Getting your device faster on the market by integrating separate processes
In many projects Usability Engineering, Risk Management and Design Control are three separate processes. Though this is partly true, there are also lots of overlap and dependencies between them. This article briefly describes how you can integrate these activities to increase the chance of success, improve collaboration between project team members, and getting your device faster on the market.
The processes in short
The figure below illustrates the relation between the three processes.
Use Specification & User Interface Evaluation Planning
The purpose of the Use Specification is to describe:
- Intended Medical Indication
- Intended Patient Population
- Intended part of the body of type of tissue applied to or interacted with
- Intended User Profile
- Intended Use Environment
- Intended Operating Principle
The Use Specification is written early in the Usability Engineering process and provides early input to which risks may be involved in using the medical device – but also the design requirement that the device must meet. For instance, the Use Specification can describe that the medical device is to be used in an ambulance (the Use Environment). This requires that the device is designed for single-hand use since the user must hold on to a handle while the ambulance is driving fast. In an ambulance, there is also the risk of the device or equipment falling to the floor if not secured or safely clamped.
Formative Evaluation and Design Improvement
Throughout the design and development process the device should be evaluated. This is typically done both analytically using brainstorming, database searches, task analysis and PCA (Perception, Cognition, Action) analysis, but also empirically by evaluating the device in the hands of representative intended users.
Formative evaluations typically identify potential use errors (new risks) and user needs. Thereby providing input for the Product Risk Evaluation and the Requirements Specification.
Risk Control and Selection of Critical Tasks
As risks are being evaluated and controlled, this provides input to the design requirements that the medical device must meet (the risk control measures) as well as which use scenarios are to be evaluated in the Summative Evaluation. The Summative Evaluation shall evaluate all critical tasks, i.e. if user tasks, if performed incorrectly or not performed at all, would or could cause serious harm to the patient or user. These are identified in the Risk Management process by sorting use-related risks where use errors may result in serious harm to the user or patient.
Summative Evaluation and Residual risk evaluation
When the Summative Evaluation is complete, the residual risk is evaluated. If unacceptable risks are still present with the device, a benefit/risk analysis conclude whether the medical device is safe to launch to the market. For instance, a scalpel will always be a potential hazard and there is a risk of the user cutting herself on the scalpel. However, mitigating the risk of the user cutting herself by making the scalpel blunt (inherent safety by design) would affect the effectiveness and intended use of a scalpel. Therefore, this risk cannot be eliminated, and it must be evaluated if the benefit outweighs the residual risk of harm. The full activity is documented in the Usability Engineering File, the Risk Management File, Verification and Validation reports as well as a traceability matrix.
We hope that this article provided you with an overview of how to integrate your usability engineering process into the Risk Management- and Design Control process. There are a lot of nuances and details to the processes, but with the general understanding in place, you are now able to start integrating the processes saving both time and reducing project risks while developing great usable products.
Morten Purup Andersen
Senior R&D Engineer, Human Factors Specialist
Telefon: 45 26 10 00