Accurate and consistent blood pressure (BP) measurement is essential to CVD risk estimation k and to guiding treatment of elevated BP. There are a number of common errors in the process of BP measurement that are easy to commit in a busy primary care practice, eg, letting patients sit quietly for 5 minutes before measurement, taking multiple measurements and switching arms.
Target:BP, a quality improvement collaboration between the American Heart Association and American Medical Association, suggests that somebody in the practice take ownership of these details because slacking on proper office-based technique has real consequences.
Find out how many mm Hg your reading may be off if you don't sweat a few important details.
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If the patient's legs are crossed ... the BP reading may be off by up to 8 mm Hg. Make sure the patient's feet are flat on the floor and not crossed at the ankles, either.
If the cuff is placed over clothing … the the BP reading may be off by anywhere from 5 to 50 mm Hg. Ask the patient to remove clothing to expose the bare upper arm.
If the cuff is too small for the patient's arm ... the BP reading may be off by 2 to 10 mm Hg. Ensure the cuff you use fits properly; if an upper arm cuff does not fit, the AHA/AMA suggests you use a wrist cuff.
If the patient has a full bladder ... the BP measurement may be off by about 10 mm Hg. If a reading seems high, suggest the patient use the restroom if there wasn't time before the reading was taken.
If the patient is talking/actively listening (to you) … the BP reading may be off by up to 10 mm Hg. Remind the patient that talking and motion can affect the reading negatively and ask for silence and stillness before you begin and throughout the measurement. Remember to follow this rule yourself.
If the patient's arm is not supported ... the reading may be off by 10 mm Hg. Make sure the arm you are using to measure is resting on a hard surface with the cuff positioned at heart level.
If the patient's back and/or feet are not fully supported ... the BP measurement may be off by 6 mm Hg. Make sure the patient is not on the exam table with feet dangling and without back support, but seated in a hard-backed chair with feet flat on the floor or on a footstool.
