A hazardous situation (German: Gefährdungssituation) is, in the risk management of medical devices, the circumstance in which people, property, or the environment are exposed to one or more hazards. It is the link between an existing hazard and a possible harm, and it becomes particularly relevant in usability engineering when it is triggered by user interaction, use errors, or deficiencies in the user interface.
Role in use-related risk management
The hazardous situation is a central element of the chain of risk development. While a hazard merely describes the inherent potential to cause harm, a hazardous situation arises only when people, property, or the environment are exposed to that hazard. In usability engineering, it is therefore analyzed which use sequences or use errors can lead to concrete exposure to a hazard. Describing hazardous situations makes it possible to establish a traceable link between use errors and potential harms.
Distinction from hazard, harm, and risk
Hazard, hazardous situation, harm, and risk are often mixed up in practice. The hazard describes the potential source of harm, for example the pharmacological effect of a drug. The hazardous situation exists when a patient is exposed to an excessive dose of that drug. The harm arises only when this results in an impairment of health. The risk, finally, results from the combination of the probability of occurrence and the severity of the harm. A clean separation of these terms considerably improves the quality of risk analyses.
| Term | Meaning, using a drug as an example |
|---|---|
| Hazard | Potential source of harm, for example the pharmacological effect of a drug |
| Hazardous situation | Exists when a patient is exposed to an excessive dose of that drug |
| Harm | Arises only when this results in an impairment of health |
| Risk | Combination of the probability of occurrence and the severity of the harm |
Relationship to use errors
Many hazardous situations arise not directly from technical defects but from use errors or from user interfaces that encourage errors. Examples are incorrect parameter entries, patient mix-ups, misinterpretation of alarms, or use of a product under unsuitable environmental conditions. Analyzing such chains of events is a core element of the use-related risk analysis (URRA). The aim is to recognize critical interaction patterns early and to control them through suitable design measures.
Identification of hazardous situations
Identification is usually based on several sources of information: requirements elicitation, task analysis, use scenarios, known incidents from post-market data, literature reviews, and findings from formative studies. It is particularly important to consider both foreseeable and already known hazardous situations. This combines product-specific risks with experience from similar products and market observation.
Relationship to hazard-related use scenarios
Hazardous situations form the basis for deriving hazard-related use scenarios. These describe a concrete chain of events consisting of tasks, user interactions, possible use errors, and the resulting hazardous situation. They serve as input for formative evaluations and as an essential basis for selecting the scenarios for the summative evaluation. Without clearly defined hazardous situations, a traceable selection of safety-critical test scenarios is hardly possible.
Typical weaknesses in practice
A common mistake is to formulate hazardous situations too abstractly. Statements such as “incorrect operation” or “use error” do not describe a hazardous situation but merely possible causes. A robust formulation describes the concrete situation in which the hazard becomes effective, for example “patient receives an infusion rate ten times too high.” Mixing harm and hazardous situation in the same description is equally problematic. This complicates the later risk assessment and reduces traceability for auditors and notified bodies (independent conformity assessment bodies designated under the EU Medical Device Regulation).
Regulatory reference
IEC 62366-1 requires the identification of known or foreseeable hazards and hazardous situations as part of the usability engineering process, in connection with the analysis of potential use errors and safety-related characteristics of the user interface. Hazard-related use scenarios must be derived from this and serve as the basis for evaluating the usability of safety-related functions. ISO 14971 uses the hazardous situation as a central element of the chain of risk development between hazard and harm; risk management must analyze sequences of events that can lead to hazardous situations. In its human factors guidance, the FDA requires the identification of critical tasks and use-related risks, whereby hazardous situations are typically operationalized through use scenarios and critical tasks. The EU Medical Device Regulation (MDR) requires in Annex I that ergonomic features and foreseeable misuse be taken into account; identifying hazardous situations as part of risk management directly supports demonstrating compliance with these requirements.
The hazardous situation is the link between hazard and harm and thus the point where usability engineering and risk management converge. Those who formulate it too abstractly lose traceability between use error, risk analysis, and later evaluation decisions.
Frequently asked questions (FAQ)
Is a hazardous situation the same as a use error?
No. A use error can be a cause that leads to a hazardous situation. The hazardous situation, by contrast, describes the state in which a person or an object is exposed to a hazard.
Must every hazardous situation arise from a use error?
No. Hazardous situations can arise from use errors as well as from technical failures, environmental conditions, or combinations of different factors.
Why are hazardous situations important for the summative evaluation?
They serve as the basis for identifying hazard-related use scenarios and thus for selecting the safety-critical scenarios that must be evaluated in the summative evaluation.
How detailed should a hazardous situation be described?
Concretely enough that it is clear who is exposed to which hazard and under what circumstances. Mere keywords or abstract descriptions of errors are usually not sufficient.
Do you want to identify hazardous situations for your medical device cleanly and integrate them into your risk management file? We support you throughout the usability engineering process according to IEC 62366-1.
More about our usability engineeringSources
- IEC 62366-1:2015+AMD1:2020, Medical devices, Part 1: Application of usability engineering to medical devices
- ISO 14971:2019, Medical devices, Application of risk management to medical devices
- Regulation (EU) 2017/745 on medical devices (MDR)