Green light shows promise in addressing oximetry racial bias: study

Dive Brief:

Researchers have created an oximetry device that uses green light and an algorithm to address the racial bias of existing noninvasive technologies.
Current pulse oximeters, which have biases that the Food and Drug Administration is examining, use red and infrared light to measure blood oxygen. Green light is less penetrative and, as such, researchers from the University of Texas at Arlington believe it may work better in people with darker skin.
By pairing green light with an algorithm that adjusted for melanin, the researchers created a noninvasive device that performed comparably to Abbott’s invasive i-STAT in a small clinical trial.

Dive Insight:

The researchers, writing in the British medical journal BMJ Innovations, explained how green light penetrates 2 mm to 3 mm below the skin surface. An earlier study found that the tissue penetration of green light is about 60% of that of red light. Because red light penetrates deeper, it may be affected pulsating arteries and be unable to detect early changes in tissue oxygenation because arterial desaturation takes time.

Using green light coupled to an algorithm that adapted for skin tone, the researchers found they could capture readings in situations when a commercial noninvasive pulse oximeter failed, specifically on two occasions because of cold extremities and in one case because of very dark skin.

The study, which enrolled 16 people, assessed the investigational device against the invasive i-STAT handheld blood analyzer and a noninvasive, commercially available pulse oximeter. The researchers saw a correlation between the investigational device and i-STAT, but not between the commercial pulse oximeter and i-STAT.

“We have used the green-blue light and have successfully tested the device in preclinical and clinical studies,” Vinoop Daggubati, one of the authors of the paper, said in the statement. “Our group has addressed the issues around shorter wavelength, scattering of light and the impact of skin melanin. The scientific community should open its mind to the concept of green light for these measurements.”