Blood Pressure

Question 1

What is the definition of blood pressure?

Answer 1

The pressure of blood against the walls of the

main arteries

Question 2

What is systolic blood pressure?

Answer 2

The peak blood pressure in the artery

following ventricular systole (contraction)

Question 3

What is diastolic blood pressure?

Answer 3

The level to which the arterial blood

pressure falls during ventricular diastole (relaxation)

Question 4

What is hypertension?

Answer 4

High BP - above 140/90mmHg

Question 5

What is hypotension?

Answer 5

Low BP - systolic reading of less than 90mmHg

Question 6

What does mmHg mean?

Answer 6

Millimetre of mercury

Question 7

What is the name of the device used to measure BP?

Answer 7

Sphygmomanometer (said: sfigg-mom-an-om-eter)

Question 8

What is the procedure for taking a BP reading? (16 steps)

Answer 8

1. Ensure correct cuff size
2. Obtain IC
3. Encourage woman to empty bladder
4. Ensure woman is relaxed with both feet on the floor
5. Wash hands
6. Identify position of brachial artery via palpation
7. Apply BP cuff 2-3cm above brachial artery site
8. Ensure valve is closed, inflate and palpate
   radial pulse – rarely seen but is correct
   procedure.
9. Deflate cuff quickly
10. Put stethoscope on and place diaphragm over brachial artery
11. Inflate cuff 30mmHg higher than expected systolic BP, deflate slowly until ‘thudding’ is heard
12. When thudding starts, record as systolic reading
13. When thudding ends, record as diastolic reading
14. Deflate cuff and remove
15. Record findings
16. Clean equipment
    Steps 8&9 often skipped in practice

Question 9

What can high BP indicate?

Answer 9

Distressed emotional state, pre-eclampsia, recent exercise, pain, sudden change in posture, pre-existing medical conditions

Question 10

3 things BP is influenced by?

Answer 10

1. Cardiac output (amount of blood pumped in 1 min)
2. Total blood volume
3. Peripheral vascular resistance (PVR) (resistence to flow of blood, factors such as lumen diameter and blood viscosity can affect this)

Question 11

What is the tunica interna?

Answer 11

A smooth, single layer of cells called the
epithelium in direct contact with the blood. The cells are easily
damaged by hypertension or toxins such as cigarette smoke.

Question 12

What is the tunica media?

Answer 12

The middle layer comprising smooth muscle and
elastin. This area is under the influence of the sympathetic
nervous system and can initiate vasoconstriction or vasodilation.

Question 13

What is the tunica externa?

Answer 13

The outer layer comprising connective tissue
fibres that protect the blood vessels and secure them to any
surrounding tissues.

Question 14

Arteries supply the body with oxygenated blood, but there are 2 exceptions to this. What are they?

Answer 14

Pulmonary arteries from the heart - these carry deoxygenated blood to the lungs
Umbilical artery - carries deoxygenated blood from the fetus to the placenta

Question 15

Which are the largest veins?

Answer 15

The superior and inferior venae cavae.

Question 16

What do capillaries do?

Answer 16

Connect arterioles to venules. They act as a semipermeable membrane allowing the exchange of nutrients, gases and waste products.

Question 17

What are some blood pressure changes associated with pregnancy and birth?

Answer 17

Haemodynamic changes: increased blood volume, cardiac
output, heart rate and blood viscosity.
Hormonal changes: progesterone acts on smooth muscle.
Impaired venous return due to gravid uterus.

Question 18

What are the stages heard when taking a blood pressure reading, and what are they called?

Answer 18

(According to BMJ)
Phase I – a thud;
• Phase II – a blowing or swishing noise;
• Auscultatory gap – in some patients, the sounds disappear for a short period;
• Phase III – a softer thud than in phase I;
• Phase IV – a disappearing blowing noise;
• Phase V – silence: all sounds disappear

Called Korotkoff sounds