Emergency use (German: Notfallnutzung) denotes the use of a medical device in a time-critical situation in which immediate or particularly fast action may be required to prevent or limit serious health consequences. Emergency use is not a defined term in IEC 62366-1 but describes a particular context of use within usability engineering.
This context can be shaped by time pressure, high workload, limited attention, noise, interruptions, parallel tasks, changing responsibilities, and emotional strain, among other factors. If emergency use is part of the intended or reasonably foreseeable use of the medical device, it must be given appropriate consideration in the use specification, the use-related risk analysis, the design of the user interface, and the usability evaluations.
- Emergency use as a particular context of use
- Importance for the use specification
- Connection to the use-related risk analysis
- User interface requirements for emergency use
- Requirements for formative and summative evaluations
- Distinction from abnormal use
- Regulatory reference
- Frequently asked questions (FAQ)
Emergency use as a particular context of use
From a human factors perspective, emergency use is a particular context of use that can occur in very different physical and organizational environments. Examples include:
- Emergency department
- Intensive care unit
- Operating room
- Trauma room
- Ambulance
- Rescue helicopter
- Public spaces
- Home environment
- Disaster and mass casualty situations
- Situations in which a patient suddenly deteriorates
Emergency use should therefore not be equated with a specific use environment. A medical device can, for example, be used in an intensive care unit both during planned treatment and in an acute emergency. Although the physical environment remains the same, tasks, priorities, available time, collaboration, and cognitive load can differ considerably.
Typical influencing factors are:
- High or suddenly arising time pressure
- Competing tasks and priorities
- Interruptions and distractions
- Limited visibility or poor lighting
- High noise levels
- Movement and vibration
- Limited workspace
- Use of gloves or protective clothing
- Several people involved at the same time
- Communication and handover problems
- Missing or incomplete patient information
- Rare or little-trained tasks
- Fatigue and high workload
- Emotional strain
These conditions do not automatically lead to use errors. However, they can influence perception, attention, working memory, decision making, and action execution, and thereby make certain errors more likely.
The user interface should therefore not work only under ideal or calm conditions. It must also support the intended users in safe and effective use under the relevant real-world conditions of use. The FDA regards the user, the use environment, and the user interface as interacting components of the device-user system.
Importance for the use specification
If a medical device is to be used in emergency situations, or if such use is reasonably foreseeable, this must already be taken into account in the use specification.
It is not sufficient merely to state "emergency use" or "use in an emergency." The relevant conditions must be described concretely enough that use-related risks, design requirements, and suitable evaluation conditions can be derived from them. The following should be considered in particular:
- Intended user groups
- Qualification and emergency experience of the users
- Frequency of use
- Possible first-time or occasional users
- Intended patient populations
- Medical urgency
- Time available for individual tasks
- Typical workflows
- People and roles involved
- Task allocation and handovers
- Available resources
- Possible interruptions
- Environmental conditions
- Required protective clothing
- Available instruction and training
- Required accessories
- Dependencies on power supply, network, or other devices
The different phases of use should also be considered:
- Retrieval and transport of the product
- Setup and start-up
- Connection and configuration
- Selection of a therapy or operating mode
- Entry of parameters
- Monitoring of the patient and the device
- Response to alarms
- Switching between operating states
- Handover to other users
- End of use
- Reprocessing or restoring readiness for use
Emergency use can also involve several user groups with different tasks. For example, emergency medical services personnel, emergency physicians, nurses, and clinical users may interact with the same device in succession. A suitable use specification must reflect these differences. A general user group such as "medical professionals" is usually not sufficient for this.
Connection to the use-related risk analysis
Emergency situations must be taken into account in the use-related risk analysis as relevant contexts of use and contributing conditions. It should be examined which use errors can occur under the respective emergency conditions and which consequences could result. The following can be particularly relevant:
- Delayed start-up
- Selection of a wrong operating mode
- Incorrect entry of patient or therapy parameters
- Confusion of units of measurement
- Confusion of connectors or components
- Incomplete connections
- Incorrect interpretation of displays
- Overlooking or misunderstanding an alarm
- Unintentional overwriting of settings
- Omission of necessary work steps
- Faulty handovers
- Operation by users who are not sufficiently familiar with the device
- Inadequate response to system errors
- Delayed recognition of an ineffective therapy
The use-related risk analysis should not assume across the board that "stress" increases the probability of all errors. Instead, concrete relationships should be described, for example:
- Because of time pressure, the user does not check a preset parameter.
- Because of competing alarms, a safety-relevant signal is not noticed.
- Because of an interruption, the user resumes a multistep procedure at the wrong point.
- Under difficult lighting conditions, a unit is misread.
- Because of unclear task allocation, each user assumes that the other person has performed a necessary step.
Such conditions can be part of a hazard-related use scenario. Emergency use should not be viewed only as a scenario in which use errors are more likely to occur. It can also aggravate the consequences of an error, since often only limited time is available for detection and correction. This can give rise to requirements for error detection, system feedback, recovery, and error tolerance of the user interface.
User interface requirements for emergency use
User interfaces for emergency use must not merely be "simple" or "intuitive." They must adequately support the intended users in concrete, safety-relevant tasks under the defined emergency conditions. Suitable design principles can include:
- Clear prioritization of safety-relevant information
- Unambiguous display of the current system state
- Immediate and understandable feedback on user inputs
- Minimization of unnecessary action steps
- Limitation of memory demands
- Avoidance of unnecessary confirmation dialogs
- Safeguarding of inputs that are truly critical
- Easily distinguishable controls
- Sufficient size and spacing of controls
- Operability with gloves or protective clothing
- Good perceptibility under the relevant lighting and noise conditions
- Unambiguous display of values and units
- Avoidance of similarly presented therapy options
- Design measures that prevent incorrect connections
- Plausibility checks for safety-relevant inputs
- Clear alarm prioritization
- Support for error detection and recovery
- Preservation of safety-relevant settings during interruptions
- Visible progress in time-critical processes
Conflicting goals can arise here. An additional safety prompt can, for example, prevent an incorrect entry but at the same time delay a time-critical action. A shortened input sequence can be faster but increase the risk of missing verification. Such trade-offs must be examined on a risk basis and checked through formative evaluations. It is not enough to provide as few action steps as possible, or as many confirmations as possible, across the board.
Among the possible results of good human factors engineering, the FDA highlights, for example, secure connections, understandable displays, suitable controls, alarm management, reduced dependence on instructions for use, and a lower need for training.
Information in the instructions for use or training may also be necessary. In time-critical situations, however, they are often available only to a limited extent. Safety-relevant measures should therefore be supported directly by the design of the user interface wherever possible.
Requirements for formative and summative evaluations
If emergency use is relevant for safe use, it must be taken into account appropriately in formative and summative evaluations. Formative evaluations can examine in particular:
- Recognizability of safety-relevant information
- Comprehensibility of displays and system states
- Speed and safety of critical workflows
- Effects of time pressure and interruptions
- Operation with gloves or protective clothing
- Perceptibility of alarms
- Collaboration of several users
- Handovers between user groups
- Behavior in the event of device or system errors
- Options for detecting and correcting input errors
Different design variants and workflows can be compared in the process. Formative evaluations should take place as early as possible so that fundamental problems are not recognized only during the summative evaluation.
For a summative evaluation, the relevant emergency scenarios, user groups, and conditions of use must be represented appropriately. This can include:
- Realistic time requirements
- Representative distractions
- Typical noise and lighting conditions
- Use of the intended protective clothing
- Parallel tasks
- Relevant devices and accessories
- Realistic patient or device simulators
- Representative team composition
- Intended training
- Appropriate interval between training and use
The simulation does not have to artificially reproduce every emotional and medical dimension of a real emergency. What matters is that the conditions relevant for safe use are reproduced with sufficient realism. An evaluation must also not be designed to be unnecessarily psychologically stressful or dangerous. Realism should be targeted at those factors that have a relevant influence on perception, decision making, collaboration, or action execution.
When analyzing results, not only task success and completion time should be considered. Relevant observations are in particular use errors, close calls, use difficulties, omissions, delays, unnecessary action steps, misunderstandings, communication problems, assistance required, incorrect or accidentally correct decisions, and options for error detection and recovery. A fast result is not automatically a safe result. Likewise, a longer completion time is not necessarily problematic if it results from a safety check that is technically required.
Distinction from abnormal use
Emergency use is not automatically abnormal use. Normal use comprises correct use and use errors within the intended or reasonably foreseeable use. Abnormal use, by contrast, denotes a conscious, intentional act or omission that violates normal use and lies beyond further reasonable means of control through the design of the user interface.
If a product is expressly intended for emergency situations, emergency use clearly belongs to normal use. Even if a particular emergency situation is not intended as a primary use case, it can be reasonably foreseeable. In this case, it must not be excluded as abnormal use solely because of stress, time pressure, or a deviation from the ideal workflow. Examples of foreseeable emergency use can include:
- Use of a device by another qualified user group
- Omission of a non-safety-critical preparation step under time pressure
- Continuation of a therapy with limited infrastructure
- Use under unfavorable lighting or noise conditions
- Switching between users during an ongoing emergency response
Whether an action is to be classified as normal use, reasonably foreseeable misuse, or abnormal use must be assessed and documented on the basis of the specific situation. IEC 62366-1 enables the analysis and control of risks associated with correct use and use error within normal use. Risks arising from abnormal use, by contrast, are neither assessed nor controlled by the process.
| Normal use | Abnormal use | |
|---|---|---|
| Scope | Correct use and use errors within the intended or reasonably foreseeable use | Conscious, intentional act or omission that violates normal use and lies beyond further reasonable means of control through the design of the user interface |
| Treatment in IEC 62366-1 | Risks associated with correct use and use error are analyzed and controlled | Risks are neither assessed nor controlled by the process |
A distinction should also be made between emergency use as a context of use and regulatory terms such as emergency use authorization. The latter denotes a regulatory mechanism for the temporary or situation-specific availability of certain products and is not a term for describing the context of use within usability engineering.
Regulatory reference
IEC 62366-1 contains no standalone product category or process stage called emergency use. It does, however, require a usability engineering process for the analysis, specification, development, and evaluation of the safety-related usability of a medical device. This includes, among other things, the use specification, user profiles, use environments, known or foreseeable hazards, and hazard-related use scenarios. If emergency use is intended or foreseeable, it must be given appropriate consideration within these activities.
ISO 14971 requires consideration of the intended use and reasonably foreseeable misuse. Emergency conditions can be part of the foreseeable sequences of events or contributing factors for use-related hazardous situations.
In the European context, the MDR and IVDR require risks to be eliminated or reduced as far as possible through safe design and manufacture. For products intended for use in emergency situations, the associated conditions of use must therefore be incorporated into the technical documentation (the manufacturer's required product documentation), risk management, and the usability assessment.
The FDA guidance "Applying Human Factors and Usability Engineering to Medical Devices" regards intended users, uses, and use environments as central foundations of human factors engineering. The aim is to minimize use-related risks and to demonstrate that the product can be used safely and effectively by the intended users.
In the FDA context, emergency use must therefore be given appropriate consideration if it is part of the intended use or relevant for performing critical tasks. This includes realistic characteristics of the use environment, workload, intended users, and the conditions under which the product is used.
ANSI/AAMI HE75 offers complementary and comprehensive human factors guidance for the design and evaluation of medical devices. Among other things, it covers environmental, organizational, and structural conditions, alarm management, training, instructions for use, and usability testing. It can therefore provide important design guidance for products used under emergency conditions.
Emergency use denotes the use of a medical device under time-critical and potentially stressful conditions. Emergency use is not a standalone product category, not automatically a separate use environment, not automatically abnormal use, and not to be equated with an emergency use authorization.
If emergency use is intended or reasonably foreseeable, it must be addressed consistently: use specification → context analysis → use-related risk analysis → user interface requirements → formative evaluation → summative evaluation.
What matters is not to document "stress" across the board but to identify concrete tasks, conditions, and contributing factors and to control them through a suitable design of the user interface.
Frequently asked questions (FAQ)
Is emergency use a separate product category?
No. In usability engineering, emergency use denotes a context of use or a particular condition of use. A product can be intended exclusively for emergency situations or be used under both routine and emergency conditions.
Is emergency use the same as an emergency use authorization?
No. Emergency use describes the use of a medical device under time-critical or otherwise special conditions. An emergency use authorization, by contrast, is a regulatory mechanism through which authorities can, under defined conditions, permit the use of certain products in a public health emergency.
Is emergency use automatically abnormal use?
No. If use of the product in an emergency situation is intended or reasonably foreseeable, it belongs to normal use and must be taken into account in the usability engineering and risk management process. Stress, time pressure, or behavior that deviates from the ideal workflow do not automatically make a use abnormal use.
Does every emergency use have to be simulated in the summative evaluation?
Not every conceivable emergency situation has to be examined as a separate scenario. The selection must be made on a risk basis. Relevant hazard-related use scenarios or critical tasks and the conditions of use essential for them must be represented appropriately. Similar scenarios can be combined where appropriate if it is justified in a traceable way that the relevant interactions, risks, and influencing factors are sufficiently represented.
Does an emergency simulation have to create maximum stress?
No. An evaluation should realistically reproduce those conditions that have a relevant influence on product use. These can include time pressure, noise, interruptions, or collaboration. Artificially maximizing psychological strain is neither required nor automatically methodologically suitable. It can also reduce the comparability of results and must remain ethically justifiable.
May the instructions for use be used as a risk control measure?
Yes, information for safety can be part of risk control. In an acute emergency situation, however, it must be examined whether users actually have the time and opportunity to find, read, understand, and apply the instructions for use. Wherever possible, safety-relevant requirements should therefore be supported directly by the design of the user interface.
How is stress taken into account in the use-related risk analysis?
Stress should not simply be entered as a general probability factor. Instead, it should be described what concrete influence the respective situation can have on the task, for example that relevant information is overlooked, an intermediate check is omitted, work steps are confused, inputs are not verified, system states are misinterpreted, or responsibilities remain unclear. Suitable requirements and risk control measures can be derived from these concrete relationships.
Are you developing a medical device for time-critical or particularly demanding situations of use? We support you with context and task analyses, the derivation of emergency-specific user interface requirements, and realistic formative and summative evaluations.
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)
- Regulation (EU) 2017/746 on in vitro diagnostic medical devices (IVDR)
- FDA Guidance: Applying Human Factors and Usability Engineering to Medical Devices