matthew geary
hospital bed usability testing
background
Most of us have spend some amount of time - minutes, hours, days - in a hospital bed. As patients, we often take that experience for granted, save the poorly placed TV controls. Proper bed design, however, aids patients ingress and egress, allows clinicians to confidently navigate their environment, and in an emergency, can make the difference between life and death.
challenge
methods
human factors
heuristic review
usability testing
fault tree analysis
role
human factors engineer, team of two at InsightPD
As a part of their next generation development, our team owned the development and execution of the usability testing for their FDA submission.
process
Human Factors Integration Planning
As part of the Design History File, we include a document explaining the prespecified activities for fully integrating Human Factors into the development process. Though this document is updated throughout the project, the goal is to define the target users, use cases, and environments and to ensure the design and evaluation procedures are appropriate and thought through in advance. Often this plan is submitted to the FDA in advance of the testing as evidence of intent.
Expert Heuristic Review
At the start of the project, we conducted an expert review of the existing product that was currently in-market. Given the primary operating functions, we attempted to complete each task without receiving instruction, noting areas of confusion, conflicting mental models, improper labeling, etc. These included physical tasks, such as raising and lowering the bed, setting brakes, and also software interactions like arming and disarming the exit alarms. By evaluating the existing product, we identified the most critical weaknesses of the current product, as well as key strengths that should be kept as we kicked off design of the follow-on.
Fault Tree Analysis
As a part of the expert review, we identified the various ways the bed could fail to perform its primary operating functions. The fault tree analysis looks at high level effects and initiators to determine the likelihood and severity of these failures and creates a framework for risk mitigation.
Formative Usability Testing I
Following the initial review, the client design and engineering team began work on the initial prototype of the new bed. Throughout this process, we stayed in close contact and advised on key design decisions during. Once the prototype was in a working state, we conducted the first round of usability testing using recruited patients, nurses, and hospital transport staff. Participants used a think-aloud method where they walked us through the completion of several key tasks to identify use errors and opportunities for improvement. Those findings informed refinement of the new bed design.
Formative Usability Testing II
Several months later, the client engineering team delivered a revised bed prototype. Using the learnings from the previous testing and improved part quality, the new prototype closely resembled the product the team intended to bring to market. In advance of the final summative / validation testing, we ran a second round of usability testing with the goal of evaluating users' ability to complete the required tasks. Unlike the first testing, this round included the strict pass/fail criteria that would be representative of a formal submission and allowed the client to objectively understand the state of the product.
results
Due to the current state of this project, detailed results cannot be shared. Results of this project will be updated as information is released by the client.