Source: "An Operator's Guide:Troubleshooting Common Problems" North American Drager Educational Services.

There are some common problems with anesthesia machines which one should be able to diagnose, primarily to save oneself the embarasement of calling a monitoring tech only to find it was something really simple. Some of the more common ones are listed below along with a list of their possible causes.

Ventilator Will Not Ventilate Patient

Has the breathing system been properly tested for leaks and/or occlusions?
Is the ventilator Turned ON?
Is the inspiratory pressure gauge reading within the low, medium, or high range?
Is the ventilator respiratory rate set at greater than zero?
Is the Tidal Volume present adjusted properly?
Is the Inspiratory Pressure Limiting Valve adjusted properly?
Is the manual/automatic selector valve set in the "auto" position?

Ventilator Bellows Will Not Compress Fully During Inspiration

Is the Inspiratory Flow set high enough to accomplish full compression of the bellows?
Is the manual/auto switch set to the "auto" position?
Is the pressure limiter set appropriately to allow full compression?
Is the bottom plate of the bellows canister securely connected to the bellows canister?
Have you checked the hose between the bellows and the manual/auto selector switch for excessive moisture?
Have you checked the entire circuit for obstructions?

Ventilator Bellows Will Not Stay Inflated

Is the total volume of fresh gas being supplied to the patient breathing circuit adequate for the patient?
Has the breathing system been tested for leaks?
Has the ventilator bellows and the 22 mm hose that connects it to the absorber been checked for leaks?
Is the patient/breathing circuit connection secure?
Is the ventilator relief valve adjusted correctly?

Check to be sure that the PEEP valve control know is rotated fully counter-clolckwise (off).
If the anesthesia system is equipped with a PEEP valve slide,a be sure it is in the off position.
Check the hose between the ventilator bellows assembly and the absorber for excessive moisture or "water".
Check the patient breathing circuit for water, excessive moisture, or any other possible obstruction.
Is the ventilator relief valve properly adjusted?
Check all scavernger gas hoses for excessive moisture