1. Copyright © 2005, Pearson Education, Inc. Case Study Medical Monitoring Devices Based on work done at Hewlett-Packard Patient Monitoring Division Circa 1993

2. Copyright © 2005, Pearson Education, Inc. Introduction HP Patient Monitoring Division (PMD), Andover MA, 1992 – 1995 Division developed various devices for use in hospitals (ICU, CCU) to help improve patient outcomes HP Medical later spun to Agilent, then sold to Philips

3. Copyright © 2005, Pearson Education, Inc. Project “Griffin” Develop a “next generation central station”, a monitoring device that resides at the nurse’s desk and displays data from individual bedside monitors

4. Copyright © 2005, Pearson Education, Inc. Usability Measures Time to learn: minimal, but training time acceptable Speed of performance: fast, must be easy to locate critical data Rate of errors: very low Retention over time: high Subjective satisfaction: not required, but good enough to maintain level of alertness over long periods of time

5. Copyright © 2005, Pearson Education, Inc. System Users Users are entirely clinicians: –Doctors, nurses –Highly trained professionals, high degree of area knowledge –Not necessarily computer savvy –Have critical tasks to perform, system plays an assistive role

6. Copyright © 2005, Pearson Education, Inc. Interaction Styles For this system, the environment drop the style as much as the users: –Minimal desk space, smaller footprint of trackball as pointing device –Potentially noisy / chaotic –Required high degree of accuracy

7. Copyright © 2005, Pearson Education, Inc. Interaction Styles Direct manipulation: usable for selecting targets and issuing commands (buttons) Menu selection: short learning curve, reduced keystrokes, error handling Forms: slow, too high a risk of errors Command language: too much training, lots of error handling Natural language: far too many keystrokes

8. Copyright © 2005, Pearson Education, Inc. Monitoring Tasks Real world object –Patients –Vital signs Actions applied to objects –Display vital signs –Raise alarms if vitals go outside acceptable ranges –Set ranges

9. Copyright © 2005, Pearson Education, Inc. Interface Objects Patient –Name –Vital signs Vital signs –Name (heart rate, blood pressure) –Value (beats per minute) –Acceptable range of value

10. Copyright © 2005, Pearson Education, Inc. Interface Representations Heart rate –Display metaphor: waveform Long history in the medical community –Display color –Alarm levels –Alarm colors –Alarm sounds

11. Copyright © 2005, Pearson Education, Inc. Interface Actions Display vital signs Set acceptable ranges Inform users of alarms (visual, audio) Silence alarms

12. Copyright © 2005, Pearson Education, Inc. Final Interface