Breathing Circuits

Question 1

What are the 4 types of breathing circuits?

Answer 1

Open
Semi-open
Semi-closed
Closed

Question 2

What circuit does not have rebreathing and does not have a reservoir? Examples?

Answer 2

Open

Insufflation
NC
Simple face mask
Open drop ether

Question 3

What circuit does not have rebreathing and does have a reservoir? Examples?

Answer 3

Semi-open

Mapleson (FGF dependent on design)

Circle (FGF>MV)

Question 4

What circuit has partial rebreathing and does have a reservoir? Examples?

Answer 4

Semi Closed

Circle system (FGF<MV)

Question 5

What circuit has complete rebreathing and does have a reservoir? Examples?

Answer 5

Closed

Circle with low flow and APL closed

Question 6

What should you do if the End Tidal does not return to baseline?

Answer 6

Increase FGF to greater than the MV

Replace absorbent

Question 7

What is unique to the circle system?

Answer 7

Has two unidirectional valves and CO2 absorbent

Question 8

What is an example of a semi-open circuit? (what is FGF set at)

Answer 8

FGF > MV

Ex: 10L during induction

Question 9

What is an example of a semi-closed circuit? (what is FGF set at)

Answer 9

FGF < MV

Ex: 2L after intubation

Question 10

What is an example of a circuit? (what is FGF set at)

Answer 10

Just enough to support O2 consumption

Question 11

What benefits does the reservoir bag provide?

Answer 11

-Exhaled gas accumulates in the bag so allows patient to rebreathe the gas and use lower FGF

-Monitor for spontaneous ventilation

-Allows you to control positive pressure

-Must not exceed internal pressure of 60 cm h2o

Question 12

What is the function of the APL valve?

Answer 12

Controls how much pressure can be generated during the bag mode

Question 13

Other names for APL?

Answer 13

Pressure relief
Relief valve
Overspill valve
Popoff valve
etc

Question 14

What are two causes of inspired CO2

Answer 14

Failure of unidirectional valve

Co2 absorbent exhaustion

Question 15

What is the best Mapleson for a spontaneous breathing patient? Worst?

Answer 15

A

B

Question 16

What is the best Mapleson for controlleD? Worst?

Answer 16

D (controlleD)

A

Question 17

What is not present in Mapleson systems?

Answer 17

Unidirectional valves
CO2 absorbent

Question 18

Which Mapleson does not have Corrugated tubing?

Answer 18

C

(corrugated starts with c)

Question 19

Which Mapleson does not have a reservoir bag or APL valve?

Answer 19

E

Question 20

Which Mapleson is the only circuit with the fresh gas inlet NEAR the bag?

Answer 20

A

Question 21

Which Mapleson is the only circuit with the APL away from the patient?

Answer 21

D

Question 22

What are the pros to Mapleson circuits?

Answer 22

Less airway resistance (good for peds)

Convenient

Easily scavenged

Question 23

What is the pro to a Bain system?

Answer 23

Prevents heat loss

Question 24

What is another name for the Bain system?

Answer 24

Mapleson D

Question 25

How does the Bain system warm fresh gas coming in?

Answer 25

By exhaled gas

Question 26

When using a Bain circuit, the FGF should be at least how many times higher than the MV?

Answer 26

2.5x

Question 27

What test should be performed on the Bain system? How is the test interpreted?

Answer 27

Pethick

If the inner tubing is patent the reservoir bag will collapse and is okay to use

If the inner tubing is occluded, the reservoir bag will remain inflated and not okay to use