Measuring and Recording a Blood Pressure

Blood Pressure (BP) is one of the four vital signs you will be required to take. It is important that your recording be accurate and that you understand what the blood pressure means.

Blood PressureA measurement of the pressure that blood exerts on the walls of arteries

during various stages of heart activity.

Main factors determining blood pressure:

• Volume (the amount of blood circulating in the system)

• Force of the heartbeat

• Condition of the arteries (arteries that have lost their elasticity give more resistance)

• Distance from the heart. Blood pressure in the legs is lower than in the arms.

Pressure varies with contraction (systole) and relaxation (diastole)

of the ventricles.

Blood pressure is measured in millimeters of mercury noted mmHg

The systolic pressure reading indicates when the pressure within the arteries is greatest, during contraction of the ventricles.

Systolic pressure is the working or active phase

Diastolic pressure is the constant pressure in the walls of the arteries when the heart is at rest, or between contractions.

Blood has moved into the capillaries and veins so the volume in the arteries has decreased. (passive phase)

Blood pressure is recorded as a fraction. The systolic reading is the top number, or numerator.

The diastolic reading is the bottom number, or denominator.

Ex. A systolic reading of 120 and a diastolic reading of 80 is recorded as

120/80 mm Hg

Pulse Pressure

• Pulse pressure is the difference between the systolic and diastolic pressure.

ex. 120/80 120-80=40

40mmHg is the pulse pressure

• It is an important indicator of the health and tone of the arterial walls.

• Normal range in an adult is 30-50mmHg

What is Normal???????

• A normal systolic reading for an adult is 120 mmHg

• A normal systolic range for an adult is 100-140 mmHg

What is normal??????

• Normal diastolic reading for an adult is 80 mmHg

• The normal diastolic range for an adult is 60-90 mmHg

High Blood PressureHypertension (HTN)

• Indicated when sustained pressures are >140 mmHg systolic and >90 mmHg diastolic

HTN Causes

• Stress• Obesity• High salt intake• Aging• Kidney disease• Thyroid deficiency• Vascular and/or heart

disease

Low Blood PressureHypotension

• Indicated when sustained pressures are < 100 mmHg systolic and <60 mmHg diastolic

Hypotension Causes

• Heart Failure• Dehydration• Depression• Severe burns• Hemorrhage• Shock

Orthostatic Hypotension

• A sudden drop in both systolic and diastolic pressure when an individual moves from a lying to a sitting or standing position

• Caused by the inability of the vessels to compensate quickly to the change in position

• Temporary Sx: lightheaded, dizzy, blurred vision

Factors that may influence BP readings. These factors can cause

pressure to be high or low.

Factors that may increase BP

• Excitement, anxiety, nervous tension

• Sex of the patient (♂slightly higher than ♀)

• Stimulant drugs

• exercise and eating

Factors that may decrease BP

• Rest or sleep

• Depressant drugs

• Shock

• Excessive loss of blood

• Dehydration

Factors that may cause miscellaneous readings:

• Lying down

• Sitting position

• Standing position

Taking a Blood Pressure

The equipment

Sphygmomanometer

There are two types:

A mercury sphygmomanometer An Aneroid sphygmomanometer

Sphygmomanometer(blood pressure measuring apparatus)

• Cuff The size and placement of the cuff is important. Cuffs that are too wide or too narrow give inaccurate readings. The length of the rubber bladder should be 80% of the circumference of the arm.

• Tubes One connected to the pressure control bulb and to the bladder inside the cuff. The other tube connected to the pressure gauge.

• Pressure Gauge may be a column of mercury or a round aneroid gauge dial

• Blood pressure is measured in millimeters of mercury noted mmHg

Stethoscope

Diaphragm

Bell

Rubber Tubing

Earpieces

PROCEDURE

Taking a blood pressure

1. Assemble equipment.

2. Clean stethoscope (ear pieces and bell/diaphragm) with alcohol swab.

3.Wash hands.

4. Introduce yourself. Identify patient. Explain procedure.

Procedure cont.

5. Roll patient’s sleeve to apx. 5 inches above the elbow. Position arm so that is supported and comfortable.Palm should be up.

6. Locate brachial artery with your fingertips.

7.Wrap the cuff smoothly and snugly around the arm. Center the bladder over the brachial artery. The bottom of the cuff should be 1” above the antecubital space.

Procedure cont...

8. Place the bulb in your dominant hand and feel for the radial pulse with the fingers of your other hand. To find out how high to inflate the cuff:

Rapidly inflate the cuff until you no longer feel the pulse.

Record the palpatory systolic pressure.Ex. 120/P

Taking a BP cont….

9. Deflate the cuff completely. Ask your patient to raise his/her arm and flex fingers to promote blood flow. Wait 30 to 60 seconds to allow blood flow to resume completely.

Taking a BP cont...

10. Use your fingertips to locate the brachial artery. The brachial artery is located on the inner part of the arm in the antecubital space. Place the stethoscope over the artery. Do not use your thumb to hold the stethoscope in place. Put the ear pieces in your ears.

Taking a BP cont…

11. Gently close the valve on the rubber bulb by turning it in a clockwise direction. Inflate the cuff to 30 mm Hg above the palpatory systolic pressure.

12. Open the valve slowly and let the air escape gradually 2 to 3 mm per second.

13. Listen for the onset of at least two consecutive beats. Note where the needle is on the gauge. This is your systolic reading.

Taking a BP cont…

14. Continue deflating the cuff. The last sound you hear is the diastolic reading. Note where the needle is on the gauge. Continue to deflate the cuff.

15. Record the reading. Indicate the arm used and the position of the patient (sitting, lying, standing)

Taking a BP cont…

16. If you need to repeat the procedure wait at least 1 minute.

17. Remove the cuff and expel any remaining air. Use the alcohol to clean the stethoscope, and replace equipment.

18. Report any abnormal findings to your supervisor.

As a healthcare worker, a major responsibility is accuracy in taking and recording blood pressure. You should not discuss the reading with the patient. This is the responsibility of the physician.