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Flashcards in hemodynamic interactions Deck (28):
1

what are venous compartments separated into?

Peripheral and central

2

What is crucial for determining how well a cv system is operating?

Cardiac filling pressure

3

What is very sensitive to small changes in pressure?

EDV

4

How much does it take to fill the circulatory system. No pressure or stretching?

3.5liters

5

What are the 2 things that affect the mean circulatory filling pressure?

1. circulating blood volume
2. state of peripheral venous tone

6

What is the amount of contents in the peripheral venous compartment?

2.5 liters

which with increase tone is added to the circulatory system!

7

Would arteries of capillaries affect other compartments with the necessary pressure?

No, their volume is small and would have a negligible effect on mean circulatory filling pressure

8

Does the presence of flow to the circuit change the total volume or mean circulatory filling pressure?

NO
- flow induced distribution
- PVS usually close to mean circulatory filling pressure

9

Which is more compliant veins or arteries?

Veins. Added blood doesnt affect pressure much

** Veins 50x more compliant

Arteries, pressures affected greatly by adding blood to arterial system

10

With flow does pressure in the peripheral venous system change much?

Nope

Flow or now flow doesnt affect mean filling pressure

11

What is a good indicator of the circulatory status?

Central venous pressure

- CV system adjusts operation continually to meet changing metabolic demands

12

Is the CV system closed or open? What are the consequences of this?

Closed

- change in pressure in one area affects pressure, flow and volume throughout the circuit

13

What consists of the central venous compartment?

Great veins of thorax and right atrium

14

What is venous return?

Rate at which blood is coming back to the central venous compartment

- should match cardiac output

15

What happens when CO doesnt match venous return?

Volume of central venous compartment must be changing

Produces change in central venous pressure

16

What is the role of CVP?

always driven to a value that makes Cardiac output = venous return

17

what essentially is the same thing as peripheral venous pressure?

Mean circulatory filling pressure

PV and CV compartment must equal the same
Q=^P/R

18

What are the 2 influences of peripheral venous pressure?

1. Changes in blood volume (increase in volume in a fixed compartment increases pressure)

2. Changes in venous tone (vasoconstriction via sympathetics)

19

When central venous pressure decreases what happens to venous return?

increases

inverse relationship

20

If pressure diff between CV and PV compartment determining venous return then??

Increase peripheral venous pressure works just as well as dropping central venous pressure on increasing venous return.

21

When are CO and VR equal to one another?

at central venous pressure of 2 mmHg

both affected by central venous pressure

22

What determines where the cardiac and venous function curves intersect?

Heart and peripheral vasculature

23

DO cardiac sympathetics affect the venous function curve?

NO

24

What is the hallmark of of CHF?

Very high central venous pressure

25

What does high central venous pressure do to a CVP CO/VR curve?

Right shift

26

What results in a left shift of the CVP CO/VR curve?

Low central venous pressure

27

What is mean circulatory filling pressure?

Hypothetical pressure related to filling of the the whole systems vasculature without stretching any of its walls or developing any internal pressure.

- Filling of the anatomical space

28

How much volume of blood do we have? How much more is this than the volume to fill the entire anatomical circuit? What would the pressure be with increased volume? (equation used)?

a. 4.5l
b. 1000
c. C=^V/^P thus P=^V/C--> P=1000/140=

- 7mmHg--> mean circ filling pressure or pressure that would result in the absence of flow!