Risk assessment is one of the most critical parts of quality assurance and regulatory compliance for medical devices. Risk management is required by all major regulatory authorities and for all medical devices. The European Medical Device and In Vitro Diagnostic Medical Device Regulations (MDR, 2017/745; IVDR, 2017/746) require medical devices to perform as intended while guaranteeing high levels of safety for the users and patients. Ensuring the safety and efficiency of medical devices includes eliminating or reducing risk as far as possible.
Failure Modes and Effects Analysis (FMEA) identifies possible failures in a medical device’s design and manufacturing, supporting manufacturers in developing compliant risk management processes for their devices. It was initially in the United States Army in the 1940s and further developed by NASA in the early 1960s. IEC 60812 Failure Modes and Effects Analysis (FMEA and FMECA).
DFMEA
Design FMEA. Design FMEAs address potential failure modes in the device design process. The goal is to improve the design process and get a better product.
PFMEA
Process FMEA. Process FMEAs address potential failure modes in specific manufacturing processes. The goal is to prevent a non-compliant or defective product from being released onto the market.
FMEA and ISO 14971
While FMEA is an effective tool for identifying potential failures, it does not focus on correcting or mitigating those risks. FMEA is part of a more extensive risk management system, but it does not cover every aspect of risk management. For example, FMEA does not include harm or risks in everyday use. To properly fulfill the requirements of the MDR and IVDR, medical device manufacturers must also ensure compliance with ISO 14971 Application of Risk Management to Medical Devices.
FMEA Basics
Risks are scored during failure mode effect analysis to identify which risks pose the highest priority. Three risk concepts are scored on a scale of 1-10 (lowest to highest) and then multiplied to get the risk priority number (RPN). The higher the risk priority number, the higher the risk priority.
The following concepts are scored to obtain your risk priority:
Severity (SEV)
The severity of the consequence of a given failure mode. While some failures can be considered low severity, such as a cosmetic defect in a radiofrequency generator, others are catastrophic and considered high severity, such as mechanical failure in a respiratory ventilator.
Occurrence (OCC)
The probability of a failure mode occurring. It is unlikely to experience failure in a titanium implant, which would result in a low occurrence score; however, cosmetic defects, such as in the example above, might occur more frequently, in which case the result would be a higher occurrence score.
Chance of detection (DET)
The probability of detecting failure modes. If you cannot detect a failure mode from your current processes, the result is a high chance of detection score.
The scoring of these concepts is subjective, so it is critical to have cross-functional teams with different areas of expertise who all have a basic understanding of the manufacturing or design processes you are evaluating.
FMEA process
- Identify all the elemental components or steps in your process. Every step in your operation must be described clearly, and its purpose laid bare.
- Review each step systematically and identify how it can fail to meet requirements.
- Describe how each potential failure can impact the subsequent steps in the process, all the way to the final user.
- Analyze the cause of each failure. It is essential to avoid ambiguity in your phrasing, so you can adequately correct and control the cause of failure later in the process.
- Rank each potential risk of failure using the risk priority method described above. The risk priority number makes it immediately clear which risks are most critical.
- Decide how to eliminate or minimize the most critical risks and draft a plan to reduce the risks as far as possible.
- Once the actions to mitigate risk are implemented, return to the original risk levels, and revise them to ensure that risk mitigation has been successful.
Common FMEA mistakes
Overcomplicating the process. Streamlining the process as much as possible avoids problems later and ensures you can trust the process to work correctly.
Inaccurate timing. FMEAs must be applied in time to ensure they appropriately impact your operations. They cannot be used as an emergency fix. FMEAs should be run early in the development process and at the end stages to ensure proper assessment of both design and manufacturing processes.
Drawing incorrect conclusions. You must analyze your FMEA results correctly to set your medical device operation on the right course. This includes working with experienced cross-functional people, using clear, concise language to avoid ambiguity, objectively analyzing your results, and assigning plenty of time and resources to the process.
Failure to let FMEA drive product and process improvements. The FMEA is not a one-and-done process – it should drive improvements in design verification plans, process control plans, product development, and testing. Manufacturers should properly implement FMEA results in their whole operation.
