Medical device design changes

The Equivalent of a Development Report for Medical Devices in the Design History File. This comprehensive file would include critical information about the device s design, changes, review, and design controls. For medical devices, the requirements for the device s history have been codified under 21CFR 820.30. 

For medical devices, there is a phenomenon recognized as feature creep , in which the specifications for the design features of a device begin to drift toward a specification limit because inadequate design reviews, output verification and change control. This same sort of variability occurs with... 

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. 

Good overviews of biopotential electrodes are found in Geddes L. A. 1972. Electrodes and the Measurement of Bioelectric Events, New York, John Wiley 8c Sons and Ferris C.D. 1974. Introduction to Bioelectrodes, New York, Rlenum. Even though these references are more than 20 years old, they clearly cover the field, and httle has changed since these books were written. Overviews of biopotential electrodes are found in chapters of two works edited by John Webster. Chapter 5 of his textbook. Medical Instrumentation Application and Design, covers the material of this chapter in more detail, and there is a section on bioelectrodes in the Encyclopedia of Medical Devices and Instrumentation... 

A large medical implantable cardioverter defibrillator (ICD) supplier had approved devices (ICD) on the market. A design change had been made to narrow the diameter of the leads. The product was approved and released to market. It was found that the leads would fatigue and fracture in the patient. In some cases the fractures were linked to perforating the patient s heart. This could cause loss of consciousness, heart failure, or death. The product was recalled. Another example of insufficient animal or bench fatigue testing. 

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