Anesthesia Machine

Question 1

Intermediate pressure begins at ___ and ends at ___

Answer 1

begins at pipeline inlet and ends at the flowmeter control valves

Question 2

Low pressure system begins at and ends at

Answer 2

begins at thorpe tubes and ends at the common gas outlet

Question 3

PISS configurations

Answer 3

Air = 1 and 5
O2 = 2 and 5
Nitrous = 3 and 5

Question 4

What is the most delicate part of the cylinder

Answer 4

The cylinder valve

Question 5

What do MRI compatible cylinders look like?

Answer 5

Mostly metallic with a strip of color indicating the gas

Question 6

Cylinders should not be exposed to temps above

Answer 6

130F (57C)

Temps above this can cause fire or explosion

Question 7

O2 pressure failure device will activate when

Answer 7

O2 pressure is

Question 8

O2 pressure failure device is also called the

Answer 8

Failsafe device

It is safe, because it protects against failed O2 pressure

Question 9

Purpose of the O2 pressure failure device (Failsafe device)

Answer 9

Detects and protects against low O2 pressure (once less than 30psi).

This also reduces or stops the flow of nitrous to protect against hypoxic mixtures! Will either reduce flow or stop completely.

Question 10

What does it mean if the O2 pressure failure device goes off?

Answer 10

Low O2 pressure (

Question 11

What pressure system is the O2 pressure failure device (failsafe device) located

Answer 11

Intermediate pressure system

Question 12

All gases besides ____ pass a failsafe device

Answer 12

All gases other than O2. This is to protect against hypoxic mixtures

Question 13

The device that keeps N20 and O2 ratio at 3:1 is called

Answer 13

Hypoxia prevention safety device
This is either pneumatic or a chain linked system
This is a proportioning device. Prevents you from setting a hypoxic mixture at the levels of the flowmeter valves.

Question 14

What is the annular space?

Answer 14

Space between the widest part of the float and the thorpe tube. Because the tube is narrowest at the base and widest at the top, this also means that the annular space is widest at the top. This variable orifice architecture provides a constant gas pressure throughout a wide range of flow rates.

Question 15

Laminar flow is dependent on gas ____

Turbulent flow is dependent on gas ____

Answer 15

Laminar flow depends on gas viscosity

Turbulent flow depends on gas density

Question 16

This is the most delicate part of the anesthesia machine

Answer 16

Flowmeters, because they’re made of glass. If any component of the flowmeter is damaged, the ENTIRE UNIT must be replaced.

Question 17

Flows less than ____ or more than ____ can lead to reduced vaporizer output (i.e.- the gas moving through the vaporizer may not become 100% saturated)

Answer 17

less than 200mL/min
or
greater than 15L/min

Question 18

Pumping effect

Answer 18

Occurs when gas that has already left the vaporizer re-enters the vaporizer. Usually happens d/t PPV or use of O2 flush.
Also more at risk with low flows, low concentration setting on dial, and low levels of liquid anesthetic in the chamber.
Modern design minimizes pumping effect.

Question 19

TEC 6 heats to what temp?

Answer 19

39C

Question 20

Effect of elevation on vaporizers

Answer 20

Conventional variable bypass vaporizers are not affected by changes in elevation.

TEC6 does NOT compensate for changes in elevation.

Question 21

Are anesthesia vaporizers in the circuit or out of circuit?

Answer 21

They are out of circuit

Question 22

Most common cause of low circuit pressure

Answer 22

Disconnect at the Y piece. If this is not an choice, then CO2 canister is the next best option.

Question 23

O2 consumption in the average adult is ___mL/min

Answer 23

250mL/min

Question 24

What to do in the event of an O2 pipeline crossover

Answer 24

Open the O2 tank and disconnect the pipeline

Question 25

Pressing the O2 flush on (inspiration/expiration) can lead to barotrauma

Answer 25

can lead to barotrauma on INSPIRATION

Question 26

Relationship between the drive gas and the spill valve

Answer 26

The drive gas is what opens and closes the spill valve.

On inspiration, the drive gas CLOSES the spill valve. This way, the drive gas is driving air into the lungs only and not lungs/scavenging.

On exhalation, the drive gas stops. Exhaled volume fills the bellows first. Once pressure in the circuit exceeds 3cmH2O, the spill valve opens and excess gas goes to scavenging. This explains the intrinsic PEEP in pneumatic ventilators.

FGF is continuously being added to the circuit. The amount of air going to the bellows is the sum of TV + flowmeter flow during exhalation.

Question 27

What happens with O2 flush?

Answer 27

O2 is delivered right from the pipeline. So, 50psi and 35-75L/min.

This does NOT go through the vaporizer, and leads to dilution.

Question 28

How many relief valves are in the piston ventilator?

Answer 28

2

One for positive pressure relief and one for negative pressure. Positive opens at 75, negative opens at -8.

Question 29

What happens to the breathing bag with piston ventilators?

Answer 29

The bag is incorporated into the vent circuit. So the bag inflates on inspiration and deflates on expiration.

Question 30

Is soda line an acid or base?

Answer 30

It’s a strong base. Remember the catalyst is NaOH.

Question 31

Ethyl violet in soda lime turns from gray to blue-purple once it falls below what pH?

Answer 31

10.3

Question 32

How hydrated is soda lime normally?

Answer 32

13-20% by weight

Remember this water is needed in the first step of the soda lime reaction

Question 33

What Vas cause CO production with desiccated soda lime?

Answer 33

Des > iso&raquo_space;»»»sevo

Question 34

This is the most unstable halogenated anesthetic in soda lime

Answer 34

Sevo.

It’s unstable in BOTH hydrated and desiccated soda lime

Question 35

CO2 absorbent capacity of soda lime vs. calcium hydroxide lime (Amsorb)

Answer 35

Soda lime = 26L CO2/100g

Amsorb = 10.6L CO2/100g

Question 36

OSHA gas concentrations in the OR

Answer 36

Nitrous alone

Question 37

2 common conditions that result in rebreathing CO2

Answer 37

1) CO2 absorbent exhaustion

2) Incompetent unidirectional valve

Question 38

Maplesons that are best and worst for spontaneously breathing pts

Answer 38

A is best
B is worst

(A>DFE>CB)

Question 39

This is the best monitor you have to determine if your FGF is high enough with a mapleson

Answer 39

EtCO2

Question 40

These maplesons are best and worst for controlled ventilation

Answer 40

D is best

A is worst

Question 41

This mapleson does not have an APL valve OR reservoir bag

Answer 41

E

also called Ayre’s T Piece

Question 42

FGF should be _____x MV for maplesons

Answer 42

2.5x your minute ventilation

Exception is Mapleson A, which requires FGF 20x MV during controlled ventilation!

Question 43

This circuit is good for preventing heat loss

Answer 43

Bain Circuit

Question 44

This mapleson is also called Jackson-Rees

Answer 44

F

Question 45

This test is used to identify kinking of the FG hose in the Bain circuit

Answer 45

Pethick’s Test

Question 46

Bain circuit is a modified Mapleson ____

Answer 46

D

Question 47

How to perform the Pethick’s Test

Answer 47

1) Occlude the elbow at the patient’s end of the circuit
2) Close the APL
3) Use the O2 flush to fill the circuit
4) Remove the occlusion from the end of the elbow while flushing the circuit

If the reservoir bag collapses from the Venturi effect, the Bain is good to use

If the bag remains inflated, the inner tubing is occluded and the circuit should be discarded.