5 Design Hurdles to Overcome with Wireless Medical Devices

Chris Newmarker

There is a big need for cutting-edge wireless medical devices consumers love. The hard part is making them.

When the original Fitbit tracker came out late in the past decade, it was a “stellar example of a first-generation product,” says Bill Saltzstein, president of Code Blue Consulting (Seattle).

“It’s easy to use. They have the backend to process the data. I can watch my weight. I can watch my steps. I don’t have to do much,” Saltzstein says. 

This promotional photo from San Francisco–based AliveCor shows one of its smartphone-based ECG readers in action.

Many people have reported that fitness trackers like the Fitbit have helped them lose weight or improve their general health. And yet, from a medical perspective, the durability of first-gen fitness trackers’s health benefits is questionable. A third of the people who use Fitbit or Jawbone or other activity trackers are no longer using them after six months, according to an Endeavour Partners study recounted by TechRepublic.

For the quantified selfers who do use fitness trackers regularly over the long haul, the question becomes: what to do with all of the data? “We’ve gotten to the point where we can collect all this stuff. The market challenge, and how we make our lives better, is the stuff we need to focus on now. It’s not a question of technology anymore,” Saltzstein says.

Mike Smith, chief technology officer at patient monitoring device company Preventice, said it well in late October at MD&M Minneapolis: “The devices are the easy part. The hard part is figuring out what to do with all the data available to us.”

Smith says it is even hard to decide what information to filter out. “Now that we can continuously monitor someone with a wearable, what does that open up for us? We’ll probably discover things we never knew to look for before,” he said.

While an automated analytics system would be helpful in sifting through the data gathered by fitness trackers, most of the analysis must still be done the old-fashioned way—by humans. Complicating matters is that most physicians have little interest in reviewing much of the data now gathered by the devices, which generally rate to activity levels.

Still, a number of firms have developed devices that harvest clinically relevant data. Whether it is San Francisco–based AliveCor and its smartphone-based ECG readers, or G-Tech Medical and its work to develop a wireless, wearable disposable electrode patch to measure digestive tract electrical activity, a growing number of companies are developing medical-grade wireless-enabled products that make early wearables like the first-generation Fitbit look like toys.

There are plenty of design challenges along the way in making mobile medical devices, however. Here are five of the most prominent.

See Bill Saltzstein, president of Code Blue Consulting; G-Tech Medical CEO Steve Axelrod; and David Albert, MD, AliveCor’s founder and chief medical officer, speak at BIOMEDevice San Jose, December 3-4, 2014.

1.  How long can it operate?

The latest iteration of Bluetooth—called Bluetooth Low Energy (LE) or Bluetooth Smart—is helping extend the battery life of newer wearable devices that make use of the technology, Saltzstein says.

San Diego–based Qualcomm announced earlier this year that its 2net Hub, the company’s plug-and-play home gateway for health monitoring devices is able to communicate with devices over Bluetooth Smart. Qualcomm says more than 90% of the medical device makers the company’s Qualcomm Life subsidiary is working with are either launching or planning to launch the next iteration of their devices as Bluetooth Low Energy.

Combine Bluetooth LE with coin cell batteries and “you’re in the realm of disposables where the battery isn’t recharged,” Saltzstein says.

There is no need to worry about sterilization issues around changing batteries because the devices are disposable.
Saltzstein says the era of single-use tracking devices has arrived: “It’s worn once and discarded in the appropriate electric stream.”

With the wireless “EKG for the gut” patch G-Tech Medical is developing, Bluetooth LE turned out to be the best option, says Steve Axelrod, G-Tech’s CEO.

Both Saltzstein and Axelrod acknowledged that Bluetooth LE works best when the device is asleep for periods of time, and only needs to send minute packets of idea.

With Mountain View, CA–based G-Tech’s patch, signals will actually be five times a second as it sends signals about what is going on in a patient’s digestive tract, but Bluetooth is still helping G-Tech to meet its goal to have a patch that lasts for up to three days.

“In the doctor’s office, they will put the patches on … and make sure the app is set up properly on the patient's phone,” Axelrod says. The patient then simply keeps the patch on for three days, with it communicating with their smartphone.

This illustration from G-Tech Medical shows how it would like its wireless “EKG for the gut” patch to work.

2. Is it flexible enough and require the least enough of effort from the patient?

As G-Tech has hashed out early stages of its prototype at the Fogarty Institute for Innovation, where it is based, it was extremely important that the roughly 2.5-in.-diameter patch was flexible and waterproof and only a few millimeters thick.

The electronics could only take up a small portion of the patch. Axelrod and his team are working toward having an ASIC board that is only 0.5 inches to 0.75 inches across. The battery had to be as thin and as light as possible

“This is going on someone’s belly. There will be three patches. And when you sit down, bellies fold. It’s not like it’s up on your shoulder or something. … We needed it to be very conformable,” Axelrod says.

“People should be able to go about their day and life, take a shower. Maybe they can even go out and play tennis. It’s about making this as super user friendly as you possibly can. … They shouldn’t have to worry about it, even think about it a lot.”

3. Are you using the right type of wireless?

Saltzstein is a big fan of Bluetooth, but he also warns, “People get enamored with the latest technology.”
“We have many tools in our toolbox. You don’t always have to use your screwdriver. … LE answers a lot of questions. But if you’re asking a lot of different questions, LE might not be the right thing,” Saltzstein says.

If a device is for a hospital environment and the hospital has Wi-Fi, use it, Saltzstein says. Cellular communications such as 4G can use a lot of energy, especially when combined with GPS, but could still be useful if a device could be used in a more remote location or requires GPS.

4. Are you communicating the right information in the right way?

Device designers should even ask whether wireless is really the way to go, Saltzstein says.

“The last thing a hospital wants is another RF running around in their hospital, where they now have to coordinate another set of frequencies, another set of access points. … There is something still called Ethernet cable,” Saltzstein notes.

Designers also need to be cognizant that as more as more data is produced, hubs for wireless devices are increasingly going to have to fact as a gateway filtering data so that it doesn’t overload networks, according to Saltzstein.

One hitch with this challenge is that there is still so much to learn when it comes to what data might be useful, Smith at Preventice said.
“We don’t know yet what’s going to be interesting. I’d hate to lose some of the data we could mine later,” Smith said.

5. Are you actually doing something useful?

The FDA granted AliveCor’s smartphone-based heart monitor over-the-counter clearance earlier this year. But what are routine ECG readings good for?

For AliveCor, the answer has been to use U.S. board-certified cardiologists and U.S.-based cardiac technicians to analyze patients’ data over the cloud to ensure that only important information and information trends are pointed out.

“The physician doesn’t need a daily reading. They physician only needs the readings that are exceptions. … Doctors don’t want more data. They want better insights. … They want actionable insights,” says David Albert, MD, AliveCor’s founder and chief medical officer.

The company recently broke the 100,000 mark for ECG readings uploaded to its cloud during a single month. Albert thinks there will soon be a time when there is enough data that algorithms can do more of the sorting.

“We’re trying to drive efficiency and insights,” Albert says.

Saltzstein summed up the situation nicely: “These things now are possible: What are we going to do with them? What are the things that are not only cool but will help people? That’s the multimillion-dollar question.”

See Saltzstein, Axelrod, and Albert speak at BIOMEDevice San Jose, December 3-4, 2014.

Chris Newmarker is senior editor of Qmed and MPMN. Follow him on Twitter at @newmarker.

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