Philips: Pulse Ox Without Skin Contact Is Possible

A standby device in hospitals, the pulse oximeter may eventually get a futuristic upgrade. While it is already a non-invasive way to measure a person's oxygen saturation, the pulse ox of the future may not even need to touch the patient's skin.

Royal Philips has been developing a contactless method of monitoring absolute oxygen saturation of arterial blood (SpO₂), and new data shows that its technology works. The technology uses camera-based monitoring to determine SpO₂ by measuring light reflected from patients' skin. According to the company, there are minute changes in skin color that can be captured and analyzed by the technology to calculate pulse rates.

In a small study of 41 healthy adults, researchers made video recordings of the adults' foreheads and then extracted remote photoplethysmography (PPG) signals, according to the study abstract. The calculations of SpO₂ were compared to SpO₂ measurements from traditional sensors. The first-of-a-kind findings show that the new technology can be calibrated without needing to be adjusted for each patient. The study, "Calibration of Contactless Pulse Oximetry," was published this month in Anesthesia & Analgesia.

Contactless monitoring could be an ideal alternative for vulnerable patients like premature infants because it could prevent skin damage and potentially lead to a faster response rate, according to a Philips press release. 

"Vital signs monitoring is crucial across all types of care settings, but for patient populations with specific conditions, managing their care in a less intrusive way is critical in order to avoid unnecessary distress," said Carla Kriwet, CEO of Philips Patient Care & Monitoring Solutions, in the release. "Contactless monitoring solutions will offer clinicians with a way to accurately measure vital signs for patients in a non-obtrusive way, and provide them with the data needed to know when to intervene."

Kriwet told MD+DI that the technology could be advantageous for patient with fragile skin and that its accessibility could offer wide applications. "The contactless monitor can be run off of any camera technology--even a smartphone or tablet--so there is potential to incorporate this technology into a multitude of care settings to measure vital signs such as respiration and heart rate," she said.

The researchers undertook the question of calibratability because a contactless monitoring technology collects light that has not travelled as far through tissue as the light a traditional contact sensor would gather. The study authors wrote that the data "provide strong evidence that a single calibration curve for a population of health adult individuals can be used to estimate SpO₂ contactlessly with an acceptable accuracy . . . "

There are still some hurdles for the technology to overcome. The study investigators noted that data for 15 of the adults studied was thrown out because of unreliable signals due to motion and/or low pulsatile strength. "Challenges such as subject motion and low pulsatile strength have to be addressed to make this new measurement practical and successful," the study authors wrote.

Kriwet told MD+DI that the technology will be validated for several applications at centers across Europe and the United States, and its algorithms will be improved. Contactless monitoring is anticipated to be commercially available on a limited basis in 2017, she added.

View the video below for more on Philips's contactless monitoring. 

[Image courtesy of PRAISAENG/FREEDIGITALPHOTOS.NET. Video courtesy of PHILIPS HEALTHCARE.]