1. Haemodynamics Flashcards
Which side of the body does the aorta branch into the brachiocephalic trunk?
Right side
What can cause a pericardial effusion?
Bacterial infection (pericarditis)
Viral infection
Heart wall rupture if weakened by previous MI
Stab wound
Name the procedure used to drain fluid from the pericardial sac.
Pericardiocentesis
What type of muscle is present in the tunica media of arterioles?
smooth muscle
Why are coronary arteries referred to as end arteries?
They have very little anastomoses
A particular branch of coronary artery will supply a discrete region of the heart with little overlap from other vessels.
What might you notice about the heart sounds of a patient with pericarditis ?
Early stages - friction rub
Later stages - obscured apex beat, soft and distant sounds
What is the difference between plasma and serum?
Plasma - from unclotted blood, contains clotting factors
Serum - from clotted blood, does not contain clotting factors (fibrinogen)
What is the biggest determinant of peripheral resistance?
Arteriole contraction state
Which part of the body is most affected by an increase in blood viscosity?
Periphery - blood cannot reach these areas
What is the commonest cause of increased plasma viscosity (leading to whole blood viscosity increase)?
Multiple Myeloma (cancer of plasma cells)
Explain why minor changes in plasma viscosity can be used to measure the inflammatory response.
Acute phase plasma proteins, released in response to inflammation, cause small increases in blood viscosity.
Which protein is most commonly used to measure inflammation?
C-reactive protein (CRP)
Name the 2 different types of blood flow.
- Laminar
2. Turbulent
What are the characteristics of laminar flow?
Velocity is greater in the middle than in the periphery - parabolic profile.
Blood flows in streamlines
How does turbulent flow differ from laminar flow?
Blood flows in all directions in the vessel, continually mixing.
In what situations would you expect turbulent flow in a vessel?
- When the rate of blood flow becomes too great
- When it passes by an obstruction in a vessel (stenosis)
- When it makes a sharp turn
- When it passes over a rough surface (atheroma)
- When there is increased resistance to blood flow
Turbulent flow is often present after an area of stenosis.What is stenosis?
Narrowing of a vessel.
Comment on the flow of blood in a stenotic blood vessel.
Flow distal to the stenosis is decreased
Comment on the velocity of blood distal to stenosis.
Velocity distal to stenosis is increased.
Why can multiple stenosis in an artery be critical?
The blood flow will become further decreased with each stenosis.
Explain why post-stenosis aneurysms occur.
When the velocity of blood increases, energy ( velocity squared) increased, causing post-stenotic dilatation.
What noise will you hear when listening to a post-stenotic artery?
Bruit noise - turbulence.
If you can palpate the turbulent blood flow, it is called a ________.
Thrill
What is the significance of the dicrotic notch on an aortic pressure tracing?
Signified the point that the aortic valve shuts, the end of systole.
