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Flashcards in Breathing Systems Deck (46):
1

Two types of breathing systems

Rebreathing
Non-rebreathing

2

Rebreathing tube types

1. Circle/Y piece
2. Universal F

3

Non-rebreathing tube types

1. Mapleson D
2. Mapleson F
3. Bain

4

Components of the Rebreathing system

1. Fresh gas and O2 flush
2. Unidirectional valves (inspiratory and expiratory)
3. Breathing hoses
4. CO2 absorber
5. Adjustable pressure limiting valve aka pop-off valve
6. Reservoir bag

5

Rebreathing system advantages

1. Lower fresh gas flow rate
2. Saves money
3. Decreases pollution
4. Patient breathes warm humidified air

6

Rebreathing system disadvantages

1. More components and potential for leaks
2. Increased resistance for smaller patients (

7

Pop-off valve

Limits pressure buildup in the system

8

Position of the pop-off valve

ALWAYS OPEN

Unless checking for leaks or administering positive pressure ventilation

9

Consequences of leaving the pop-off valve closed

Increases pressure in breathing system

Results in possible cardiopulmonary injury

10

Breathing system pressure gauge

SHOULD ALWAYS BE ZERO

Except: performing leak checks or providing positive pressure ventilation

11

Most common CO2 absorber medium

Soda lime

Calcium hydroxide with small amounts of sodium hydroxide and crystal violet (colour indicator)

12

Colour change in soda lime

White- fresh
Violet- exhausted

13

Signs of exhaustion

1. Increase in tidal CO2
2. Increased ventilation, HR/BP (then drop) if light enough
3. Rebreathing capnograph
4. Respiratory acidosis
5. Red mucous membranes due to carbon monoxide production/inhalation

14

Reservoir bag function

Observe ventilation, inspiratory reserve, administer manual positive pressure ventilation

15

Calculation for reservoir bag size

Tidal volume = 10-20mL/kg x 6

Round UP if between sizes

16

Oxygen flow rate-
Rebreathing Small animal

Induction/ Recovery= 50-100 mL/kg/min O2
Maintenance= 20-50mL/kg/min O2

17

Oxygen flow rate
Rebreathing Large animal

Induction/ Recovery= 20-50 mL/kg/min O2
Maintenance= 10-20mL/kg/min O2

18

Non-rebreathing system components

1. Fresh gas
2. Non-rebreathing tubes
3. APL (mapleson D) or open/close (mapleson F) valve
4. Reservoir bag

19

Non-rebreathing Advantages

1. Very light with minimal dead space
2. Minimal resistance to ventilation (better for

20

Non-rebreathing Disadvantages

1. High Gas flow rate
2. More expensive to run larger patients
3. Increased environmental pollution
4. Gas cold and dry

21

Non-rebreathing Oxygen flow rates

2-3x tidal volume in most cases

200-300mL/kg/min O2

22

Indications for endotracheal intubation

1. Maintain patent airway
2. Protect airway from foreign material
3. Provide intermittent positive pressure ventilation (IPPV)
4. Apply tracheal or bronchial suction
5. Administer oxygen
6. Deliver inhalant anesthesia

23

Benefits of intubation

1. Reduced anatomical deadspace
2. Maintain inhalant anesthesia with minimal environmental contamination (with properly inflated cuff)

24

Routes of Intubation

1. Oral
2. Nasal
3. External pharyngotomy
4. Tracheostomy

25

E-tube materials

PVC, rubber, or silicone

26

Purpose of cuff

Protects airway and environment from contamination

27

Types of e-tubes

1. Murphy- most common
2. McGill
3. Wire reinforced (do not use with MRI)
4. Cole- avian
5. Tracheostomy

28

What type of tube provides the least air resistance

Larger radium and shorter length (Poiseuille's law)

29

Cat e-tube sizing

3.5-4.5mm generally

30

Dog e-tube sizing

8.0-12mm depending on size of dog
14-16mm for giant breed dogs

31

Sheep e-tube sizing

10-12mm

32

Horse e-tube sizing

26-30mm

33

Safe e-tube inflation

No audible release of gas around e-tube when pop-off is closed and reservoir bag is squeezed to 20cmH2O

Air should be escaping at 30cmH2O- prevents over inflation

34

Potential complications of intubation

1. Laryneal damage- small animal espeically
2. Tracheal damage
- over inflated cuff
- moving/twisting of inflated cuff
3. Tube obstruction
4. Endobronchial intubation (hypoxemia, tachypnea, cynosis)
5. ETT inhalation/ingestion

35

Purpose of scavenging

Collection and transport of waste gasses from the anesthetic machine to a safe disposal area

36

Types of scavengers

Active and passive

37

Elements of a scavenger

1. Collecting system (APL valve)
2. Transfer system/interface
3. Receiving system
4. Disposal system

38

Olfacotry ppm of gasses

>= 125ppm

39

Exposure limits to anesthetic gasses

40

Scavenging principles

1. Scavenge everything
2. No leak technique (

41

Passive scavenging system medium

Charcoal

F-air canisters; does not scavenge nitrous oxide

42

Passive scavenging piping

Atmosphere (window etc)

43

Active scavenging system

Piped vacuum (WHITE drop and tubing)

44

Charcoal scavenging advantages

1. Absorbs hydrocarbons
2. Does not release to ozone
3. Portable

45

Charcoal Scavenging disadvantages

1. Does not absorb N2O
2. Limited flow
3. Added resistance
4. Weigh before use and record weight
5. Discard with 50grams+ or after 8-12 hours continuous use

46

Active scavenging system flow rate capacity

30L/min