You can measure blood pressure with a mobile phone camera. Is this APP really so “god”?

The development of technology has made people's grasp of physical conditions more timely and accurate. For example, the smart watches or bracelets that many people choose now can monitor heart rate, blood oxygen and even electrocardiogram.

▲ Picture from: Apple

However, the body data monitoring function of smart watches is still very limited, and the acquisition of many body data still requires professional instruments, such as blood pressure measurement. Although many people with chronic diseases monitor blood pressure almost every day, this work requires a blood pressure monitor to complete.

Not long ago,, a foreign company running a health platform, added a blood pressure monitor to the health tools on its app, and announced the launch of a new technology that can use the video of the user's face obtained by the camera to obtain blood pressure. data. said that the monitoring of blood pressure through cameras uses a technology called "photoplethysmography" (PPG). The principle is to use the light reflected from the human face to calculate blood pressure through artificial intelligence and deep learning algorithms. Changes in the stream to derive the data.

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There are roughly these types of blood pressure measuring instruments that are widely used at present: mercury column sphygmomanometer, electronic sphygmomanometer and barometer sphygmomanometer. The principle is basically similar. The blood flow is blocked by the wrist-arm band compressing the measurement site, and then the blood flows again by discharging the gas in the wrist-arm band, which is obtained according to the changes in the blood flow sound and vibration when the blood flows again. blood pressure data.

In the early years, the mercury column sphygmomanometer using the Korotkoff sound measurement method was more common. The upper arm was surrounded by a rubber tube. One end of the leather sleeve was connected to the pressure gauge with a rubber tube, and the other end was connected to a rubber balloon, and the stethoscope was inserted into the sphygmomanometer. in. During the measurement, repeatedly compressing the rubber to hit the balloon and blowing air into the rubber cuff will flatten the arteries of the upper arm, temporarily suspend the blood flow, and then slowly reduce the pressure.

▲ Picture from: Sanding Health Network

During the process of depressurization, monitor the sound of arterial blood vessels. When the pressure in the rubber cuff drops to a little lower than the systolic pressure of the heart pumping blood, the blood will start to flow and make a sound. The pressure at this time is the systolic pressure (again. called high pressure). Then continue to slowly release the air in the cuff and monitor the sound of blood flow. When you can't hear it, it means that the blood flow is completely unobstructed. The pressure at this time is the diastolic pressure (also known as low pressure).

It can be seen from the measurement principle that the use of a mercury column sphygmomanometer requires a certain degree of subjective judgment by the user, and the data obtained will naturally have errors. In addition, the equipment is large in size, and mercury with a certain degree of toxicity is used. , so it is gradually replaced by electronic sphygmomanometer.

Many household electronic sphygmomanometers are relatively small in size, and use the more accurate oscillometric method to measure blood pressure. Because the pulse pressure shock wave has a relatively stable correlation with blood pressure, the blood pressure measured by the oscillometric principle is more accurate than the auscultation method when the actual home blood pressure is measured.

▲ Picture from: Getty Images

Going back to's PGG (photoplethysmography) technology, in fact, this technology has been applied to some smart wearable devices to monitor data such as heart rate and blood oxygen. And the company said it would evaluate the device using the low-accuracy device standard, the international standard for blood pressure measuring devices that can be used at home.

But whether it can actually measure blood pressure, Jordana Cohen, an assistant professor of medicine at the University of Pennsylvania, said: "It is theoretically possible, but there is not enough data to show how reliable this technology is clinically."

▲ Picture from: THE VERGE

Although the current relevant data is not sufficient, I hope that the vision and expectations of this technology can be achieved in the future. If blood pressure monitoring can be completed with the help of cameras, there is no need to purchase other equipment, which can not only reduce the cost of measurement, but also make us better Mastering your own physical condition can be said to serve multiple purposes.

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