Anesthesia Gas Machine

Question 1

What happens when the inspiratory unidirectional valve remains closed?

Answer 1

Airway obstruction

Question 2

What happens when the unidirectional inspiratory valve remains open?

Answer 2

Dead space

Question 3

What happens when the expiratory unidirectional valve remains closed?

Answer 3

Airway obstruction, breath stacking, barotrauma

Question 4

What happens when the expiratory unidirectional valve remains open?

Answer 4

Dead space

Question 5

When the unidirectional valves are working properly, where does dead space begin and where does it end?

Answer 5

Begins at the y-piece
Ends at the terminal bronchioles

Question 6

When is the inspiratory unidirectional valve closed/open?

Answer 6

Closed during expiration
Open during inspiration

Question 7

When is the unidirectional expiratory valve open/closed?

Answer 7

Open: during exhalation
Closed during inspiration

Question 8

What are the two more common causes of inspired CO2?

Answer 8

Carbon dioxide absorbent exhaustion
Incompetent unidirectional valve

Question 9

Which mapleson circuit is best for a spontaneously ventilating patient? Which is the worst?

Answer 9

All Dogs Bite

A: is the best
D: is ok
B: is the worst

Question 10

Which mapleson circuit is best for controlled ventilation?

Answer 10

Don’t Be Arrogant

D: is the best for controlled
B: is ok
A: is the worst

Question 11

Which mapleson circuit does not contain an APL valve or reservoir bag?

Answer 11

E

Question 12

In the mapleson A circuit, where is the APL and fresh gas inlet?

Answer 12

APL: near patient
Fresh gas inlet: near bag

Question 13

In the mapleson B circuit, where is the APL and fresh gas inlet?

Answer 13

Apl: near the patient
Fresh gas inlet: near the patient

(Very similar to C, just has corrugated tubing)

Question 14

In the mapleson C circuit, where is the APL and fresh gas inlet?

Answer 14

APL: near patient
Gas Inlet: near patient

(Similar to B but does NOT have corrugated tubing)

Question 15

In the mapleson D circuit, where is the APL and fresh gas inlet?

Answer 15

APL: away from patient
Gas inlet: near patient

(Opposite of A)

Question 16

Which two mapleson circuits do not have a circuits do not have an APL valve?

Answer 16

E and F

Question 17

What are the advantages of Mapleson circuits?

Answer 17

Less airway resistance (great for peds)
Convenient
Easily scavenged
Bain circuit prevents heat loss

Question 18

What are the disadvantages of Mapleson circuits?

Answer 18

Increased dead space
Requires high FGF
Loss of heat and humidity
Inefficient use of inhaled anesthetics
Risk of environmental pollution
Unrecognized kinking of fresh gas hose (Bain circuit)

Question 19

What is a general rule in the how much FGF required to prevent rebreathing?

Answer 19

2.5 times the patient’s minute vent.

Question 20

What are some traits about the Bain circuit?

Answer 20

Modification of the Mapleson D
FGF enters an inner tube

Question 21

What are some downfalls of the Bain circuit?

Answer 21

It’s possible for the inner tubing to become kinked or disconnected.

A Pethick test is required to test inner tube