Anaesthetic Machines Flashcards
What are the main components of an anaesthetic machine? (6)
Gas supply, pressure gauges, pressure regulators (reducing valve), flowmeters and needle valves, emergency oxygen flush, vaporizers.
In what 3 ways can gas be suppled to the anaesthetic machine?
Cylinders (small - usually size E attached to machine), Pipelines (plug into wall with outside cylinder usually size J), oxygen extractor
What are the three important gases to have in anaesthetic machines? What are their corresponding colours?
Oxygen -white
Nitrous oxide - blue
Medical grade air - black and white.
When using cylinders as your gas supply, what is the PIN-index for? What is a Bodok seal?
PIN-index stops you putting wrong cylinder in wrong place. The Bodok seal has to be present between the cylinder and machine, it creates an air tight seal.
What do the pressure gauges measure? What is different about the NO pressure gauge?
The amount of has pressure in the cylinders/pipes. It tells you how much is left in the air/O2 cylinders, but not in NO as it is liquid and needs to be weighed.
What does the pressure regulator (reducing valve) do?
Reduces cylinder pressure to a safe operating pressure, and keeps it constant.
What does the flowmeter and needle valves measure?
Flow rate of gase passing through each (each one is for a different gas).
If you have a bobbin in a flowmeter, where do you measure from? If you have a ball bearing in a flowmeter, where do you measure from?
Bobbin - measure from TOP
Ball-bearing - measure from the MIDDLE.
What does the emergency oxygen flush do? Why do you have to be careful?
Oxygen bypasses vaporizers and flow meters. It is good because it can dilute the anaesthetic. However, it is very high pressure so have to be careful.
What does the Vaporizer do?
Vaporizes the liquid volatile anaesthetic agent.
What is the path of fresh gas flow going into the vaporizer?
It is split in half, so half (or proportion) is mixed with anaesthetic and half is not. This helps to get the concentration of anaesthetic correct.
What is an in-circuit vaporizer? What are it’s pro’s and cons?
An incircuit vaporizer is in an anaesthetic circle system. The gas flow is generated by the patient’s breathing rate (good), however, it is difficult to know the exact vapour output (bad).
