FDA Anesthesia Machine Pre-Use Check
The latest version (1993) of the anesthesia machine pre-use checklist
as developed by the FDA is shown. These recommendations are valid only
for an anesthesia system that is equipped with an ascending bellows
ventilator and at least the following monitors: capnograph, pulse oximeter,
oxygen analyzer, spirometer and a breathing system pressure monitor
with high and low pressure alarms.
Users are encouraged to modify this guideline to accommodate differences
in equipment design and variations in local practice. Such local modifications
should have appropriate peer review. Refer to the appropriate operator
manuals for specific procedures and precautions. If an anesthesia provider
uses the same machine in successive cases, the steps shaded in gray
need not be repeated or can be abbreviated after the initial checkout.
For convenience, a disposable 1993 FDA checklist is formatted to print
as a PDF, FlashPaper,
or Word document on one page
which, when folded in four, should fit in a medical scrub pocket. Print
as many copies as you need. Click
here to access the free Anesthesia Patient Safety Foundation/University
of Florida transparent reality simulation of the 1993 FDA anesthesia
machine pre-use check.
Emergency Ventilation Equipment
1. Verify backup ventilation equipment is available
and functioning (e.g. Ambu bag).
High Pressure System
2. Check oxygen cylinder supply:
a. Verify that at least one backup cylinder is
available and check to see that it is at least half full (about 1000
psi) by opening the cylinder valve and verifying that the cylinder
pressure gauge goes up. No other cylinders need to be checked.
b. Close the oxygen cylinder valve after checking.
3. Check central pipeline supplies:
Check that hoses are connected and that the pipeline
pressure gauges read about 50 psi.
4. Check initial status of low pressure system.
a. Close the flow control valves and turn the
b. Check the vaporizer fill levels and tighten the vaporizer filler
caps, test interlock system.
5. Perform leak check of low pressure system.
a. Verify that the machine master switch and flow
control valves are off.
b. Attach a suction bulb to the common gas outlet.
c. Squeeze the bulb repeatedly until it is fully collapsed.
d. Verify that it stays collapsed for at least 10 seconds (a vacuum
cannot be created if there is a significant leak).
e. Open one vaporizer at a time and repeat step c & d (the bulb
will initially re-inflate due to the gas that was in the vaporizing
f. Remove the suction bulb and reconnect the fresh gas flow hose to
the common gas outlet.
6. Turn on the machine master switch and all other
The low pressure alarm should be heard because of the sudden increase
of gas pressure in the oxygen pipeline.
7. Test flowmeters.
a. Adjust flow of all gases through their full
range, checking for smooth operation of floats and undamaged flowtubes.
The minimum flowrate of oxygen should be 200 ml/min in Ohmeda Modulus
I and II machines.
b. Attempt to create a hypoxic O2/N2O mixture by adjusting flowmeters
and make sure the hypoxic safeguard mechanism prevents this from happening.
8. Adjust and check scavenging system.
a. Ensure proper connections between the scavenging
system and both the APL valve and ventilator relief valve.
b. Adjust waste gas vacuum.
c. Fully open APL valve and occlude the Y-piece.
d. With minimum O2 flow, allow the scavenger reservoir bag to collapse
completely and verify that the absorber pressure reads about zero
(this tests the negative pressure relief valve - room air is drawn
into the scavenging system).
e. With the O2 flush activated allow the scavenger reservoir bag to
distend fully, and then verify that the absorber pressure gauge reads
< 10 cm H2O (this tests the positive pressure relief valve - the
high flow of the O2 flush will overcome the scavenging system and
excess gas will vent through the valve).
Breathing Circle System
9. Calibrate the oxygen monitor.
Two different oxygen analyzers are actually used in our operating
One type is an electrochemical (slow) sensor that measures FiO2 in
the inspiratory limb of the circuit. The FiO2 will be displayed in
the same display as the ventilator settings.
The other type is a paramagnetic sensor (fast) that is inside the
gas-analyzing unit that also does infrared absorption spectrometry
of the anesthetic gases and shows the capnogram.
a. Ensure the oxygen monitor reads 21% in room air.
b. Verify that the low O2 alarm is enabled and functioning.
c. Reinstall the sensor in the circuit and flush breathing system
d. Verify that the monitor now reads greater than 90%.
10. Check initial status breathing system.
a. Set the selector switch to Bag mode.
b. Check that the breathing circuit is complete, undamaged and unobstructed.
c. Verify that CO2 absorbent is adequate and not exhausted.
d. Install breathing circuit accessory equipment (e.g. PEEP valve)
that is to be used during the case.
11. Perform (positive pressure) leak check of the breathing system.
a. Set all gas flows to minimum.
b. Close APL valve and occlude the Y-piece.
c. Pressurize the breathing system to about 30 cm H2O with O2 flush
(check the inspiratory pressure gauge).
d. Ensure that the pressure does not decrease for at least 10 seconds.
e. Open the APL valve and ensure that the pressure decreases.
12. Test ventilation systems and unidirectional valves.
a. Place a second breathing bag on the Y-piece.
b. Set appropriate ventilator parameters for next patient.
c. Set the selector switch to Ventilator mode.
d. Turn the ventilator on and fill bellows and breathing bag with
e. Set O2 flow to minimum and other gas flows to zero.
f. Verify that during inspiration bellows delivers appropriate tidal
volume and that during expiration bellows fills completely.
g. Set fresh gas flow to about 5 L/min.
h. Verify that the ventilator bellows and simulated lungs fill and
empty appropriately without sustained pressure at end expiration.
i. Check for proper action of the unidirectional valves.
j. Exercise breathing circuit accessories to ensure proper function.
k. If everything works satisfactorily, turn the ventilator off and
switch the selector switch to Bag mode.
l. Ventilate manually and feel if there is an appropriate amount of
system resistance and compliance during inflation and deflation of
the "artificial lungs".
m. Remove the second breathing bag from the Y-piece.
13. Check, calibrate and/or set alarm limits of all monitors.
14. Check final status of machine.
a. Vaporizers off
b. APL valve open
c. Selector switch to Bag mode
d. All flowmeters to zero or minimum (oxygen)
e. Patient suction level adequate
f. Breathing system ready to use