Ultrafiltration- Final Exam Flashcards Preview

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Flashcards in Ultrafiltration- Final Exam Deck (94):
1

What is hemoconcentration?

Increase in the number of red blood cells resulting from a decrease in plasma volume

2

What does hemoconcentration increase?

HCT

3

Why is it important to know if it's whole blood or PRBCs?

Whole blood has normal HCT.

4

Conventional Ultrafiltration (CUF)

removes plasma water and low molecular weight solutes by a convective process using hydrostatic pressure forces across a semipermeable membrane

5

Zero Balance Ultrafiltration (ZBUF)

technique utilizing a hemoconcentrator to maintain a controlled equalized input and output over the CPB pump run
In=Out

6

Slow Continuous Ultrafiltration (SCUF)

technique utilizing a slow, steady ultrafiltration during the CPB pump run; slow rate over time

7

Modified Ultrafiltration (MUF)

ultrafiltration occuring after the separation from CPB

8

When were the first concepts related to the use of ultrafiltration in hospital practice?

1928

9

Where do modern hospitals incorporate ultrafiltration?

In many areas of surgical and medical therapy

10

What are two areas constantly requiring ultrafiltration as a significant part of their respective protocols of patient's management?

Medicine and surgery

11

What does ultrafiltration allow?

filtration of body water across a semi-permeable membrane utilizing a hydrostatic pressure gradient

12

What are 4 hemoconcentrator companies?

Minntech (Hemocor)
Terumo
Maquet
Sorin/Cobe

13

Where is the blood flow path in a hemoconcentrator?

Inside the hollow fibers

14

Where is the effluent path in a hemoconcentator?

Outside the hollow fibers

15

How does water get to the effluent side in a hemoconcentrator?

Letting the pressure gradient "pushes" body water to the effluent side (can be used with or without vacuum)

16

What does dialysis use?

Dialysate solution on the effluent side to control precise solute excretion

17

Diffusion

exchange of things dissolved in fluid (solutes) across a membrane due to differences in amount of the solutes on the two sides (concentration gradient)

18

What will happen if a higher concentration of a given solute is on one side?

Diffusion will try to make the concentrations the same on both sides

19

What else is ultrafiltration referred to as?

Convection

20

What is ultrafiltration?

Fluid flow through the membrane, forced by a difference in pressure on two sides of the membrane

21

Osmosis

net movement of water across a selectively permeable membrane

22

What drives osmosis?

Difference in the amounts of solute on the two sides of the membrane

23

What does osmosis refer to in dialysis?

Water movement across cell membranes (not across hemodialyzer membrane)

24

Achieving filtration across a membrane requires __________ and ____________.

Blood flow; hydrostatic pressure gradient

25

The ability of a solute to be filtered through the membrane depends on what?

The molecular weight compared to the pore size of the filter (sieving coefficient)

26

The rate of solute removal through the membrane depends on ________ and ___________.

Flow rate; transmembrane pressure (TMP)

27

What is pore size measured in?

Daltons

28

Where are pore size and transmembrane pressure (TMP) limites noted?

IFUs

29

What does a dalton quantitate?

Mass

30

Definition of a dalton.

1/12th the mass of carbon-12 nucleus

31

What is a dalton also called?

atomic mass unit (amu or u)

32

How can you convert kg to amus?

1 amu (u) = 1.6605655(86) x 10^-27

33

What does removing body water in ultrafiltration allow?

An elevation in the Hct without transfusion

34

What can you do if you have extra volume in your reservoir?

Ultrafiltration

35

When ultrafiltration is combined with other procedures it can become....

CUF, SCUF, Z-BUF, MUF

36

What is the sieving coefficient?

Ratio of blood solute concentration to plasma concentration

37

What is the range of sieving coefficient?

0 to 1.0
1.0= solute concentrations equilibrate on both sides of the membrane
0= no solute passed the membrane (large molecular weight/ size)

38

What ions/drugs have a sieving coefficient of 1.0?

K+
Mg++
Aprotinin

39

What is the sieving coefficient of Ca++?

0.55

40

What is the sieving coefficient of heparin?

0.20

41

What is the sieving coefficient of furosemide?

0.05

42

If you see pink urine on bypass, what is the first thing you should be thinking about?

Occlusions; or a lot of air/blood interface

43

What should you do if you see pink urine on bypass?

Slow down flow through hemoconcentrator; turn down vacuum

44

What makes the filter selectively permeable?

Pore size

45

Diffusion in dialysis

movement of solutes from an area in which they are in high concentration to one of a lower concentration

46

What kind of gradient is diffusion in dialysis?

Electrochemical gradient

47

Can an ultrafilter be dialysis?

Yes, but not necessarily

48

Describe the dialysis setup.

Electrolyte solution runs countercurrent to blood flowing on the other side of the membrane. Small molecules such as urea move along into the dialysate fluid. Larger molecules are poorly removed by this process. Solute removal is directly proportional to the dialysate flow rate.

49

What's more expensive? Dialysis or ultrafiltration.

Dialysis

50

What is solvent drag?

Solute is carried (in solution) across a semipermeable membrane in response to a transmembrane pressure gradient; as in convection/ultrafiltration

51

What does the rate of ultrafiltration dpeend on?

Porosity of the membrane and the hydrostatic pressure of the blood

52

Ultrafiltration is very effective at removing what size molecules? What do these cause?

Middle-sized molecules, which are thought to cause uremia (cytokines in sepsis are also middle-sized)

53

Transmembrane pressure

the pressure across the filter capillary tubes

54

Pore Size

the molecule weight cut off the filter is designed for (in Daltons)

55

Transmembrane pressure is a pressure drop (T/F).

False! Transmembrane pressure is not a pressure drop.

56

What two equations are "pressure principles"

P=QxR
TMP=[Filter P(in) + Return P(out)]/2 + [Vacuum] asbolute value of vacuum

57

TMP Membrane Capacity

+450 mmHg

58

Membrane material and type of Minntech Hemocor Hemoconcentrator

Material: Polysulfone
Type: Microporous Hollow Fibers

59

Memrane Area of Minntech Hemocor

0.3m^2

60

Pressure drop of Minntech Hemocor

61mmHg

61

Max Transmembrane pressure of Minntech HEmocor

500mmHg

62

Priming volume of Minntech Hemocor

27 ml

63

Molecule Weight Cut off Minntech Hemocor

65,000 Daltons

64

Conventional Ultrafiltration (CUF) improves potential for what?

Increasing adequate oxygen delivery to tissue (increases Hct); draws in extravascular fluid

65

Your level in the venous reservoir will drop in CUF. (T/F)

True

66

MUF may utilize the existing _________ and allows concentration of the circuit contents to be hemoconcentrated.

Cannulas

67

MUF allows post-op reduction in __________.

Total body water

68

What is considered the standard of care in pediatrics?

MUF

69

What 4 places can ultrafilters go?

Oxygenator Recirculation Line
Purge Line
Sampling Manifold
Cardioplegia Circuit

70

Sampling Manifold: ANy _______ will work

A-V Shunt

71

What's the downside of placing ultrafiltration in sampling manifold?

Small tubing, may want to increase the diameter of that tubing. Not enough flow to do a lot with and flow is key

72

What 3 parameters do we monitor in ultrafiltration?

Flow, pressure volume

73

The _________ through the ultrafilter should be monitored, it will be easier to control when a ___________ is used exclusively for the ultrafilter.

Blood flow; roller pump

74

When the blood to the ultrafilter is removed directly from the _________, flow depends on the characteristics of the ultrafilter and may be reduced by ______________.

Arterial line; partially clamping the inlet

75

The mean pressure on the inside of the fibers depends on what?

Pressure drop through the ultrafilter

76

How can we vary the TMP?

Varying the negative pressure applied

77

What negative pressures of vacuum may be applied to an ultrafilter?

100-200 mmHg

78

How can effluent flow be augmented?

Regulating the vacuum source; more vacuum equals more H20 removal

79

Greater ultrafiltration can be achieved by (3)?

1. increasing TMP
2. Partially clamping the outlet line of the ultrafilter
3. increasing in vacuum applied to the external surface of the membranes

80

CPB causes increased ___________.

Capillary permeability; including the systemic inflammatory response triggered by CPB

81

Capillary permeability propitiates and increase in what?

Increase in the total body water; affects functions of major organs.

82

What 4 organs are affected by ultrafiltration?

LUngs, heart, kidneys, brain

83

What does pulmonary edema do?

Reduce the efficiency of gas exchange

84

What does myocardial edema affect?

Ventricular function making (diastolic filling difficult and reducing the efficiency of systole)

85

The most severe systemic inflammatory response may manifest as ______________.

Multiple system organ failure (MSOF)

86

CPB activates the ________ and several _________of the plasma.

Leucocytes; proteic systems

87

Activation of leukocytes and proteic systems in plasma results in production of large number of what 3 substances?

Cytokines, complement fractions, vasoactive substances

88

WHt are the main pro-inflammatory cytokines?

Tumor necrosis alpha factor
IL-1 beta
IL-6
IL-8

89

The resides of the activation of complement system is hte activation of ______ and ______.

C3a and C5a

90

C3a and C5a with the vascular endothelium and neutrophils produce a set of alterations that result in what?

Systemic inflammatory reaction of the organism

91

What should you always be doing when you're filtering?

Watch your reservoir! You are losing volume.

92

Pink effluent is a result of ________.

too high TMP

93

_______ will increase effluent and increase hemolysis.

Vacuum

94

Why is it important to note that hemoconcentration is a shunt?

It must be off if the pump is off. Compensate for it.