image: Blood oxygen sensor prototype created by Worcester Polytechnic Institute (WPI)
Credit: None
– The National Institutes of Health (NIH) has awarded $1.1 million to a team led by Worcester Polytechnic Institute (WPI) researcher Ulkuhan Guler to develop a first-of-its-kind wearable sensor for premature infants that will address racial bias in healthcare by monitoring oxygen levels two different ways and correcting the measurements to account for variations in skin color.
The four-year project will create a convenient, affordable, noninvasive sensor about the size of a bandage that will enable infants at risk of lung disease to leave hospitals sooner and be accurately monitored at home, said Guler, an associate professor in the Department of Electrical and Computer Engineering, and principal investigator on the project.
“Premature infants are at risk of respiratory distress, and oxygen monitoring is critical to their care so that they can leave hospitals and go home,” Guler said. “Some tools widely used at home to monitor oxygenation, however, do not accurately measure oxygen levels in infants with pigmented skin tones. There is a great need for new technology that mitigates the impact of racial bias in measurements and provides important information to the clinicians who are treating these infants.”
Guler will collaborate on the research with co-investigators Dr. Lawrence Rhein, associate professor and chair of the Department of Pediatrics at UMass Chan Medical School, and Bige Unluturk, assistant professor of electrical engineering and biomedical engineering at Michigan State University.
The researchers will develop a wireless patch with a miniaturized low-power electronic sensor that will use light to measure blood oxygen levels two different ways: A transcutaneous blood gas monitor will sense oxygen gases diffusing through the skin, and a pulse oximeter will measure reflected or refracted light to determine oxygen saturation in hemoglobin, a protein found in red blood cells.
The sensor will transmit data to a small communications hub that could be placed on an infant’s crib or carrier. A bias-mitigation algorithm to correct for inaccurate measurements in people of color will run on the hub. The researchers will integrate hardware and software into a system that will be pilot tested on adults and infants in a clinical setting.
The project addresses a complex health and equity problem. Doctors need to assess a respiratory patient’s ability to take in oxygen and distribute it to the body’s tissues. The best way to do that is by drawing blood from an artery, but the process is invasive, painful, and provides data for just one point in time.
Pulse oximeters, including those that clip onto a fingertip, use indirect methods to estimate arterial oxygen levels, but the technology has been shown to underestimate oxygenation in patients with pigmented skin. A retrospective study of 7,126 patients during the COVID-19 pandemic showed that pulse oximetry overestimated oxygen saturation among Asian, Black, and Hispanic patients compared to White patients. The overestimation led to a failure to identify Black and Hispanic patients who qualified for treatment.
A separate study of 294 premature infants showed that pulse oximetry consistently underestimated oxygen levels and hypoxemia, or abnormally low oxygen levels, in Black infants compared to White infants. In addition, Guler said, pulse oximetry fails to detect excessive oxygenation, or oxygen poisoning, in infants who receive oxygen therapy.
The researchers’ project builds on Guler’s previous work to develop better, more accurate oxygen sensors. She received a prestigious CAREER Award from the National Science Foundation in 2022 for development of a noninvasive sensor for infants that indirectly measures oxygen and carbon dioxide levels in arterial blood. Her work is the subject of several patent applications. Guler, Rhein, and Unluturk recently presented their research at “New Directions in Transcutaneous Blood Gas Monitoring,” a WPI symposium they organized.
Although the initial focus of the new research is on infants with respiratory issues, the sensor technology also could be used to monitor adults with respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD).
“Improved sensors have the potential to help many patients, not just premature infants,” Guler said. “If doctors could accurately, effectively, and continuously monitor patients at home, they could potentially discharge premature babies and adults from hospitals earlier and reunite families, which could improve health outcomes and prevent health disparities that can have lifelong consequences.”