Analysis of a “Simple” Medical Device

Abstract

Contrary to manufacturers' claims about ease of use, real users report a number problems with complex devices at home. f Definitely Not "As Easy as 1, 2, 3" "It's as easy as 1, 2, 3" begins the videotape that accompanies a commonly used blood glucose meter. "Simply set up the meter, check the system, and test your blood." However, our analysis of the system suggested that it is not quite that easy. Sure, there are three general steps involved in using the system, but implementation of those steps requires the user to do 52 substeps! The first column of the table on pages 8-9 lists all the steps required to test one's blood using a typical blood glucose meter. Setting up the meter requires 6 steps, checking the system requires 22 steps, and testing of the blood glucose level requires 24 steps. This level of complexity is not unique to one particular meter; we conducted a task analysis on another commonly used meter and found 61 substeps. When people are told that a system is trivially easy to use but have difficulties with it, they tend to blame themselves. They may be too embarrassed to ask for assistance, stop using the system altogether, or continue to use it without realizing they're using it incorrectly. Additional evidence that blood glucose meters are not trivially easy to use comes from a study conducted to assess the accuracy of the blood glucose readings obtained by diabetics using blood glucose meters (Colagiuri, Colagiuri, Jones, & Moses, 1990). Colagiuri et al. tracked 90 patients using two different meters for one month. Participants were asked to test previously measured solutions. The results showed that 62 % of the patients made at least one error that was classified as "clinically significant," meaning that the patient either would have taken a medically inappropriate action or failed to take a medically appropriate action based on the incorrect reading. According to the error classification conducted by Colagiuri et al., the most frequent cause of the error was a "faulty technique" on the part of the user. In these researchers' words, "the most commonly encountered error arose from the patient not adhering to the EDICAL DEVICES ARE DESIGNED TO 6 ERGONOMICS IN DESIGN• WINTER 2001 12 ERGONOMICS IN DESIGN. WINTER 200 I

The Human Factors of Home Health Care

“…Despite manufacturers' assertions about ease of use of their products, it is not unusual to find multiple steps, substeps, and buried routines when devices are subjected to human factor testing and evaluation. 56 More than traditional usability testing by able-bodied individuals under well-lit, laboratory conditions is needed if a device is to function well in the variable conditions of the home environment. Testing in the environment of use and performing in-depth user and home assessments can reveal a host of problems not anticipated by designers and standard forms of usability testing.…”

Exploring medical device design and use through layers of Distributed Cognition: How a glucometer is coupled with its context

“…Studies that look at glucometer usability have identified problems. For example, Rogers et al [54] carried out a usability test of home use glucometers. They report that they are not simple, typically involving over 50 procedural steps to take a reading.…”

Usability Model for Medical User Interface of Ventilator System in Intensive Care Unit

“…This approach includes a video analysis consisting of verbal and non-verbal analysis along with micro-level coding [24]. Rogers et al have analyzed a blood glucose meter for its usability using video analysis, in which transcription and coding is used [35]. During this research work, selected task performances are video-recorded in real-time ICU environment.…”