BAC - Chapter 2: The Anaesthetic Machine

Question 1

What is the function of the anaesthetic machine?

Answer 1

1. Receive compressed gases from a supply source
2. Provide continuous flow of a gas mixture
3. Of known composition and flow rate

Question 2

The anaesthetic machine consists of:

Answer 2

1. A supply of gases and vacuum
2. Means of controlling flow of gases
3. Means of administrating anaesthetic vapours

Question 3

Pipelines - gas/colour/pressure

Answer 3

1. Oxygen - white colour - 4x100 kpa
2. Nitrous oxide - blue colour - 4x100 kpa
3. Medical air - black & white colour - 4x100 kpa
4. Vacuum - yellow colour - 40L/min & 60kpa

Question 4

How are the pipelines attached to the machine?

Answer 4

1. Non-interchangeable screw threads (NIST)

2. Diameter index safety system (DISS)

Question 5

How are the cylinders attached to the machine?

Answer 5

1. By PISS

Question 6

How does the anaesthetic machine control flow of gases?

Answer 6

1. Flow rotameters

Question 7

Colours of different vapours:

Answer 7

1. Sevoflurane - yellow
2. Isoflurane - purple
3. Enflurane - orange
4. Halothane - red
5. Desflurane - blue

Question 8

Function of O2 alarm:

Answer 8

1. Indicates O2 failure

2. N2O will shut off

Question 9

Function of O2 analyser:

Answer 9

1. O2 falls < 25%

2. N2O will also be reduced

Question 10

Function of O2 flush valve:

Answer 10

1. Gives high flow O2 (35-75 L/min)
2. Directly to common gas outlet
3. Bypasses flow meters and vaporises

Question 11

High pressure zone of machine consists of:

Answer 11

1. Gas supply - pipelines/cylinders
2. Pressure gauges
3. Pressure regulators

Question 12

Types of breathing systems:

Answer 12

1. Circle - common
2. Jackson-Reese (paeds)
3. Bain
4. ADE

Question 13

Components of Circle system:

Answer 13

1. 1 way valves
2. Soda lime
3. Rebreathing bag
4. Afferent & efferent breathing tubes
5. Y-piece
6. Right angle connector

Question 14

Check emergency ventilating equipment: (checklist)

Answer 14

1. Switch on machine
2. Check pipeline pressures
3. Open O2 & nitrous rotameters
4. Disconnect O2 pipeline & check O2 flush
5. Check O2 failure alarm & dumping of N2O
6. Open O2 cylinder & check gauge
7. Reconnect O2 pipeline & perform “tug test”
8. Calibrate O2 analyser
9. Test suction
10. Check vaporisers & check for leaks in low pressure system
11. Check breathing system
12. Check ventilator
13. Test scavenging
14. Check defibrillator
15. Switch on monitors & check probes, leads, cuffs & nerve stimulator
16. Test accessories - metals + plastics

Question 15

Check of airway trolley:

Answer 15

I-MALES
I - Introducer + bougie
M - Masks + Magill's forceps
A - Airways - OP + LMA + Artery forceps
L - Laryngoscope - x2 + 2 blades
E - ETT - 3 sizes 6.5/7.0/7.5
S - Sundries - Suction + Strapping + Syringe + Scissors + Ambubag + KY-jelly