Easing the Medical Device Life Cycle with Virtual Instrumentation

Anyone who uses a cellular phone has experienced the frustration of a dropped call in the middle of a conversation. Though inconvenient, there generally are no catastrophic consequences when this device fails – you just call the other person back, apologize, and continue your conversation. In contrast, consider devices whose failure can result in a serious injury (such as a simple safety system), a single death (such as a pacemaker), or multiple deaths (such as an aircraft control system). For such devices, agencies have been put into place to oversee the development process and ensure the integrity and safety of the final system. These agencies place regulations on the development process and offer guidelines for best practices for all phases of development, from concept through manufacturing. This article examines the medical device life cycle as an example and looks at ways that virtual instrumentation can help you meet requirements such as Food and Drug Administration (FDA) certification and ultimately help develop high-quality devices ahead of schedule.

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Figure 1. This diagram shows the medical device design life cycle as defined by the FDA.[1]

Figure 1 shows the FDA definition of the medical device life cycle. The stated purpose of these guidelines is to ensure the safety of the general public by preventing fraudulent or hastily developed medical products from entering the marketplace. Generally, these regulations must be applied to any software used as a component, part, or accessory of a medical device; any software used in the production of a device (for example, programmable automation controllers, or PACs, in manufacturing equipment); and any software used in the implementation of the device manufacturer’s quality system (such as software that records and maintains the device history record).[1] While compliance to regulations and the necessary corresponding documentation can be intimidating and overwhelming, National Instruments hardware and software solutions provide several advantages to assist in the validation and verification of your medical device design.

Figure 2.Applying virtual instrumentation early in the product life cycle gives you a clear understanding of the problem to be solved early on. In addition, graphical system design can help you develop functional prototypes of the end device.

The medical device life cycle can be divided into three main phases. The first is the early product life cycle (see Figure 2). This is the least regimented of the phases, and is primarily focused on the research and development of theories and ideas. This phase can last from a few weeks to many years depending on the complexity of the systems and phenomena being studied.

A fundamental part of the early development phase is data collection and analysis. To help streamline this process, National Instruments offers several options for life science research lab automation. You can easily use National Instruments LabVIEW instrument drivers that communicate over Ethernet, USB, or GPIB to control hundreds of medical instruments, from a simple scale to a gas chromatograph. In addition, using NI data acquisition hardware and modular instruments, you can bypass third-party instruments and read the sensors directly or customize your measurements.

Once you understand the problem, you can design a solution. NI LabVIEW provides a single graphical system design platform for device development and prototyping. Using LabVIEW math and signal processing capabilities along with intuitive graphical programming, you can quickly develop an algorithm. Then, using NI data acquisition hardware, you can verify the algorithm’s performance against real-world data. Finally, the National Instruments CompactRIO embedded prototyping platform is an ideal solution for developing a functional yet experimental prototype of the final device. Programmed with the LabVIEW Real-Time and FPGA modules, NI CompactRIO lets you quickly iterate between the algorithm design and the device prototype. Using off-the-shelf hardware like CompactRIO for prototyping reduces the time-consuming step of hardware development and integration, making it easier for you to focus on developing a bulletproof software design.

Figure 3. Software designs are typically validated and verified during the middle of the product life cycle.

The second phase of the medical device life cycle can be called the middle product life cycle (see Figure 3), which addresses the productization, verification, validation, and manufacturing of the designed device. The focus in this phase begins with well-defined specification documents that have clear and measurable requirements. Once these specifications are defined, it is time to develop a clear mapping between requirement documentation and actual implementation code. You can use NI Requirements Gateway software as a requirements traceability solution that links to formal requirements stored in documents and databases. NI Requirements Gateway performs coverage and impact analysis, graphically displays coverage relationships, and generates comprehensive reports to ease the formal validation and verification process.

Once you validate the device design and it is time to ramp up to production, you must be sure to follow FDA guidelines in the manufacturing and testing process. Remember that any software associated with the product life cycle is considered critical to the overall quality of the device. With human machine interface (HMI) packages like the LabVIEW Datalogging and Supervisory Control (DSC) Module, you can develop your manufacturing line application with the same quality control mechanisms that you used to develop the device itself. Furthermore, you can apply these same concepts to the manufacturing test procedure by using test executive software packages like NI TestStand.

Figure 4. The late product life cycle takes the product to market, and market feedback helps determine the features for the next generation of the device. This completes the cycle and returns you to the concept phase.

The third and final phase of the life cycle is called the late product life cycle (see Figure 4). Very little engineering work is necessary in this phase, but customer feedback and market successes do help drive concept development of the next-generation product when the cycle starts anew.

In all aspects of the medical device life cycle, it is important to choose the appropriate software and hardware solutions to help ensure that the necessary regulations are met and that your end device is safe and effective. Whether it is concept development, product prototyping, validation, manufacturing, or test, National Instruments has reliable and effective solutions for all phases of the product life cycle.

Learn more about medical device development using LabVIEW.

[1] Total Product Life Cycle. David W. Feigal, M.D., M.P.H., Director, Center for Devices and Radiological Health, FDA (www.fda.gov).

[2] General Principles of Software Validation; Final Guidance for Industry and FDA Staff. Center for Devices and Radiological Health.

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