Breathing systems Flashcards
What is dead space?
Volume of gas that does not eliminate CO2
What is tidal volume?
Volume of gas entering the lung with each inspiration
What is the minute volume?
Volume of gas entering the lungs in each minute
What is rebreathing?
When the inspired gases reaching the alveoli contain more CO2 than can be accounted for by mere re-inhalation from the patients dead space gas
What are metabolic oxygen requirements?
Amount of oxygen required each minute for metabolic processes
How big should the reservoir bag be?
3-6 x tidal volume
What are the two types of breathing system tubing?
Coaxial vs parallel
What is coaxial tubing?
One tube inside the other
What are the pros and cons of parallel tubing in breathing systems?
Increased drag
Less resistance
What is a problem with coaxial tubing in breathing systems?
Inner hose can disconnect
What type of breathing system is circle?
Rebreathing
What type of breathing system are T-piece, bain and lack?
Non rebreathing
What features does a rebreathing system have that are different to a non-rebreathing system?
Has a soda lime canister on it to remove CO2
Has unidirectional valves - so gas flow is in one direction
What happens when soda line absorbs CO2?
Water and heat are produced
What does a non-rebreathing system use to remove CO2?
Fresh gas flow
When are rebreathing systems not used?
For smaller animals - has a higher resistance
What are the disadvantages of a non-rebreathing system?
Higher fresh gas flow - more expensive
What is the equation for minute volume?
Tidal volume x resp rate
How do you work out tidal volume?
10mL/kg
How do you work out the fresh gas flow in non-rebreathing systems?
Minute volume x circuit factor
What is the circuit factor in T-piece and bain?
2-3
What is the circuit factor in lack?
1
How do you work out the fresh gas flow in rebreathing systems?
Large animals - 5mL/kg
Small animals - 10mL/kg then reduce to 1L/min
Which system is not suitable for prolonged ventilation (IPPV)?
Lack
What breathing system is the best for very small animals (<10kg)?
Ayres T-piece - low resistance
What size animals are bain and lack suitable for?
> 10kg
What size animals is the circle breathing system suitable for?
Variety
Which breathing system has a mini version for animals >1kg?
Lack - mini lack
What part of the breathing system most commonly causes incidents if left closed?
APL valve - adjustable pressure limiting valve
