Haemodynamics

Question 1

What is serum?

Answer 1

Plasma minus the clotting factors (in particular fibrinogen)

Question 2

What can a marked increase in plasma viscosity mean for the blood as a whole?

Answer 2

Increase in blood viscosity and slugging of blood in peripheries

Question 3

What is the most common cause for increased plasma viscosity?

Answer 3

Multiple myeloma (cancer of the plasma cells)

Question 4

What is an increase in red blood cells called?

Answer 4

Polycythaemia

Question 5

What is an increase in red blood cells called?

Answer 5

Thrombocythaemia

Question 6

What is an increase in white blood cells called?

Answer 6

Leukaemia

Question 7

What can polycythaemia/thrombocythaemia/leukaemia all lead to?

Answer 7

Increased whole blood viscosity and sludging of blood in peripheries

Question 8

What is used to measure inflammation?

Answer 8

C-reactive protein (CRP)

Question 9

How can minor changes in plasma viscosity be used to measure inflammation?

Answer 9

Changes to plasma viscosity arise from raised levels of acute phase plasma proteins which increase in response to inflammation.
The two things are indirectly linked

Question 10

What is the difference between laminar and turbulent flow?

Which flow type is typical for blood?

Answer 10

Laminar- straight lines
Turbulent- all directions

Laminar

Question 11

When laminar flow occurs where does the blood have the greatest velocity? What kind of profile does this cause?

Answer 11

Centre of vessel

Parabolic profile

Question 12

When might the blood flow in a turbulent manner? (5)

Answer 12

• blood flow too great
• passing an obstruction
• sharp turns
• passing over rough surfaces
• increased resistance to blood flow

Question 13

How do we measure flow?

Answer 13

In terms of volume per unit time

Question 14

How is blood fed into the coronary arteries?

Answer 14

Due to peripheral resistance, the elastic walls of the aorta stretch. Some blood is pushed back towards the heart and into the coronary arteries. This mechanism also causes the valves to snap shut

Question 15

When does the pressure in the aorta increase during the cardiac cycle?

Answer 15

When the L ventricle ejects

Question 16

Diagrammatically speaking what is the rise in pressure in the aorta pressure tracing called?

Answer 16

Anacrotic limb (caused by LV contraction)

Question 17

Diagrammatically speaking what is the drop in pressure in the aorta pressure tracing called?

Answer 17

Dicrotic limb (LV relaxation)

Question 18

There is a blip in the dicrotic notch when looking at the aortic pressure tracing, what is this called and what causes it?

Answer 18

Dicrotic notch

Point at which the aortic valve shuts

Question 19

The shutting of the aortic valve signifies the end of what in the cardiac cycle?

Answer 19

Systole

Question 20

What is pulse pressure? (How is it calculated)

Answer 20

(The peak systolic pressure)-(end diastolic pressure)=pulse pressure

Or more commonly: systolic pressure-diastolic pressue= 120-80=40mmHg

Question 21

How can the mean arterial pressure be estimated?

Answer 21

Diastolic pressure + 1/3 of the pulse pressure

Roughly: 80 + 13 = 93mmHg

Question 22

Is the MAP falls below 70mmHg what is said to be impaired?

Answer 22

Organ perfusion

Question 23

At the beginning of diastole, what kind of flow is common particularly in the arterial peripheries? And why?

Answer 23

Retrograde flow (reverse flow)
Due to peripheral resistance- blood 'bounces back'

Question 24

If there is a constriction in a vessel, where is the pressure greatest?

Answer 24

Before the obstruction

Question 25

When there is a constriction in a vessel what happens to rate of flow?

Answer 25

It decreased after the constriction

Question 26

When there is a constriction in a vessel what happens to the velocity of the blood?

Answer 26

It is increased after the constriction

Question 27

What is a narrowing in an artery called?

Answer 27

A stenosis

Question 28

When there is a stenosis in an artery, what happens to the distal flow?

Answer 28

It is decreased

Question 29

When there is a stenosis in an artery, what happens to the distal velocity?

Answer 29

It increases

Question 30

What do you call an enlargement of an artery?

Answer 30

Aneurism

Question 31

As we get older what can happen to our arteries and what effect does this have on the pulse?

Answer 31

They calcify | Th pulse cannot be felt as well

Question 32

When you feel an artery with a stenosis in what do you feel, how do you describe this?

Answer 32

Turbulence in blood flow | Called a thrill

Question 33

When listening with a stethoscope to an artery with a stenosis, there is an abnormal sound created by turbulent flow, what is this sound called?

Answer 33

A bruit

Question 34

What two things effect the strength/volume of the pulse?

Answer 34

- force of LV ejecting blood | - pulse pressure

Question 35

What does a greater pulse pressure mean?

Answer 35

There is a stronger bulse- bounding

Question 36

What can cause a reduce pulse strength/volume causing a thread pulse? (3)

Answer 36

LV failure Aortic valve stenosis Hypovolaemia (severe hydration, bleeding)

Question 37

How can bradycardia lead to a bounding pulse?

Answer 37

It widens pulse pressure therefore pulse felt is stronger | Dicrotic limb is extended

Question 38

What effect does a lower peripheral resistance have on the diastolic pressure?

Answer 38

It lowers it

Question 39

Why do pregnant women often have lower BP?

Answer 39

Because the foetus produces lots of heat and it needs to be gotten rid of through vasodilation- lowers peripheral resistance, causing a lower diastolic pressure

Question 40

How does low peripheral resistance causes a bounding pulse?

Answer 40

It lowers diastolic pressure- widens pulse pressure- pulse volume= increased

Question 41

Why is it important to use the correct size cuff when taking BP?

Answer 41

Too small a cuff= too high a BP