Kate Dobson, Senior Human Factors Engineer, StarFish Medical11.09.23
User-centered design (UCD) is an iterative design process based on ISO 9241-210:2019, in which designers focus on users and their needs in each phase of the design process. We use UCD methodology to drive our product development journey, where we commit to understanding users and meeting their unique needs.
This article describes a series of recent examples that illustrate how UCD helps to reduce risk and create medical products and systems that are intuitive, efficient, and safe for users.
To illustrate, let's examine a real-world example developing a product designed for use by surgeons during surgery. Our journey began by engaging directly with surgeons, observing surgical procedures, and closely examining the tools they relied on. Insights gleaned from these experiences had a profound impact on the product's design. As we considered factors like the patient population, reimbursement models, patient recovery periods, and the diverse nature of surgeries, we determined the product would better serve an alternative market with different end users. This realization prompted a significant pivot in our design approach.
One illuminating example underscores the value of this approach. As we analyzed the workflow of a first responder wearing medical gloves in the confines of a moving ambulance, it became evident that adjustments were necessary. The layout of information on the screen and the sequence of button inputs had to be redefined to prevent inadvertent and erroneous inputs in this high-pressure scenario.
In our pursuit of informed design, we harness the power of a valuable tool—Use-Related Risk Analysis (URRA). This tool catalogs specific use cases for the product, enabling our team to systematically evaluate each user task. Using the PCA framework, recommended by the FDA in their Human Factors guidance from February 2016, we examine potential sources of use errors and categorize them into perception, cognition, and action—key causes of use-related risks.
In another instance, we were developing a reusable device to be sterilized between patients. A significant concern emerged in our URRA analysis—the risk of residual patient data inadvertently transferring to the next patient's file if a nurse forgot to erase the data. This revelation prompted an innovative solution where our design team reimagined the hardware and software to automatically wipe patient data when the device was connected to the charging unit, eliminating the risk entirely.
The UCD approach empowers us to make informed design decisions early in the process. By reducing or even eliminating use-related risks, we ensure the device’s behavior aligns with user expectations, enhancing safety and effectiveness.
Human factors experts often have a knack for recognizing nuances in their colleagues' anthropometry. We can discern who's the tallest, who boasts the biggest head, and even the quirks in hand sizes, which invariably play a pivotal role in designing products that cater to diverse user profiles.
Conducting quick and easy formative evaluations in our laboratory environment equips us to make the most of our interactions with key opinion leaders in the field. Given their demanding schedules, efficiency is paramount. In some cases, I've taken it a step further, improvising by taping up the fingers of my cooperative colleagues to simulate reduced dexterity—an invaluable exercise when designing for elderly and arthritic patients, helping us tailor our attachment mechanism’s design to their unique needs.
Furthermore, the URRA tool assumes a multifaceted role. It helps determine what testing is needed with end users, validating any of our internal team’s assumptions. A recent evaluation with clinicians serves as an exemplary case: We aimed to ascertain the legibility and comprehensibility of information displayed on a device screen, meticulously adhering to ISO standards. However, when we placed the device in the capable hands of a clinician, a significant revelation emerged—a need for an additional performance indicator, vital to assist with patient clinical assessments.
Experience taught me that when we engage with end users, we uncover invaluable insights that extend beyond our initial considerations. For instance, we stumbled on a revelation—despite some design components being disposable, cleanliness remained the paramount concern for nurses. As a result, we refined our material selection, prioritizing hygiene and usability.
Assessments and user feedback loops play an integral role in fine-tuning prototypes, ensuring the final product aligns seamlessly with user expectations and clinical demands.
Our “Validate” journey commences with the URRA’s finalization, discerning which tasks are deemed critical. These critical tasks require validation, illustrating to regulatory bodies like the FDA that the device is optimized in terms of user safety and effectiveness. Any oversight or error in this phase could potentially lead to subsequent retesting requirements should unforeseen use errors surface during evaluation.
A vital lesson learned from our experience in design validation is the importance of early planning. Commencing preparations as soon as possible is indispensable. We advocate submitting a draft of the human factors testing protocol to the FDA for preliminary review and acceptance before the testing phase. Ensuring the testing methods align with industry standards and regulatory expectations is instrumental in achieving a smooth path to regulatory success.
In certain scenarios, a deeper exploration of regulatory strategies can yield significant benefits. For instance, during a recent regulatory submission for the EU's Medical Device Regulation (MDR), we collaborated with notified body representatives to identify a unique pathway. This pathway allowed our client's device to undergo evaluation against Annex C: Evaluation of a User Interface of Unknown Provenance (UOUP) of IEC 62366-1:2015. The outcome was substantial, as it enabled our client to expedite their regulatory submission, ultimately saving considerable time and resources.
Hopefully, the examples in this article underscore the paramount importance of the UCD process in medical device development. Meticulously researching user requirements and conducting rigorous testing captures the device's capabilities and embraces intrinsic human limitations. The UCD approach ensures the final product meets user needs, aligns with industry standards, and stands as a beacon of safety and effectiveness in the medical device landscape.
Kate Dobson
Kate Dobson is a Senior Human Factors Engineer at StarFish Medical with over 15 years of experience in human factors. Kate delivers the usability engineering activities for StarFish's projects in accordance with IEC 62366-1:2015 and FDA’s guidance “Applying Human Factors and Usability Engineering to Medical Devices”. Kate’s experience at Starfish Medical includes a broad range of medical device development projects including dental robotics, stroke diagnostics, pulse oximetry monitors, surgical tools for pain relief, cell therapy products, and wellness devices.
This article describes a series of recent examples that illustrate how UCD helps to reduce risk and create medical products and systems that are intuitive, efficient, and safe for users.
1. Identify: Unearth User Needs and Uncover the Right Problem
The initial phase in the UCD process delves into the specific needs of end users to ensure we're solving the right problem. This step includes identifying the user demographic, understanding their device usage patterns, evaluating the use environment, and anticipating potential challenges. While these considerations may appear straightforward, my experience has shown they often unveil complex intricacies.To illustrate, let's examine a real-world example developing a product designed for use by surgeons during surgery. Our journey began by engaging directly with surgeons, observing surgical procedures, and closely examining the tools they relied on. Insights gleaned from these experiences had a profound impact on the product's design. As we considered factors like the patient population, reimbursement models, patient recovery periods, and the diverse nature of surgeries, we determined the product would better serve an alternative market with different end users. This realization prompted a significant pivot in our design approach.
2. Inform: Enhance User-Centered Design Insights
The next phase of the UCD journey is crucial to informing our design decisions. Recently, our team has been immersed in designing a product for the emergency response sector. With our user workflow map in hand, we embarked on the process of shaping the device’s form and digital interactions. This approach allowed us to carefully consider the complexity of the user journey and the dynamic usage environment in which the product would be deployed.One illuminating example underscores the value of this approach. As we analyzed the workflow of a first responder wearing medical gloves in the confines of a moving ambulance, it became evident that adjustments were necessary. The layout of information on the screen and the sequence of button inputs had to be redefined to prevent inadvertent and erroneous inputs in this high-pressure scenario.
In our pursuit of informed design, we harness the power of a valuable tool—Use-Related Risk Analysis (URRA). This tool catalogs specific use cases for the product, enabling our team to systematically evaluate each user task. Using the PCA framework, recommended by the FDA in their Human Factors guidance from February 2016, we examine potential sources of use errors and categorize them into perception, cognition, and action—key causes of use-related risks.
In another instance, we were developing a reusable device to be sterilized between patients. A significant concern emerged in our URRA analysis—the risk of residual patient data inadvertently transferring to the next patient's file if a nurse forgot to erase the data. This revelation prompted an innovative solution where our design team reimagined the hardware and software to automatically wipe patient data when the device was connected to the charging unit, eliminating the risk entirely.
The UCD approach empowers us to make informed design decisions early in the process. By reducing or even eliminating use-related risks, we ensure the device’s behavior aligns with user expectations, enhancing safety and effectiveness.
3. Assess: Refine Prototypes and Gather User Feedback
Transitioning to prototype development, our human factors team steps in to conduct hands-on assessments. Once, we were designing a device featuring a cable linked to a finger attachment. Our first action involved delving into anthropometric data—evaluating hand length and wrist sizes specific to our target population. This data served as a compass guiding us toward determining the optimal cable length. We proceeded to assess multiple cable lengths on a low-fidelity prototype with various hand sizes, all within the confines of our office.Human factors experts often have a knack for recognizing nuances in their colleagues' anthropometry. We can discern who's the tallest, who boasts the biggest head, and even the quirks in hand sizes, which invariably play a pivotal role in designing products that cater to diverse user profiles.
Conducting quick and easy formative evaluations in our laboratory environment equips us to make the most of our interactions with key opinion leaders in the field. Given their demanding schedules, efficiency is paramount. In some cases, I've taken it a step further, improvising by taping up the fingers of my cooperative colleagues to simulate reduced dexterity—an invaluable exercise when designing for elderly and arthritic patients, helping us tailor our attachment mechanism’s design to their unique needs.
Furthermore, the URRA tool assumes a multifaceted role. It helps determine what testing is needed with end users, validating any of our internal team’s assumptions. A recent evaluation with clinicians serves as an exemplary case: We aimed to ascertain the legibility and comprehensibility of information displayed on a device screen, meticulously adhering to ISO standards. However, when we placed the device in the capable hands of a clinician, a significant revelation emerged—a need for an additional performance indicator, vital to assist with patient clinical assessments.
Experience taught me that when we engage with end users, we uncover invaluable insights that extend beyond our initial considerations. For instance, we stumbled on a revelation—despite some design components being disposable, cleanliness remained the paramount concern for nurses. As a result, we refined our material selection, prioritizing hygiene and usability.
Assessments and user feedback loops play an integral role in fine-tuning prototypes, ensuring the final product aligns seamlessly with user expectations and clinical demands.
4. Validate: Ensure User-Centered Design Excellence
In the culmination of the UCD approach, the principal goal is to validate the final design of the device seamlessly caters to intended users’ ease and safety in the anticipated use environment. To achieve this, we carefully plan and conduct Human Factors validation testing using our internal guide: Planning-and-Usability-Testing-eGuide, marking the conclusive phase of usability testing before regulatory submission.Our “Validate” journey commences with the URRA’s finalization, discerning which tasks are deemed critical. These critical tasks require validation, illustrating to regulatory bodies like the FDA that the device is optimized in terms of user safety and effectiveness. Any oversight or error in this phase could potentially lead to subsequent retesting requirements should unforeseen use errors surface during evaluation.
A vital lesson learned from our experience in design validation is the importance of early planning. Commencing preparations as soon as possible is indispensable. We advocate submitting a draft of the human factors testing protocol to the FDA for preliminary review and acceptance before the testing phase. Ensuring the testing methods align with industry standards and regulatory expectations is instrumental in achieving a smooth path to regulatory success.
In certain scenarios, a deeper exploration of regulatory strategies can yield significant benefits. For instance, during a recent regulatory submission for the EU's Medical Device Regulation (MDR), we collaborated with notified body representatives to identify a unique pathway. This pathway allowed our client's device to undergo evaluation against Annex C: Evaluation of a User Interface of Unknown Provenance (UOUP) of IEC 62366-1:2015. The outcome was substantial, as it enabled our client to expedite their regulatory submission, ultimately saving considerable time and resources.
Hopefully, the examples in this article underscore the paramount importance of the UCD process in medical device development. Meticulously researching user requirements and conducting rigorous testing captures the device's capabilities and embraces intrinsic human limitations. The UCD approach ensures the final product meets user needs, aligns with industry standards, and stands as a beacon of safety and effectiveness in the medical device landscape.
Kate Dobson
