The principle and characteristics of the watch blood pressure monitor? How to use it?
The device for measuring blood pressure is called a blood pressure monitor. There are two types of sphygmomanometers: direct and indirect. The working principles of the two sphygmomanometers are different. The direct type uses a pressure sensor to directly measure the pressure change; the indirect type works by controlling the pressure applied to the measured part from the outside, and correlates the control results with it. The information on the occurrence and disappearance of Korotkoff sounds can be judged. The former can continuously test both arteries and veins, while the latter can only measure arterial systolic and diastolic blood pressure.
How does the indirect method measure blood pressure?
Blood flows in a blood vessel like water in a smooth channel, usually without sound, but when blood or water flows through a narrow channel to form a vortex, it can make sound , The sphygmomanometer that measures human blood pressure is designed according to this principle.
At present, the clinical measurement of blood pressure adopts indirect measurement method, and the sphygmomanometer used consists of three parts: balloon, cuff and manometer. The two rubber tubes of the cuff are respectively connected with the balloon and the pressure gauge, and the three form a closed pipeline system. There are two types of pressure gauges: mercury column type and spring type.
When measuring blood pressure, first use a balloon to inflate and pressurize the cuff wrapped around the upper arm, and the pressure acts on the brachial artery through the soft tissue. When the applied pressure is higher than the systolic pressure, the balloon is slowly deflated outward, and the pressure in the cuff drops accordingly. When the pressure in the cuff is equal to or slightly lower than the systolic pressure, the Blood, the blood can flush the blocked blood vessels to form a vortex, and the pulsating sound can be heard with a stethoscope. At this time, the pressure value indicated by the manometer is equivalent to the systolic blood pressure. Continue to deflate slowly to gradually reduce the pressure in the cuff. When the pressure in the cuff is lower than the systolic pressure, but higher than the diastolic pressure, a sound can be heard every time the heart contracts. When the cuff pressure is reduced to be equal to or slightly lower than the diastolic pressure, the blood flow will resume and the sound accompanying the heartbeat will suddenly weaken or disappear. At this time, the pressure value indicated by the pressure gauge is equivalent to the diastolic pressure.
Other sphygmomanometers are also made according to this principle. But the expression is different.
