Rapid Changes with Portable Medical Devices
Kirk Barker, electronic product manager at maxon motors, was a part of the staff written article, “Portability Is the Name of the Game.” He took time to present a full array of responses that were not able to be included in the article, so they are presented here.
Q: How are advances in components helping the industry move to portable healthcare?
Barker: From the simple standpoint of Intel co-founder Gordon Moore, who contends that advances in computing power will essentially double every eighteen month, one can see that this would have broad reaching effects across a number of industries. Size, cost, and availability of electronic components have contributed significantly to the development of portable devices.
Q: How are consumer electronics impacting the design of electronic medical devices?
Barker: I really don’t have all the facts to support my argument, but it seems like everywhere you look someone is using their PDA, cell phone, iPad, or Kindle. So from a user perspective—nurses, doctors, and even patients—people appear to be more comfortable adapting to the utility and functionality of portable, digital devices. Adapting to the change, involving any non-traditional product, is always a hurdle but in reality this looks to be a non-issue. As with most industries, cost is a major driver and the sheer numbers of components like gyros, accelerometers, inclinometers, and high resolution displays, found in every day consumer electronics, has not only brought these costs down significantly but I would argue that is has inspired new product development. Giving portable medical device smart phone usability should really be a design consideration with any new product. We have adapted that approach with our evolving family of servo and position controllers.
Q: What is the biggest limitation currently holding back medical electronics from developing further?
Barker: Well I certainly would not say a lack of innovation or creativity is the case. The United States remains the leader in both these areas. I would first look at the regulatory bodies and the difficulty and costs associated with bringing new products to market. Given Moore’s Law’s and a supposed window of eighteen month, it’s easy to see how quickly one concept or design can be displaced by technological advances. Technology is just moving too quickly today to let new products languish in the certification process. I would question what measure can be taken, at the regulatory level, to streamline and fast track the introduction of some of these products?
I would also point out that one area of particular concern is software verification and validation. We are talking about engineered products in a digital environment, and this necessarily requires software and firmware support. The amount of documentation required and the level of detail can be onerous. It’s easy to argue that the core competency of a programmable device is the firmware – and the exposure of the source code is a sensitive issue. I really don’t have a good answer but once a new patent is released or your source code is exposed, you become extremely vulnerable to the competition.
Q: What advances need to be made in power solutions for portable technologies to advance further?
Barker: The obvious answer is just lower the resistance, but that is certainly easier said than done. From a technical challenge, this is really a Catch 22. On one hand you’ve got this awesome capabilities increase, as larger numbers of transistors are crammed onto an IC. However, with the increased chip density and operating frequency, you significantly increase the power requirements in your circuit design. If the portable device operates within the proximity of an outlet or a generator then it’s basically a consideration of size and power consumption vs. heat dissipation. If you are operating on battery power then it gets a little trickier and the choices for portable devices are most likely Ni-Cd, Ni-MH or Li-Ion. Issues like storage life, intrinsic safety and recharge ability are all important considerations. As far as performance goes, there is always a trade-off, but it boils down to amp hour life and one’s ability manage the current discharge rate. Battery efficiency decreases as the average current increases and even when the average discharge current remains constant, different current profiles will affect the battery life. Another consideration is Vdd (voltage drain drain) or the positive operating voltage of a field effect transistor, and that is a nice segue into power stage dynamics. Here is where you switching loss really impact the efficiency of your device. A number of efficient power stage designs are incorporating FPGA’s to minimize the effects of switching.
Q: How are electronics impacting traditional non-electric devices?
Barker: I will limit my discussion to the portable electronics designs and applications that I am most familiar with. It is well recognized that there are three serious health issues that we are contending with in the U.S. today, diabetes, heart disease and Alzheimer’s. I think few people would argue that the portable insulin pump has improved the quality of life for hundreds of thousands of people around the world. When you consider the physical effects of self-injection versus a controlled dosage from a portable device this is a remarkable improvement. I also view robotics as an improvement over non-electric devices. This would include pharmaceutical delivery, patient assist and surgical robotics. The ability to perform surgery with robotic assistance seemed so futuristic a decade ago. Doctors are now performing complex surgeries and extending their careers with the help of robots. I would also consider some of the advancements in prosthetics as a quasi-robotic application and we have only begun to scratch the surface when it come the advancement made with biomechanics. Finally, I can also remember back to the first heart transplant and now double and quadruple bypasses are performed on a routine basis with bridge-to-bypass electronic devices assisting. And I cannot overlook the electronic pacemaker, although it seems like it has been around for years this product continues to extend an save the lives of countless patients.
Q: How are advances in electronic components impacting the functionality and capacity of implantable devices?
Barker: When you are able to place more computing power and more efficient power devices onto smaller IC’s it stands to reason that the enhanced utility of the component is far reaching. Processing power, size and power density are critical factors, as quoted from Louis Pasteur, “The role of the infinitely small is infinitely large.”
Q: Where are medical electronics headed over the next five to ten years?
Barker: I can only imagine what the creative minds of the engineers and physicist working within the medical community with come up with. I envision a great deal of new products emerging as a function of wireless communication and bus development. It’s a blank sheet of paper but the ability to transmit bundles of secure, real-time, high-speed data opens up a whole new dimension with respect to portable devices.
Q: Any thoughts/comments on medical electronics or other related areas that you would like to share with device manufacturers to aid them?
Barker: As engineering disciplines continue to search for better way to improve our quality of life, it should be noted that our universities are producing some of the brightest young mind ever and they are a resource to be welcomed. I’ll leave the futuristic stuff to the theoretical physicists but a recent publication by Michio Kaku, Physics of the Future, is an interesting and quick read.