Blood Pressure Cuff Needed For Accurate Measurement
The only way to determine if a person has high blood pressure is to check it periodically, at least once every two years if there are no signs of problems. However, a person diagnosed with hypertension will need it checked significantly more often. The most accurate method is with a Mercury sphygmomanometer consisting of a blood pressure cuff and the sphygmomanometer.
The blood pressure cuff is typically made of rubber or some other elastic material and designed to hold air pressure when inflated. It is connected to a rubber bulb on manual units, used to inflate the blood pressure cuff. A tube containing mercury, long considered the standard for obtaining accurate blood pressure readings will show an increase as the cuff is inflated.
The person taking the blood pressure will hold a stethoscope on the artery on the inside of the elbow and as the blood pressure cuff is inflated will listen to the blood flow through the artery. When enough pressure has been achieved to stop the blood flow, they will then slowly allow air to escape from the cuff until blood is heard flowing again, usually by a whooshing sound and make note of the pressure showing on the scale. This is the systolic pressure, the upper number that is the amount of pressure on the arterial walls when the heart is pumping.
Reducing Pressure Returns Blood Flow
When the blood flow is resumed, they will continue to listen while continuing to slowly reduce the inflation pressure in the blood pressure cuff until they can no longer hear the blood flowing. This measurement is the diastolic pressure, the lower number, and is the amount of pressure on the arterial walls when the heart is not beating. Typically noted as 120 over 80, is considered a good blood pressure reading.
Automatic blood pressure machines have been developed for home use with which the blood pressure cuff will automatically inflate and release pressure as it takes the user's blood pressure. Most cuffs are designed for a variety of users as a one-size-fits-all but there may be some who require a smaller or larger blood pressure cuff in order to obtain an accurate reading.
While automatic units are gaining in popularity due to their ease of use, there are also many things that can go wrong with them and cause inaccurate blood pressure readings, which can cause a false alarm or a false feeling of security. If using an automatic unit in the home, a doctor's office may help calibrate the unit periodically to insure proper readings.