M1 Lecture: Hemodynamics and Vascular Principles

Question 1

What is the main function of blood

Answer 1

transports oxygen to tissues

Question 2

What is the main force responsible for blood flow

Answer 2

pressure

Question 3

What is required for blood to flow

Answer 3

pressure difference

Question 4

How does blood flow

Answer 4

from areas of high to low pressure

Question 5

What is the primary propelling force for blood flow

Answer 5

the heart

Question 6

What is vasoconstriction

Answer 6

smaller vessels, results in high resistant flow

Question 7

What is vasodilation

Answer 7

larger vessels, results in lower resistant flow

Question 8

What is the best vasodilator

Answer 8

excersize

Question 9

What does low resistant flow mean

Answer 9

flow to organs that always need blood, flow always occurs when heart is pumping and at rest
ex. liver, kidneys, brain

Question 10

What does high resistant flow mean

Answer 10

when flow only occurs when the heart is pumping
ex. skeletal muscles, arteries in arms/legs

Question 11

What is the resistive index

Answer 11

an indicator of resistance to perfusion, determined by diastolic flow

Question 12

What is diastolic flow

Answer 12

flow when the heart is refilling

Question 13

What is systolic flow

Answer 13

flow when the heart is pumping

Question 14

What is the formula for resistive index

Answer 14

(PSV-EDV) / PSV

Question 15

What is PSV

Answer 15

peak systolic velocity

Question 16

What is EDV

Answer 16

end diastolic velocity

Question 17

What is triphasic flow

Answer 17

normal flow to organs that don’t require constant flow, 3 phases (foward, back, foward)

Question 18

What is biphasic flow

Answer 18

flow to organs that require moderate flow, 2 phases (upstroke, flow reversal)

Question 19

What is monophasic flow

Answer 19

1 phase (continued foward flow), does not go below baseline, low resistant flow, flows to organs that require constant flow

Question 20

What happens during inhalation in the lower extremeties

Answer 20

pressure in thorax decreases and pressure in abdomen increases

Question 21

What happens during exhalation in the lower extremeties

Answer 21

pressure in thorax increases, and pressure in abdomen decreases

Question 22

What happens during inhalation in the upper extremities

Answer 22

decreases thoracic pressure and increase in abdominal presssure

Question 23

What happens during exhalation in upper extremeties

Answer 23

increase in thoracic pressure and decrease in abdominal pressure

Question 24

what is plug flow

Answer 24

flow that travels at the same velocity and direction

Question 25

what is laminar flow

Answer 25

flow that is foward and parallel to vessel wall, flow along vessel wall is slightly slower

Question 26

what is disturbed flow

Answer 26

flow is foward but not parallel, occurs at bifurcation or stenosis

Question 27

what is turbulent flow

Answer 27

flow is random and chaotic, moves in different directions, swirling, still maintains foward direction

Question 28

what is poiseuille’s law

Answer 28

the relationship between pressure, volume flow, and resistance

Increase in resistance= increase in viscosity, increase in length of vessel, decrease in diameter (most significant)

Question 29

what is bernoulli’s principle

Answer 29

pressure and velocity are inversely proportional

increase in velocity equals a decrease in pressure and vice versa

Question 30

what is the continuity rule

Answer 30

volume flow rate must remain constant

body must adjust to maintain same amount of oxygen flow

Question 31

what is a hemodynamic significant stenosis

Answer 31

occurs when there is a 50% diameter reduction

Question 32

what is the diameter reduction equation

Answer 32

<1-(d-D)> x100

Question 33

what is D in the diameter reduction equation

Answer 33

original/true lumen

Question 34

What is d in the diameter reduction equation

Answer 34

residual lumen

Question 35

what is area reduction

Answer 35

2D measurement
measure vessel then lumen area
machine usually auto calculates this

Question 36

what is the doppler effect

Answer 36

the change in frequency of an echo relative to motion between sound source and reciever

Question 37

what is doppler shift

Answer 37

the actual changed frequency

motion toward probe= positive shift
motion away from probe= negative shift

Question 38

what is ideal doppler shift

Answer 38

when the sound beam is paralell with flow (impossible)

45-60 degree angle is used

Question 39

what is the continuous wave doppler

Answer 39

a probe that produces continuous sound wave

this is always on

2 crystals

detects any movement along sound beam

Question 40

what is the pulsed wave doppler

Answer 40

this produces soun waves in pulses

1 crystal

sends out pulse then listens for pulse to return

Question 41

what is sample volume

Answer 41

it is from a specific location

has no info about flow in other parts of vessel

placement is very important (45-60 degree angle)

Question 42

what is spectral analysis

Answer 42

when flow direction is displayed relative to transducer

Question 43

what is antegrade

Answer 43

when flow is above baseline and toward transducer

Question 44

whats is retrograde

Answer 44

flow is below baseline and away from transducer

Question 45

what is color doppler

Answer 45

it is a variation of PW doppler

angle dependent

Red=towards us
Blue=away

Question 46

what is power doppler

Answer 46

uses color to represent differences in amplitude and energy

does not indicate direction, detects any flow

not angle dependent

can detect slow flow