controlled operating room devices. J Clin Monit 1991; 7: 217–226Google Scholar
  15. 15.
    Isla R, Lin L. Investigation of the Effectiveness of the User Interface of Patient Controlled Analgesia Machines. Unpublished B.A.Sc. Thesis, University of Toronto, Toronto, Ontario, 1993Google Scholar
  16. 16.
    Doniz K, Harkness H. Interface for Patient Controlled Analgesia Machine. Unpublished B.A.Sc. Thesis, University of Toronto, Toronto, Ontario, 1994Google Scholar
  17. 17.
    Wickens CD. Engineering psychology and human performance. 2nd ed. NewYork: Harper-Collins, 1992Google Scholar
  18. 18.
    Molich R, Nielson J. Heuristic evaluation of user interfaces. In Proceedings of CHI'90. NewYork: ACM Press, 1990: 249–256Google Scholar
  19. 19.
    Cook RI, Woods DD, Howie MB. The natural history of introducing new information technology into a high-risk environment. In Proceedings of the Human Factors Society Annual Meeting. Santa Monica, CA: Human Factors Society, 1990: 429–433Google Scholar
  20. 20.
    Association for the Advancement of Medical Instrumentation. Human factors engineering guidelines and preferred practices for the design of medical devices (AAMI HE-1988). Arlington,VA: AAMI, 1988Google Scholar

Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Laura Lin
    • 1
    • 2
  • Racquel Isla
    • 1
  • Karine Doniz
    • 1
  • Heather Harkness
    • 1
  • Kim J. Vicente
    • 1
    • 2
  • D. John Doyle
    • 2
    • 3
  1. 1.Cognitive Engineering Laboratory, Department of Mechanical & Industrial EngineeringUniversity of TorontoCanada
  2. 2.Institute of Biomedical EngineeringUniversity of TorontoCannada
  3. 3.Department of AnaesthesiaUniversity of TorontoCanada

Personalised recommendations