INDUSTRY SPECIAL Power electronics in medical technology
IoT technology is providing many opportunities for medical equipment innovation - but any new products must always be compliant with legislation, and completely safe for operators and patients using them. This article looks at some major medical device innovation trends and devices, and the power supplies that allow them to meet these requirements.
Whether we realize it or not, the IoT is increasingly impacting our daily lives through applications like home automation, intelligent vehicles, smart infrastructures, and many others. And, as it is improving our lives, it is also creating opportunities for electronics manufacturers and systems integrators – they can compete for emerging opportunities if they can develop or source better sensors to gather edge data, improved communications to collect it, or more sophisticated software to make sense of it.
And all this applies to medical technology as much as to other IoT-enabled developments. Innovation has the potential to improve health outcomes via earlier and more accurate diagnosis and safer, more effective and appropriate treatment. This particularly applies to the impact of advances in diagnostic technologies and devices.
However, one factor always differentiates medical equipment from any other type of device - the overriding requirement for uncompromised safety. One obvious reason for this is that medical devices are typically in close proximity to, in contact with, or even inserted into vulnerable patients. But there is another consideration; many medical products are now available for use in patients’ home settings, where they will be handled by untrained users in uncontrolled environments.
How to get power supply for IoT devices right
Innovative medical equipment scenarios
Accordingly, let’s look at some innovative applications that typify these issues, and next at how power supply design and legislation can mitigate them. Then, we can gauge the true impact of these factors by reviewing their effect on the current and projected market size for medical power supplies.
Distant health technologies: Geographical barriers and long wait times in hospitals and other healthcare facilities have paved the way for telehealth technologies. An increase in mobile technology and consumer demand helps this widespread adoption, and a reported 90 % of healthcare executives are building or have built a telehealth program.
Centralized monitoring of hospital patients: New innovative medical devices have emerged that use advanced equipment like sensors and high-definition cameras to monitor everything from a patient’s blood pressure to their heart rate, respiration rate, pulse oximetry and more. This complex data is then analyzed to trigger on-site intervention if anything is amiss while filtering out unimportant alarms. Before centralized monitoring, the American Heart Association reports that up to 44 % of inpatient cardiac arrests were not detected appropriately, mainly due to “alarm fatigue” experienced by nurses who become desensitized to cardiac telemetry monitoring systems .
As one specific example, the FDA-approved CardioMEMS advanced heart failure monitoring system is proven to improve quality of life and reduce hospital admissions by 33 % over an average of 18 months. The system features a small pressure-sensing device that is implanted directly into the pulmonary artery, sending information which doctors can use to adjust treatment in real-time and as needed. The system includes a home electronics unit that wirelessly sends information instantly to a doctor who can make changes to a patient’s treatment before they feel symptoms.
Fulfilling these scenarios safely
For medical equipment to perform safely and effectively in these scenarios, it must be designed to eliminate any risk of electric shock; it must also comply with legislation applicable where it is being used. These objectives are most commonly achieved by designing to the IEC 60601-1 series of technical standards, which have become a de facto requirement for bringing new medical devices to market in many countries. Additionally, Europe’s EN 60601-1 and Canada’s CSA 60601-1 are harmonized to these IEC standards.
The original standard was published in 1977, but it was the second edition, appearing in 1988, which focused on safety for devices within a six-foot radius from a patient, referred to as ‘patient vicinity’. This comprised three categories:
- Type B (body) equipment that operates within the patient vicinity, but without patient contact.
- Type BF (body floating) equipment is characterized by having direct contact with the patient.
- Type CF (cardiac floating) equipment has direct contact with the patient's heart.
Each classification had different required standards for isolation, insulation, creepage, clearance, and leakage. The third IEC 60601-1 edition extended the patient focus to require an overall means of protection (MOP) that combined one or more "means of operator protection" (MOOP) and "means of patient protection" (MOPP), recognizing that the potential hazards seen by each user are different. For instance, an operator has access to a control panel, while the patient may be connected via probes.
An ISO 14971 Risk Analysis / Management process is then used to define one of four possible "means of protection" classifications:
- ONE MOOP: Single "Means of Operator Protection"
- TWO MOOP: Two "Means of Operator Protection"
- ONE MOPP: Single "Means of Patient Protection"
- TWO MOPP: Two "Means of Patient Protection"
The changes from the second to third edition as they apply to power supplies were more a matter of definition than actual performance. For example, second edition Type BF applications need to meet the third edition's "two MOOP" and "one MOPP" requirements, and second edition Type CF not only requires an IEC 60601-1 qualified supply, but must ensure an additional isolation barrier between the supply and the part that touches the patient. This is typically achieved with an isolation transformer or dc-dc converter with 8 mm creepage and double insulation.
IEC 60601-1 Edition 3.1 was introduced in 2012 to address many issues identified as unclear or ambiguous in the original third edition. Then, with increasing use of wireless devices like cell phones and laptops, the IEC 60601-1-2 collateral standard was introduced to address electromagnetic compatibility (EMC) issues affecting both the medical devices and other equipment in the vicinity. This became essential as medical equipment is increasingly intended for use in home and other environments outside the hospital. The Standard’s Fourth Edition defines three such ‘intended use environments’: professional healthcare facilities, home healthcare, and "special" environments.
Expected growth of the medical power supply market
According to Market Data Forecast, Inc, the size of the global medical power supply market is projected to reach USD1.37 billion by 2026, from USD980 million in 2021 – a CAGR of 5.92 % for the period. The growing need for smaller, more proficient, consistent, cheaper and lighter-weight medical devices is a key market driver. Other significant factors include an increasing number of healthcare facilities, a rising incidence of chronic diseases, and growing demand for wearable and household devices. Healthcare technologies are evolving in every possible aspect, from patient registration to data monitoring and from laboratory tests to self-care devices.
Public and private spending on health has increased considerably, due to population increases and the prevalence of various diseases. Additionally, rapidly changing lifestyles drive the demand for advanced healthcare solutions, accelerating the need for medical power supplies globally. The increase in healthcare spending has led to the popular adoption of wireless technologies and implantable devices, and a strong preference for health facility alternatives.
The APAC region dominated the global medical power supply market in 2020, with a share of 43.3 % in value. This was followed by Europe, North America, Latin America, the Middle East, and Africa.