Arterial blood pressure can be measured by using a sphygmomanometer (blood pressure kit). A standard blood pressure kit usually consists of an inflation bulb, a cuff, and a gauge (device to measure the pressure). The bulb is used to pump air into the cuff, and the pressure produced is indicated by the rise in the needle on the gauge. If a mercurial sphygmomanometer is used, the pressure is indicated by the rise in mercury.


To measure blood pressure, the cuff is wrapped around the upper arm. Make sure that you can fit two fingers between the cuff and the arm. Air is pumped into the cuff using the bulb until the pressure exceeds the pressure in the artery (usually, pump the bulb until just over 180 on the gauge). As a result, the vessel is squeezed closed, and blood flow is stopped. As air is slowly released from the cuff, the air pressure inside decreases and the artery opens enough for a small amount of blood to sift through. When this happens, a sound can be heard through the stethoscope. When the first sound is heard this represents the systolic pressure (make sure you record the number on the gauge when you hear this sound). You will hear loud thumps as the pressure continues to fall and eventually the sound becomes lower and lower. The final sound that is heard represents the diastolic pressure (again, making sure that you record the number on the gauge when you hear this final sound). Thus, a result of a blood pressure measurement reads like. 120/80. The upper number being the systolic pressure in mm Hg, and the lower number indicates the diastolic pressure in mm Hg.


A digital blood pressure kit consists of the main unit, the cuff, and the inflation bulb. This unit does not have a gauge. Wrap the cuff around the upper arm approximately one inch above the elbow. When wrapping the cuff, make sure you can place two fingers between the cuff and the arm. Turn on the unit and wait for the zero to appear in the display window. Using the bulb, rapidly pump air into the cuff until the pressure exceeds the pressure in the artery (cut-off pressure is normally 180mm Hg, unless the client has hypertension, in which case higher than 180mm Hg is required). Gently place the bulb down on the table and the pressure will automatically begin to decrease. Once the results appear in the window, all the air should be released from the cuff, and results should be recorded. Finally the unit should be turned off.


• Patients should rest for five minutes before taking blood pressure.

• Patients should be in a quiet area and remain completely still until the procedure is complete.

• Always have results recorded for quick and easy reference.

• Sleeves should be rolled up without cutting off circulation as this hinders a proper reading.

• Be sure to remove battery before storage, and always check to make sure the battery is working properly. It is recommended to have the unit checked every two to three years.

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