Breathing Systems Flashcards
Two types of breathing systems
Rebreathing
Non-rebreathing
Rebreathing tube types
- Circle/Y piece
2. Universal F
Non-rebreathing tube types
- Mapleson D
- Mapleson F
- Bain
Components of the Rebreathing system
- Fresh gas and O2 flush
- Unidirectional valves (inspiratory and expiratory)
- Breathing hoses
- CO2 absorber
- Adjustable pressure limiting valve aka pop-off valve
- Reservoir bag
Rebreathing system advantages
- Lower fresh gas flow rate
- Saves money
- Decreases pollution
- Patient breathes warm humidified air
Rebreathing system disadvantages
- More components and potential for leaks
2. Increased resistance for smaller patients (
Pop-off valve
Limits pressure buildup in the system
Position of the pop-off valve
ALWAYS OPEN
Unless checking for leaks or administering positive pressure ventilation
Consequences of leaving the pop-off valve closed
Increases pressure in breathing system
Results in possible cardiopulmonary injury
Breathing system pressure gauge
SHOULD ALWAYS BE ZERO
Except: performing leak checks or providing positive pressure ventilation
Most common CO2 absorber medium
Soda lime
Calcium hydroxide with small amounts of sodium hydroxide and crystal violet (colour indicator)
Colour change in soda lime
White- fresh
Violet- exhausted
Signs of exhaustion
- Increase in tidal CO2
- Increased ventilation, HR/BP (then drop) if light enough
- Rebreathing capnograph
- Respiratory acidosis
- Red mucous membranes due to carbon monoxide production/inhalation
Reservoir bag function
Observe ventilation, inspiratory reserve, administer manual positive pressure ventilation
Calculation for reservoir bag size
Tidal volume = 10-20mL/kg x 6
Round UP if between sizes
Oxygen flow rate-
Rebreathing Small animal
Induction/ Recovery= 50-100 mL/kg/min O2
Maintenance= 20-50mL/kg/min O2
Oxygen flow rate
Rebreathing Large animal
Induction/ Recovery= 20-50 mL/kg/min O2
Maintenance= 10-20mL/kg/min O2
Non-rebreathing system components
- Fresh gas
- Non-rebreathing tubes
- APL (mapleson D) or open/close (mapleson F) valve
- Reservoir bag
Non-rebreathing Advantages
- Very light with minimal dead space
2. Minimal resistance to ventilation (better for
Non-rebreathing Disadvantages
- High Gas flow rate
- More expensive to run larger patients
- Increased environmental pollution
- Gas cold and dry
Non-rebreathing Oxygen flow rates
2-3x tidal volume in most cases
200-300mL/kg/min O2
Indications for endotracheal intubation
- Maintain patent airway
- Protect airway from foreign material
- Provide intermittent positive pressure ventilation (IPPV)
- Apply tracheal or bronchial suction
- Administer oxygen
- Deliver inhalant anesthesia
Benefits of intubation
- Reduced anatomical deadspace
2. Maintain inhalant anesthesia with minimal environmental contamination (with properly inflated cuff)
Routes of Intubation
- Oral
- Nasal
- External pharyngotomy
- Tracheostomy
