AHA Issues Scientific Statement on Accurate BP Measurement

The American Heart Association (AHA) has released a new scientific statement on how technicians and healthcare providers can obtain the most accurate blood pressure (BP) measurement.

“Studies have shown substantial differences in BP when measured outside versus in the office setting,” according to the researchers. “Ambulatory BP monitoring is considered the reference standard for out-of-office BP assessment, with home BP monitoring being an alternative when ambulatory BP monitoring is not available or tolerated.”

BP Measurement Training

In order to accurately measure BP, the researchers highlight certain training aspects crucial for technicians and providers:

  • Physical and cognitive competencies
    • Vision: be able to accurately see the manometer dial at eye level and read the sphygmomanometer at three feet away without straining
    • Hearing: be able to hear the Korotkoff sounds
    • Eye/hand/ear coordination: be able to simultaneously conduct cuff deflation, listen to Korotkoff sounds, and read the sphygmomanometer
  • Knowledge requirements
    • Types of observer bias
    • General techniques/measurement interpretations
    • Be aware of potential variables, such as time of day, exercise, and medication
  • Important steps to be aware of
    • Only use validated, well-maintained devices
    • Perform BP measurement in a quiet room with adequate temperature, about 72 degrees Fahrenheit
    • Make sure the patient is in proper position, does not move or talk, and does not have a full bladder at the time of measurement
  • Other skills the technician/provider should demonstrate
    • Patient positioning
    • Correct cuff size selection
    • Accurate measurement recording
    • Reporting abnormal levels

Selecting the Appropriate Cuff Size

The statement also highlights key points in determining the right cuff size, noting that “miscuffing” is the most common office BP measurement area. Undercuffing large arms makes up the majority (84%) of miscuffings.

In order to ensure accurate cuff size choice, the following recommendations are made:

  • Measure arm circumference at the midpoint of the acromion and olecranon
  • The BP cuff bladder length should be between 75% and 100% of the patient’s measured arm circumference
  • BP cuff bladder width should be half of or less (as low as 37%) of the patient’s arm circumference
  • Place the cuff on bare skin—but do not roll up shirt sleeves as this could result in a tourniquet effect

BP cuff bladder length differs for adult and large adult cuffs, and there also may be differences across manufacturers. “Individual cuffs should be labeled with the ranges of arm circumferences; lines should be added that show whether the cuff size is appropriate when it is wrapped around the arm,” according to the statement.

Body Position

A patient’s body position may also impact the reading. The AHA statement provides information on how this could vary and tips on the most appropriate position:

  • Systolic blood pressure (SBP) could be 3–10 mmHg higher if a patient is in the supine position as opposed to seated, and diastolic blood pressure (DBP) may be about 1–5 mmHg higher
  • When the arm rests on the bed in the supine position, it is below heart level
  • Supine BP measurements should have the cuffed arm supported by a pillow
  • When seated, the right atrium level is the midpoint of the sternum or fourth intercostal space
  • Without back support, SBP and DBP could be elevated by 5–15 mmHg and 6 mmHg, respectively; crossed legs could increase SBP and DBP by 5–8 mmHg and 3–5 mmHg, respectively; and readings will be too high if the upper arm is below the level of the right atrium

To read the scientific statement in full, click here.