By Dr. Ashwani Mehta
Senior Consultant Cardiologist, Sir Ganga Ram Hospital, New Delhi,
In 2011, the World Health Organization declared, “Medical devices should be available to everyone, everywhere. But where they are most needed, they are least available.” Since then, we have made tremendous progress making available advanced medical devices across numerous disease areas, instilling a sense of hope in patients and giving them a chance at a healthier and longer life. The progress we have made in implantable medical devices is particularly notable, with the recent years seeing massive technological advancements, greater device sophistication and increased reliability.
Medical devices may be either battery or non-battery powered. While longevity of the device is a key advantage for both, it has even greater significance for battery powered medical devices. The Implantable Cardiac Defibrillator (ICD), a medical device implanted to treat sudden cardiac arrest and help the heart restore normal rhythm. When the battery of an ICD is close to being exhausted, it must be
surgically replaced immediately to avoid causing an emergency cardiac event. It is crucial therefore for such battery-powered
medical devices to last for a longer period before their need to be replaced. Not too long ago, ICDs needed replacement every 5-7
years, but today we have those powered with innovative battery technology that are projected to last 12 years, clearly offering a
better advantage to patients.
A battery-powered medical device performs two functions: acts as a primary or secondary power source, and retains critical parameters, data and patient information in the event of power disruption. Examples of medical devices that run on batteries include infusion pumps,
pacemakers, ICDs, Cardiac Resynchronization Therapy Defibrillators (CRTDs), ventilators, transport physiological monitors, intra-aortic balloon pumps and ventricular assist devices.
About a decade ago, battery circuitry was not as well understood or efficient as it is today. Moreover, the capacity of batteries has increased since then, with medical device manufacturers exploring various chemical compositions to improve battery longevity. Performance requirements for implantable medical devices do vary but some pre-requisites are common to all: high safety, reliability and longevity.
Long lasting battery helps to avoid unnecessary early replacements of the device, increase in chances of infections related to surgical procedure, economic burden and inconvenience for both
Advantages of long lasting Devices include:
Reduction in the frequency of surgery to remove and replace the device. In the long term, this proves to be more economical and easier on the patient’s pocket.
Reduced frequency of surgery also reduces the risk of infection that is a known possibility during surgical procedures. patients and clinicians. In fact, these factors prompted the United Kingdom’s 7.5 million USD to the National Health Service in England in the first five years.
Change in battery chemistry coupled with increased battery capacity and energy efficient circuitry has improved the battery longevity considerably. In fact, a leading medical device manufacturer switched to producing batteries with a Lithium Manganese Di-oxide chemistry in 2008 to ensure a predictable decline in the capacity of the battery. These advanced battery systems have nearly two times the usable battery capacity when compared to competitive devices and manufacturers.
Recently, The Association for the Advancement of Medical Instrumentation (AAMI) identified batteries as one of the top ten challenges that biomedical departments face, with longevity being one of the leading issues. While we do our best to ensure good battery behavior, much of it is influenced by the battery’s inherent chemical makeup, environmental conditions and user patterns. It is my hope that we never cease to improve these systems and work towards developing models with greater efficiency, which will ultimately benefit patients in more than one way.