Breathing systems Flashcards
What are the two families of breathing systems?
Rebreathing and non-rebreathing
name three functions of a breathing circuit?
- Supply oxygen
- Supply anaesthetic
- Remove carbon dioxide
What are the two ways to remove carbon dioxide?
- via high flow rates e.g. flushed out (no soda lime)
2. via soda lime absorption facilitating lower flow rates.
Name an extra function of the breathing circuit?
Allows you to perform IPPV e.g. squeezing the bag to provide a breath.
What determines the breathing system family?
The way the system gets rid of carbon dioxide.
Which type of system contains soda lime?
Re-breathing system.
What is the advantage of re-breathing systems?
Allows us to use much lower flow rates.
What therefore is a feature of a non-rebreathing system?
Higher flow rates.
What is a disadvantage of non-rebreathing systems?
They are very expensive as they require higher flow rates therefore much more isoflurane.
Name the 5 Non-rebreathing circuits?
1, Maguill (Mapleson A)
- lack
- Mini lack
- Bain (& mini bain)
- T piece
Where is the valve and the bag in Maguill?
The valve is near the patient and the bag is near the machine
What is Maguill efficient for?
Spontaneous breathing
Is Maguill good for IPPV?
No, inefficient for IPPV.
What is the issue with lots of weight being by the animals mouth in Maguill?
can pull the tube out of the animal’s mouth.
What is the MV equation for Maguill?
0.7-1 x MV
What size animal are MV designed for?
Over 10kg - no good for small.
Does Maguill need high or low gas rate?
High to push out carbon dioxide at expiratory pause where the oxygen pushes out the carbon dioxide..
What if there was a rapidly breathing patient with Maguill?
There would not be enough time for the oxygen to remove the carbon dioxide and the animal would re-breath carbon dioxide.
Is Maguill commonly used?
NO -CHEAP AND NASTY!
What is another name for Lack?
Modified Mapleson A
What is Lack efficient for?
Spontaneous breathing
What is it inefficient for?
IPPV, okay for a short while
What kind of circuit is Lack?
Parallel
What is the MV equation for lack?
0.7-1x MV
What size animal is Lack used for?
> 10kg
Why is lack better than Maguill?
Because the valve and the bag are at the same end, away from the patient therefore no weight to pull the tube out of the mouth.
What is the Mini lack known as?
Modified Mapleson
What does lack look like?
Two tubes!
Is there much resistance in a mini lack circuit and why?
minimal resistance because it is smooth bore tubing.
Why do a 1/3 flow rates of mini lack have a T piece?
Saves gas and money and inhalant
What size animal is the mini lack used for?
2-10kg
When is mini lack suitable for long-term IPPV?
When the FGF is increased to 600ml/kg/min
What is the normal flow rate for mini lack circuits?
200ml/kg
Which circuits have a CF of 1?
maguill and lack
Which circuits have a CF of 2-3?
Bain and T piece
What is Bain (&mini bain) otherwise known as?
Mapleson D modified
What does bain look like and which tube supplies gas?
Tube inside a tube and the internal tube supplies the gas.
What is the MV equation of bain?
2.5 x MV
For what sized animals is Bain used for?
7-20kg
What is one of Bains main downfalls?
It requires high flow rates therefore very expensive