The Frightening Earlier Days of Wireless Medtech—#ThrowbackThursday

Another Thursday, another look back at earlier days of medical device manufacturing and, specifically, my coverage of it in Editor’s Letters of the past. If you are enjoying this look back, click here to peruse through the other entries I have for this series.
 
In the July 2000 issue of Medical Design Technology, I focused on the growing trend of wireless medical devices. As the letter reveals, however, these were uncommon enough the FCC had only assigned medtech-specific bands just a year earlier. That’s crazy to think medical devices being used in hospitals could have been on the same band as other technology. The lack of safety for this type of scenario is simply astonishing.
 
Without further ado, we’ll get right into gaining insight into how companies were “Going Wireless…Safely” in 2000. (I’m still guilty of overusing ellipses in my Letter headlines.)
 
As electronic medical devices continue to get smaller and more compact while still retaining, and in some cases, adding a variety of features, medical device manufacturers are seeking to also make these “gadgets” wireless. This will allow patients much greater range of mobility and freedom while requiring the use of the devices.
 
Nothing new here. The same is said of medtech manufacturers of today’s products—smaller, more functional, wireless, etc. As we’ll see, it’s the world around these types of devices that have advanced substantially (and for the better) with regard to paving the way to their safe use.
 
There are a number of applications where a wireless device would be much more favorable to use in place of one that is constrained by cables and wires. Currently, the most common form of wireless medical device available is physiological sensor equipment, such as heart, pressure, and respiratory monitors. There are also self-contained devices that could be improved or modified with the addition of wireless technology. Examples of these include hearing aids and pacemakers.
 
While I’m not in hospitals very often (fortunately), when I do see physiological sensors being hooked up to a patient, they still seem to be wired quite often. I’d think there are more instances of wireless being used today, but I’m uncertain of the market size of each. Does any manufacturer of these devices want to share some market data with me?
 
As for the “self-contained” devices such as hearing aids and pacemakers, the former has certainly moved to wireless as the primary technology. For the latter, leadless pacemakers are not uncommon either. Those examples may have been better for the modern-day than wireless sensors for measuring bodily functions, but both are relevant today.
 
However, there have been growing concerns over the safety of wireless devices. Other sources emitting radio frequencies, such as television and land mobile radio, are capable of interfering and scrambling the signals of the wireless medical device. Imagine being a patient lying in a hospital bed and needing to be concerned that the readings from the wireless heart monitor are incorrect or not being received at all due to a local television broadcast. That could be a disturbing thought for a patient with a serious heart condition.
 
First, I’ll come out and admit I’m not entirely certain what a “land mobile radio” is. I’m guessing I just meant radio, such as a car stereo or hand radio that receives transmissions. But regardless, the fact there was the chance that this type of interference existed in very real-world scenarios is frightening, to say the least.
 
The industry seemed to force the hand of agencies involved in regulating these “airwaves” as the infrastructure for wireless medical devices seems to have been established well beyond when it was needed.
 
In addition, there is concern that wireless medical devices could potentially interfere with other devices in the immediate area. If two monitors are being used in the same room or even on the same patient, they must be able to perform successfully without interfering with the use of the other.
 
Similarly, non-medical devices are currently under investigation to see how they react with certain medical devices. Wireless phones, most notably, are being tested to see how they interfere, if at all, with such devices as hearing aids and pacemakers. In addition, until further research is done, many hospitals have banned the use of devices such as wireless phones within the building.
 
It’s critical devices, wireless or otherwise, go through the necessary interference testing to ensure they aren’t adversely affected by all the devices they will potentially encounter in today’s world. As more devices leave the hospital, it’s not enough to be certain devices will not adversely interact with healthcare-type devices; rather, devices cannot be affected by devices in the car, home, offices, or anywhere a patient may need to use them.
 
Undoubtedly, this is understood much more today than in 2000, but the industry is still far from perfect in safeguarding against interference. In 2022, Baxter announced it was issuing an Urgent Medical Device Correction for its WatchCare Incontinence Management System. The company took this action due to the device’s potential for radio frequency interference with other medical devices.
 
Not interference-related but associated with wireless medical devices, the FDA warned patients, providers, and device makers in 2020 about the cybersecurity concerns with Bluetooth Low Energy and its use with certain medical devices. The set of vulnerabilities known as “SweynTooth” could be used to access the device and cause harm.
 
In 2023, Abbott took action due to a potential concern over its CardioMEMS HF System. The firm sent letters to physicians warning of the potential for the technology to interfere with certain other medical devices when nearby. Although no interference had been confirmed and there had only been two complaints indicating the possibility of it, the company still took action to warn doctors who had patients using the system.
 
With these concerns in mind, steps are being taken to ensure safer wireless medical devices. Recently, the FCC has made strides to curb the instance of interference in these life-saving devices. Upon a recommendation from the American Hospital Association, the commission has assigned 608-614 MHz, 1395-1400 MHz, and 1429-1432 MHz bands for wireless medical devices.
 
Frankly, this part of the Letter blows my mind. I looked it up and apparently, this action took place in 1999. It took a recommendation from the American Hospital Association for someone at the FCC to think it wise to assign medical devices their own bands? Am I alone in being simply astonished that this wasn’t already in place by 1999? And if you think that’s bad, read the next part and find out how bands used to be doled out to medical devices.
 
This is a change for the better over the method used in the past for assigning medical devices bands on which to operate. They had been operating on less-used, licensed television bands and were forced to deal with and attempt to avoid the interference that this often led to. In addition, these bands were not licensed for the medical devices.
 
Are you kidding me? Bands that may have delivered Sesame Street to televisions could have also been used for medical devices? Please, someone reach out to me and clarify how much I’m misunderstanding all of this because frankly, it sounds like a nightmare.
 
Later this year, the FCC will continue to evaluate other bands for possible allocation for wireless medical devices.
 
According to the FCC’s website, “The Medical Device Radiocommunications Service (MedRadio) is in the 401 – 406, 413 – 419, 426 – 432, 438 – 444, and 451 – 457 MHz range. MedRadio spectrum is used for diagnostic and therapeutic purposes in implanted medical devices as well as devices worn on a body. For example, MedRadio devices include implanted cardiac pacemakers and defibrillators as well as neuromuscular stimulators that help restore sensation, mobility, and other functions to limbs and organs. In addition, Medical Body Area Networks (MBANs), which are low-power networks of sensors worn on the body controlled by a hub device that is located either on the body or close to it, operate in the 2360-2400 MHz band.”
 
In addition to radio frequencies, EMI (electromagnetic interference) is of equal concern. Since the 1960s, the Center for Devices and Radiological Health (CDRH) has been involved in the testing of medical devices. As with all medical devices, wireless units will have to be manufactured so that they are compatible with the surrounding EM environment. However, due to the varying environments in which medical devices are used, significant time needs to be spent on testing.
 
Very quick history lesson: the CDRH was established in 1982. FDA was given authority to regulate medical devices on May 28, 1976. Before the FDA’s oversight, medical devices were under the authority of other agencies with focuses not specific to human healthcare. I blame my lack of knowledge of the industry at the point this Letter was written combined with the lack of information available on the internet at the time. No idea how I came up with the ‘60s date.
 
Otherwise, EMI is certainly an important factor to test with medical devices, especially those leaving the hospital environment.
 
Wireless medical devices will certainly enable greater mobility and convenience to patients. However, safety must be the primary concern with designing and manufacturing these units. With improvements in regulation and continued cooperation from the FCC, the wireless medical device marketplace will begin to grow exponentially.
 
And so it has. Fortunately, the infrastructure to support it is in much better shape than in 2000.