Accurate Measurement of Blood Pressure in the Office

1. Preparing the Patient

  1. Explain to your patient ahead of time that you will be taking their blood pressure. Ask the patient to avoid caffeine, exercise, and smoking for at least 30 minutes before BP measurements.
  2. Before you seat the patient, ask the patient to empty their bladder, as this can cause an increase in blood pressure.
  3. Seat the patient comfortably for at least 5 minutes in a non-dental chair, with their arm slightly flexed, palm up and the entire forearm supported on a level surface, even with the heart. Feet are flat on the floor (legs not crossed) and back supported.
  4. Neither the patient or the provider should be talking during the rest period or during BP measurements.
  5. Take BP measurements over your patient’s bare arm, not over clothing.
  6. At the first visit, record BP in both arms. Use the arm that gives the higher reading for subsequent readings. It is important that the patient always be in the same position using the same arm. Differences in body position and arm used can make a difference in the reading of 10 mm Hg or more.
  7. Separate repeated measurements by 1-2 minutes.

2. Apply the Cuff

  1. Apply the completely deflated cuff to the patient’s arm, supported at the level of the heart.
  2. Place the portion of the cuff that contains the inflatable bladder directly over the brachial artery. The cuff may have an arrow to show the point that should be placed over the artery (Figure 4). The lower edge of the cuff is placed one inch above the antecubital fossa (inside crease of the elbow). The key is to fasten the cuff evenly and snugly (Figure 5).
  3. Adjust the position of the gauge for convenient reading.
  4. Palpate the area between the antecubital fossa and cuff to locate the brachial artery pulse found on the inside of the forearm. The stethoscope end piece is placed over the spot where the brachial pulse is felt (Figure 5).
  5. Position the stethoscope earpieces in your ears, with the tips directed forward.
Figure 4.
ce490 fig04 bp postition
Figure 5.
ce490 fig05 bp postition
  • The patient should be seated in a non-dental chair with feet flat on the floor (legs not crossed), with one arm resting at the level of their heart.
  • Wrap the deflated cuff around the arm snugly about 3 cm above the elbow.
  • Try to keep the cuff as flat as possible.

3. Locate the Radial Pulse

  1. On the same arm, feel the inside of the wrist, above the thumb with your index and middle fingers until you feel the pulse.
  2. Hold your fingers on the pulse.

4. Inflate the Cuff

  1. Close the needle valve (air lock) attached to the hand control bulb firmly by turning it clockwise, but not too tight so it may be released easily.
  2. Pump to inflate the cuff until the radial pulse stops. Note the mercury level at which the pulse disappears.
  3. Look at the dial, and pump to 20 or 30 mm Hg beyond where the radial pulse was no longer felt. This is called the Maximum Inflation Level (MIL). It means that the pressure of the cuff collapses the brachial artery and no blood is flowing through the artery.

5. Position the Stethoscope End Piece

  1. Place the end piece of the stethoscope over the palpated brachial artery, in the one-inch space above the antecubital fossa, and slightly toward the inner side of the arm. Hold tightly in place.
  2. It is important the stethoscope can detect sounds easily. The provider should not strain to hear sounds. If so, it is recommended stethoscope parts are replaced or the entire stethoscope is replaced if necessary.

6. Deflate the Cuff Gradually

  1. Release the air lock slowly counterclockwise 2 to 3 mm per second, so the dial drops very gradually and steadily.
  2. Listen for the first Korotkoff sound: systole (“tap, tap”). Note the number on the dial, which is the systolic pressure. This is the beginning of the flow of blood past the cuff.
  3. Continue to release the pressure slowly. The sound will continue, first becoming louder, then diminishing and becoming muffled, until finally disappearing. Note the number on the dial where the last distinct tap was heard (not the muffled sound). This number is the diastolic pressure.
  4. Let the rest of the air out rapidly.

7. Repeat for Confirmation

  1. Wait 1-2 minutes before inflating the cuff region again. More than one reading is needed to determine an average and ensure a correct reading.
  2. The new guidelines recommend an average of >2 readings be obtained on >2 occasions to estimate the patient’s level of BP.

8. Record SBP and DBP

  1. Write the date and arm used.
  2. Record systolic (SBP) and diastolic (DBP) as a fraction. Example: R Arm, Nov. 3, 20XX 120/80.
  3. The new guidelines recommend noting the time of the most recent BP medication taken by the patient before BP measurements.
  4. The new guidelines also recommend patients are provided with their SDP/DBP readings both verbally and in writing.