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Flashcards in HEMODYNAMICS Deck (31):
1

poiseuille equation

- relationship of flow, pressure and resistance
- single vessel, organ

2

poiseuille equation

- flow= to pressure gradient/resistance
- P1 upstream pressure
- P2 pressure at the end of segment/circuit
- R resistance of vessel bet. P1 and P2

3

resistance is inverse to

- flow
- radius

4

the most important factor determining resistance of a vessel

- vessel radius

5

resistance is proportional ....
to but inversely proportional to flow

- viscosity
- polycythemia vera (increase viscosity and resistance, decrease flow leading to thrombosis)
- anemia (decrease viscosity and resistance, increase flow hyper dynamic flow fast rush of blood bruit)

6

50% occlusion of the left anterior descending artery

- 16x decrease in flow (r4)

7

polycythemia vera

increase viscosity and resistance,
decrease flow leading to thrombosis
an increase in hematocrit, increase in viscosity

8

turbulent flow

- murmurs
- bruits
- severe stenosis
- more resistance
- > 2000 flow

9

laminar flow

- least resistance
- good flow
- away from the wall towards the vessel
-

10

reynolds number

- diameter x velocity x density/ viscosity

11

resistance

series
parallel

12

series

- flow is dependent flow must be equal at all points
- resistance to the total series is equal to the sum of individual system
- equal flow
- Rt > Ri
- with in organs

13

parallel

- flow is independent to each other
- flow is not equal
- Rt

14

the total resistance(Rt) is always

- less than any of the individual resistance (Ri)

15

organ donor (Kidney) parallel

- as we add total becomes less
- subtract resistances the total resistance increase
- increase resistance
- flow is decrease
- CO decrease to compensate for increase BP
- HR decrease to decrease BP
- bradycardia normal for donor
- wt gain
- increase TPR, MAP

16

CO

= mean arterial pressure/TPR

17

mean arterial pressure

= CO x TPR

18

CO

= HR x SV

19

LaPlace relationship (wall tension)

- T- wall tension
- P- pressure
- r- radius
- dysfunction can lead to aneurysm

20

aorta

- is the artery with the greatest wall tension (greatest pressure while lying down and RADIUS)
- reason for aorta predispose to aneurysm
- causing dissecting aneurysm

21

increase in radius and pressure

- increase in tension agains the wall
- increase pooling of blood causing less blood goes to the heart

22

compliance

- change in volume/ change in pressure
- vessel is easily stretched
- 60 y/o has more compliance in his lung
- aging loose elasticity

23

elasticity

- inverse to compliance
- recoil
- more elasticity less compliance

24

VEINS

- 20x more compliant than arteries
- 70% of systemic blood volume
- major blood reservoir
- less elasticity(to have more compliance, has the ability to change volume) due to less muscles in the walls
- no recoil
- small change in pressure will cause a large change in volume
- have high compliance

25

veins pathophysiology

- in hemorrhage
- venous pressure decreases
- causing passive constriction of veins
- decrease blood storage
- blood is removed from the vein to the arteries to increase CO to compensate to hemorrhage
- SYMPATHETIC INNERVATION causing VASOCONTRICTION alpha 1

26

artery

- decrease in compliance
- increase radius increase flow

27

venodilator (nitrates)

- decrease in venous return
- decrease preload
- decrease flow

28

arteriolar dilator

- increase flow
- decrease in pressure in the system
- decrease TPR arteries

29

volume loading

- increase venous pressure which causes passive dissension of veins

30

hemorrhage affected VEINS

- decrease volume
- decrease pressure
- sympathetic response
- alpha 1
- constriction
- decrease pooling

31

fluid infusion, fluid overload

- increase pressure
- increase pooling of blood
- by distention of the vein
- less blood will go to the heart
- decreasing the venous return in the heart
- will cause massive dilation of the veins