A Systems Approach for Safe – But Not Too Safe – Medical Devices
Is it possible to be too safe? When it comes to features for medical device, the answer is yes. Oftentimes, medical devices have too many safety components or not enough – both can be hazardous to patients. By applying clinical insights, field experience and utilizing a requirements-driven systems approach, along with verification and validation (V&V) procedures from the beginning of the project, safety evaluations can produce optimum safety with minimum cost.
For example, engaging a nurse, radiological technologist, doctor and/or pharmacist early in the design cycle has proven to be critical in “right sizing” the system safety analysis. These individuals can be part of the team, brainstorming for hazards, frequency evaluations and an acceptable risk definition. I believe that it is better for a design team to focus on minimizing or eliminating select hazards that are most plausible. Attempting to capture and mitigate every possible hazard often leads to overrated risk levels.
I recommend that the team’s systems engineer progressively lead the team through a top level evaluation, followed by increasingly detailed analyses (as appropriate) as development proceeds. By defining what risk level is acceptable for the particular device from the start of the project, the team can focus on the top key hazards and how to mitigate them.
As current International Council of Systems Engineering (INCOSE) President John Thomas, ESEP, wrote in his position paper, “Why Systems Engineers are Essential to Your Organization”
A systems engineer is invaluable to an organization by preventing system problems from impacting the cost and schedule of programs. They rely on their technical and leadership skills to reduce the potential for rework associated with changes in design, interpretations with requirements or confusion with the user’s intent. They are the ones who pay attention to the system details and ensure the user, the buyer and the investor are all satisfied with the project’s outcome – which is the ultimate measure of success.
If systems engineering techniques (model-based systems engineering works well for more complex systems) are interwoven with the safety analysis, we are able to seamlessly capture hazard-defined requirements into the fabric of the architecture, interfaces and V&V.
A few examples of “too much” or not appropriate mitigations that I have witnessed include:
- Redundancy in an MR contrast delivery system
- Extensive V&V procedures for a medical cardiac pump, which carried into quality control (QC) for all of the production testing
- An inadequate V&V on a syringe-loading product, leading to a major software error
- The cost of prostate probes, which are now often sterilized and re-used
This topic will be explored and discussed more thoroughly on July 10, 2012 during the “Biomedical Panel: Patient Safety, Systems Engineering on Center Stage in the Biomedical Industry” session at the 2012 INCOSE International Symposium in Rome, Italy.
John Gardner, who is one of the panelists at INCOSE International Symposium, is the vice president of product development at Syncroness, Inc., a company offering complete development expertise in complex development environments, such as medical devices. Synchroness assists organizations in becoming more competitive through optimization of research, development and sustaining engineering.