Blood Pressure Cuff
What is it?
A blood pressure cuff is used to take blood pressure.
The cuff has an inflatable rubber bladder that is fastened around the arm.
A pressure meter indicates the cuff's pressure.
A small, handheld air pump inflates the blood pressure cuff.
After the cuff has been inflated an air valve is used to slowly release air pressure.
As the pressure is released, a stethoscope is used to listen to arterial blood flow sounds.
The heart's beating pushes blood through the arteries causing a rise and fall of arterial pressure.
The highest pressure is called systolic pressure and is followed by a decrease in pressure.
This low blood pressure point is called the diastolic pressure.
When taking blood pressure, a stethoscope is positioned to listened to blood flow turbulence.
The cuff is initially inflated well above expected systolic pressure.
At this time, blood flow is stopped. No sounds are heard with the stethoscope.
As the value is opened, pressure slowly diminishes.
When the cuff's pressure equals the arterial systolic pressure, blood begins to flow past the cuff.
This creates blood flow turbulence and can be heard with the stethoscope.
When this sounds are initially head, the doctor or nurse makes a note of the cuff's air pressure value.
As the cuff's air is continued to be released, the blood turbulence sounds continue to be heard.
When the cuff's air pressure falls below the patient's arterial diastolic pressure, the sounds stop.
This pressure when the blood flow sounds stop indicates the diastolic pressure.
Types of Blood Pressure Cuffs
There are mercury, aneroid (a mechanical dial) and digital blood pressure cuffs.
Digital cuffs are automated while mercury and aneroid cuffs are used manually with a stethoscope.