Anaesthetic machine and airway management Flashcards
1
Q
What does the anaesthetic machine do?
A
- Produces and delivers safe concentrations of anaesthetic vapour
- Produces a means of supplying O2 and administers IPPV
2
Q
What are the features of the anaesthetic machine?
A
- Gas supply
- Pressure reducing valve
- Pressure gauge
- Flowmeter
- Vaporiser
- Oxygen flush
- Warning device
- Scavenging
3
Q
What are the different gas supply?
A
- Cylinders with a yoke and pin to prevent attaching the wrong cylinder to the wrong port
- Piped gases
4
Q
What are the different gases used and their cylinder colours?
A
- Oxygen = White shoulder
- Nitrogen Oxide = Blue shoulder
- Medical air = Half black shoulder
- Carbon dioxide = Grey shoulder
5
Q
What is the O2 pressure gauge?
A
- Measures the amount of gas remaining in the O2 cylinder; the cylinder pressure will decrease as the cylinder empties (Boyle’s Law)
6
Q
What is the N2O pressure gauge?
A
- Saturate vapour sits above the liquid; the pressure remains constant
- Pressure will decrease once all the liquid is evaporated
- To estimate N2O remaining, cylidners should be weighed
7
Q
What are oxygen generator/concentrators?
A
- Concnetrate atmospheric oxygen from 21% to 95% by using zeolite crystals that remove nitrogen and water, but not argon
- Provide low pressure flow and crystals last for 20,000 hours before the need of replacement
8
Q
What is the pressure reducing valve?
A
- Reduces pressure to something safer and workable
- Allows a constant supply of gas under a steady pressure
9
Q
What are vapourisers?
A
- Used to administer a volatile agent, so liquid to gas
- Can become non-calibrated if put on their side, which can give wrong anaesthetic volume
10
Q
What is a oxygen gas outlet?
A
- Connects anaesthetic machine to breathing circuit
- Swivel gas outlet common as it prevents kinking
11
Q
What is an oxygen flush?
A
- Receives oxygen direct from cylinder
- Bypasses flowmeter and vaporiser
- Used to provide emergency oxygen or to flush the anaesthetic machine
- Lung damage possible due to over extension
12
Q
What is the oxygen warning device?
A
- Falling oxygen supplies should sound an alarm
- The two common alarms are Bosun and Ritchie whistle
13
Q
What are the 4 parts of scavenging?
A
- Collecting system: from APL or ventilator
- Transfer system: tubing and connectors
- Receiving system
- Disposal system: fan, suction, expiration, environment, air circulation or activated charcoal
14
Q
How is exposure minimised?
A
- Leak test equipment
- Connect patient before turning on vapouriser
- Use low flow anaesthesia
- Flush before disconnecting
- Active monitoring
15
Q
What do endotracheal tubes consist of?
A
- Length markings to pre-measure to eliminate dead space in patient
- Pilot balloon and one-way valve to inflate the cuff
- Murphy eye to prevent complications associated with bronchus intubation
- Radiopaque line to visualise the tube on radiographs in case lost in patient
16
Q
What are the different types of endotracheal tubes?
A
- Silicone ETT
- Red rubber ETT
- PVC ETT
17
Q
What are the armoured ETT?
A
- Tubes lined with a coiled wire inside which helps to prevent kinks that may cause an obstruction and lead to complications
18
Q
How are laryngospasms minimised in cats?
A
- Should be sprayed with lidocaine (local anaesthetic) and left for 30-60s before intubation
19
Q
What are advantages of ETT?
A
- Provides a method of inflating lungs
- Prevents aspiration of foreign material
- Better maintenance of gas volume in breathing systems
- Less atmospheric pollution
- Can be secured with ties
20
Q
What are disadvantages of ETT?
A
- Can be accidentally inserted into oesophagus and bronchus
- Can be a kink or become obstructed
- Can become disconnected
- Can be bitten or inhaled
- Can damage the trachea or larynx
- Can cause tracheal rupture or tear
