Compiling a Hazards and Harms List (HHL) at the beginning of medical device development is a simple technique to improve all risk management activities for that product (or family of products). Have you ever been in an audit trying to explain to the auditor why the severity of a particular harm is rated differently in one risk document versus another? The obvious explanation is that two different teams performed the risk analyses in the two documents but that won’t satisfy the auditor (and it shouldn’t satisfy your company either). Risk management is too important to let everyone decide for themselves what harms are possible and the severity of each harm. Risk management needs a standardized approach based on clinical expertise.
Hazards and Harms List (HHL)
Instead of ad hoc definitions of severity of harm in each risk analysis, start your risk management activities by compiling an authoritative list of all hazardous situations and harms associated with the intended use of the medical device. This is typically a table with a column for hazardous situations, for the corresponding harms, and for the severity of each harm. The table is carefully reviewed and finalized with the Chief Medical Officer (or other clinical expert). Then the HHL serves as the foundation for all types of risk assessment for the product (System Hazard Analysis, Design FMEA, Usability Risk Analysis, etc.).
Note that there are multiple possible formats for an HHL and multiple names (AKA “Master Harms List”, “Hazards List”). The important point is to have a single, authoritative list that will form the basis for all risk assessments for a particular medical device.
Central Role of HHL
This flowchart shows the central role of the HHL in medical device risk management. The top part of the diagram shows three key inputs to hazard analysis and initial compilation of the HHL. The rest of the diagram shows how the HHL feeds into multiple types of risk assessment for the new device. There are many methods for risk assessment. This example shows a top-down System Hazard Analysis as the ‘main’ risk assessment (could also be a Fault Tree Analysis or analogous method), as well as a Usability Risk Analysis focused on use error, and multiple design FMEAs focused on failures in different parts of the system.
The primary output of all the risk assessments is identification of the set of risk controls (mitigations) needed to ensure the medical device is safe. During the risk assessments, additional hazardous situations may be discovered and this information is used to refine the HHL.
Example Format for HHL
This is an example of a few rows of an HHL for a hypothetical drug infusion pump. Other formats can be used for the same purpose–standardization of risk assessments and collection of key clinical knowledge about hazardous situations and harms. I like to include a Comments column to capture important context or clinical insights for some of the rows. This can be very useful for engineers studying the HHL without the CMO or other clinical expert present to explain its nuances.
How to Get Started
For a new medical device, how does the Risk Management Team ensure that their hazard analysis is comprehensive? What if they overlooked some key hazard and hazardous situations? Here are some resources to leverage when performing an initial hazard analysis and compiling a comprehensive HHL.
- Annex C of the ISO 14971:2019 risk management standard has a list of hazards to check to see which may apply to a new device
- Annex A of the TIR24971:2020 risk management guidance has a list of 37 questions to consider in analyzing hazards for a new device (note that not all of them will apply to any one device)
- The IMDRF website contains sets of standardized terminology for adverse events and other medical device problems: https://www.imdrf.org/working-groups/adverse-event-terminology/imdrf-adverse-event-terminology-web-browser
- The FDA website has multiple databases containing information on adverse events and product failures (MAUDE, Medsun, etc.): https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/medical-device-databases
Additional Resources
“5 Tips for Efficient Risk Assessments” – a very useful article full of practical advice by Karl Larsson of Aligned Elements
The Big Picture for Medical Device Risk Management – an overview of key concepts for risk management