Wireless device’s respiratory measurements correlate with standard of care

Cerna Sanchez JA, et al. Safety and feasibility parameters of a novel wearable sensor device in children with asthma. Presented at: American Thoracic Society International Conference; May 19-24, 2023; Washington, D.C.

Cerna Sanchez JA, et al. Safety and feasibility parameters of a novel wearable sensor device in children with asthma. Presented at: American Thoracic Society International Conference; May 19-24, 2023; Washington, D.C.

WASHINGTON — A wireless device that assesses respiratory measures in children with asthma produced results comparable to traditional measurements, according to data presented at the American Thoracic Society International Conference.

"The innovation we’ve got is pretty much what the evolution has been in glucose monitoring. It moved from a finger prick to a continuous glucose monitoring device," Faizan Jav e d , PhD, MSc , senior manager of product development at ResMed, told Healio.

"So, we thought, ‘Hey, why don't we have any continuous respiratory measuring device?’ Then you can measure at home," he said. "You have something which is portable enough that people can just wear it and give you a continuous trace of respiratory function."

The LEO wearable sensor platform uses sensors, adhesives, a charging cable, a mobile application and a cloud-based analytics platform to collect and analyze respiratory data to interpret breathing patterns associated with pulmonary function.

It is the first wearable sensor that accurately captures pulmonary function remotely, especially for children, the researchers said. Measuring 3.7 inches by 0.9 inches by 0.2 inches, it uses impedance pneumography to measure pulmonary function.

"It's not just respiratory rate. You can actually get flow and volume waveforms," Javed said.

The LEO's passive measurements were designed for children and other patients who may find spirometry difficult since spirometry forces them to breathe, Javed continued.

The device's sensors also measure heart rate and ECGs, in addition to the body's posture. It can record up to 40 hours of data, and it uses Bluetooth to transmit its findings to a mobile app. It is rechargeable for multiple uses as well.

"Once the recording is finished, you can download the data from the app onto the cloud," Javed said, adding that the data is processed in the cloud before it is sent back to the app for user and physician review.

Users wear the device on their chest, where a disposable silicon-based adhesive from 3M keeps it in place. The adhesive and device are not waterproof, but they can stay in place for up to 72 hours of continuous use.

"It's pretty strong, not like standard acrylic," Javed said.

The design also is flexible, enabling users including children to go about their daily activities without impeding or damaging it, the researchers said. Users can wear it while they are asleep or awake as well.

"There's a clear difference between normal and abnormal breathing at night," Javed said.

The researchers aimed to compare measurements from the LEO against those taken through the standard of care and to assess its feasibility and usability among children, clinicians and caregivers.

The single-visit study recruited 30 stable children aged 2 to 18 years (median age, 10.3 years ± 4.3; 26.7% girls; 86.7% white) with asthma from Children's Hospital Colorado.

These children performed a series of breathing tests in sitting, supine and lateral postures while wearing the LEO in the mid-sternum and breathing through a facemask connected to a pneumotachometer (PNT). The researchers performed oscillometry and spirometry as the children were in different positions and wearing the LEO as well.

The mean rho of greater than 0.9 in all body postures and tidal volumes indicated a strong agreement between the LEO and PNT measurements, the researchers said.

These correlations were consistently high for patients with normal tidal volumes of less than 500 mL and high tidal volumes of 500 mL or greater as well, according to the researchers.

Also, the researchers said the correlation between the respiratory rates measured by the LEO and the end-tidal carbon-dioxide (Et-CO2) device was high (r > 0.98; P = .04).

The researchers also tested the impact of the LEO's continuous use on the skin. Patients were instructed to wear it for 24 hours and then take it off, giving them a chance to bathe, before putting it on for another 24 hours for up to 7 consecutive days.

Once the device was removed, 46.7% of the patients had no skin irritation, 50% had slight irritation and 3.3% had defined irritation. Similarly, 23.3% had no skin redness, 73.3% had slight redness and 3% had defined redness.

"For most of them, it was slight redness, which is typical of ECG-type electrodes," Javed said. "When you take it off, after a couple of hours, it becomes normal, which is barely perceptible."

The LEO remained adhered for the entire duration of the study for 86.7% of the patients. Also, patients rated it "pretty comfortable" (4.17 ± 0.87) on a 5-point Likert scale.

"Nobody complained that, ‘Hey, this is too much for me,’" Javed said.

The researchers now are looking for clinicians who may be interested in using the LEO in clinical practice.

"For example, they can use it in [emergency room] visits to triage patients. They can use it to discharge patients and monitor them while they’re at home continuously," Javed said.

Or, Javed continued, physicians can use it for preoperative or postoperative measurements in the hospital instead of using more invasive devices.

"We just put on this particular device, and then they just measure all the vital signs and everything that clinicians are interested in," he said.

Faizan Javad , PhD , MSc, can be reached at [email protected].