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WorksheetsAnesthesia Machine Pre-use Checks and Safety
Total questions: 25
Worksheet time: 13mins
Before the start of each operating day, the primary oxygen supply pressure on the anesthesia machine should read approximately:
25–35 psi
45–55 psi
100–150 psi
2000 psi
The first step in a pre-use machine check (AAGBI 2021) is to:
Check vaporizer levels
Verify alternate oxygen source
Calibrate flow meters
Check scavenging system
Which of the following should be checked daily before anesthesia starts, even if cases are postponed?
Vaporizers only
Leak test and circuit pressure check
Anesthetic agent expiry dates
CO₂ absorber weight
A common cause of machine hypoxia due to pipeline crossover is prevented by:
Flowmeter sequence O₂-last
Anti-hypoxia link (fail-safe)
Pressure relief valve
Vaporizer interlock
A modern anesthesia workstation should alarm if pipeline pressure drops below:
70 psi
60 psi
40 psi
25 psi
Which component ensures no two vaporizers can be used simultaneously?
Check valve
Pin-index system
Vaporizer interlock system
Key-indexed filler
If the O₂ flush valve is activated during inspiration, the risk is:
Barotrauma
Hypoxia
Awareness
Hypotension
Which pre-use test confirms the integrity of the low-pressure system?
Oxygen flush test
Leak test with oxygen analyzer
Negative pressure leak test
Cylinder pressure gauge
According to ASA machine check guidelines, vaporizers must be:
Interlocked, filled, and positioned upright
Checked only weekly
Tested by chemical indicator
Disconnected when not used
Which of the following devices must be tested by occluding the Y-piece and closing the APL valve?
Pressure relief valve
Breathing circuit integrity
Gas scavenging system
Flow sensors
The soda lime canister should be replaced when:
Moisture content increases
50% of granules turn purple
Expired more than 1 month
80% used
If nitrous oxide is turned on but flowmeters do not move, most likely cause is:
Cylinder empty
Flowmeter crack
Vaporizer malfunction
Check valve closed
The circle system check includes verifying:
Unidirectional valve movement
Cylinder color coding
Vaporizer agent level
Capnography calibration
Before induction, the O₂ analyzer should read:
19–21%
30–40%
100%
50%
Which monitor is mandatory before the first case each day as per ASA Standards?
BIS monitor
Capnograph
Neuromuscular monitor
EEG
The pre-anesthetic room air oxygen concentration should not fall below:
19%
21%
23%
25%
During the morning check, the APL valve is tested by:
Occluding the scavenging outlet
Closing it fully and pressurizing to 30 cmH₂O
Disconnecting it
Opening the flowmeters fully
The leak test of the circuit should not fall more than how much pressure per minute?
1 cmH₂O
3 cmH₂O
5 cmH₂O
10 cmH₂O
Which item is not part of the daily pre-anesthetic equipment check?
Suction apparatus
Laryngoscopes
Blood gas analyzer calibration
Difficult airway cart
Before anesthesia, suction pressure should be maintained at:
100 mmHg
300 mmHg
500 mmHg
Which oxygen failure safety device proportionally reduces N2O flow as O2 pressure drops?
Oxygen supply failure alarm
Link-25 proportioning system
Hypoxic guard system
Flow restrictor valve
The pre-induction checklist must confirm which of the following before patient arrival?
Vaporizer calibration certificates
Emergency drug availability (atropine, suxamethonium, ephedrine)
Ventilator battery level only
Oxygen cylinder expiry date only
What is the correct order of “machine to patient” daily check as per AAGBI?
High pressure → low pressure → breathing system → monitoring → backup
Low pressure → breathing circuit → vaporizers → scavenging
Electrical → gas → vapor → monitors
Any order if all parts checked
The most reliable method to detect circuit obstruction before induction is:
Visual inspection
Occlusion pressure test with reservoir bag
Leak test
Flowmeter calibration
Which parameter must be recorded on the pre-anesthesia morning checklist according to AAGBI?
Gas pipeline pressures
Cylinder serial numbers
Vaporizer model
Flowmeter calibration date
