Watching your blood pressure might soon be as easy as a selfie video, experts say
Smartphones are already replacing cameras and landlines. Is the blood pressure cuff next?
Selfie videos that can capture blood flow beneath the skin on the face might someday help monitor patients’ blood pressure, researchers wrote in a new study published this week in the American Heart Association journal “Circulation: Cardiovascular Imaging.”
Digital sensors in smartphones can map out blood flow patterns because light penetrates the outer layer of our skin — and so-called “transdermal optical imaging models” can then be used to turn that data into blood pressure predictions, according to an American Heart Association news release on the findings.
Almost half of Americans suffer from high blood pressure, some unwittingly, the heart health organization said — meaning the innovation could make a big impact.
“High blood pressure is a major contributor to cardiovascular disease — a leading cause of death and disability,” Kang Lee, a University of Toronto professor and study lead author, said in a statement. “To manage and prevent it, regular monitoring of one’s blood pressure is essential.”
But with current tools, that watchful monitoring isn’t always happening.
“Cuff-based blood pressure measuring devices, while highly accurate, are inconvenient and uncomfortable,” Lee said. “Users tend not to follow American Heart Association guidelines and device manufacturers’ suggestion to take multiple measurements each time.”
To complete the study, researchers used iPhones loaded with transdermal optical imaging software and recorded two-minute videos of more than 1,000 Chinese and Canadian adults who had normal blood pressure — and then compared systolic, diastolic and pulse pressure measurements from the videos with readings taken using the cuff-based tool familiar from doctors’ offices.
Next the team harnessed their data to create technology that could accurately measure both pulse and blood pressure based on the blood flowing under people’s faces, researchers said. And it was a success: The team said their imaging technology was about 95 percent accurate at predicting systolic blood pressure and 96 percent accurate at predicting diastolic blood pressure. That’s a level of accuracy that meets international standards, according to the team of researchers.
“This study shows that facial video can contain some information about systolic blood pressure,” Ramakrishna Mukkamala, a Michigan State University professor and Circulation Imaging editorial author, said in a statement. “If future studies could confirm this exciting result in hypertensive patients and with video camera measurements made during daily life, then obtaining blood pressure information with a click of a camera may become reality.”
Does that mean patients will soon be checking their blood pressure from their phones in bed?
Not so fast: Selfie videos used in the research were taken in “a well-controlled environment with fixed lighting, so it’s unclear whether the technology can accurately measure blood pressure in less controlled environments, including homes,” researchers said.
The researchers also cautioned that “while the study’s participants had a variety of skin tones, the sample lacked subjects with either extremely dark or fair skin tones.”
And those aren’t the only obstacles.
“In order to improve our app to make it usable, particularly for people with hypertension, we need to collect a lot of data from them, which is very, very hard because a lot of them are already taking medicine,” Lee said in a statement released by the University of Toronto. “Ethically, we cannot tell them not to take medicine, but from time to time, we get participants who do not take medicine so we can get hypertensive and hypotensive people this way.”
Though the paper focuses on blood pressure, Lee’s work started elsewhere: He researches how kids tell lies, and originally aimed to make a phone-based lie detector, Quartz reports.
“With lie detectors, it only benefits a very small group,” Lee said. “But if I can measure blood pressure, we can benefit a lot of people.”
This story was originally published August 7, 2019 at 1:38 PM with the headline "Watching your blood pressure might soon be as easy as a selfie video, experts say."
