Blood pressure cuffs work by temporarily stopping blood flow in your arm to allow measurement of the pressure exerted by your blood against your artery walls. Here's a breakdown:
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Placement: The cuff is placed around the bare, extended upper arm.
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Inflation: The cuff is inflated to a pressure high enough to completely occlude (stop) blood flow in the brachial artery. According to the provided reference, the cuff is inflated until no blood can flow through the brachial artery.
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Deflation and Auscultation: The air in the cuff is then slowly released.
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Measuring Systolic Pressure: As the pressure decreases, the point at which blood starts flowing back into the artery is noted. This is heard through a stethoscope as a pounding sound and represents the systolic blood pressure (the pressure when the heart beats). The reference mentions that as soon as blood starts flowing into the arm, it can be heard as a pounding sound through the stethoscope.
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Measuring Diastolic Pressure: The cuff continues to deflate, and the sound eventually disappears. The point at which the sound disappears indicates the diastolic blood pressure (the pressure when the heart is at rest between beats).
Essentially, the blood pressure cuff uses controlled inflation and deflation to indirectly measure the blood pressure in your arteries.
