Blood pressure is a measurement of the force that blood exerts against a vessel wall, during heartbeats. The chambers of the heart that contract to produce the systolic (top) number are called ventricles. When the ventricles relax, the diastolic pressure is the bottom number, in blood pressure measurement. Normal blood pressure, according to The American Heart Association, is less than 120 over less than 80. Some of the factors that influence blood pressure are the strength of the heartbeat, elasticity of artery walls, resistance of the capillaries and the volume of blood. Many automatic devices are available to measure blood pressure conveniently. The ability to measure another person's blood pressure with a stethoscope is a skill that requires practice.
Step 1
Support the forearm of the arm, at heart level, and with the palm of the hand turned upward. If the patient is sitting, the arm can be supported on a hard surface, such as a table top. Remove the patient's sleeve, unless it is loose and can be rolled up to at least five inches above the elbow. Make certain the sphygmomanometer cuff is completely deflated.
Step 2
Wrap the cuff evenly and securely around the upper arm, with the tubing in the front at the bottom. Make sure the lower edge of the cuff is one inch above the bend of the elbow. Smooth any velcro closures. The gauge should be positioned where it can be read easily. Place the ear tips of the stethoscope in the ears. Close the valve on the rubber bulb.
Step 3
Use fingertips to locate the strongest pulse of the brachial artery, inside the bend of the elbow. Gently position the bell of the stethoscope over this spot, making certain the entire bell is against skin and not touching the cuff.
Step 4
Squeeze the bulb quickly and inflate the cuff, until the pulsations of the artery can no longer be heard. Watch the needle on the gauge. Open the valve on the rubber bulb a tiny bit: The cuff will slowly begin to deflate.
Step 5
Listen for the first sharp, clear, rhythmic sound, and note the number indicated by the gauge's needle--this is the systolic pressure reading. As the cuff continues to deflate, listen for a sudden change in the sound to a soft muffled thump, and again note the number on the dial. This is the diastolic pressure reading. Open the valve to release all air in the cuff and let the meter fall to zero. Write down the reading, the date and time, and which arm was used.
The most accurate blood pressure is an average of three readings taken at least five minutes apart.
Tips and Warnings
- Emotions, exercise, pain and fear can cause blood pressure to rise, temporarily. However, a physician should evaluate consistent readings of more than 140 over more than 90. The blood pressure cuff should cover about two-thirds of the upper arm. Large cuffs are more accurate on obese patients.
- Seek emergency care for blood pressure that is 180 or higher over 110 or more.
Things You'll Need
- Sphygmomanometer (aneroid type)
- Stethoscope
- Paper and pencil
References
- "Modern Bedside Nursing"; Vivian Culver, R.N., 1969
- American Heart Association: Understanding Blood Pressure Readings
