The blood pressure measured sphygmomanometer by is (AIPG 2008)
|A||Lower than the intraarterial pressure|
|B||Higher than the intraarterial pressure|
|C||Same as the intraarterial pressure|
|D||The same with different cuff sizes|
I. The arterial blood pressure in humans is routinely measured by the auscultatory method —Korotkoff ’s sounds.
II. The cuff pressure at which the sounds are first heard is the systolic pressure.
III. As the cuff pressure is lowered further, the sounds become louder, then dull and muffled. Finally in most individuals, they disappear.
IV. The pressure at which they disappear or become muffled is the diastolic pressure.
V. Since the cuff pressure gets dissipated between the cuff and the artery by the interspersed tissues the blood pressure measured by the sphygmomanometer is always higher than the intraarterial pressure.
VI. Other points to be noted while measuring BP by sphygmomanometer are:
a. The apparatus must be always kept at the heart level.
b. Arm cuff should not be used to measure BP from lower limbs as this gives false high values.