Ultrafiltration / Test 3/3 Flashcards
1
Q
3 benefits of Hemodilution ?
A
↓ Strain on Blood Banks
↓ Exposure to blood-born
pathogens.
Improved microcirculatory blood flow.
2
Q
Enormous variation in degree of hemodilution accepted:
Loma Linda ?
Bostoon ?
A
Loma Linda 5%
Bostoon 30%
3
Q
Hemodilution relies on the relationship of:
A
Oxygen delivery to
Metabolic needs of
4
Q
the study of deformation and flow of materials
A
Rheology
5
Q
Name 3 Newtonian Fluids?
A
water, saline, plasma
6
Q
Viscosity does not vary with shear rate in what fluids?
A
Newtonian Fluid
7
Q
New-Newtonian Fluid ?
A
Blood
8
Q
Viscosity decreases with increasing shear rate with what fluids?
A
New-Newtonian Fluid
9
Q
If were not supplying enough oxygen what is the c\body producing ?
A
Lactic Acid
10
Q
Velocity Gradient AKA ?
A
Shear Rate
11
Q
For a given fluid, the velocity gradient varies with ?
A
the amount of force applied (shear stress)
12
Q
Viscosity =
A
shear stress/shear rate
13
Q
During Physiological Effects of Hemodilution, what must be considered ?
A
Viscocity
14
Q
Flow (C.O.) =
A
Perfusion Pressure
______________________
Total peripheral resistance
15
Q
Flow =
A
Perfusion Pressure
____________________
Resistance x Viscosity
16
Q
When you ↓ temp you ↑ Viscosity.
What should you do?
A
↑ Hemodilution
17
Q
Decreased O2 in the microcirculatory system is offset by what?
A
↑ Flow in the capillaries from ↓ viscosity.
18
Q
Hemodilution Rationale for CPB
A
Reduce donor exposure
Optimize Cerebral perfusion
19
Q
Advantages of Hemodilution
A
↓ viscosity
↓ exposure to homologous blood
↑ Regional Flow
↑ O2 delivery
20
Q
Adverse effects of hemodilution
A
- Reduced concentration of vital substances
- Extracellular/interstitial fluid accumulation
- Redistribution of coronary blood flow
- Intra-pulmonary shunting
21
Q
What population is more susceptible to fluid overload and capillary leak ?
A
Neonates
22
Q
Natural ultrafilter
(glomerular basement membrane) statistics?
A
5 x 10^6 hollow capillaries
8 x 10^-4 cm
parallel & interconnecting configuration
23
Q
Artificial ultrafilter (hemofilter) statistics ?
A
4000-12,000 hollow fibers
.02 cm
parallel configuration
24
Q
Natural and Artificial ultrafilters both produce an ?
A
Albumin Free filtrate containing electrolytes and metabolic wastes
25
Size of Albumin ?
68,000 daltons
26
The Ideal Ultrafiltration Material Should have the following 3 characteristics:
Good biocompatibility
No passage of Albumin
High Plasma water flux
27
Membrane Materials are formulated from a
| wide range of thermoplastics, name 6?
```
Polysulfone
Polyestersulfone
Polyacrylonitrile (PAN)
Polyamide
Polymethyl methacylate
Cellulose triacetate
```
28
During Fiber Manufacturing Thermoplastic Polymer is dissolved in a solvent, then
Precipitation of the polymer is accomplished by exposure with a non-solvent. This describes what phase ?
Phase Inversion
29
During Fiber Manufacturing the PRECIPITATION step Determines the membrane structure and permeation properties, describe this ?
solvent/polymer ratio
resin/non-solvent ratio
casting temperature
30
In regards to the Anatomy of a Hollow Fiber, the inner diameter is ?
200 um
31
In regards to the Anatomy of a Hollow Fiber, the wall thickness is ?
75 - 150 um
32
The Anatomy of a Hollow Fiber is Divided into two domains, what are they?
Skin AKA Active layer (inner)
Substrate Layer ( body)
33
Within a hollow fiber, what controls all transport related activities?
Skin Layer because it contains the pores.
34
Large porous (micron sized) structure that gives mechanical support & strength to the hollow fiber?
Substrate Layer
35
Polyamide Hollow Fiber wall thickness?
50 um
36
Membrane surface area can be altered by changing:
of fiber in a bundle
Length of fibers
Fiber diameter
37
What ultrafilter would I use for cytokine removal ?
Polyacrylonitrile (PAN)
38
Molecular Weight Cut Off can vary from material to material and within each polymer depending on formulation
Typical range in CPB application:
55,000 - 65,000 daltons
39
standard unit that is used for indicating mass on an atomic or molecular scale
Dalton
40
Minntech Polysulfone
&
Jostra Polyamide
Daltons ?
55,000 Daltons
41
Bentley Polysulfone
| Daltons ?
60,000 Daltons
42
COBE PAN
| Daltons ?
65,000 Daltons
43
5 Factors affecting Filtration
```
Pore size
Surface charge
Hydrostatic pressures
protein adsorption
protein interactions
```
44
Sieving coefficient =
[conc] ultrafiltrate
______________
[conc] filter inlet
conc = concentration of whatever where looking at.
45
K+
Aprotitnin
Mg++
Sieving coefficients ?
1.0
Freely crosses
46
Ca++
| Sieving coefficients ?
.55
| Protein bound
47
Heparin Sieving coefficients?
.20
| Protein bound
48
Fentanyl Sieving coefficients?
.28
| Protein bound
49
Midazolam Sieving coefficients?
.06
| Protein bound
50
For drugs that are highly protein bound, what was the primary factor limiting drug sieving?
protein binding
51
Sieving properties of what membranes tend to be different from the other materials?
PAN
52
Early 1990’s: Gomez/Grootendorst/Lee suggested what?
filtering blood of septic animals may remove several mediators simultaneously.
53
When examining the data dealing with mediator removal several things must be consisdered:
- Complement & cytokines are “middle molecules” 10 - 20 kD
- Behavior of these molecules in-situ
- Type of membrane used
54
PreBypass Ultrafiltration ?
Pre-BUF
55
During CPB Ultrafiltration:
CUF
DUF
Z-BUF
56
CUF
Conventional Ultrafiltration
57
DUF
Dilutional Ultrafiltration
58
Z-BUF
Zero-Balance Ultrafiltration
59
After CPB Ultrafiltration:
Modified Ultrafiltration:
| MUF
60
Modified Ultrafiltration breaks down into two other categories?
AV MUF
| VV MUF
61
Conventional ultrafiltration ?
Removal of volume
62
PRE-BUF results in a more ?
Physiologic Prime
```
↓ potassium levels
↓ glucose levels
↓ lactate levels
↓ bradykinin levels
↓ ammonia levels
↑ pH levels
```
63
PRE-BUF Rationale:
The substrate load of the pump priming fluid has a major influence on the metabolic response of children during cardiac surgery and may be ?
neurologically detrimental
64
PRE-BUF - Rationale:
| The addition of banked blood to pump prime elevates what?
```
↑ primed potassium
↑ Glucose
↑Bradykinin
↑ Citrate
↑ Lactate levels
```
65
```
PRE-BUF - Rationale:
What determines the level of any one of these substances.
potassium levels
glucose levels
lactate levels
bradykinin levels
ammonia levels
pH levels
```
The AGE of banked blood
66
BLOOD STORAGE LESION : As the RBC metabolize glucose during storage, what happens ?
↑ [ H+]
| ↓ pH over time
67
BLOOD STORAGE LESION: As the pH decreases during storage, what happens
↓ in 2,3 DPG
| = Release of O2 to tissues will decrease
68
Within 3-8 hours after transfusion previously stored RBC will regenerate ___ of normal 2,3 DPG levels
50%
69
BLOOD STORAGE LESION: As the blood sits in storage, red cells lyse over time causing what?
↑ K+ in the unit
70
BLOOD STORAGE LESION: What does not function in the cold temperatures which will result in K not being pumped into the RBC ?
Na/K+ pump
71
BLOOD STORAGE LESION: What gradually decreases as RBC use it for glycolysis?
ATP
72
What do you use to “Wash” the blood prime of the circuit at Duke ?
1 liter of Normosol R +
500 units of heparin
25 mEq. NaHCO3
73
Manage intraoperative volume and Increase hematocrit during an intraoperative procedure using what ?
Conventional Ultrafiltration
74
4 Technical considerations for the use of conventional ultrafiltration ?
- Adequate volume
- Arterial line shunt may reduce blood flow to pt.
- Level Detector
- Aggressive CUF = inadequate volume for weaning from CPB.
75
Rationale for High-Volume Hemofiltration during CPB?
```
↓ edema
↑ Hemodynamics
↑ Hct
- Remove certain
inflammatory mediators
- Improvement in lung
compliance
- Reduction in postoperative blood loss
```
76
High volume hemofiltration improves RVEF and cardiac performance by ?
Removal of vasoactive mediators responsible for myocardial depression.
77
Which are the kissing cousins and are very similar in a lot of ways?
Zero-Balance
&
Dilutional Ultrafiltration
78
Z-BUF Composition of Replacement Solution?
```
To 1 Liter Normosol-R, add;
25 mEq NaHCO3
500 units heparin
2 ml 50% glucose
2.8 ml CaCl2 (warming)
```
79
Use High-Volume, Zero-Balanced Hemofiltration to ?
Reduce Delayed Inflammatory Response to Cardiopulmonary Bypass in Children
80
Significant removal of TNF, IL-10, C3a and myeloperoxidase observed at end of bypass and Markedly lower levels (TNF, IL-1B, IL-6) at 24 hr describes what method of ultrafiltration ?
Z-BUF
81
Dilutional and Modified Ultrafiltration Reduces Pulmonary Hypertension After Operations for ?
Congenital Heart Disease
82
High-Volume, Continuous Hemofiltration braches out into 2 other groups, name them?
(Z-BUF, DUF)
83
Combination of HVHF and MUF shows to be more effective in ?
Although beneficial effects may be more pronounced in high-risk patient groups.
- Reducing capillary leak
| - May reduce delayed inflammatory response
84
Z-BUF Technique?
2 tubings inserted in single, dual roller pump:
- 1 from ultrafiltrator port
to collection waste
reservoir.
- 1 from replacement solution to cardiotomy reservoir.
Blood flowrate: 200ml/min/m2
Ultrafiltration rate: 3000-6000 ml/m2
85
CURT definition ?
Continuous Ultrafiltration Replacement Therapy.
86
What type of ultrafiltration is popular with the pediatric population ?
MUF
87
Babies are more susceptible to what ?
Capillary leak
88
What are 4 great characteristics of MUF?
↓ TBW/Edema
↑ hemodynamics
↓ need for blood products
↓ circulating cytokines
89
Modified Ultrafiltration Attenuates what in Pediatric Open Heart Operations?
Dilutional Coagulopathy
90
attenuate definition
reduce the force, effect, or value of:
91
Only 42% of Pediatric centers are using ?
MUF
92
3 Published Modes of MUF ?
1) AV MUF “Classical /
dominate method”
2) VV MUF
3) VA MUF
93
With which modes of MUF must we avoid retrograde flow in the arterial line?
VV MUF
| VA MUF
94
Re-circulation line around oxygenator
| > Pump > Right Atrium describes what method of MUF ?
AV - MUF
95
Benifits of using the blood cardioplegia system (BCPS) to MUF ?
```
- Has a heat exchanger
to prevent cooling
- Acts as a bubble trap
- Allows for convenient
pressure monitoring
- Pressure relief shunt
```
96
What if you don’t use blood cardioplegia?
- Consider VV-MUF
- Select a pump to act
as a “MUF Pump”
- Take steps to prevent patient cooling
97
When using the blood cardioplegia system, where should you position the hemoconcentrator ?
between the roller pump and heat exchanger
98
Non-BCPS users should invert hemoconcentrator prior to MUF to ?
optimize bubble trapping.
99
Transitioning from CPB to MUF, Before termination of CPB:
```
- Completely de-air
MUF circuit
*BCPS users*
- warm heater-cooler
- clamp out crystalloid
portion
- chase out residual BCSP
- Ready servo-regulation and/or safety devices
```
100
Transitioning from CPB to MUF, Termination of CPB in usual manner then: 5 steps
- Surgeon attaches MUF infusion line to right atrial access and indicates “You can MUF”.
- Clamp out arterial line (filter if applicable).
- Communicate with MD’s on desired filling pressures.
- Begin MUF pump flow
- Open ultrafiltrate line
101
MUF Flow Rates For neonates and infants ?
Index Flow Rates to Weight.
15 - 30 cc/kg/min
102
As volume is being removed, it will become necessary to titrate in circuit volume to maintain the desired filling pressures. In general, it is best to set MUF pump at ?
Constant
103
Increase or decrease the arterial pump to adjust filling pressures up or down. The arterial pump should ?
not exceed the flow rate of the MUF pump.
104
A good practice is to begin MUF conservatively, with little or no vacuum applied to the hemoconcentrator.
After MUF flows are established and stable, vacuum can be increased slowly to ?
180 mmHg.
105
The number one problem that can happen is when a negative arterial line pressure occurs and cavitates air out of solution or pulls air across the membrane oxygenator. (AV-MUF)
What should you monitor?
Monitor arterial line pressures like a hawk!!!
If possible, Servo-regulate the MUF pump to stop if a negative arterial line pressure develops.
106
Monitor MUF circuit pressures for ?
over-pressurization
107
What gives you actual data regarding direction and rate of flow in arterial line. Allows fine tuning during MUF.
Flowmeter attached to the arterial line
108
When do you stop MUFing?
| For “end-point” use a combination of:
-Duration 15-20 minutes
-Complete salvage of
circuit contents
- Increased HCT
- Surgeon’s patience
109
When would you consider the need to add a one way check valve in the circuit to prevent exsanguination during MUFing ?
VV-MUF
| with a Non-occlusive arterial pump (Centrifugal Pump)
110
Venous line > MUF pump > hemoconcentrator > SVC describes what method ?
VV-MUF
111
Advantages of VV MUF?
```
- no retrograde flow
down arterial line
- no aortic “steal”
- Easy to re-initate CPB
- Safer?
```
112
Disadvantage of VV MUF?
oxygenated blood not delivered to pulmonary vasculature
113
How can I prevent complications?
- Preparation
- Servoregulation
- Communication
- Congregation
- Information
114
What if I need to go back on pump during AV-MUF?
Have aortic line visually checked for air
115
What if I need to go back on pump during BCPS-MUF?
hemoconcentrated blood will have to be chase out.
116
What if I need to go back on pump during MUF?
- Terminate MUF (Clamp ultrafiltrate line)
| - Reposition clamps
117
3 benefits of Hemodilution ?
↓ Strain on Blood Banks
↓ Exposure to blood-born
pathogens: Hepatitis, HIV
Improved microcirculatory blood flow.
