Which of the following is not true about measurement of BP?
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Correct Answer:
Diastolic pressure is indicated by Korotkoff sound
Description:
Korotkoff sounds are thought to originate from a combination of turbulent blood flow and oscillations of the aerial wall and have been classified as 5 phases. The Korotkoff sound method tends to give values for systolic pressure that are lower than the true intra-aerial pressure, and diastolic values that are higher. There is general consensus that the fifth phase or disappearance of sound should be taken as DBP, except in situations in which the disappearance of sounds cannot reliably be determined because sounds are audible even after complete deflation of the cuff, for example, in pregnant women, patients with aeriovenous fistulas and aoic insufficiency. The "ideal" cuff should have a bladder length that is 80% and a width that is at least 40% of arm circumference (a length-to-width ratio of 2:1). Cuff should be tied at the level of hea. Due to gravitational force BP decreases above the hea and increases below the hea by 0.77 mm Hg/cm. For this reason, when measurements are taken in the supine position the arm should be suppoed with a pillow. In the sitting position, the right atrium level is the midpoint of the sternum or the fouh intercostal space. The lower end of the cuff should be 2 to 3 cm above the antecubital fossa to allow room for placement of the stethoscope. Recommended deflation rate: 2 to 3 mm Hg per second Blood pressure is measure falsely high when the cuff is too small relative to the patient's arm circumference. At the initial visit, blood pressure should be measured in both arms. The patient should be instructed to relax as much as possible and to not talk during the measurement procedure; ideally, 5 minutes should elapse before the first reading is taken. In older patients with a wide pulse pressure, the Korotkoff sounds may become inaudible between systolic and diastolic pressure, and reappear as cuff deflation is continued. This phenomenon is known as the auscultatory gap.
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