blood pressure measurement

Question 1

what instruments are required

Answer 1

It is performed using a sphygmomanometer and stethoscope. Previously mercury sphygmomanometers were used; current practice is to use aneroid and digital models.

Question 2

first thing you do

Answer 2

W-­‐‑ Wash your hands.

I-­‐‑ Introduce yourself to the patient

P-­‐‑ Permission. Explain that you wish to measure their blood pressure and obtain
consent for the examination.

E-­‐‑ Expose the necessary parts of the patient. Sleeve rolled up
.
R-­‐‑ Reposition the patient. Blood pressure is usually measured seated. The
sphygmomanometer and the supported arm should be at the same level as the heart.

Question 3

Taking the Measurement

Answer 3

1. Choose the correct cuff size for the patient (in normal adults this is 30-­‐‑35cm in
   length and 12cm wide).
2. Position cuff in correct position with tube pointing downwards over brachial
   artery. There is usually a mark or arrow that should be lined up with the brachial
   artery.
3. Close valve.
4. Palpate radial artery and then inflate cuff until pulse disappears. This is a rough measure of systolic pressure.
5. Deflate cuff.
6. Locate brachial pulse and position stethoscope over pulse.
7. Re-­‐‑inflate cuff to 20-­‐‑30mmHg above previous reading obtained by palpation.
8. Deflate cuff slowly until regular heart sounds (Korotkoff sounds) can be heard. This is the systolic pressure.
9. Continue to deflate no faster than 1-­‐‑2 mm/Hg per second. Record the point when the sounds disappear. This is the diastolic pressure.
10. Deflate cuff fully and then remove cuff from arm.
11. Thank the patient and help to dress again if appropriate.

Question 4

Why do you put the arm at the same level as the heart?

Answer 4

Why do you put the arm at the same level as the heart?
If it was higher or lower than the heart you would get a falsely high/low blood pressure (low if arm
above heart, high if below).

Question 5

Why do you need to choose an appropriate cuff size?

Answer 5

Because if you use a cuff that is too small it has to exert a greater pressure on the arm and you’ll get
a falsely high reading.

Question 6

Why do you check the radial pulse pressure?

Answer 6

To ensure that you don’t miss an auscultatory gap.

Question 7

How would you know if someone was hypertensive?

Answer 7

In adults 160/95mmHg or more is the WHO definition of hypertension. However, as the patient may
be nervous the first time they have BP checked it should be rechecked at the end of the consultation
and again on a separate date for confirmation. You must also check for signs of retinal changes, LVH
and proteinuria.

Random facts:
Wide pulse pressure (160/30mmHg) suggests aortic incompetence

Narrow pulse pressure (95/80mmHg) suggests aortic stenosis

patients with AF are difficult to obtain a BP from as they have a variable pulse.

Question 8

What might you conclude if there was a pressure difference between the two arms?

Answer 8

A difference >20mmHg suggests arterial occlusion, eg. Dissecting aneurysm or atheroma. A
difference of 10mmHg is found in 25% of healthy people