Abstract:

Biomedical engineering students learn product design by designing prototypes in their capstone courses using relevant principles and applying them to design a product to function properly to meet the specified requirements. Despite good approach to designing, building and testing prototypes to meet the overall functional requirements, several products tend to fail in the field. A major reason for such mishaps is that the failure modes might not have received adequate emphasis in the design process. The study of failures of devices, especially in the medical field, can play a vital role in product improvement and safety assurance. The aspects of failure analysis and improving the design can be exemplified in a life-saving medical device, namely, the automated external defibrillator (AED). The objective of this project is to review the failures of AEDs, perform failure analysis, and propose corrective actions in order to achieve improvements in the product design.

AED is a lifesaving device and hence it should work without any failure. Reports have been surfacing recently of AED failures and possible causes which point back to errors in the design process. Malfunction of AEDs, as a result of various errors and complications, can lead to the failure to resuscitate a patient and result in the victim’s death. AEDs are complex devices comprising of electrical, electronic, mechanical, and software subsystems. Failure of any one or more of the above sub systems can cause malfunctioning of the AED. It has been reported that an AED failed due to a tolerance problem of a resistor impacting the ECG analysis circuit. Batteries have reportedly failed to maintain the appropriate charge level to operate the AEDs. Software packages have been said to contain undetected bugs in the programming. Another design flaw was missing or covered discharge buttons intended to shock the victim. In the design review phase, these factors must be thoroughly analyzed and addressed.

Utilization of failure mode and effects analysis and simplified fault tree analysis can lead to the development of a medical device with greater reliability. The regulatory agencies also require rigorous design reviews, comprehensive testing and continued improvement in product development. The AEDs can have better self-testing features to alert the operators by a warning light if there are problems. Other medical devices whose performances have been impacted by design failures include external defibrillators, Implantable Cardioverter Defibrillators, etc. In future, it is intended to extend the scope of the present work to design improvements in other clinical medical devices.
In conclusion, device failure is an important factor to learn from, especially for students in their interdisciplinary design projects. Introducing Failure mode analysis and simplified risk tree analysis and improving the product into the design process can lead to a more reliable and hence acceptable and successful product.

Keywords:

Failure analysis, medical product design, improving design.