CPR Circulation and Hemodynamics Flashcards Preview

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Flashcards in CPR Circulation and Hemodynamics Deck (19)
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1

Which vessels have the greatest cross sectional area? Second greatest?

Capillaries
Veins

2

Which vessels hold the greatest blood volume?

Veins (~65%)

3

What does constriction of veins do?

Pushes blood into arteries to increase BP, doesn't change resistance that much

4

What does constriction of arteries/arterioles do?

Doesn't shift much blood over to veins but DOES increase resistance

5

What is the equation of velocity of blood flow?

V = Q/A
velocity = flow/area

6

What is the relationship between blood flow, pressure, and resistance?

Q = delta P/R
flow = pressure gradient/resistance

7

How are flow and resistance related?

Flow is inversely proportional to resistance

8

How is vessel radius related to resistance?

R = (8nl)/pi r^4)
R = resistance
r = vessel radius (one of main ways to regulate BP)

9

How is vessel length related to resistance?

As length increases, resistance increases (in parallel circuits total resistance decreases)

10

What is laminar flow?

Even blood flow, not turbulent

11

What is Reynolds number?

Nr = pdv/n
p= density of blood
d= diameter of vessel
v= velocity of blood
n= viscosity of blood

If Nr is >2000 then transition from laminar to turbulent flow

12

What is a bruit

Turbulent flow

13

What is compliance of blood vessels?

How easy it is for a vessel to expand, opposite of elasticity. Higher elasticity = less compliance

14

Which vessel has the highest compliance?

Veins - lowest elasticity
Arteries - lower compliance
Old arteries - very low compliance

15

What does smooth m contraction in veins do to compliance?

Decreases compliance, causes increase in pressure and shift of blood from veins to arteries

16

What is pulse pressure?

Pulse pressure = systolic - diastolic

17

What is mean pressure?

Mean pressure = diastolic + 1/3 pulse pressure
Mean pressure closer to diastolic pressure than systolic pressure

18

What is pulmonary wedge pressure?

Catheter in pulmonary artery with balloon, measure pulmonary venous circulation pressure to find left atrial pressure

19

Why is pulmonary wedge pressure important?

Helps determine extent of cardiac failure