Topic 14

Question 1

Hemoconcentration=

Answer 1

an increase in the number of red blood cells resulting from a decrease in plasma volume.
–Increases Hct

Question 2

Conventional Ultrafiltration (CUF)=

Answer 2

a technique that removes plasma water and low molecular weight solutes by a convective process using HYDROSTATIC PRESSURE forces across a semipermeable membrane

Question 3

Zero Balance Ultrafiltration (ZBUF)=

Answer 3

technique utilizing an hemoconcentrator to maintain a controlled EQUALIZED INPUT and OUTPUT
–IN = OUT

Question 4

Slow Continuous Ultrafiltration (SCUF)=

Answer 4

a technique utilizing a slow, steady ultrafiltration during the CPB pump run

Question 5

Modified Ultrafiltration (MUF)=

Answer 5

ultrafiltration occurring AFTER THE SEPARATION FROM CPB

Question 6

how is Ultrafiltration achieved?

Answer 6

(using a hemoconcentrator) in the CPB circuit and allows the filtration of body water across a semi-permeable membrane utilizing a hydrostatic pressure gradient

Question 7

Hollow Fiber Hemoconcentrators:
Blood flow path is ____ the fibers
Effluent path is ____ the fibers

Answer 7

Blood flow path is inside the fibers

Effluent path is outside the fibers

Question 8

Hemoconcentration involves letting the pressure gradient “push” body water to the effluent side, can be used with or without a?

Answer 8

vacuum

Question 9

Dialysis will use a dialysate solution on the _____ side to control precise solute excretion

Answer 9

effluent

Question 10

HOW DO ULTRAFILTERS WORK?

Answer 10

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)

Question 11

If a higher concentration of a given solute is on one side, then diffusion will try to do what?

Answer 11

make the concentrations across the membrane the same

Question 12

fluid flow through the membrane, forced by a difference in _____ on two sides of the membrane

Answer 12

pressure

–referred to as convection

Question 13

Osmosis=

Answer 13

the NET MOVEMENT OF WATER across a selectively permeable membrane

Question 14

Osmosis is driven by what?

Answer 14

a difference in the amounts of solute on the two sides of the membrane.

Question 15

In dialysis, this refers not to water movement across the hemodialyzer membrane, but across…

Answer 15

cell membranes

Question 16

Achieving filtration across a membrane requires what 2 things?

Answer 16

blood flow and hydrostatic (pressure gradient)

–Pressure /flow and resistance is key

Question 17

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

Answer 17

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

Question 18

The rate of solute removal through the membrane depends on what?

Answer 18

the flow rate and transmembrane pressure (TMP)

Question 19

A dalton quanitates mass, defined as 1/12 the mass of a carbon-12 nucleus. It’s also called the atomic mass unit, abbreviated as either “amu” or “u”. You can convert kg into u using this conversion factor:

Answer 19

1 u = 1.6605655(86) × 10-27 kg

Question 20

Removing body water will allow an elevation in the Hct without doing what?

Answer 20

transfusion

–This is what you can do when you have extra volume in your reservoir

Question 21

Sieving Coefficient=

Answer 21

Ratio of blood solute concentration to plasma concentration. Ranges from 0 to 1.0

Question 22

Sieving Coefficient of 1=

Answer 22

the solute concentrations equilibrate on both sides of the membrane

Question 23

Sieving Coefficient of 0=

Answer 23

no solute passed the membrane (large molecular weight/size)

Question 24

Sieving Coefficient of Ca++

Answer 24

0.55 (so it will dilute systemic calcium)

Question 25

Sieving Coefficient of K+

Answer 25

1

Question 26

Sieving Coefficient of Mg++

Answer 26

1

Question 27

Sieving Coefficient of Aprotinin

Answer 27

1

Question 28

Sieving Coefficient of Heparin

Answer 28

0.20 (so it will decrease your ACT)

Question 29

Sieving Coefficient of furosemide

Answer 29

0.05

Question 30

Sieving Coefficient of digoxin

Answer 30

0.75

Question 31

how do you find net pressure gradient of membrane

Answer 31

add positive and negative pressures

Question 32

what does pink effluent mean

Answer 32

red cells are being lysed so decrease occlusion or vacuum pressure

Question 33

Diffusion in dialysis=

Answer 33

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

Question 34

Diffusion in dialysis: An electrolyte solution runs _____ to blood flowing on the other side of the membrane. Small molecules such as ___ move along the into the dialysate fluid. Larger molecules are ____ removed by this process. Solute removal is _____ proportional to the dialysate flow rate

Answer 34

countercurrent urea poorly directly

Question 35

describe the process known as solvent drag

Answer 35

Convection / ultrafiltration – solute is carried (in solution) across a semipermeable membrane in response to a transmembrane pressure gradient

Question 36

Ultrafiltration: This is very effective in removal of ___ and ___, which are thought to cause ___. Moreover, most of the ____ involved in ____ are “middle molecules”

Answer 36

fluid and middle-sized molecules uremia cytokines sepsis

Question 37

Transmembrane Pressure=

Answer 37

the pressure across the filter capillary tubes

Question 38

Pore Size=

Answer 38

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

Question 39

Transmembrane pressure is NOT

Answer 39

pressure drop

Question 40

transmembrane pressure (TMP)= [formula]

Answer 40

[ (Filter P(in) + Return P(out)) / 2] + Vacuum | *Treat vacuum as an absolute number (so just drop the negative sign and treat as a positive number)

Question 41

membrane surface area ranges

Answer 41

0.09-1.3m2

Question 42

max transmembrane pressure

Answer 42

500 mmHg

Question 43

what ultrafiltration method will improve potential for increasing adequate oxygen delivery to tissue (increases Hct)

Answer 43

Conventional Ultrafiltration (CUF)

Question 44

what ultrafiltration method will Draws in extravascular fluid

Answer 44

``` Conventional Ultrafiltration (CUF) --Your level in the venous reservoir will drop ```

Question 45

what ultrafiltration method has a Slow rate over longer time

Answer 45

Slow Continuous Ultrafiltration (SCUF)

Question 46

what ultrafiltration method may utilize the existing cannulas and allows concentration of the circuit contents to be hemoconcentrated (allows post-op reduction in total body water)

Answer 46

Modified Ultrafiltration (MUF)

Question 47

what ultrafiltration method is Considered a “standard of care” in pediatrics

Answer 47

Modified Ultrafiltration (MUF)

Question 48

PRACTICE DRAWING THE DIFFERENT CIRCUITS

Answer 48

NOW :)

Question 49

with ULTRAFILTRATION 3 main parameters are critical to monitor?

Answer 49

Flow Pressure Volume

Question 50

The blood flow through the ultrafilter should be monitored, it will be easier to control when?

Answer 50

a roller pump is used exclusively for the ultrafilter

Question 51

When the blood to the ultrafilter is removed directly from the arterial line, flow depends on the characteristics of the ultrafilter and may be reduced by doing what?

Answer 51

partially clamping the inlet

Question 52

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

Answer 52

the pressure drop through the ultrafilter.

Question 53

We can vary the TMP by varying what?

Answer 53

the negative pressure applied. In general, negative pressures (vacuum) of 100 to 200 mmHg may be applied

Question 54

The effluent flow can be augmented by regulating what?

Answer 54

the vacuum source

Question 55

More vacuum equals what?

Answer 55

more H2O removal

Question 56

increased resistance (clamping) with increase effluent flow- this relationship is _____ proportional

Answer 56

directly

Question 57

greater ultrafiltration can be achieved by what 3 things?

Answer 57

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

Question 58

CPB causes increased capillary permeability, including the systemic inflammatory reaction-->Capillary permeability increases total body water-->This increase of the extravascular fluid affects the functions of what?

Answer 58

the major organs

Question 59

ultrafiltration effects on the lungs=

Answer 59

Pulmonary edema may reduce the efficiency of gas exchange and pulmonary complacency

Question 60

ultrafiltration effects on the heart=

Answer 60

Myocardial edema may affect ventricular function making (diastolic filling difficult and reducing the efficiency of systole)

Question 61

ultrafiltration effects on the brain=

Answer 61

Cerebral edema may have serious consequences

Question 62

ultrafiltration effects on the kidney=

Answer 62

Renal function may also be impaired and the renal immaturity may make elimination of liquids more difficult

Question 63

The most severe systemic inflammatory response may manifest as what?

Answer 63

multiple system organ failure (MSOF)

Question 64

CPB activates the leucocytes and several proteic systems of the plasma. Activation results in the production of a large number of what 3 things?

Answer 64

cytokines, complement fractions and vasoactive substances

Question 65

The main pro-inflammatory cytokines are? (4)

Answer 65

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

Question 66

The residues of the activation of complement system is the activation of what?

Answer 66

C3a and C5a --These substances with the vascular endothelium and neutrophils produce a set of alterations that result in a systemic inflammatory reaction of the organism

Question 67

When you filter you are losing volume- so make sure to...

Answer 67

watch your level

Question 68

Pink effluent is often a result of what?

Answer 68

too high TMP

Question 69

Vacuum will increase effluent and increase hemolysis but...

Answer 69

more is not necessarily better

Question 70

Hemoconcentration is usually a SHUNT... so you need to

Answer 70

turn it off when the pump is off (compensate for it)