Anesthesia Machine Basics

Question 1

An anesthetic machine is a highly sophisticated mixing machine that mixes ___ with the ___ vapor in a controlled manner, delivers ___ to the animal, removes exhaled ___ ___, provides a mechanism to assist or control the animals ___, and provides a mechanism for the scavenging of ___ anesthetic gases

Answer 1

1. Gas
2. Anesthetic
3. Oxygen
4. Carbon dioxide
5. Ventilation
6. Waste

Question 2

What is the purpose of an anesthetic machine? (2)

Answer 2

1. Deliver inhalation anesthesia to a patient and removed unneeded gases from the patient & Sx suite.
2. To deliver oxygen as the sole gas, as in CPR

Question 3

For an anesthetic machine to perform its purpose as intended it must: (3)

Answer 3

1. Deliver O2 at a controlled rate
2. Vaporize a designated concentration of liquid anesthetic, mix anesthetic with O2, & deliver mixture to the patient.
3. Remove exhaled gases from the patient, then dispose of the gases thru a scavenging system or recirculate them to the patient.

Question 4

Word bank:
- Inhalation hose - Exhalation hose
- Connecting port - Pop-off valve
- Vaporizer - Flowmeter
- CO2 absorber canister - O2 tank
- Tank pressure gauge - Flush valve
- Reservoir bag - Port to ET tube
- Pressure reducing valve - To scavenger
- Inhalation valve - Exhalation valve

Answer 4

Question 5

T/F: The oxygen source for an anesthetic machine is a localized moveable cylinder or a large centrally located source.

Answer 5

True

Question 6

A full tank will read at ___psi

Answer 6

2200 psi

Question 7

E tank & H tank
1. Size:
2. Attachment style:
3. Liters it holds:

Answer 7

E tank
1. Small
2. Portable
3. 660-700L
H tank
1. Large
2. Attached to wall
3. ~7000L

Question 8

Tanks should always be ___ prior to surgery or oxygen emergency, and always ___ at the end of the day.
Remember, ___ will be fueled by an open oxygen source!

Answer 8

1. Opened
2. Closed
3. Fires

Question 9

The first pressure reducing valve is near the ___ source.
This valve reduces pressure leaving the tank & entering the machine to ___-___ psi.
At this low pressure, the gas flows thru the ___, which when opened, delivers a known amount of gas to the ___ and ___ ___.
Lower pressure ___ is now carried thru the source lines to the machine.

Answer 9

1. Oxygen
2. 40-45 psi
3. Flowmeter
4. Vaporizer & breathing circuit
5. Gas

Question 10

The flowmeter further reduces the pressure of gas to ___psi. This is close to ___ pressure and is well ___ by patients.

Answer 10

1. 15 psi
2. Atmospheric
3. Tolerated

Question 11

What does a flowmeter regulate?
How is it measured?

Answer 11

1. Regulates how much O2 is entering the system & delivered to the patient
2. Measured in L/min or mL/min

Question 12

What is the function of the flush valve?

Answer 12

Allows a quick infusion of straight O2 into the breathing circuit

Question 13

The flush valve should ___ be used on a ____ as the O2 pressure coming out of the machine is too ___ and can harm the patient.
Plus, these systems are already using a ___ O2 flow.

Answer 13

1. Never
2. Non-rebreather
3. High
4. High

Question 14

What is the function of the vaporizer?

Answer 14

Hold liquid anesthetic and vaporize into a gas form that can be delivered in a controlled manner.

Question 15

The vaporizer inlet is where O2 ___ the vaporizer to carry the ___ molecules to the patient.
The outlet is where the ___ and gas ____ the vaporizer to ___ the circuit.

Answer 15

1. Enter
2. Gas
3. O2
4. Leave
5. Enter

Question 16

When should you fill the vaporizer? How should you go about that?

Answer 16

1. When the level is 1/2 to 1/4 remaining
2. Make sure to close down the vaporizer in order to prevent contamination & open filling knob

Question 17

Standard precision vaporizer is used with ___ pressure anesthetics. These ___ pressure anesthetics vaporize ___ and must be delivered at a ___ rate.
It compensates for ____, carrier gas flow ___, and back ___.

Answer 17

1. High
2. High
3. Quickly
4. Controlled
5. Temp
6. Rate
7. Pressure

Question 18

Non-precision vaporizers are an ____ vaporizer.
Only ___ pressure anesthetics can be used, those that vaporize ___, about __% concentration is the max that will reach carrier gas.

Answer 18

1. Uncontrolled
2. Low
3. Slowly
4. 4%

Question 19

What are three factors that affect non-precision vaporizers?

Answer 19

1. Temperature
2. Gas flow
3. Back pressure

Question 20

Inspiratory valve is also called a dome, float, or ___ valve. It is designed to allow movement of ___ in only ___ direction.
As the patient inspires, the gases move thru the ___, thru the ___ tubing and delivered via the ___ ___ to the patient.

Answer 20

1. Flutter valve
2. Gases
3. One direction
4. Valve
5. Breathing/corrugated
6. ET tube

Question 21

T/F: The inspiratory valve usually has a positive-pressure relief valve

Answer 21

False! It usually has a NEGATIVE-pressure valve

Question 22

Why do inspiratory valves allow room air to enter the system?

Answer 22

The patient is trying to breath and the valve lets room air in because if the O2 tank runs out, instead of the patient suffocating, the machine allows the patient to breath room air.
- Safety valve allows patient to breath if the O2 supply runs out or is shut off

Question 23

Expiratory valve work with ___ gas.
As the patient ___, the gases travel thru the ___ tubes thru this ___ valve.

Answer 23

1. Expired
2. Exhales
3. Breathing
4. Unidirectional

Question 24

T/F: The movement of both inspiratory & expiratory valves is a good visual indicator of the patients respiration

Answer 24

True

Question 25

Pop off valve functions (2)

Answer 25

1. It can act as a vent when in the open position, it prevents build up of pressure.
2. It can also be used to determine flow rate techniques.
   - High flow rates need wide-open valve, lower flow rates can be used with it partially closed.

Question 26

T/F: The only time the pop-off valve should be temporarily completely closed is when “bagging” a patient

Answer 26

TRUE

Question 27

What is a manometer? Unit of measurement?

Answer 27

1. Pressure gauge that measures pressure within the system. DOESN’T REGULATE!
   - Indicator of pressure within a patients lungs
2. Measurement is cm of water (cm H2O)

Question 28

The reading of a manometer should never exceed ___cm H2O.
The pop-off valve & manometer have a ___ relationship. The more the “pop-ff” is ___, the ___ the pressure reading on the manometer.

Answer 28

1. 20cm H2O
2. Direct
3. Closed
4. Higher

Question 29

Rebreathing bag function & purpose (3)

Answer 29

1. Bag will deflate as the patient inspires and inflate when the patient expires.
2. Movement is a good visual indication of respiratory rate & quality.
3. Allows for manual ventilation for the patient

Question 30

How to “bag” a patient (3)

Answer 30

1. Close the pop-off valve.
2. Bag is squeezed to no more than 20cm H2O on manometer.
3. Open pop-off valve

Question 31

The bag stores excess ___ and provides back up quantities to be ___.
A bag should be ___ to ___ times the ___ volume.

Answer 31

1. Gases
2. Inspired
3. 5 to 6 times
4. Tidal vol

Question 32

How is the tidal volume calculated?

Answer 32

10mL/kg of the body weight.
Round UP not down!

Question 33

CO2 absorber is made up of what two materials?
What is the color change that occurs?

Answer 33

1. Either sodasorb or baralyme
2. White to purple after CO2 is absorbed

Question 34

Scavenging System
1. Function
2. Passive
3. Active

Answer 34

1. Tubing attached to the pop-off valve pass to an active charcoal canister.
2. Passive
   - Rely on gravity as anesthetic gases are the heaviest of expired gas.
3. Active
   - Attached to the machine producing a vacuum that removes gases out of the building.

Question 35

Rebreathing circuit
1. Function
2. Who can use it
3. Tube names

Answer 35

1. Recirculation of some expired gases, & lower flow of oxygen.
2. Patients weighing 10lbs+
3. “Y” piece or Universal F

Question 36

Non-rebreathing
1. Function
2. Who can use it

Answer 36

1. No gases rebreathed. Req higher O2 flow to push gases to Pt. Less effort for lungs of a small Pt.
2. Patients weighing less than 10lbs or respiratory compromised Pt