Mobile Blood Pressure - Assessment Plan

The toolkit for mobile blood pressure products took TTAC testing in a different direction than is typical for most other products. Where most products evaluated to date have had a larger focus on clinical equipment and applications that would be used by an organization's employees and medical staff, the blood pressure products are focused directly at a consumer market. In some ways, this new direction provided clarity as to the scope of the product testing, but in other ways added complexities that have not needed to be addressed in the past.

Defining the Users

The consumer focus of these devices does limit the scope of some of the product usability testing that would have to be performed, as it eliminates the question of which clinical applications and uses might be interested in utilizing the devices. Generally speaking, the TTAC expected the typical user to be largely untrained, with some uncertainty as to the general mobility and technical ability of this person.

The uncertainty of who the target user would be led the TTAC to include a range of ages in the testing group, with the youngest subject being 20 and the oldest 40. Subjects ranged from clinicians and technologists to support staff and untrained individuals. A range of body types were also selected, as there were concerns that there would be issues using and getting accurate data from the devices if an individual's body type were especially thin or overweight.

Defining the Requirements

The requirements set for this particular test were fairly limited. The products had to be able to communicate with a mobile device, though it was decided that having a direct software interface on a smartphone was not necessary. Devices had to fit the range of subjects, either through different cuff sizes or a single cuff that would accommodate the various arm diameters that would be tested.

Output of the data to a third-party personal health record application was not a firm requirement, but was desirable as it would allow a consumer to save and review data and integrate with other health data that they might be recording. Accuracy of data was also decidedly important, as these devices would be used to track key medical data and may be used to drive healthcare decisions.

Testing the Devices

Individual subjects were brought in and tested on the devices in a single testing session. Each subject would be tested three times on all four of the devices that were brought in, with a thirty second resting period between each test. The patients' pulse was manually recorded during the testing and was compared to the pulse information displayed on each device. This data was anonymized and entered into a spreadsheet, with the data for all three tests on a single device averaged together (mean), and then with results for all of the averaged data for all devices combined to get an average (mean) for each subject.

Notes were made throughout the use, including observations of users struggling to secure the device, use the software, and get accurate readings from the devices. Some of the users, especially those with slender arms, occasionally struggled with getting the equipment to work properly.