The role of user requirements research in medical device development

Aims and Objectives: This research aims to suggest a concise framework to help in the better conceptualisation and integration of users in the medical device development (MDD) process. The current economic, political and social climate concerning the matter of healthcare delivery has resulted in the emergence of numerous users and user groups for whom the healthcare system has not previously catered for. These users have created ambiguity for the designers and manufacturers of medical devices as the boundaries between their needs and requirements have blurred, outdating current methods of MDD to meet consumer needs. Research Design and Methodology: The research methodology begins primarily with conducting a literature search on the theories relating to user requirements and medical device development. The paper outlines these findings through initially describing users and user involvement and relating them to medical devices. The cross-disciplinary nature of healthcare influenced the investigation into multiple disciplines including; IT, Ergonomics – particularly participatory research, Psychology and Design. These disciplines expose various methods and processes, which are useful to user requirements research. These methods were analysed for their compatibility, and then used to construct a conceptual framework for user involvement in MDD. Results: The research insinuates the true significance of user involvement and hence resulted in the formation of a conceptual framework to aid user involvement in the MDD process. The framework is produced by the amalgamation of relevant methods examined across the disciplines, in a complimentary fashion. Conclusion: The originality of this research lies in its use of a multidisciplinary approach. Previous research claiming multi-methods has dealt with combining two disciplines or methods at a time i.e. Computer supported cooperative work (CSCW) with participatory research (Scandurra et al, 2008) for the needs analysis of healthcare professionals only. Collaboration across disciplines has also been investigated (Johnson et al, 2005), but this was for the purpose of redesign rather than initial designs. This framework can help medical device designers to fully access all user requirements through more extensive collaboration right at the start. It reduces the risk of high costs involved in device rejection, usually associated with belated recognition of user needs in the design cycle

Managing the variability of biomechanical characteristics before the preliminary design stage of a medical device

The very high level of requirements for certification procedures often limit research and development departments to innovate using increments and iterations during the design process for medical devices (MD). Instead of this semi-empirical approach, a structured procedure, a breakthrough innovation should be used when designing an articular MD (prosthesis, implant). The search for concepts can be based on functional analysis and producing behavioural models of the joint in its natural state and/or equipped with the prosthesis. This paper shows how anatomical variables can be managed and integrated using a modular design approach.This study has been realized under the two joint action projects PESSOA 14630YA and PTDC/EME-PME/112977

Recent Topics in Electromagnetic Compatibility

Recent Topics in Electromagnetic Compatability discusses several topics in electromagnetic compatibility (EMC) and electromagnetic interference (EMI), including measurements, shielding, emission, interference, biomedical devices, and numerical modeling. Over five sections, chapters address the electromagnetic spectrum of corona discharge, life cycle assessment of flexible electromagnetic shields, EMC requirements for implantable medical devices, analysis and design of absorbers for EMC applications, artificial surfaces, and media for EMC and EMI shielding, and much more

Lessons Learned from Customizing and Applying ACTA to Design a Novel Device for Emergency Medical Care

Preclinical patient care is both mentally and physically challenging and exhausting for emergency teams. The teams intensively use medical technology to help the patient on site. However, they must carry and handle multiple heavy medical devices such as a monitor for the patient's vital signs, a ventilator to support an unconscious patient, and a resuscitation device. In an industry project, we aim at developing a combined device that lowers the emergency teams' mental and physical load caused by multiple screens, devices, and their high weight. The focus of this paper is to describe our ideation and requirements elicitation process regarding the user interface design of the combined device. For one year, we applied a fully digital customized version of the Applied Cognitive Task Analysis (ACTA) method to systematically elicit the requirements. Domain and requirements engineering experts created a detailed hierarchical task diagram of an extensive emergency scenario, conducted eleven interviews with subject matter experts (SMEs), and executed two design workshops, which led to 34 sketches and three mockups of the combined device's user interface. Cross-functional teams accompanied the entire process and brought together expertise in preclinical patient care, requirements engineering, and medical product development. We report on the lessons learned for each of the four consecutive stages of our customized ACTA process.Comment: Accepted for publication at the 29th IEEE International Requirements Engineering Conferenc

A hazard analysis method for systematic identification of safety requirements for user interface software in medical devices

© Springer International Publishing AG (outside the US) 2017. Formal methods technologies have the potential to verify the usability and safety of user interface (UI) software design in medical devices, enabling significant reductions in use errors and consequential safety incidents with such devices. This however depends on comprehensive and verifiable safety requirements to leverage these techniques for detecting and preventing flaws in UI software that can induce use errors. This paper presents a hazard analysis method that extends Leveson’s System Theoretic Process Analysis (STPA) with a comprehensive set of causal factor categories, so as to provide developers with clear guidelines for systematic identification of use-related hazards associated with medical devices, their causes embedded in UI software design, and safety requirements for mitigating such hazards. The method is evaluated with a case study on the Gantry-2 radiation therapy system, which demonstrates that (1) as compared to standard STPA, our method allowed us to identify more UI software design issues likely to cause use-related hazards; and (2) the identified UI software design issues facilitated the definition of precise, verifiable safety requirements for UI software, which could be readily formalized in verification tools such as Prototype Verification System (PVS).- U.S. Food and Drug Administration(NORTE-01-0145-FEDER-000016)Sandy Weininger (FDA), Scott Thiel (Navigant Consulting, Inc.), Michelle Jump (Stryker), Stefania Gnesi (ISTI/CNR) and the CHI+MED team (www.chi-med.ac.uk) provided useful feedback and inputs. Paolo Masci’s work is supported by the North Portugal Regional Operational Programme (NORTE 2020) under the PORTUGAL 2020 Partnership Agreement, and by the European Regional Development Fund (ERDF) within Project “NORTE-01-0145-FEDER-000016”.info:eu-repo/semantics/publishedVersio

Formal Specifications and Analysis of the Computer Assisted Resuscitation Algorithm (CARA) Infusion Pump Control System

Reliability of medical devices such as the CARA Infusion Pump Control System is of extreme importance given that these devices are being used on patients in critical condition. The Infusion Pump Control System includes embedded processors and accompanying embedded software for monitoring as well as controlling sensors and actuators that allow the embedded systems to interact with their environments. This nature of the Infusion Pump Control System adds to the complexity of assuring the reliability of the total system. The traditional methods of developing embedded systems are inadequate for such safety-critical devices. In this paper, we study the application of formal methods to the requirements capture and analysis for the Infusion Pump Control System. Our approach consists of two phases. The first phase is to convert the informal design requirements into a set of reference specifications using a formal system, in this case EFSMs (Extended Finite State Machines). The second phase is to translate the reference specifications to the tools supporting formal analysis, such as SCR and Hermes. This allows us to conclude properties of the reference specifications. Our research goal is to develop a framework and methodology for the integrated use of formal methods in the development of embedded medical systems that require high assurance and confidence

Medical Device Software: From Requirements to Certification

The role of software in healthcare is getting more and more pervasive. Nevertheless, manufacturers sometimes forget that these software are medical devices and must be certified according to the EU Medical Device Regulation 2017/745. In this work we propose a pipeline for developing a Medical Device Software (MDS) compliant with the regulations and certifiable. The pipeline includes the phase of requirements elicitation, risk assessment and analysis of effectiveness as key elements. The preparation of the technical file should be carried out in parallel with the MDS development. In the overall, it can be stated that the certification process starts with the conceptualization of the MDS and proceeds all along its design and implementation

Design and Finite Element Analysis of Patient-Specific Total Temporomandibular Joint Implants

In this manuscript, we discuss our approach to developing novel patient-specific total TMJ prostheses. Our unique patient-fitted designs based on medical images of the patient’s TMJ offer accurate anatomical fit, and better fixation to host bone. Special features of the prostheses have potential to offer improved osseo-integration and durability of the devices. The design process is based on surgeon’s requirements, feedback, and pre-surgical planning to ensure anatomically accurate and clinically viable device design. We use the validated methodology of FE modeling and analysis to evaluate the device design by investigating stress and strain profiles under functional/normal and para-functional/worst-case TMJ loading scenarios

A systems approach to improving patient safety through medical device purchasing

The purchase of medical devices involves engaging various stakeholders as well as balancing clinical, technical and financial requirements. Failure to consider these requirements can lead to wider consequences in the delivery of care. This study first builds a general knowledge base of current purchasing practice in a sample of NHS Trusts, which confirms the direction and guidance given by policy documents and literature as to the extent of the challenges faced by purchasing stakeholders. This then leads to an analysis to identify inefficiencies in the purchasing process, and how such practice can lead to risks in the delivery of care. These risks range from injury to individuals, impacts to the healthcare delivery service, and financial and litigation risks. Finally, a framework that highlights these potential risks in the life-cycle of medical devices in hospitals is presented. Key policy guidance has encouraged both researchers and implementers of healthcare services to approach patient safety from a systems perspective, acknowledging that medical device errors are not only directly related to device design, but to the design of the healthcare delivery service system in which the device operates. Little evidence exists of successfully applying systems approaches specifically to medical device purchasing practice. Medical device purchasing, because of its implications to patient safety on the one hand, and the uniqueness of the healthcare context, requires a unique approach. By demonstrating the influence of purchasing practice to service delivery and patient care, the thesis made is that taking a holistic systems approach is one method to improve device purchasing practice, and hence influence better care.This work was supported by the UK Engineering and Physical Sciences Research Council [EP/E001777/1

Closed-loop Verification of Medical Devices With Model Abstraction and Refinement

The design and implementation of software for medical devices is challenging due to the closed-loop interaction with the patient, which is a stochastic physical environment. The safety-critical nature and the lack of existing industry standards for verification, make this an ideal domain for exploring applications of formal modeling and closed-loop analysis. The biggest challenge is that the environment model(s) have to be both complex enough to express the physiological requirements, and general enough to cover all possible inputs to the device. In this effort, we use a dual chamber implantable pacemaker as a case study to demonstrate verification of software specifications of medical devices as timed-automata models in UPPAAL. The pacemaker model is based on the specifications and algorithm descriptions from Boston Scientific. The heart is modeled using timed automata based on the physiology of heart. The model is gradually abstracted with timed simulation to preserve properties. A manual Counter-Example-Guided Abstraction and Refinement (CEGAR) framework has been adapted to refine the heart model when spurious counter-examples are found. To demonstrate the closed-loop nature of the problem and heart model refinement, we investigated two clinical cases of Pacemaker Mediated Tachycardia and verified their corresponding correction algorithms in the pacemaker. Along with our tools for code generation from UPPAAL models, this effort enables model-driven design and certification of software for medical devices