Several cautions and problems should be noted in the measurement of arterial blood pressure. The cuff must be placed at or near heart level. Placing the arm below heart level will allow gravity to exert an effect on the hydrostatic column. Consequently, the blood pressure value obtained will be higher than normal.
Wider cuffs must be used on fatty arms and on thighs, because the cuff pressure must be transmitted through the overlying skin and fat to occlude the blood vessel. If the cuff is not wide enough, the pressure is not effectively transmitted to the vessel, and the measurement of blood pressure will be inaccurate.
Prolonged cuff inflation may provoke generalized reflex vasodilation, venous congestion, and pain. This will lead to inaccurate values. A period of at least 30 sec. should be allowed between individual measurements of blood pressure, since blood flow in the limb is stopped during the time the cuff is inflated.
Blood pressure should be measured in both arms, because large differences would indicate vascular obstruction.
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