Researchers have demonstrated that the camera and flash module of a smartphone may be used to monitor blood oxygen saturation levels as low as 70%. Although the research is still in its early phases, it paves the way for a time when people may detect their blood oxygen saturation levels using readily available smartphones.
A proof-of-concept study was published in the npj Digital Medicine journal by researchers from the Universities of Washington and California, San Diego. For the technology, the researchers have submitted a patent application.
All people taking part in the study have to place their fingers on a Google Nexus 6P smartphone camera and flash module to assess their blood oxygen levels. Fresh blood flows through the portion of the finger that is lit by the flash with each heartbeat. The camera captures a video in three channels—red, green, and blue—to gauge the amount of light from the glass that is absorbed by the blood.
A deep-learning algorithm was trained using data from some of the individuals to determine blood oxygen levels from the numbers. The model was subsequently tested on the other individuals. The system not only correctly predicted blood oxygen levels, but it also did so even after the research team’s participants’ blood oxygen levels were lowered by administering a regulated blend of nitrogen and oxygen.
The use of cell phones to measure SpO2 levels has been the subject of numerous prior research, and some apps make the same claims. However, the objective of the new study was to validate these readings over the whole range of clinically significant SpO2 values.
Early in 2020, there were a few available on the app store, but by the middle of the decade, some had been taken down over worries about their accuracy. There may still be apps available, but none of them is branded as health apps and none of them has medical approval. We feel our work offers a route forward to maybe increase the accuracy in the future because these can be dangerous if consumers are unaware of the potential inaccuracy, said co-lead author Jason Hoffman in an email to indianexpress.com. Hoffman is a University of Washington PhD candidate.
Though only one smartphone model has been used to test the technology and setup thus far, the researchers are certain that in the future a wider range of phones will support it.
Additionally, the technology needs to be validated on many devices before it can be used more widely because the researchers had to modify the smartphone’s setup before using it to take measurements.
“We have to perform the research on a large scale to validate on a greater population, and then forward our data to the FDA for observation and approval if we wanted to become the first FDA-cleared test for SpO2 on an unmodified smartphone. Although we do not currently have firm plans to conduct this study, we would estimate that the entire procedure would take 18 to 24 months to complete after the start of the new study, Hoffman continued.
The study’s data collection phase took place while the Nexus 6P was a recent model, which was a few years ago. The COVID-19 pandemic’s urgency motivated the researchers, but it took a while for the researchers to see results. The paper had to go through the peer review process for two more years after that. Additionally, the method of data gathering is expensive, thus without a follow-up study, the researchers won’t have the funds to re-collect the data using a new methodology.
The paper’s co-authors are Southern Methodist University PhD student Xinyi Ding, Southern Methodist University associate professor Eric Larson, University of Washington undergraduate Caiwei Tian, and University of Washington professor Shwetak Patel. The University of Washington provided funding for the investigation.
