The Vascular function curve

Question 1

The equilibrium pressure when vasculature is separated from the pumping activity of the heart and equilibrium is reached

Answer 1

Mean systemic filling pressure

Question 2

What two factors effect the mean systemic filling pressure?

Answer 2

Blood volume 
Venomotor tone (Think size of the container and the amount of fluid in the container)

Question 3

How does RAP affect mean systemic filling pressure?

Answer 3

If RAP decreases then venous return should increase

Question 4

What does the plateau indicate in the vascular function curve?

Answer 4

Eventually when the RAP becomes so negative, the extra thoracic vessels begin to collapse and blood return cannot increase any more

Question 5

In order to get flow back to the heart, what two factors determine the change in pressure?

Answer 5

change in pressure = PSF - RAP

where PSF has to be greater than RAP to get flow back to the right atria

Question 6

What two factors would cause an upward shift in the vascular function curve?

Answer 6

Increased venomotor tone (SNS stimulation)
Increased volume (transfusion, bolus)

Question 7

Why is only the venous side considered when referring to the container of blood in the body?

Answer 7

Majority of the blood in the body is on the venous side, capacitance vessels

Question 8

In a patient that has heart failure, how will that affect their blood return to the heart?

Answer 8

As RAP increases vascular return decreases

Question 9

What three factors affect venous return?

Answer 9

Volume within the container
Size of the container
Arteriolar resistance