Oxygenators Bruce's Final Exam

Question 1

What
is
an
oxygenator?

Answer 1

• Gas Exchanger: –Removes CO2
–AddO2
–Adds Other gases
(anesthe)cs)

Question 2

The Ideal Oxygenator should ?

Answer 2

• Oxygenate venous	
 blood 
• Cause minimal blood  
  trauma 
• Minimal	priming volume 
• Designed formaximum	
 safety

Question 3

3oxygenator designs?

Answer 3

• Film oxygenators
• Bubble
• Membrane

Question 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 ___.

Answer 4

• Silicone

- Diffusion

Question 5

Microporous membrane was made of ?

Answer 5

• Polypropylene
• Polymethylpentene
- Flat Plate
- Hollow Fiber

Question 6

3 Disadvantages of film oxygenators ?

Answer 6

–Huge prime
volumes
–Huge surface area
–Lots of blood trauma

Question 7

2 Pros for bubble oxygenators?

Answer 7

• Inexpensive

- Low prime volume

Question 8

3 Cons for Bubble Oxygenators ?

Answer 8

– Massive air
interface
– Huge surface area
– Air embolus

Question 9

2 types of Types of membrane oxygenators?

Answer 9

• True Membrane
• Microporous
  membrane

Question 10

3 Pros for “True Membrane” Oxygenators?

Answer 10

– Silocone envelope
– No blood to gas interface
– Approved for long termuse

Question 11

2 Cons for “True Membrane” Oxygenators?

Answer 11

– High resistance
– Large priming
volume

Question 12

Microporous Membrane
Pore size=
Thickness=

Answer 12

Pore size = 0.5-1 um

Thickness= 25-50 um

Question 13

Microporous
Membrane
flat sheet surface area ?

Answer 13

.5 - 4.5 M^2

Question 14

Hollow fiber mat
diameter =
Length =

Answer 14

diameter = 200 - 250 um
Length = 10 - 15 cm

Question 15

2 pros of microporous membrane which increased efficiency ?

Answer 15

• Reduced Surface Area

- Reduced priming volume

Question 16

4 pros of microporous membrane

Answer 16

• Transient gas interface
• Pore Wetting
• Pulmonary Edema
• Short term use <6hrs

Question 17

2 styles of futuristic membrane implantations ?

Answer 17

• In series

- In parallel

Question 18

Passive Diffusion through an oxygenator formula.

Answer 18

=(A/T) (D) (P1-P2)

A: Surface Area
D: Diffusion Coefficient
P: Pressure Gradient

Question 19

Surface area M^2
Oxygenator =
Lung =

Answer 19

Oxygenator = .5-4
Lung = 70

Question 20

Blood path width/length
Oxygenator =
Lung =

Answer 20

Oxygenator = 200 /250,00
Lung =  8 /200

Question 21

Membrane thickness
Oxygenator =
Lung =

Answer 21

Oxygenator = 150
Lung = .5

Question 22

Max O2 transfer
Oxygenator =
Lung =

Answer 22

Oxygenator = 400 - 600
Lung = 2000

Question 23

Design issues of artificial lungs

Answer 23

• Diffusion coefficient
• Transit time
• Boundary Layer

Question 24

What happens with O2 as distance increases from the membrane?

Answer 24

decreases

Question 25

2 fluid characteristics of Laminar flow closest to the wall?

Answer 25

- Highest sheer force | - lowest velocity

Question 26

As laminar flow continues ?

Answer 26

The layer becomes progressively thicker

Question 27

True or false | Is there a cell free layer of plasma on the membrane?

Answer 27

True

Question 28

Secondary flow through cross fibers and integral screens creates?

Answer 28

Turbulent flow

Question 29

What was the solution to boundary layer problems?

Answer 29

Induction Secondary flows

Question 30

Blood phase

Answer 30

Blood path through the oxygenator

Question 31

Gas phase

Answer 31

Gas path through the oxygenator

Question 32

Blood path through the oxygenator is referred to as the blood phase. What is the blood path in the lung?

Answer 32

Capillary

Question 33

Gas Path through the oxygenator is referred to as the Gas phase. What is the Gas path in the lung?

Answer 33

Alveoli

Question 34

The Gas phase pressure must never exceed what ?

Answer 34

the Blood phase pressure

Question 35

Microporous oxygenators have numerous vents on the exit of the gas phase to protect against what ?

Answer 35

Pressurization

Question 36

Formula for blood phase oxygen transfer?

Answer 36

VO2= (Q) (CaO2 - CvO2)

Question 37

C.O. Formula based on the Oxygen transfer formula.

Answer 37

C.O. = VO2 / (CaO2 - CvO2)

Question 38

100 ml blood =

Answer 38

Vol %

Question 39

Average value of VO2 fro the anesthetized adult?

Answer 39

120 ml/min/^M2

Question 40

Oxygen transfer across the membrane is dependent upon 5 variables including*:

Answer 40

- Driving gradient  - Blood flow rate  - Blood path thickness - Membrane surface area  - Membrane diffusion characteristics

Question 41

FiO2 is plotted on the Y-axis and total Oxygen transfer is plotted on the X-axis. the area of the chart ABOVE the normal line represents what?

Answer 41

oxygenator performance that is worse than predicted

Question 42

FiO2 is plotted on the Y-axis and total Oxygen transfer is plotted on the X-axis. the area of the chart BELOW the normal line represents what?

Answer 42

oxygenator performance that is better than predicted