1. Connect a rebreathing circuit and bag on your machine as if you were about to perform a surgery.

2. Close the pop-off valve and cover the end of the rebreathing circuit (where the E/T tube connects) with your palm or finger.

3. Push the oxygen flush button or turn the flowmeter on until the pressure gauge reads at least 20 cmH2O.

4. Turn the oxygen off and watch the pressure gauge. If the reading drops rapidly (faster than 1 cmH2O per second), you have a leak.

5. Check hoses, rebreathing bag, vaporizer inlet and outlet, any mechanical fittings, and the seals of the canister for leaks. When the pressure remains fairly constant, with the flow meter turned off, your machine can be considered leak free.

6. With your thumb still over the y-piece, open the pop-off valve to ensure the gases have an unobstructed path out of the evacuation system.

If you are unable to find a leak and your patients continue to be “light,” be sure to contact your local anesthesia service company for a service appointment. There may be issues with your vaporizer or scavenger system, and your system should be serviced by a professional.