The growing role of human factors and usability

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The growing role of human factors and usability engineering for medical devices What s required in the new regulatory landscape. Background, Medical errors have been cited as the cause of nearly 100 000 deaths per year in the US healthcare system by the. US Institute of Medicine in 1994 in its book To err is human Building a safer health system According to the World Health. Organization s website similar trends exist for European healthcare systems with estimates that 8 to 12 per cent of. hospitalizations involve adverse events and that as many as 18 per cent of patients report having experienced a medical. error induced problem Costs in the UK alone for hospital infection intervention is estimated at 1 million per year. Adverse events over the past two decades have shown disturbing trends in post market events that are attributable to. design issues regarding the user interface UI of medical devices Infusion pumps automatic electronic defibrillators. ventilators and combination products such as drug auto injectors have a history of use related design problems. resulting in overdoses improper therapy delivery incorrect diagnoses and dangerous delays in therapy As part of. the systematic process to reduce errors by regulatory bodies medical device companies in the US and EU have. been introduced to the disciplines of Human Factors and Usability Engineering HF UE HF UE has been applied in. the automotive aerospace and telecommunications industries for more than 60 years but has only recently been. applied in the medical industry, HF UE focuses on the synergy of human operators or users with systems and their UIs by applying knowledge of. human capabilities and limitations and performing tests and evaluations of user system performance Human factors. also apply known principles and best practices in the design of displays controls and other UI aspects to optimize. use and eliminate or limit use related risks, Is usability different from human factors How do these. terms relate, The term usability engineering often used as a synonym for human factors is also focused on creating qualities of. UIs that result in rapid learning user satisfaction and efficient interaction The term usability is a multi dimensional. quality that refers to the ability of a human to interact easily and relatively error free with a system or product Terms. such as user friendly and intuitive have emerged as descriptors of usability which translate to subjective attributes. regarding whether a system or device works and acts in the way the user expects therefore avoiding frustration and. annoyance in carrying out an intention,What is the impact of usability on healthcare.
Usability has a major impact on healthcare particularly with regard to the overall effectiveness of medical devices. Simply put if usability is lacking the completion of user tasks may be slower and more error prone Therefore. A child with an inhaler,2 BSI UK 565 ST 0215 en HL. bsigroup com, delivery of therapy will suffer and patient safety may be compromised Moreover it is well known that easy to use. products are more popular resulting in market discrimination and a competitive advantage Therefore usability can. be a positive attribute from a business and sales perspective as well as controlling risk. How have medical device regulations incorporated HF UE in. regulatory activities, Because of the rising instances of UI induced adverse events the US Food and Drug Administration FDA has begun. to include HF UE reviews as a routine part of their pre market approval process at the Center for Devices and. Radiological Health s CDRH Office of Device Evaluation This process is described in a draft guidance issued in June. 2011 entitled Applying human factors and usability engineering to optimize medical device design. Likewise the international regulatory community has incorporated IEC 62366 Medical devices Application of usability. engineering to medical devices as a part of the approval process outside the US Both the FDA HF UE guidance and. IEC 62366 outline a process including activities throughout device development culminating in validation testing. with the final UI design in simulated use environments In the following sections of this paper we will summarize the. major expectations of both the international and FDA expectations of manufacturers regarding HF UE. From the international regulatory perspective what are. the expected HF UE outputs requested and reviewed by. regulatory organizations, IEC 62366 2007 BS EN 62366 2008 is undergoing significant revision to provide improved organization and. harmonization with the FDA s 2011 draft guidance on human factors As a result compliance with IEC 62366 2007. requires evidence of the conduct of a usability engineering process UEP which means that manufacturers would. have to document their HF UE work in accordance with the nine clauses comprising the process. Why was IEC 62366 2007 revised, IEC 62366 2007 was revised for several reasons These were the main motivations for modification.
In 2011 the FDA published its own updated HF UE guidance to the industry Several important aspects of risk. and summative testing were not in alignment between IEC 62366 and the FDA guidance The new version. of IEC 62366 will reflect a much more synergistic approach with the FDA guidance. Nomenclature differences also existed between US FDA and European terminology regarding usability and human. which have since been resolved, There was a need for more clarity on implementation of the HF UE process An informative counterpart document. created dividing the standard into the streamlined normative part 62366 1 and an informative part 62366 2. which will also be listed as a TR Technical Report. What are the basic activities in the HF UE process and what is. their alignment with device risk assessment, HF UE activities can be categorized into three major phases. 1 preliminary analyses,2 user interface design evaluation. 3 simulated use testing validation,BSI UK 565 ST 0215 en HL 3. The growing role of human factors and usability engineering for medical devices What s required in the new regulatory landscape. These phases of HF UE activity align with both the EU and the FDA s pre market human factors approval and. compliance requirements described in IEC 62366 and the FDA HF UE guidance The relationship of these phases of. HF UE in the context of risk assessment and risk management are shown in Figure 1. Preliminary analyses, Preliminary analyses are conducted to identify device user profiles use environments and use scenarios These.
elements are vital to completing a detailed use risk analysis These three elements are part of both the FDA and. IEC 62366 documentation requirements, a User profiles are descriptions of user group training experience knowledge and potential limitations such as. decreased visual acuity and manual dexterity User groups are often differentiated on the basis of what use. scenarios they perform i e some users may do different tasks or interact differently than others with the device. This information is vital in determining the composition of user group testing in summative testing with the. device and in establishing design requirements to accommodate special needs of certain users. b Use environments are brief descriptions of the ambient conditions of the places that the device will be used. including parameters such as range of lighting noise temperature and vibration Other environmental factors. should be noted such as distractions or interruptions in the user device interaction caused by interacting with. other devices or personnel in the use environment, c Use scenarios are brief descriptions of the sequences of user device interaction that result in some intended. healthcare outcome e g initiating delivery of a given drug therapy altering a previously initiated drug delivery. order troubleshooting or responding to alarms Each use scenario will comprise multiple tasks or steps that can. be further analysed from a use risk perspective in the use error use risk analysis. d Task analysis is the analytical foundation for several other key activities that are conducted in preliminary analyses. including use error use risk analysis user interface design and formative and summative usability testing Task. analysis provides a detailed description of the human requirements to perform the steps required to accomplish a. use scenario, e Use error use risk analysis also a key method in preliminary analyses should be performed in conjunction with. conventional risk analyses to determine specific potential risks of user device interaction across the use scenarios. Use risk analysis is sometimes referred to as use failure mode effects analysis U FMEA which identifies potential use. errors for each task or step from the task analysis that could lead to potential patient or user harm Such use errors. should be identified from past history of device interaction identifying potential confusion or incorrect assumptions. about how the device works and by observing user behaviour in formative usability as the UI design matures. Table 1 provides an example of combining task analysis with use error use risk analysis using a simple blood glucose. meter to illustrate the format of a typical use risk analysis two columns on the right based on task analysis two. columns on the left, Table 1 Illustration of task analysis and use risk analysis. User task Task requirements Potential use errors Consequences risk severity. Power on meter Know which button is Failure to find button and Delay in knowing status of blood. power and push for two hold for two seconds glucose low risk. Set correct time and date Compare setting with Failure to notice The history of blood glucose. today s time date use incorrect time date or readings used in setting insulin. arrow keys to input inputting wrong info therapy will be inaccurate. settings potentially leading to wrong,therapy decisions high risk.
Check test strip Compare today s date Failure to notice out of Potential of 10 per cent error in. expiration with expiry date on the date strips reading accuracy medium risk. strip vial,4 BSI UK 565 ST 0215 en HL,bsigroup com. The use error use risk analysis is a complementary process to conducting conventional risk analyses as described in. ISO 14971 Medical devices Application of risk management to medical devices the risk assessment standard for medical. devices The challenges of conducting use risk analyses within the scope and intent of ISO 14971 will be discussed. later in this paper,User interface design evaluation. Both the FDA and IEC 62366 stress the importance of a UI design process that is driven by iterative formative. evaluations Formative evaluations are usability tests and assessments conducted early and throughout the design. process Formative evaluations address two design goals a to make the device interface intuitive and easy to use. and b to control or mitigate potential use related risks These goals can pose design dilemmas because in some. instances ease of use and safety may be in conflict For example placing the power button for an IV drug delivery. device next to the start stop button controlling the infusion may appear convenient however the potential of an. accidental shutdown of the device instead of halting the infusion may preclude this convenience and dictate that the. power button be mounted well away from the start stop mechanism. Formative evaluation method resources, AAMI HE75 Human factors engineering Design of medical devices Clause 9 Usability Testing provides an excellent. guide to the types of formative evaluations that are useful in early device UI development such as cognitive. walkthroughs heuristic evaluations and walk through talk through usability tests Annex D of IEC 62366 also. provides descriptions of these formative techniques. Standards for interface design, Interface design standards and best practice references such as HE75 provide excellent guidance for the design of. displays controls software graphical UIs alarms surgical tools instructions for use IFU and other elements of the. UIs However HE75 stresses the value of iterative user testing during the course of UI design The role of formative. techniques such as cognitive walkthroughs heuristic evaluations and walk through talk through usability tests are. vital for obtaining feedback for the design team regarding both ease of use and use error control and mitigation. Different elements of user interface,BSI UK 565 ST 0215 en HL 5.
The growing role of human factors and usability engineering for medical devices What s required in the new regulatory landscape. Simulated use testing validation, Summative testing also referred to as simulated use validation testing of the UI with representative users. performing a set of use scenarios is the central source of evidence of use safety for both IEC 62366 and the FDA. human factors pre market evaluations To avoid obvious safety concerns to test participants summative testing can. be conducted under simulated use conditions that are representative of real world conditions. How does summative testing differ from other usability testing. There are several important differences in test methodology regarding summative simulated use tests compared to. other usability evaluations such as formative tests listed here. 1 The summative test is not meant to be an exploratory effort seeking inp. usability engineering for medical devices BS EN 62366 2008 The growing role of human factors and usability engineering for medical devices Whats required in

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