Alternate Names: Diastolic blood pressure; Systolic BP; BP; Diastolic BP; Systolic blood pressure
How Performed: The blood pressure is usually taken while the person is seated with the arm resting on a table and slightly bent so that the arm is at the same level as the heart. The upper arm needs to be bare (with the sleeves rolled up, but not tight or uncomfortable).
Blood pressure readings are usually given as two numbers: 110 over 70 (written as 110/70). The first number is called the systolic blood pressure reading and represents the maximum pressure exerted when the heart contracts. The second number (the lower number) is called the diastolic blood pressure reading and it represents the pressure in the arteries when the heart is at rest.
To perform the blood pressure measurement, the blood pressure cuff is wrapped snugly around the upper arm and positioned so that the lower edge of the cuff is 1 inch above the bend of the elbow. The large artery on the inside of the elbow is located by feeling for the pulse. The ear piece of the stethoscope is placed in the ears and the head of the stethoscope is placed over the artery below the cuff. It should not rub the cuff or any clothing because it can make noises that will block out the pulse sounds. Correct positioning of the stethoscope is important to get an accurate recording.
The valve on the rubber inflating bulb is closed. The bulb is squeezed rapidly to inflate the cuff until the dial or column of mercury reads 30 mm Hg (millimeters of mercury) higher than the usual systolic pressure. If the usual systolic pressure is unknown, inflate to 210 mm Hg.
Now the valve is opened slightly, allowing the pressure to fall gradually (2 to 3 mm HG per second). As the pressure falls, the level on the dial or mercury tube at which the pulsing is first heard is recorded. This is the systolic pressure. As the air continues to be let out, the sounds will disappear. The point at which the sound disappears is recorded. This is the diastolic pressure (the lowest amount of pressure in the arteries as the heart rests).
The procedure may be repeated 2 or more times.
How To Prepare: The test can be done at any time. When it is performed for comparison purposes, it us usually done after resting for at least 5 minutes. One needs to have a blood pressure cuff and a device for detecting the pulse in the artery (stethoscope or microphone).
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child’s age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child’s age:
How It Feels: The pressure of the cuff on the arm is felt.
Risks: There is no risk.
Why Performed: Most people cannot sense if their blood pressure is high (hypertension) because there are usually no symptoms. High blood pressure increases the risk of heart failure, heart attack, stroke, and kidney failure. For people who have high blood pressure, it is a way of monitoring the effectiveness of medications and dietary modifications on the blood pressure.
Normal Values: Generally, the systolic pressure is approximately 120 mm Hg and the diastolic pressure is approximately 70 to 80 mm Hg.
Abnormal Results:
- Mild hypertension: diastolic pressure consistently 90 to 104 mm Hg
- Significant hypertension: systolic pressure above 200 mm Hg or diastolic pressure above 100 mm Hg
- Hypotension: blood pressure below normal
Conditions that may alter test results include:
Blood pressure readings may be affected by many different conditions, including:- cardivascular disorders
- neurological conditions
- kidney and urological disorders
- pre-eclampsia in pregant women
- phychological factors such as stress, anger, or fear
- various medications
Cost:
Special Considerations: Consult the health care provider if the measurements are consistently high or low- or if the symptoms are present at the same time as the high or low reading.
Repeated measurements are important for screening or monitoring. A single high measurement does not necessarily mean hypertension. A single normal measurement does not necessarily mean that high blood pressure is not present.
