From asthma to Covid-19, a number of conditions may require regular blood oxygen measurements.
Currently, these measurements are taken with a pulse oximeter — a device that clamps to the tip of your finger or ear — although this can complicate the test on the go.
Hoping to make this process easier, scientists have developed a smartphone app that uses the device’s camera and flash to measure blood oxygen levels.
During testing, researchers from the University of Washington and the University of California San Diego have shown that smartphones can detect blood oxygen saturation levels down to 70% – the lowest value that the device can detect. pulse oximeter can be measured.
Scientists have developed a smartphone app that uses the device’s camera and flash to measure blood oxygen levels.
The system involves the user placing their finger on a smartphone’s camera and flash, before recording a video.
A deep learning algorithm can then decode blood oxygen levels based on the footage.
For the test, the researchers recruited six participants between the ages of 20 and 34.
Each participant wore a standard pulse oximeter on one finger, then placed the other finger on the same hand on the camera and smartphone flash.
Senior author Edward Wang said: ‘The camera is recording video: Every time your heart beats, fresh blood flows through the part illuminated by the flash.
‘The camera records how much blood absorbs light from the flash in each of the three color channels it measures: red, green and blue.
‘We can then feed those intensity measurements into our deep learning model.’
For 15 minutes, each participant inhaled a controlled mixture of oxygen and nitrogen to slowly lower their oxygen levels.
The results showed that the smartphone accurately predicted whether the subject had low blood oxygen levels up to 80% of the time.
The researchers hope to continue the study by testing the algorithm on more people.
Each participant wore a standard pulse oximeter on one finger, then placed the other finger on the same hand on the camera and smartphone flash.
Jason Hoffman, co-author of the study said: ‘One of our subjects had a thick callus on his finger, which made it difficult for our algorithm to accurately determine the oxygen concentration in their blood.
‘If we extend this study to more subjects, we will likely see more people with calluses and more people with different skin tones.
‘We could then have an algorithm with enough complexity to be able to better model all these differences.’
The researchers emphasize that most people now have a smartphone.
Dr Matthew Thompson, co-author of the study, said: “This way, you can take many measurements with your own equipment at no cost or expense.
‘In an ideal world, this information could be transmitted seamlessly to the doctor’s office.
‘This is really beneficial for telemedicine appointments or for reliever nurses to be able to quickly determine if a patient needs to go to the emergency department or if they can continue to rest. at home and make an appointment with their primary care physician afterwards.’
The study comes shortly after Huawei launched a smartwatch that can inflate around the wrist to measure blood pressure accurately, much like a cuff around the arm when a doctor does surgery.
The new Huawei Watch D has an airbag on the inside of the strap that will slowly inflate around your wrist.
Blood pressure is an important indicator of overall health, but when taken by a doctor, it can be altered by something known as the ‘white coat’ effect.
This is where the blood pressure rises slightly when we go to the doctor, due to the slight increase in anxiety about being in the clinical setting.
