A new study is exploring whether monitoring blood oxygen levels from the ear could be more precise than current fingertip tests. Researchers at University Hospitals Birmingham are investigating a device designed to address concerns about the accuracy of traditional pulse oximeters for individuals with darker skin tones.
Fingertip pulse oximeters, widely used since the Covid-19 pandemic, work by sending light waves through the skin to estimate oxygen levels. However, research has indicated that this light can behave differently depending on skin tone, potentially overestimating oxygen levels in people with darker pigmentation, especially when levels are already low.
The new monitor, developed by EarSwitch founder Dr Nick Gompertz, shines light into the external ear canal. The developers suggest this method could be more consistent across different races because the inside of the ear canal is typically non-pigmented and closer to the core central blood supply.
As part of the testing, 29 volunteers, including Carlos Lee, an Asian man from Birmingham, participated in the clinical study. Volunteers were given slightly lower blood oxygen levels, and researchers took arterial blood samples for analysis using laboratory equipment to calibrate the device. The study aims to meet new international testing requirements for pulse oximeters, which call for at least 24 volunteers and 480 data points to ensure reliability across a wide range of people.