Anesthesia Machine Checkout Procedure
relliott@ottawahospital.on.ca
INITIAL STEPS
 Quick visual
□ Obvious damage/missing parts
□ BioMed return to service tags
□ Machine is plugged into (red) receptacle with generator backup
 green receptacles have no backup
□ System Master switch is OFF
 Back-up ventilation equipment
□ Ambu bag
□ O2 source (cylinder at back)
HIGH PRESSURE SYSTEM
 Central pipeline
□ Hoses are connected correctly (colour, DISS)
 misconnections
□ Pipeline gauges (at front) read 50-55 psi
 Line pressure fluctuations
 Failure of central O2 supply
□ Disconnect the O2 pipeline → gauge drops to 0
 O2 reserve cylinder supply
□ Bleed O2 cylinder pressure to 0 with flush
 Avoid reading old cylinder pressure
□ Open O2 cylinder at back and verify that it is at least half full (1000psi)
 Wrong cylinder
 Dust protection cap still in place
□ Listen for an audible leak
 Missing gasket, cylinder not seated properly in yoke
 Cylinder valve system is loose
 Unused yoke vacant with no yoke plug
□ Open and close the O2 flow meter (front) → no flow seen
 Machine master switch allows leak
□ Close the cylinder → pressure gauge drops to less than 100 psi in 5min
 Cylinder control valve leaks
 Leaking pipeline (check valve)
LOW PRESSURE SYSTEM
 Vaporizer installation
□ Tops are parallel to manifold (cannot be lifted off)
 Vaporizers are not locked onto manifold properly
□ Vaporizers are full and fill ports are closed/off
 Overfilling of vaporizer
 Low Pressure Leak Test
□ Check bulb with hand
 Defective suction bulb
□ Suction bulb on auxiliary (fresh) gas outlet → stays collapsed for >10secs
 Leak somewhere b/w flow control valves and common gas outlet
□ Cracked, loose or misaligned flow tubes
□ Loose connections (internal piping components)
□ Repeat leak test for each flow meter (O2, N2O, Air)
□ Repeat leak test for each vaporizer (set dial to 1% concentration)
 Partially open filler/drain port
 Missing vaporizer port o-ring on the manifold
□ Other vaporizers cannot be turned ON
 Faulty interlock mechanism
 Will not turn ON if interlock is obstructed
□ Vaporizers are OFF, auxiliary gas outlet is closed and flush system with O2
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Electrical power and O2 supply failure alarm
□ Unplug the machine power from the outlet
□ Turn ON master switch
□ Verify “Battery Power OK” message
□ Plug in power cord → message disappears
 Battery discharge b/c machine was previously left ON and unplugged from
AC outlet
□ Turn ON vital signs monitor (allows the gas analyzer to warm up)
Verify O2 supply failure alarm
 Alarm mechanism malfunction
□ Drain O2 by pressing the flush
□ Listen for the distinctive auditory pattern
□ Look for visual message on the vent
□ Turn on the O2 cylinder to silence the alarm
□ Remove the O2 sensor from the circuit (exposes O2 sensor to room air for later
calibration)
Test flow meters
□ Minimum flows are 25mL/min for O2 and 0mL/min for other gases
 No flow → broken tip of needle valve
□ Test floats through their full range (turn ↓ O2 after turning N2O ↑↓)
 Sticks → dirt, grease, static
 Ensure that float does not stick to top of tube
□ Inability to provide hypoxic flow rates (N2O:O2 – 3:1 proportioner) by turning
↑N2O and watching for proportional ↑ in O2
 Linkage broken or gear stop misaligned
□ Turning vaporizers ON does not lower gas flows
 Obstruction in vaporizer or manifold
□ Ensure that low O2 pressure stops N2O flow, but NOT Air
→ Set all 3 floats to mid-range
→ Close O2 cylinder
→ Push O2 flush
 O2 supply failure alarm sounds (when O2 supply pressure is at 30 psi) and
N2O float drops (when O2 supply pressure is at 20 psi), while Air continues
□ Close all 3 gas flow controls
□ Reconnect the O2 pipeline
 Verify pipeline pressure (50-55 psi)
BREATHING SYSTEM
 Calibrate the O2 monitor
□ Ensure that the monitor reads 21% with sensor in room air
 Faulty fuel cell if unable to calibrate
□ Verify low O2 alarm by breathing on the sensor through mask
 Crossover b/w O2 supply and other gas (hosp piping, hoses or in gas
machine)
□ Reinstall sensor in circuit
□ Flush breathing system with O2 → monitor should read >95%
 Wrong gas in central supply/cylinder
 Check initial status of breathing system
□ Set selector switch to “Bag/APL”
□ Circuit is complete, undamaged, unobstructed
 Manufacturing defects
□ CO2 absorbent is adequate (colour, quantity)
□ Attach gas sampling line to the circuit
□ Set all flows to 0/min
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Check the function of unidirectional valves
□ Attach the spare breathing bag to the inspiratory outlet and close the APL valve
completely
□ Fill both the test bag and reservoir bag with O2 flush until pressure gauge reads
35cm H20 → pressure should hold if both valves are competent
 Missing, incompetent valves or incorrectly seated
□ Open APL valve → pressure holds, but only the reservoir bag deflates
 If the reservoir bag deflates before opening APL valve, the expiratory valve is
leaking
□ If needed, repeat the test on the expiratory inlet with the inspiratory outlet
occluded
Leak test: Bag/APL valve circuit
□ Set the selector switch to Bag/APL
□ Close the APL valve and attach the spare breathing bag to the Y-piece
□ Inflate the bag with O2 flush to just <40cm H2O
□ Circuit pressure holds steady for >10secs
□ Ventilator bellows does not move
NUMEROUS POSSIBLE LEAK SITES
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Auxiliary FGF outlet left open
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CO2 canister not locked into position
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Faulty canister seals or granules are preventing good seal

CO2 drain plug partially open

Unidirectional valve housing loose
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O2 sensor not firmly seated in port or sensor housing is cracked
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Flow sensor housing cracked
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Pressure sensing tubing from gauge is not tightly connected (internal)
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Leak in breathing bag, circuit hoses
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Unused sampling ports not capped
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Faulty selector switch → allows cross-over of gas into ventilator circuit
Check APL valve and scavenging system
□ With APL valve still closed and circuit occluded, squeeze inflated bag until
pressure reaches ~70cm H2O
→ high pressure alarm sounds with 40cm H2O limit is exceeded
→ APL valve partially releases and reservoir bag on scavenger fills
 Improperly adjusted APL valve (set to release either too high or too low)
 No alarm → upper limit is set too high
□ Open APL valve slowly until pressure drops below 20cm H2O, then stop
→ pressure should stabilize and hold
→ sustained pressure alarm stops
 Cannot adjust pressure (valve sticking)
 Sustained pressure limit is high – max set at 30cm H2O
□ Open APL valve fully, flush occluded circuit with O2
→ circuit pressure stays <10cm H2O
 Hose from the circuit to scavenger is blocked
→ scavenging reservoir bag fills and then positive pressure relief valve releases
 Faulty positive pressure relief valve on scavenger
□ APL valve fully open, flows are set to min and circuit is still occluded
→ circuit breathing bag does not deflate
 Too much vacuum and faulty negative pressure relief valve
→ scavenging reservoir bag does deflate
 No vacuum
 Needle valve closed
VENTILATOR SYSTEM
 Test automatic ventilation system
□ Selector switch set to Ventilator – all flows set to min, breathing bag on Y-piece
 Defective ventilator relief valve
□ Fill bellows with O2 flush b/w ventilator breaths
→ pressure should not exceed 15cm H2O
→ release flush
 Relief valve does not close to allow bellows to fill completely
 Bellows housing is not fastened tightly
□ Set appropriate ventilator parameters for next patient
→ inspiration: bellows delivers correct tidal volume
→ expiration: bellows fills completely
→ volume monitor is consistent with the ventilator
→ proper action of unidirectional valves
 Drive gas hose is not firmly attached
 Connection from absorber to bellows is leaking
 Volume sensor is faulty
 Valves stick or do not seat properly
□ Remove breathing bag from Y-piece while ventilator is still working
□ Low pressure alarm sounds (“Cannot drive Bellows”) until breathing bag is
replaced
 Alarm faulty
 Ventilator senses pressure 4-9cm H2O with breathing bag off (obstruction)
□ Set selector switch back to Bag/APL (turns ventilator OFF) when bellows is fully
inflated
□ Ventilator bellows does not drift downward
 Leak somewhere
 Test manual ventilation system
□ Switch in Bag/APL mode
□ Ventilate manually and assure inflation and deflation of artificial lung and
appropriate feel of system resistance and compliance
 Faulty APL valve
 Incorrect pressure adjustment
□ Remove second breathing bag from Y-piece
FINAL STATUS CHECK
 Gas machine and breathing systems
□ Vaporizers off
□ Selector switch to Bag/APL and adjust APL valve to MIN
□ Set O2 flow to 3L/min (other gases to 0)
□ Attach face mask to Y-piece and through a surgical mask breath in and out
through the circuit as a final test
□ Set O2 flow to minimum
 Monitors
□ Check that capnometer registers CO2 from your breath
□ Apnea alarm sounds after appropriate interval (check alarm settings)
□ Check oximeter on your own finger (check alarm settings)
□ Make sure manual BP cuff is available
□ Patient suction is adequate (thumb test)
□ Flashlight available.