Resting blood pressure measurements can indicate signs or risks of disease. Blood pressure is comprised of systolic and diastolic pressures. Systolic pressure is the top number in a blood pressure reading and is the amount of pressure when the heart is contracting. Diastolic pressure, the bottom number, is the amount of pressure while the heart is filling with blood. It is a good idea to get into the habit of taking your own blood pressure readings. When visiting the doctor, this can give her an accurate representation of your actual vital signs throughout a normal day. Otherwise, a doctor is only exposed to your blood pressure as it is measured in her office, which for some can read unusually high. There are certain considerations to take into account when taking a blood pressure, one of which is the cuff size of the sphygmomanometer.
Equipment
There are several types of home monitoring blood pressure systems. According to the Mayo Clinic, every blood pressure monitor has three similar components: cuff, gauge and stethoscope. The cuff wraps around your arm and has an inner bladder that inflates. The gauge will display the blood pressure reading. The stethoscope allows you to listen to blood flow sounds, but not all home monitoring systems contain a stethoscope. These components comprise two types of monitors: manual or digital. It does take some skill to use a manual stethoscope. It contains all three components and is used by matching blood flow sounds to measurements of mercury. Digital monitors are more common for home use and just consist of a cuff and a digital gauge.
Process
According to "Exercise Testing and Prescription," by David Nieman, a blood pressure reading starts with the accurate position of the cuff. Place the deflated cuff about one inch above the inner elbow. If a stethoscope is also being used, it should sit just above the elbow crease and toward the inside of the arm. As the cuff is pumped, you should hear the brachial pulse. When those sounds disappear, the cuff should be pumped to 20 to 30 millimeters of mercury (mmHg) above the mark of the last sound. Deflate the cuff at a rate of two mmHg per second. As this occurs, you should be listening for the Korotkoff sounds, the auditory progress of the blood flow back to the artery. The systolic pressure is marked by the appearance of sound and the diastolic pressure is characterized by the disappearance of the sounds. If using a digital device, simply place the cuff in the correct position and tap the start button. The machine will do the rest.
Sizes
"Exercise Testing and Prescription" states that the rubber bladder of a cuff should encircle at least 80 percent of the arm. Blood pressure cuffs are sized as juvenile, adult and obese adult. Each manufacturer may have differing measurements for each size. In general, you will use a juvenile cuff for an arm with a circumference of 18 to 24 centimeters, an adult cuff for 24 to 32 centimeters and an obese adult cuff for arms sized 32 to 42 centimeters.
Importance
If a blood pressure cuff is too small, an incorrectly elevated reading will be obtained. If a blood pressure cuff is too large, an incorrectly low reading will be given. The Mayo Clinic suggests asking your doctor which cuff size is the right one for you.
Expert Insight
The correct strategy can give you a better idea of a true resting blood pressure. "Exercise Testing and Prescription" suggests taking a blood pressure reading twice and averaging the two results. A period of rest of 30 to 60 seconds between each reading should allow normal circulation to return. It is also suggested that you take the pressure in a quiet environment, with a comfortable temperature and in a seated position. The arm on which the pressure is being taken should be resting at heart level, with the palm turned up.
References
- The Mayo Clinic
- Exericse Testing and Prescription; Nieman, David C.; 2007.
