Anesthesia Machine

Question 1

Endotracheal Tubes (ETT)

Answer 1

Endotracheal intubation ensures
* A patent airway
* Facilitates patient ventilation
* Provides easy delivery of volatile
anesthetics

Question 2

Anesthesia Machine

Answer 2

Delivers inhalation anesthesia and oxygen to the patient
* Delivers oxygen at a controlled rate
* Vaporizes (turns liquid into gas) an anesthetic, mixes it with oxygen, and delivers the
mixture to the patient
* Removes exhaled gas and disposes of the gases

Question 3

Oxygen Supply

Answer 3

• May be delivered from compressed gas cylinders attached to the anesthesia machine
  or a central oxygen source
• There will be a pressure gauge that indicates how full the tank is
• A full tank will be at 2200 psi
• Handle tanks with care!

Question 4

Oxygen Flowmeter

Answer 4

*Purpose is to deliver a constant oxygen flow to the machine and patient
*A larger patient will need a higher oxygen flow
*A floating ball in the tube indicates the amount of gas passing through the
tube
*Measures flow in Liters/minute (L/min)

Question 5

Flush Valve

Answer 5

*Allows a quick infusion of oxygen only
*Found near the oxygen flowmeter
Why would we use this button?

Question 6

Vaporizers

Answer 6

*Inhalation anesthetic agents are volatile liquids that vaporize at room
temperature
*A vaporizer is a controlled enhancer of anesthetic vaporization (specific for
each gas)
*Delivers a constant concentration of anesthetic gas (measured in
percentage)
*Most common anesthetic gas used in veterinary medicine is Isoflurane

Question 7

Breathing Circuits

Answer 7

*Anesthetic gas and oxygen pass from the anesthesia machine into the
patient through tubing known as the breathing circuit

Two types
* Rebreathing
* Non-rebreathing

Question 8

Reservoir Bags

Answer 8

Reservoir Bags
*Rebreathing bag
*Can also be used to ‘bag’ (manually ventilate) a
patient
*Bag sizes range from 0.5 to 5 Liters
*Ideal bag is 5-6x the patient’s normal tidal volume
of 10 ml/kg
*The bag should never be too empty or too full
*Will expand and deflate when patient breaths in
and out

Question 9

Manometer

Answer 9

*Monitors the pressure of gases in the
breathing circuit
*Excessive pressure can damage the
patient’s lungs
*When ‘bagging’ (manually ventilating) the
patient – dogs and cats are ventilated to 15-
20 cm H2O
*When breathing spontaneously, the
manometer should normally be at 0 cm
H2O

Question 10

Pop-off Valve

Answer 10

*Prevents build up of pressure in the system
*Usually located near the expiratory tubing
*Left open when the patient is breathing spontaneously
*Closed when ‘bagging’ the patient
*Can be very dangerous!

Question 11

Carbon Dioxide Absorbent
Canister

Answer 11

Carbon Dioxide Absorbent
Canister
*As the patient exhales, the waste gases pass either
to the carbon dioxide absorber or to the scavenger
*Canister with crystals that absorb carbon dioxide
from exhaled gases before the gases are returned
to the patient
*The CO2 granules should be changed every 6-8
hours of use
*Will turn purple as the granules are exhausted

Question 12

Scavenger

Answer 12

*It is important to use some type of system to evacuate waste gases from
the anesthesia machine and out of the surgery suite to the outside of the
building.
*Active – connects to a general building source that produces a vacuum to
remove gases
*Passive
* Relies on gravity – anesthesia gases are heavy!
* Charcoal canister connected to anesthesia machine stand