Principles and Techniques of Blood Pressure Measurement

The accurate measurement of blood pressure (BP) is essential for the diagnosis and management of hypertension. Regardless of who is measuring BP or the method used (eg, auscultatory or oscillometric), the accuracy of the BP readings relies on standardized techniques and appropriate observer training. 

Principles and Techniques of Blood Pressure Measurement

Step 1: Properly prepare the patient

  1. Have the patient relax, sitting in a chair with feet flat on floor and back supported. The patient should be seated for 3–5 min without talking or moving around before recording the first BP reading. A shorter wait period is used for some automated office BP (AOBP) devices.
  2. The patient should avoid caffeine, exercise, and smoking for at least 30 min before measurement.
  3. Ensure that the patient has emptied his/her bladder.
  4. Neither the patient nor the observer should talk during the rest period or during the measurement.
  5. Remove clothing covering the location of cuff placement.
  6. Measurements made while the patient is sitting on an examining table do not fulfill these criteria.

Step 2: Use proper technique for BP measurements

  1. Use an upper-arm cuff BP measurement device that has been validated, and ensure that the device is calibrated periodically.
  2. Support the patient’s arm (eg, resting on a desk). The patient should not be holding his/her arm because isometric exercise will affect the BP levels.
  3. Position the middle of the cuff on the patient’s upper arm at the level of the right atrium (midpoint of the sternum).
  4. Use the correct cuff size such that the bladder encircles 75%–100% of the arm.
  5. Use either the stethoscope diaphragm or bell for auscultatory readings.

Step 3: Take the proper measurements needed for diagnosis and treatment of elevated BP/hypertension

  1. At the first visit, record BP in both arms.* Use the arm that gives the higher reading for subsequent readings.
  2. Separate repeated measurements by 1–2 min.
  3. For auscultatory determinations, use a palpated estimate of radial pulse obliteration pressure to estimate SBP. Inflate the cuff 20–30 mmHg above this level for an auscultatory determination of the BP level.
  4. For auscultatory readings, deflate the cuff pressure 2 mmHg/s, and listen for Korotkoff sounds.

Step 4: Properly document accurate BP readings

  1. Record SBP and DBP. If using the auscultatory technique, record SBP and DBP as the onset of the first of at least 2 consecutive beats and the last audible sound, respectively.
  2. Record SBP and DBP to the nearest even number.
  3. Note the time that the most recent BP medication was taken before measurements.

Step 5: Average the readings

  1. Use an average of ≥2 readings obtained on ≥2 occasions to estimate the individual’s BP.

Step 6: Provide BP readings to patient

  1. Provide patients their SBP/DBP readings both verbally and in writing. Someone should help the patient interpret the results.

AOBP indicates automated office blood pressure; BP, blood pressure; DBP, diastolic blood pressure; and SBP, systolic blood pressure.
*When a BP measurement is obtained in 1 arm followed by the other arm and the BP is substantially lower in the second arm, it is possible that the difference could be caused by acclimation. In this circumstance, BP should be remeasured in the first arm.

 

References:

  1. Muntner P, Shimbo D, Carey RM, Charleston JB, Gaillard T, Misra S, Myers MG, Ogedegbe G, Schwartz JE, Townsend RR, Urbina EM, Viera AJ, White WB, Wright JT Jr. Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association. Hypertension. 2019 May;73(5):e35-e66. [Medline]
  2. Whelton PK, Carey RM, Aronow WS, Casey DE Jr, Collins KJ, Dennison Himmelfarb C, DePalma SM, Gidding S, Jamerson KA, Jones DW, MacLaughlin EJ, Muntner P, Ovbiagele B, Smith SC Jr, Spencer CC, Stafford RS, Taler SJ, Thomas RJ, Williams KA Sr, Williamson JD, Wright JT Jr. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018 Jun;71(6):e13-e115. [Medline]

 

Created Nov 03, 2020.