Medical device design process

One feature that has significant implications for medical device design processes at the fiber scale level is the great exchange surface provided by fibers toward the biological... 

Keywords medical devices, design process, model-driven analysis, MORE, model- driven design, model-driven test, and model-driven safety analysis. 

As medical devices continue to improve and change, the materials and processes used must similarly be modified. Predicting and managing the interaction between these materials and the body makes the surface engineer a key player in the device design process. 

The manufacturing processes need to take a holistic view of tlie total life cycle of products including tlieh manufactme and disposal (from factory and from patient). Tlie choice of chual syntheses, metabolically engineered cells, microreactors for optimized processes, and medical devices designed for function and recycling (and manufacturability) are key considerations to be applied early in the development process. 

There are various types of medical device users who need devices that can be used safely and effectively. To satisfy these user needs, it is important to clearly understand the limitations and abilities of all medical device potential users, i.e., patients, professional health care providers, and yoimg and old individuals. Factors that can affect the ability of such users include fatigue, stress, and medication. Some of the important characteristics of the medical device potential users that must be taken into consideration during the device design process are shown in Figure 10.1 [6]. 

Important characteristics of the medical device potential users for consideration during the device design process. 

Money AG, Barnett J, Kuljis J, Craven MP, Martin JL, Young T (2011) The role of the user within the medical device design and development process medical device manufacturers perspectives. BMC Med Inf Dec Making 11 15... 

Fibers have many features that could be advantageously used in implantable textile medical device design to confer them specific properties. However, expected to monofilaments, fibers generally need to be assembled within the stracture to be exploited. Cohesion is needed to withstand the textile process and/or handling. 

Down to the present day the medical device sector lacks in specifications and legally binding standards on how to address the security question in the medical device development process. This is especially a problem for design and implementation of security-aware communication interfaces and protocols for critical medical equipment. After all, the Medical Device Directive [6] (MDD, Directive 93/42/EEC) at least demands that medical device manufacturers have to show that the applied solutions take account of the generally acknowledged state of the art . 

With new plastics and processing techniques always becoming available, the design challenge becomes easier, even when taking today s solid-waste problem into account. Today s plastics and processes allow designers to incorporate and interrelate all the aspects of success. In products such as electronics, medical devices, transportation controls, and many others where user-friendly design is required, it has to be obvious to all that plastics play an important role. 

The previous chapter outlined how device classification and the use of standards provide the basis for effective regulation of medical devices, with particular focus on the application of design control standards to the development of devices. In this chapter we look at the process for evaluation and authorisation of devices, and see how the regulatory requirements vary depending on the perceived risk of the device as indicated by its classification. It will be noted that there is considerable variation between the approaches adopted in Europe and the US and that, compared to dmgs, practical harmonisation of requirements still remains to be adopted. 

The relationship between the main subsystems and other minor systems is illustrated schematically in Figure 12.4. This places management at the core of the quality system, with the other systems arranged as major and minor satellites that revolve around it. This perspective provides the basis for the Quality System Inspection Technique (QSIT), which the FDA uses for auditing medical device facilities. This is based on a top-down approach, which starts with management controls and then looks at three other key subsystems of Design Controls, Corrective and Preventative Actions (CAPA) and Production and Process Controls. The belief is that by focussing on just these four subsystems, you will actually touch on all the other subsystems and obtain a sufficiently satisfactory overview of the state of compliance of the facility. 

Category 1 Medical devices that are controlled by in-process tests, with critical specifications designed for both individual products and a group, but not implemented in human and animals. 

The medical devices in category 4 of Table 1 are controlled in-process testing with critical specifications designed for individual products or a group of products and are implanted. The compatibility of product materials with tissue and cells, the stability of product in the implanted site, and the sterility of product should be key factors to assure the product safety. Intraocular lenses and pacemakers are included in this category. 

Validation in quality systems includes establishment of procedures on how to qualify the equipment and machinery, how to verify the design of products, how to verify the process designed, how to verify the achievement of production procedures, how to validate the process developed, and how to validate the methods for measurement and assay. Validation also requires verification of specifications or acceptance criteria of in-process parameters relating to both raw materials and intermediate (in-process product) and finished products, and verification of acceptance criteria for in-process parameters relating to operating conditions of machinery and equipment. Further, when the medical device is assembled at the user s site, validation includes establishing procedures of how to verify assembly. 

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