A team of Canadian experts from the University of Toronto has developed a program for determining heart rate and blood pressure from video recordings of patients' faces. About the application for a smartphone, the measurement accuracy of which during the tests was almost inferior to traditional tonometers, reported in the journal Circulation: Cardiovascular Imaging of the American Cardiology Association.
The team, led by Professor of the University of Toronto Kang Lee, set the task of finding a simple solution for patients who do not want or cannot be regularly examined by a cardiologist and monitor their own blood pressure. The traditional method of monitoring using tonometers with an inflatable cuff is inconvenient, and patients tend to skip measurements, the researchers say.
- © Kang Lee / newsroom.heart.org
The proposed measurement method uses short two-minute recordings of patient faces made using a conventional smartphone. Modern gadget cameras are capable of detecting changes in the subcutaneous vessels even under ordinary lighting, and a program specially developed by scientists analyzes these changes in order to draw conclusions about the work of the circulatory system based on special algorithms and to accurately determine blood pressure.
The study involved 1328 volunteers from Canada and China. To measure the pressure, the subjects recorded two-minute video selfies and then passed them through a special program that calculates the pressure and also the heart rate. In addition, they fixed the same parameters using traditional devices.
In laboratory experiments, the results obtained using a smartphone in 95% of cases coincided with the results obtained using conventional tonometers. According to scientists, this value is within the permissible error established for medical devices by international organizations.
The authors of the work note that at the moment the results of the experiments do not allow making final conclusions about the effectiveness of the application. The videos were recorded under specially exposed lighting, which may not always be available to smartphone users. In addition, there were no people with very dark or very fair skin among the subjects. It is also noted that studies were conducted in people with normal blood pressure.
Researchers are now working to reduce the length of the video required for analysis to 30 seconds: this should also make measurements more convenient for users.
“If further studies confirm our results and determine the suitability of the proposed method for patients with pathologically high or low blood pressure, we will have at our disposal a method that will allow us to track this indicator of our health status in a non-contact, non-invasive and comfortable way. Moreover, it is likely that such measurements will be possible anytime, anywhere, ”concluded Professor Lee.