Andy Selvy, chief system designer at industrial heater manufacturer Watlow, explains why medical device manufacturing needs a new approach and where heating technology fits in.
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In light of COVID-19, healthcare organisations have been, where possible, moving patients to home care settings to reduce the pressure on conventional healthcare facilities. This has been a double-edged sword for medical device manufacturers as demand has surged for specific home medical devices, but it has prompted heightened scrutiny and more rigorous safety regulations.
Medical device manufacturing is a burgeoning market. The UK is home to over 3,000 device manufacturing companies and is the third largest medical device market in Europe, and the sixth largest in the world.
Each component used to create a medical device must be built with patient safety, reliability, and effectiveness in mind. What’s lesser known is the role heating technology plays in some of the most used medical devices.
Watlow
Andy Selvy
From anaesthesia delivery systems and respiratory therapy devices to blood and intravenous (IV) fluid warmers and transfusion equipment, heating plays a crucial function in many medical devices. Without heaters, humidity could not be added to respiratory equipment, instruments could not be sterilised and fluids that help to stabilise body temperature post operation could not be injected into the body.
Thermal system safety
IEC 60601-1-11 standard for medical electrical equipment requires manufacturers of home medical devices to identify product safety risks associated with using their equipment in an uncontrolled environment by untrained users.
Meeting safety standards is sometimes possible with traditional technology, but that adds to both the bulk and the cost of medical devices. Device manufacturers understandably want to make devices that are smaller, cheaper, and easier to use — which can be at odds with safety compliance measures. This is where innovation in thermal solutions, including heaters, sensors, temperature controllers, power controllers and their supporting software can make a difference.
Many medical devices require heaters to warm gas or liquids, and these require a fair amount of power that increases the possibility of leakage current and hence the risk of electrocution. This is an example of where stricter standards for home care medical devices exist and how evolving heating technology can better meet them.
Unlike medical devices in a clinical setting, home medical devices cannot be designed with the assumption that there is a trained operator on site that can use tested outlets and equipment according to a set procedure. As a result, safety precautions must be built into the device design itself.
One way to improve patient safety is to incorporate an isolation transformer to step down the voltage going into the device, like the “brick” used to step down voltage for a smartphone charger. But isolation transformers are notorious for being big, bulky, and expensive, which works against the goal of miniaturisation for home medical devices.
Safety versus miniaturisation
Ensuring safety without the need for bulky and expensive technology starts by designing devices within a systems approach.
For instance, it’s not sufficient to create a heater that runs at 95 microamps leakage so that it can be incorporated into a device that must be rated to run under 100. Although this type of heater would meet the given specification, it would take up most of the available leakage budget. Adequate heater design of the entire thermal system must consider these difficult system level requirements.
Using a systems approach
A new generation of thermal solutions is being used to ensure safety and economy of space especially in home haemodialysis machines and respiratory devices.
When selecting an industrial heating equipment manufacturer to support with a medical device project, it’s important to consider a company’s portfolio of thermal solutions for the industry.
For instance, with haemodialysis machines, it’s necessary to keep blood at body temperature to prevent thermal shock. Higher temperatures are also needed to disinfect the machine itself.
Today, home medical devices must adhere to elevated safety standards, while upholding a compact, user-friendly, lightweight design. Achieving this necessitates the implementation of a systems approach in component design, which involves using thermal components to enhance devices, making them smaller, lighter, and more thermally efficient for improved patient usability and comfort.
