New technology means positive airway pressure devices for sleep apnea can fit even more easily on a bedside table or in a suitcase. But they aren’t necessarily a fit into the lifestyles and habits of all users.

By Kristen Fischer

As smaller-sized positive airway pressure devices enter the market, innovations found in these exceedingly travel-friendly CPAPs could pave the way to improve the therapy category overall.

“Consumers are looking for convenience and comfort,” says Ed McCarthy, director of business development at Somnera, which received FDA clearance for its positive airway pressure system in 2020. “Consumers are very interested in small, effective, easy-to-use options.”

The size of the unit does not provide a medical advantage, but some patients may find a smaller device more convenient, McCarthy says.

Chelsie Rohrscheib, PhD, head sleep specialist and neuroscientist at Tatch, which is developing a patch to detect sleep apnea, has also noticed a trend toward producing smaller CPAP machines.

Smaller CPAPs: Benefits and Disadvantages

Compact devices generally are more portable, making them popular for frequent travelers. And these devices also have other perks.

Some have sleek, more flexible tubing that can make use more comfortable for some people, Rohrscheib says, adding, “a smaller machine means there is less cleaning and maintenance involved.”

But dental sleep medicine practitioner Jamison Spencer, DMD, MS, organizer of mentoring group Spencer Study Club, cautions that while smaller devices can make CPAP more transportable, the smaller profile does not tend to make CPAP therapy more adoptable. “Those who aren’t able to tolerate a regular-sized CPAP may find themselves in the same situation with a smaller version,” Spencer says. He treats sleep apnea patients who cannot use CPAP by fitting them for oral appliances.

And some models of small CPAPs have disadvantages, at least for patients who want to use them as their regular every-night device. For example, they tend to be pricier than their full-sized counterparts, observes Rohrscheib, and the ones that rely on battery power must be charged before use.

She also finds that some models of small CPAPs haven’t fine-tuned their pressure variance and algorithm responsiveness as well as larger devices. Rohrscheib says, “This means you may require a higher pressure setting for your mini-CPAP to be effective.”

Michelle Worley, RN, director of clinical operations at durable medical equipment supplier Aeroflow Sleep, says many units designed primarily for travel don’t include humidification, a feature that when included can improve comfort.

“Just because the machine is smaller does not mean it is better,” Worley says. “Of course, these smaller machines meet all the same pressure requirements to be considered a CPAP as the larger units, but they should really only be used for traveling.”

That said, smaller CPAPs can be great for travel, Worley says. “For patients that travel often, they’ll find it easier to include a smaller CPAP machine when packing,” she says.

Greg Dench, senior director of PAP devices at sleep and respiratory diagnostics and therapy company ResMed, says that comfort—not just device size—is key for improving patient adherence and ultimately helping improve health outcomes.

“The more a device fits into a patient’s lifestyle, the more likely they are to embrace it, adhere to treatment, and therefore improve their apnea symptoms and overall health,” Dench says.

Design Challenges

There are several constraints that impact how small a device can be, which include the airflow requirement, McCarthy says. CPAP devices provide positive airway pressure by continuously forcing air through a closed system. As a user breathes against the airflow, it creates back pressure that “splints” the airway so it stays open throughout the night, he says.

“The airflow is provided by a fan that needs to be able to deliver a maximum of 150 liters of air per minute,” he says. “This requirement limits how small the fan can be made and therefore the size of the CPAP device.”

The fan also requires insulation to keep it quiet enough to allow for sleep, another size limitation. For devices with traditional water-based humidification, the humidifier also adds to the bulk.

Newer, Smaller Devices

Somnera’s Airbox device is 5.25 in wide, 3.5 in deep, and ~2.5 in tall and eliminates the need for continuous rushing airflow to create the positive airway pressure necessary to treat sleep apnea effectively, McCarthy says. But it’s not made to replace CPAP.

“Somnera is great for a newly diagnosed patient that prefers the low airflow breathing experience, or a current CPAP user that struggles to tolerate CPAP and is looking for a different experience,” he says.

The Somnera Airbox provides the same positive airway pressure as CPAP via a valve that sits up in the user interface right next to the airway. The valve gets charged with approximately 75% less airflow than a traditional CPAP device, producing a cyclical breathing experience, he says. When breathing in, users draw air from the room through the valve, combined with supportive airflow from  the Airbox. Upon exhaling, the patient creates backpressure using their own respiratory effort by breathing against the valve to reach the therapeutic pressure at the end of every breath. 

“It is important to note that unlike CPAP the user does not experience any airflow from the device when they exhale,” McCarthy says.

Creating positive airway pressure with drastically reduced airflow requirements enables the company to make many device components, such as its hose, smaller.

The ResMed AirMini is another small device, weighing in at less than a pound. It comes in three modes: CPAP, AutoSet, and AutoSet for Her. It has a waterless humidification system that delivers the comfort of humidity without the hassle of carrying distilled water everywhere.

The AirMini works with a wide range of ResMed AirFit and AirTouch masks and features ResMed’s proven algorithms, Dench says. Patients can control settings on a smartphone, where they can track their sleep.

Since it launched a few years ago, Dench says, the company has received positive feedback on device size and convenience—especially because it doesn’t require water.

The Philips Dreamstation 2 is another well-known small profile CPAP device. It features the company’s smallest diameter tubing and is compatible with the Philips DreamMapper sleep apnea mobile app and clinician-facing Philips Care Orchestrator. The company also makes DreamStation Go, a travel device.

What’s Next

Companies are always looking to innovate, especially since some patients struggle to use beneficial CPAP technology due to its bulkiness.

From a hardware perspective, advancements in fan design have the potential to radically impact the footprint of CPAP devices, McCarthy says. He adds, “From a software perspective, [artificial intelligence] will make a big impact on further refining the algorithms that drive the devices—making them more accurate at identifying and preventing events, which will improve the therapy these devices provide.”

Kristen Fischer is a New York-based copywriter, journalist, and author.

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