February 26, 2021
CIRCUL Ring Pulse Oximeter clinical study validates efficacy and reliability in dark-pigmented participants, positioning as a superior continuous blood oxygen monitoring device for minority populations in the US and globally.
The reliability of pulse oximeters, noninvasive devices for assessing heart rate and oxygen-saturated hemoglobin, have recently been critiqued following an article published in the New England Journal of Medicine that suggested Black patients were at higher risk for hypoxemia and subsequent negative health impacts due to less accurate pulse oximeter measurements relative to those of white patients.
The CIRCUL™ Ring clinical validation study, conducted at the Tongde Hospital of Zhejiang Province, China, compared simultaneous measurements for the CIRCUL™ Ring and an arterial blood gas (ABG) test from 12 individuals (4 Black, ~33% of total enrollment). ABG test results are considered to be the most accurate method for measuring blood oxygenation levels but are more invasive due to the necessity of intravenous blood sampling. For Black individuals, 100 oxygen saturation measurements from the CIRCUL™ Ring showed excellent correlation with data obtained simultaneously from ABG testing for oxygen saturations ranging from 100% to 70%. The mean difference between CIRCUL™ and ABG values was only 1.06%.
The ongoing COVID pandemic highlights the importance of monitoring individuals’ blood oxygenation (SpO2) before, during, and after exposure or infection.
This was emphasized in a January 25, 2021 letter to the US Food and Drug Administration (FDA) by Senators Elizabeth Warren (D-Mass.), Cory Booker (D-N.J.), and Ron Wyden (D-Ore.) requesting a review of the accuracy of pulse oximeters across racially diverse patients and consumers.
The letter cites several studies suggesting pulse oximeters provide less accurate measurements for Black patients when compared to white patients, likely the result of racial bias in device calibration.
One such study found that low levels of blood oxygenation were up to three times as likely to go undetected in Black patients. The authors of that study further conclude their findings “highlight an ongoing need to understand and correct racial bias in pulse oximetry and other forms of medical technology.”
1 Oversight Letter to FDA dated January 25, 2021, “Senators Warren, Booker and Wyden Urge FDA to Address Concerns about Dangerous Pulse Oximeter Inaccuracies for Patients of Color”, https://www.warren.senate.gov/oversight/letters/senators-warren-booker-and-wyden-urge-fda-to-address-concerns-about-dangerous-pulse-oximeter-inaccuracies-for-patients-of-color