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Who hasn’t finished a project, only to discover that you’d done something wrong and the whole thing would need to be redone? Perhaps you hadn’t checked your work along the way, confident that all would be well in the end. Imagine the costs involved if this scenario were to take place on a commercial production line. The Systems Engineering Approach to things helps ensure this doesn’t happen. Last time we wrapped up our discussion on the Production stage of the systems engineering approach to medical device design, and today we’ll cover the final stage, Utilization. The Utilization stage marks the point at which the medical device has been sold and is in actual use in the marketplace. Despite the fact that the product has at this point undergone many reviews and revisions and a great investment has been made into deciding whether or not to put it into production, changes can still take place in its design. Markets aren’t static, and products may be made to change due to stakeholders’, that is, those with a vested interest, changing requirements, whether those are aimed at further cost reduction, or perhaps to implement innovations to make the product more appealing to end users. Other reasons for change may be initiated by the sales and marketing departments. They keep their fingers on the pulse of consumer trends, and they may want the design modified according to market research and feedback they receive from dealers, service technicians, and end users. For example, the sales staff may have been apprised by end users that the keypad to their electronic muscle stimulating device needs modification. Patients have voiced they would prefer to here a clicking sound when depressing the buttons, in order to receive some auditory feedback. In addition, distributors of the device reported that although the electronic stimulators were functioning as intended, end users didn’t like the feel of the buttons. The lack of tactile feedback often led to confusion because they weren’t sure whether they had depressed the button or not. Another interesting discovery concerning lack of feedback was that product service technicians were reporting premature wearing out of the keypads. Absent the satisfying click sound, users were inclined to push on the pads too strenuously, which drove up warranty service costs. The medical device manufacturer’s stakeholders are always concerned with costs, and increased service costs definitely raise the red flag. Considerations like these typically arise after a medical device enters the Utilization stage. Fortunately, the objective of the systems engineering approach is to ensure that stakeholders’ needs are met in view of ever-changing requirements, even after the device has entered the marketplace. No matter what may happen during the life cycle of a product, the systems engineering approach is used every step of the way, from the Concept stage through to Utilization. That ends our discussion on the systems engineering approach to medical device design. Next time we’ll begin unraveling some of the mysteries and misconceptions behind patenting inventions. ___________________________________________
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Posts Tagged ‘systems engineering approach’
Systems Engineering In Medical Device Design – Instructions, Part 4
Sunday, January 27th, 2013| Last time we wrapped up our discussion on the development of quality control instructions for use during the Development stage of the systems engineering approach to medical device design. These instructions are used to guide quality control inspection and testing during the Production stage. Now let’s continue our discussion on the development of instructions for the Utilization stage, the stage when the medical device is actually put into operation by the end user.
In the systems engineering approach to medical device design, design engineers must work closely with technical writers, those responsible for writing operating and product service instructions. The objective here is to share the engineering staff’s intimate knowledge of the medical device’s design with the writers in order to ensure that instructions are clearly written, comprehensive, and follow a logical progression. Instructions must be written so as to be easily understood by lay people outside of the engineering profession and medical device industry, because most of the individuals using the device will be healthcare professionals and service technicians, individuals lacking a background in engineering or medical device development. Instructions are not only meant for the eyes of end users. They are also subject to review by governmental agencies. This fact acts as a safeguard to ensure device compliance both with regulatory requirements and industry standards as regards cautions and warnings. For example, instructions may be required to caution the user to allow the device to warm up for a certain period of time before use to avoid patient discomfort when coming into contact with cold metal. Instructions might also warn against a harmful interaction if the device is used in conjunction with other devices. For example, an electronic muscle stimulator may send electrical pulses into a patient’s body that can interfere with the operation of their heart pacemaker. No doubt this is something that the operator of the device and the patient would want to be informed of. At this point our medical device design has been completed, and instructions and procedures written, but the Development stage is not yet complete. Next time we’ll continue our discussion on this stage to see how a systems engineering step helps us to be safe rather than sorry after full production of the device has begun. ___________________________________________
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Systems Engineering In Medical Device Design – Finished Design
Sunday, December 30th, 2012 Last time we opened our discussion on the Development stage of the systems engineering approach to medical device design and discovered that the best design concept is the one that meets all stakeholder requirements. Let’s use the flow chart shown in Figure 1 to illustrate what comes next in this stage.
Figure 1To begin the transformation from concept to completed design, engineers review documentation created during the Concept stage, including design notes, concept sketches, and of course the final requirements specification which has been approved by all stakeholders. Once the review is completed, it serves as a guide to the creation of detailed design documentation, including mechanical drawings, electrical schematics, and wiring diagrams. A bill of materials, or BOM, is also created, listing all parts needed to produce the final product. Each part designated within the BOM is associated with a specific manufacturer or supplying vendor, and each has been qualified with regard to price, availability, functionality, and quality. The design documentation and BOM are also subject to a review by a fresh set of eyes, engineers who have no involvement in the project. If they should discover a problem, the design is rejected and sent back to the design engineers for revision. This process of evaluation and correction are repeated until the design successfully passes a final review. Only then can the fully approved finished design move on to the production stage. Next time we’ll continue our discussion of the Development stage, moving our concept medical device further along its journey to the Production stage. ___________________________________________ |
Systems Engineering In Medical Device Design – Concept and Requirements
Monday, December 10th, 2012| Last time we introduced the first phase of the systems engineering approach to medical device design, the Concept Phase. It’s a phase which emphasizes clear communication between design engineers and stakeholders in the project. Effective communication results in clearly defined stakeholder requirements.
Stakeholder requirements are of three basic types, serving the needs of functionality, performance, and constraint. A functional requirement is a basic starting point, specifying the tasks to be accomplished by the system and its basic operation. For example, a medical diagnostic imaging device can be required to operate on a dedicated 15 amp branch circuit when plugged into a 115 volt wall outlet. Performance requirements delineate specific expectations as regards the system’s functionality, typically specifying parameters within which the system is to perform. For example, a medical device can be required to process a minimum number of test samples per hour. As for constraint requirements, they’re typically concerned with satisfactorily complying with both governmental regulations and industry standards. Governmental regulations include those established by the US Food and Drug Administration, as well as any applicable foreign agencies that may be involved should the medical device be introduced to other countries. Once the draft specification is written, design engineers review it in painstaking detail. Stakeholders’ requirements must all be accounted for and interpreted correctly. This is typically done by sitting down with each stakeholder and reviewing the draft. Finally, each stakeholder’s signature is obtained, signifying their approval. Now complete, the approved specification is used as a roadmap to guide project development through to the next and final step of the concept stage, devising alternate medical device concepts. Why discuss alternate concepts? Just like consumer comparison shopping for TVs and other goods, you’ve got to have a basis of comparison in order to make a sound judgment. This holds true for the medical device industry as well as private households. Next time we’ll proceed to the next stage of the design process, Development. We’ll see how alternate concepts are evaluated to find the best overall option, thus beginning the actual design process leading to manufacture. ____________________________________________
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