1.The
cuff is placed around the arm of the patient, when the cuff is inflated, the circulation in the
artery is blocked temporarily, and when the cuff is deflated, sounds are generated because
of the blood throbbing inside the artery.The cuff is placed around
the upper arm and rapidly inflated to pressure 30 mmHg above the prospective systolic
blood pressure, occluding the blood flow in the brachial artery.2.1 Auditory method
This method usually employs a mercury column, an occlusive cuff, and a stethoscope.The principle of blood pressure measurement using this technique depends on the
transmission of intra-arterial pulsations through the occluded arm.The oscillations on the arterial pressure are processed to
establish an oscillometric curve to calculate the Both numbers automatically and display the
result in the monitor.Then the cuff is deflated
gradually while the detecting system, by means of a pressure sensor, detects the
oscillometric signal step by step.The most common site for indirect measurement is the upper arm
where the brachial artery is located, although many other sites may be used.When the sounds
disappear, we have the diastolic pressure.2.