Blood Pressure Measurement (BP)

Blood Pressure Measurement (BP) - sphygmomanometer

Operation:
The cuff is placed snugly around an upper arm, at roughly the same vertical height as the heart while the subject is seated with the arm supported. It is essential that the correct size of cuff is selected for the patient. Too small a cuff results in too high a pressure, while too large a cuff results in too low a pressure. For clinical measurements, it is imperative to measure both arms in the initial consultation, to determine if the pressure is significantly higher in one arm than the other. A difference of 10 mm Hg may be a sign of coarctation of the aorta. Records notes should be made as to which arm measures the highest. Afterwards, measure the higher reading arm. The cuff is inflated until the artery is completely occluded. Listening with a stethoscope to the brachial artery at the elbow, the examiner slowly releases the pressure in the cuff. As the pressure in the cuffs falls, a "whooshing" or pounding sound is heard (see Korotkoff sounds) when blood flow first starts again in the artery. The pressure at which this sound began is noted and recorded as the systolic blood pressure. The cuff pressure is further released until the sound can no longer be heard. This is recorded as the diastolic blood pressure. In noisy environments where auscultation is impossible (such as the scenes often encountered in emergency medicine), systolic blood pressure alone may be read by releasing the pressure until a radial pulse is palpated (felt).

Significance:
By observing the mercury in the column while releasing the air pressure with a control valve, one can read the values of the blood pressure in mm Hg. The peak pressure in the arteries during the cardiac cycle is the systolic pressure, and the lowest pressure (at the resting phase of the cardiac cycle) is the diastolic pressure. Systolic pressure (first phase) is identified with the first of the continuous Korotkoff sounds. Diastolic is identified at the moment the Korotkoff sounds disappear (fifth phase).

Measurement of the blood pressure is carried out in the diagnosis and treatment of hypertension (high blood pressure), and in many other healthcare scenarios.

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Education

Tags:

• Blood
• Pressure
• Measurement
• BP
• sphygmomanometer