Flashcards in Oxygenators Bruce's Final Exam Deck (42)
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1
What
is
an
oxygenator?
• Gas Exchanger: –Removes CO2
–Add O2
–Adds Other gases
(anesthe)cs)
2
The Ideal Oxygenator should ?
• Oxygenate venous
blood
• Cause minimal blood
trauma
• Minimal priming volume
• Designed for maximum
safety
3
3 oxygenator designs?
• Film oxygenators
• Bubble
• Membrane
4
“True” Membrane oxygenators were made of ___ .
-Provide a complete barrier between the gas and the blood phase so that gas transfer depends totally on ___.
- Silicone
- Diffusion
5
Microporous membrane was made of ?
• Polypropylene
• Polymethylpentene
- Flat Plate
- Hollow Fiber
6
3 Disadvantages of film oxygenators ?
–Huge prime
volumes
–Huge surface area
–Lots of blood trauma
7
2 Pros for bubble oxygenators?
- Inexpensive
- Low prime volume
8
3 Cons for Bubble Oxygenators ?
– Massive air
interface
– Huge surface area
– Air embolus
9
2 types of Types of membrane oxygenators?
- True Membrane
- Microporous
membrane
10
3 Pros for "True Membrane" Oxygenators?
– Silocone envelope
– No blood to gas interface
– Approved for long term use
11
2 Cons for "True Membrane" Oxygenators?
– High resistance
– Large priming
volume
12
Microporous Membrane
Pore size=
Thickness=
Pore size = 0.5-1 um
Thickness= 25-50 um
13
Microporous
Membrane
flat sheet surface area ?
.5 - 4.5 M^2
14
Hollow fiber mat
diameter =
Length =
diameter = 200 - 250 um
Length = 10 - 15 cm
15
2 pros of microporous membrane which increased efficiency ?
- Reduced Surface Area
- Reduced priming volume
16
4 pros of microporous membrane
- Transient gas interface
- Pore Wetting
- Pulmonary Edema
- Short term use <6hrs
17
2 styles of futuristic membrane implantations ?
- In series
- In parallel
18
Passive Diffusion through an oxygenator formula.
=(A/T) (D) (P1-P2)
A: Surface Area
D: Diffusion Coefficient
P: Pressure Gradient
19
Surface area M^2
Oxygenator =
Lung =
Oxygenator = .5-4
Lung = 70
20
Blood path width/length
Oxygenator =
Lung =
Oxygenator = 200 /250,00
Lung = 8 /200
21
Membrane thickness
Oxygenator =
Lung =
Oxygenator = 150
Lung = .5
22
Max O2 transfer
Oxygenator =
Lung =
Oxygenator = 400 - 600
Lung = 2000
23
Design issues of artificial lungs
-Diffusion coefficient
- Transit time
- Boundary Layer
24
What happens with O2 as distance increases from the membrane?
decreases
25
2 fluid characteristics of Laminar flow closest to the wall?
- Highest sheer force
- lowest velocity
26
As laminar flow continues ?
The layer becomes progressively thicker
27
True or false
Is there a cell free layer of plasma on the membrane?
True
28
Secondary flow through cross fibers and integral screens creates?
Turbulent flow
29
What was the solution to boundary layer problems?
Induction Secondary flows
30
