How to use a blood pressure measuring instrument?

Balloon sphygmomanometer is commonly used in hospitals, and there are many instruments for measuring blood pressure in society. Generally, it is automatically measured by computers, and the accuracy varies greatly. Pay attention to it when choosing. The use method of airbag sphygmomanometer is as follows:

Tie the cuff to the upper arm, with the lower edge 2-3 cm away from the elbow socket, neither too tight nor too loose. Place the chest of the stethoscope where the brachial artery beats at the elbow. Then inflate the cuff, and when the brachial artery pulsation disappears, raise the mercury column by 2.6-4.0 kPa (20-30 mmHg).

At this time, the pressure in the cuff acts on the brachial artery through soft tissue. Because the pressure exceeds the systolic pressure of the artery, the blood vessels are squeezed. There is no blood passing through the blood vessels here, and no sound can be heard with the stethoscope.

Then slowly deflate outward from the balloon valve, so that the pressure in the gas sleeve is reduced and the mercury column is slowly reduced. When the pressure in the cuff is equal to or slightly lower than the systolic pressure, with the contraction of the heart and the ejection of blood, the blood can burst the squeezed artery, form a vortex and find the noise.

When you hear the first sound, the pressure displayed by the sphygmomanometer is the systolic pressure. Continue to deflate. During the time when the pressure in the cuff is lower than systolic pressure and higher than diastolic pressure, the heart can hear sound every time it contracts. When the pressure in the cuff is equal to or slightly lower than the diastolic pressure, the blood flow becomes smooth again and the vortex disappears. At this time, the sound suddenly weakens and disappears soon. At this time, the value displayed by the sphygmomanometer is diastolic pressure.