Anesthesia Breathing Systems

What are the two main breathing system types?

Circle breathing system

Non-rebreathing

What is the basic arrangement of circle breathing systems?

Gas moves in only one direction to separate inspiratory and expiratory channels

How is CO2 removed in a circle breathing system?

An abosrbent

T/F oxygen and anesthetic is continuously delivered to the circle system?

True

What breathing system is cheaper to use because less oxygen is used and therefore less isoflurane?

Circle breathing systems

In what system does the vaporizer setting not represent the inspired concentration of anesthetic?

Circle breathing systems

Circle breathing system

What are the components of the circle breathing system?

Y-piece, breathing tubes, uni-directional valves, fresh gas inlet, canister, relief (pop-off) valve, rebreathing bag, pressure gauge

What is done to breathing tubes to prevent crimping?

Corrugated

What is different in the y-piece and corrugated tubes in small vs large animal?

They are bigger in large animal

What breathing systems have 2 unidrectional valves?

Circle

What happens if the valve disc from a directional valve is bent?

It will not make a seal and the unidirectional flow of air will not work

Where can the fresh gas inlet be located?

CO2 absorber canister

Inspiratory arm

Many others

What does the CO2 absorber and canister do?

Remove CO2 from expired gas

What volume does the CO2 canister need to be?

2x the patients tidal volume

Where can patient expired gas enter the canister?

Either top or bottom depending on machine

What is a surgivet soda lime canister?

CO2 is absorbed in a U shape but is very high pressure and should not be used

Describe soda lime?

12-19% water and it is an exothermic reaction

T/F if soda lime was violet but turned back white than it has regenerated and can be reused?

False

When should you change the soda lime?

If 1/3 of the canister is violet

How large does the reservoir bag need to be?

Exceed patients largest tidal breath (small animal 4x tidal breath size)

How do you calculate tidal breath?

10-15 mL/kg

What indicates the pressure in the breathing circuate?

Breathing circuit manometer in cmH20

Breathing circuit manometer

What relieves the breathing system of excess gas if input exceeds uptake by the patinet?

Pop-off valve

What side is the pop-off valve on?

Expiratory side

Before you start JSL what do you need to do with the pop off valve?

MAKE SURE IT IS OPEN

When are pop off valves closed?

To give a breath to the patient or check endotracheal tube seal

What is the danger of keeping a pop off valve closed?

Barotrauma and death due to high pressure in the lungs

What happens after a few breaths of breathing with 2% iso on a circle breathing system?

They are actually breathing less than 2% due to some recycling

What happens after several hours of a patient breathing 2% iso?

It reaches anesthetic equilibrium so they are actually breathing 2%

What is our recommended flowmeter settings on a circle system?

30mL/kg/min

Why do we use 30mL/kg/min as our flowmeter settings?

A higher flow than necessary will allow us to increase anesthetic concentration quicker

How do you know if a patient is not getting enough oxygen by looking at the anesthetic machine?

The bag will be flat because all the oxygen will be consumed

Where does excess oxygen and anesthetic exit?

Pop-off valve

In what system does the patient breath exactly what the vaporizer is set to?

Non-breathing

What are the benefits of using a bain circuit adaptor with a non-rebreathing circuit?

There is an airway pressure manometer

There is a pop-off valve with custom pressure relief valve

Learn this flow

Ok

What tube has fresh gas only in a Bain breathing circuit?

Inside tube

Where does CO2 go down in a Bain breathing circuit?

Outside tube

Why is flowmeter so important with a non-rebreathing bain circuit?

If it is too low, then the expired CO2 will not be pushed down the outside tube and will be inspired again

How do you calculate the flowrate in a non-rebreathing system?

200mL/kg/min

What types of systems are there for scavenging waste anesthetic gas?

Passive and active systems

What waste gas scavenger relies on an activated charcoal canister?

Passive system

What waste anesthetic gas system is attached to a vacuum system and vents to the outside atmosphere. You also need an interface to prevent positive and negative pressure being reflected back to the breathing circuit?

Active systems

When do you need to change a passive waste gas scavenge system?

If it has increased in weight by 40 grams. Total capacity is 50 grams

T/F nitrous oxide is resorbed by a passive system?

False (i think double check this 8:19 on 9/10)

Where is the biggest exposure to isoflurane in vet med?

During recovery because it is still in the patient