Accuracy of blood pressure readings can be affected by many things during the measurement, such as improper cuff sizing, tight clothing, improper posture, excessive movement, stress, talking, and physical position. Follow the steps below to complete a proper blood pressure reading.

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Select the proper cuff size for the patient. If the cuff is too small or too large, you may obtain false high or low readings respectively. The cuffs have a sizing scale printed on them. After properly applying the cuff to a patient’s arm, check to see if the pointer arrow is within the size range indicator. If the pointer falls outside the range, use either a smaller or a larger cuff size as needed.

Have the patient seated comfortably, feet on the floor and back supported. Have the patient remove loose clothing or push sleeves up above the elbow. 

Allow the patient to rest for five minutes in this position before taking a blood pressure reading.

Place the blood pressure cuff snuggly on the patient’s arm. The preferred blood pressure measurement site is the left upper arm because the left arm is closer proximity to the heart. Position the cuff on the bare arm midway between the shoulder and the elbow. Position the alignment mark, the arrow, on the cuff directly over the branchial artery. The brachial artery is located on the inside of the elbow just above and to the inside of the arm.

Be sure the cuff is neither too snug nor too tight. When putting a cuff on a patient, you should be able to comfortably fit two fingers between the cuff and the arm. Also, be sure that the blood pressure hose is not kinked or twisted. While taking a blood pressure measurement, limit the movement of the cuff and the cuffed extremity.

Once the cuff is secured, raise the arm to heart level and place your arm beneath it to support it asking the patient to relax his or her arm. Palpate, feel for, the brachial pulse and place the diaphragm of the stethoscope on this spot. Listen for the brachial pulse.

Inflate the cuff, continue inflating until the pressure on the gauge is 20 to 30 millimeters of mercury above systolic. On most patients, 160 to 180 millimeters of mercury is a good starting point if you don’t know the systolic pressure.

With your stethoscope in place, open the valve slowly and allow the cuff to deflate at a rate of roughly five millimeters of mercury per second while listening. The first Korotkoff sound often sounds like a clicking or swooshing. It occurs when the pressure in the cuff is just slightly below the pressure the heart creates when contracting. Mentally record the gauge reading when you hear this first sound. This is the systolic pressure.

Continue deflating the cuff until you no longer hear any sound. Mentally record the reading on the gauge where sounds disappear. This is the diastolic pressure. At this point, you can open the valve completely to allow the cuff to deflate rapidly. If you did not hear clearly, wait at least one minute before repeating the procedure.