Discussing battery issues with biomedical technicians A retiring biomed technician recently organized a workshop in a large hospital in Michigan to discuss battery problems in healthcare. The participants were experienced biomed techs; mostly aged 50 with plenty of hands-on experience. Cadex Electronics participated by asking questions to assist in developing new battery diagnostic technologies. Cadex also participated in a similar workshop in Belgium to learn about battery problems in Europe.
1. Are batteries a problem in medical devices? Do you trust them? There is a general distrust in batteries and the bio-med techs agree with the FDA’s statement that up to 50% of issues in hospitals are battery related. Having been a service technician myself, I know well that battery failure accounts for about half the service calls.
2. Who is responsible for the battery in a medical device? Here, battery-fit plays a role. If the battery is built into a device, the responsibility to test and replace a battery goes to the technician. The procedure changes if the battery is removable for charging. Devices with removable batteries have an advantage in that the user can replace an empty pack with a charged one, check it with a battery analyzer and retire when faded without the involvement of service.
3. When should a battery be replaced? What percentage denotes end-of-life? The answers were mixed. Unless checked with a battery analyzer, the capacity is not known. Batteries come oversized to allow for some fading; end-of-life is commonly at 80%. Battery capacity should be verified as part of servicing a device and before replacing the pack.
4. What are the regulatory procedures in battery testing? In the absence of a battery analyzer, device manufacturers recommend replacing batteries on a date stamp that allows for 2 and 3 years of service. Fabrication-to-destination causes delay and a battery can be one year old when entering service. Date stamping leads to discarding of good batteries. After two years in service, the capacity of a defibrillator battery can still be over 90%. A manager at DOE discovered that every year about one million usable lithium-ion batteries are discarded.
Device manufacturers are aware of high replacement costs when many packs are under-utilized. As a general guideline, lead- and nickel-based batteries are good for about 3 years, but Li-ion can last for more than five years. In contrast, batteries for the electric vehicle are guaranteed for eight years. This longevity is also attainable in healthcare with diagnostic equipment. To demonstrate battery endurance, the organizer for this workshop reused spent batteries from patient heart pumps to cut the grass with his electric lawn mower.
