How To Take Blood Pressure


Sphygmomanometers

  • sphygmomanometers (blood pressure cuffs) are used to measure blood pressure. There are three types of cuffs: aneroid (dial), mercury and digital.
  • Reading blood pressure manually, using a stethoscope is the gold standard per the NIH.
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Subject

  • Position: supine, seated, standing.
  • In seated position, the subject's arm should be flexed.
  • The flexed elbow should be at the level of the heart.
  • If patient is sitting, their feet should be flat on the floot or foot rest.
  • If the subject is anxious, wait a few minutes before taking the pressure.
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Procedures

  • To begin taking blood pressure use an appropriate blood pressure cuff size. The length of the cuff's bladder should be at least equal to 80% of the circumference of patient's upper arm.
  • Wrap the cuff around the patient's upper arm. Position the lower edge of the cuff about one inch above the antecubital fossa.
  • Lightly press the stethoscope's bell over the brachial artery just below the cuff's edge. Some health care workers have difficulty using the bell in the antecubital fossa, so you can try to use diaphragm.
  • Quickly inflate the cuff to at least 180mmHg then begin to release air from the cuff at a moderate rate (3mm/sec).
  • Observe the sphygmomanometer while listning for sounds. The first knocking sound marks the patient's systolic pressure. At the point when the knocking sound disappears, the diastolic pressure is shown on the sphygmomanometer.
  • Record the pressure and also note the subject's position and which arm was used.
  • If the patient's pressure is elevated, re-take the patient's blood pressure two additional times, waiting a few minutes between measurements.
  • A BLOOD PRESSURE OVER 180/120mmHg REQUIRES IMMEDIATE ATTENTION!
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Precautions

  • Aneroid and digital manometers may require periodic calibration.
  • Use a larger cuff on obese or heavily muscled subjects.
  • Use a smaller cuff for pediatric patients.
  • For children, lower blood pressure can indicate the presence of hypertension, so use the NIH tables.
  • Don't use the blood pressure cuff over clothing.
  • Flex and support the subject's arm.
  • In some patients the Korotkoff sounds disappear as the systolic pressure is bled down. After an interval, the Korotkoff sounds reappear. This interval is referred to as the "auscultatory gap." This pathophysiologic occurrence can lead to a marked under-estimation of systolic pressure if the cuff pressure is not elevated enough. It is for this reason that the rapid inflation of the blood pressure cuff to 180mmHg was recommended above. The "auscultatory gap" is felt to be associated with carotid atherosclerosis and a decrease in arterial compliance in patients with increased blood pressure.
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Practice

  • Use our aneroid and mercury sphygmomanometers simulators to practice your blood pressure measurement skills.
  • Then take one of our courses that feature blood pressure, auscultation, and other physical examination skills.
  • For pediatric patients, the NIH provides tables which use age, sex and height to interpret blood pressure findings. View our pediatric blood pressure drills for more information.



Blood Pressure Reading

Blood Pressure Simulator

aneroid manometer

Our blood pressure simulator allows you to practice reading arterial blood pressure. In each lesson, you will be able to practice measuring blood pressure by these steps:
1) Inflate the cuff by pressing the 'Inflate Cuff' button several times
2) Deflate the cuff by selecting one of the 'Open Valve' settings
3) Close the valve
4) Read the blood pressure values while listening for Korotkoff Sounds
5) Switch between dial and mercury sphygmomanometers

Practice taking blood pressure using our blood pressure cuff simulator.

Practice Taking Blood Pressure Simulator