Multiple studies have shown that people with darker skin pigmentation run a higher risk of being misdiagnosed and undertreated than patients with lighter skin due to inaccurate oxygen level readings
Now, scientists at multiple institutions are working to improve the basic pulse oximeter’s design by making it capable of measuring multiple biomarkers, as well as addressing long-standing inaccuracies in the device when used on people with darker skin pigmentation.
This ongoing research demonstrates how new technologies are enabling innovators to add useful functions to standard, well-accepted devices.
Valencia Koomson, PhD (above), Associate Professor, Electrical and Computer Engineering, and head of the Advanced Integrated Circuits and Systems Lab at Tufts University, has developed a pulse oximeter that measures oxygenation in tissue, rather than in blood. Her approach could ensure patients with darker skin pigmentation will be accurately diagnosed at the point-of-care. Though generally not used in clinical laboratory settings, medical technologists will be interested to learn of these new innovations in pulse oximeters. (Photo copyright: Tufts University.)
Measuring Tissues Instead of Blood
The pulse oximeter—a device that attaches to a person’s finger—uses red and infrared light to measure blood oxygen saturation (SpO2) and display pulse rate.
Studies in 2022 that looked into how hospitals administered oxygen to different patients found that inconsistent pulse oximeter readings could cause caregivers to administer less oxygen than is actually needed to people with darker skin pigmentation.
This is because melanin in the skin can interfere with “absorption of light used to measure oxygenated blood in a person’s finger,” according to a National Science Foundation (NSF) news story. Such inaccurate pulse oximeter readings can lead to “inaccurate readings and poorer treatment outcomes” for people with dark skin tones, the NSF wrote.
“Addressing this problem will require innovation in pulse oximeter design and revised regulatory standards,” said Valencia Koomson, PhD, Associate Professor, Electrical and Computer Engineering, Tufts University, Medford, Massachusetts, in the NSF news story.
Koomson, who leads the Advance Integrated Circuit and Systems Lab at Tufts, has developed a prototype pulse oximeter device, which NSF explained, measures oxygenation in biological tissues instead of blood.
“My lab’s work on pulse oximeter devices will provide an alternative technology to address many confounding factors that affect pulse oximeter accuracy, including skin pigmentation, motion artifact, and others,” Koomson said.
National Public Radio (NPR) said Koomson’s device has built-in “technology that can measure a person’s skin tone.”
“We can send more light if there’s a higher level of melanin present, so that melanin doesn’t become a confounding factor that obscures our results,” Koomson told NPR.
Another Pulse Oximeter Redesign
Another new approach to pulse oximetry was developed at Brown University in Providence, Rhode Island.
Rutendo Jakachira, Research Assistant, School of Engineering, and a PhD student in physics, turned to new optical techniques to address the challenge of oxygen saturation levels in dark skin tones, according to a Brown University news release.
Jakachira and Kimani Toussaint, PhD, Professor of Engineering and Senior Associate Dean in the School of Engineering, say they have created possibly the first LED-based light source to emit radially polarized light.
When the LED passes light through a person’s finger, the device calculates the amount of light the hemoglobin in the blood absorbed, NPR explained.
“We did a preliminary study on about five people, and although it was a small study, the results are promising,” said Jakachira, who plans a larger study and clinical trial.
Study Suggests Patients with Darker Skin May Have Received Delayed COVID-19 Care
The researchers analyzed electronic health record (EHR) data from 43,753 patients at Sutter Health in Sacramento, California, who had SpO2 measurements done between January 2020 and February 2022, and 8,735 patients seen for COVID-19 between July 2020 and February 2021 in the hospital’s emergency department.
In their AJE paper, they wrote, “We investigated whether or not pulse oximetry systematically underestimated oxygen saturation in patients who identified as NHB [non-Hispanic Black/African-American] as compared with NHW [non-Hispanic White] counterparts. We also assessed whether or not differences in oxygen saturation measurement affected hospital admission, care delivered, or return to the hospital post discharge among patients with COVID-19.
“We found evidence of differential pulse oximeter measurement error in NHB individuals, resulting in nonrandom overestimation of blood oxygenation as compared with NHW individuals. NHB individuals were also more likely to have hypoxemia [abnormally low oxygen levels in the blood] not detected by pulse oximetry.
“For NHB patients presenting in the ED with COVID-19, we found that overestimation of oxygen saturation was associated with underestimation of the need for admission and underestimation of the need for treatment with dexamethasone and supplemental oxygen. Additionally, we observed associated delays in dexamethasone initiation and initiation of oxygen supplementation.
“There are also broader implications beyond COVID-19, as differential pulse oximeter accuracy has the potential to exacerbate disparities for any condition that relies upon blood oxygenation measurement to inform clinical decision-making.”
Importance of Accurate Readings
Developing pulse oximeters that are accurate for all people, regardless of skin tone, is clearly an important breakthrough. Medical laboratory leaders and pathologists recognize that SpO2 data—along with clinical laboratory test results—are critical for successful diagnostics and treatment. Thus, new technologies that add useful functions to well-accepted devices are positive developments and worth watching.
Will health monitoring with finger rings become more popular than wrist worn devices? One company hopes the answer is yes!
Personal health monitoring devices continue to grow smaller. Now there is a company selling a smart ring that fits on an individual’s finger. Clinical laboratory managers and pathologists may find this an interesting development, particularly because it shows progress in miniaturizing diagnostic capabilities and putting them into ever-smaller devices.
At the same time, health monitoring devices are becoming increasingly popular with consumers who want to track their overall health and certain medical conditions. However, devices currently on the market generally attach at the wrist like the Apple Watch and Fitbit.
Introduced by Movano, Inc. of Pleasanton, Calif., at the 2022 CES (Consumer Electronic Show) in Las Vegas, the Movano Ring tracks “sleep, heart rate variability, body temperature, and more,” according to the company’s website. Whether clinical laboratories will be involved with this data remains to be seen.
Primarily targeted at women, the Movano Ring offers “superior health-tracking technology and the convenient form,” according to Digital Trends.
The new smart ring device is expected to be released in beta form later this year. It is similar to the Oura Ring, which was launched in 2017 by OURA, located in Oulu, Finland (US office in San Francisco).
The Movano Ring (above) will come in four styles and be available later this year. The monitoring device “measures a user’s heart rate, temperature, SpO2, calories consumed, and steps taken, among other parameters generally tracked by smart wear. However, Movano’s app is the killer feature, as it can give actionable insights to users into their health so that they can make short-term, as well as long-term, changes,” Digital Trends reported. Clinical laboratories may one day be processing data streamed from these devices if the FDA grants class II medical device designation. (Photo copyright: Movano.)
Movano Seeks FDA Clearance
In an interview with MedTech Intelligence, Movano’s CEO John Mastrototaro, PhD, said the company saw a gap in the wearables market. “There was a real lack of solutions designed specifically for women and some of the unique health challenges women face as they age.”
Cuffless blood pressure testing and blood glucose monitoring are “holy grails for wearable tech,” and Movano plans to add them over time and testing of its radio frequency, The Verge reported.
“We’re taking the regulatory side of things very seriously,” Mastrototaro told The Verge.
In a news release, Movano announced completion of a study it conducted with University of California San Francisco “to assess the accuracy of the Movano Ring’s blood oxygen saturation (SpO2) and heart rate data.
“With results that exceeded the requirements of the industry standard used by FDA for evaluating SpO2 devices, this successful study is a promising step toward the company’s goal to provide medically-validated data to consumers and healthcare professionals,” the news release stated.
Seven participants wearing Movano Ring prototypes participated in the study to test the device’s accuracy during mild, moderate, and severe hypoxia, as well as heart rate changes while they were deprived of oxygen.
Comparing data to other reference devices, the researchers found the Movano Ring resulted in a 2% margin of error, which was well below the FDA’s 4% margin of error requirement for blood oxygen saturation, the news release stated.
Ring Works with Sensors, App
Sensors embedded in the Movano Ring collect data which is available to wearers through a smartphone application.
“Data from sensors that are embedded within the ring revolve around heart rate, heart rate variability, sleep respiration rate, temperature, blood oxygen, steps, calories, and other women-centric features. We want to have the app experience where all that sensor data is going to the app,” Mastrototaro explained in an interview with Medical Device and Diagnostic Industry.
“One of our goals is to translate those measures into what it means about your overall health. We don’t want to bombard people with data … we want to distill it all down to insights for people that help them understand how activities of daily living and their lifestyle affect their overall health,” he said.
Another Smart Ring
Meanwhile, wearable health device developer OURA recently released a third-generation ring model of its Oura Ring, which Engadget called a “technical marvel.”
“Taking the sensors from a smartwatch or fitness tracker and shrinking them into a ring is worthy of enormous praise … There’s much more tech crammed in this time around … including continuous heart rate tracking, temperature monitoring, blood oxygenation, and (menstrual) period prediction,” Engadget said.
OURA developed a new SpO2 feature to help ring wearers uncover problems in breathing while sleeping. In a blog post, scientists explained: “Typically, SpO2 is measured by placing a pulse oximeter on the tip of the finger … the Oura Ring measures light reflected back from the tissue. Fingertips provide good optical characteristics for this noninvasive measurement as blood vessels have thinner walls and are more diffused.”
The Oura Ring Generation 3 costs $299 and comes in silver, black, stealth, and gold finishes. There is a $5.99 monthly membership fee, and the app is compatible with Android and Apple iOS operating systems.
Wearable Health Monitoring Device Trend on the Rise
Over the years, Dark Daily and our sister publication The Dark Report have regularly covered the growing trend of consumers using wearable technologies to monitor their own health and the health of loved ones.
It should be clear to clinical laboratory leaders that popularity of wearable monitoring devices and digital healthcare is expanding among consumers. The data collected may soon find its way into new treatments for chronic illnesses and early warnings for diagnosticians.
New device is designed to perform clinical laboratory testing by using nanoelectronic technology to measure multiple diagnostic parameters in patients’ homes
Researchers have developed yet another device that takes its readings from a patient’s internal bio-markers. This devices analyzes, then transmits the data directly to doctors’ smartphones to assist in the diagnosis and treatment of disease. Developers say use of this system may potentially enable doctors to treat patients in their homes without meeting with them in person.
Mobile Wireless System Designed to Help Patients with Chronic Illnesses
For pathologists and clinical laboratory managers, this research is another example of how technology can be used to take diagnostic testing out of centralized laboratories and put it closer to the patient. This particular miniature device is part of a mobile wireless system designed to aid the elderly and those with chronic illnesses remain independent by allowing continuous monitoring in the home and helping physicians diagnose problems including myocardial infarction early.
