Oxygenators Bruce's Final Exam Flashcards Preview

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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

Blood phase

Blood path through the oxygenator