Final answer:
Pressure tests on an anesthetic machine require closing the common gas outlet and the adjustable pressure-limiting valve to ensure the system is not leaking and is safe for patient use.
Step-by-step explanation:
When conducting pressure tests on an anesthetic machine, it is important to ensure that all connections are secure and that the system is closed to prevent leakage. To facilitate this, one must close the common gas outlet where the anesthesia circuit is normally attached. An essential aspect of the pressure test is to confirm that the machine holds pressure, thereby not leaking, when 'bag mode' is selected, and the adjustable pressure-limiting (APL) or pop-off valve is closed. This procedure is to be done before using the machine on a patient to ensure patient safety. The catheters mentioned would not be directly related to the pressure test of the anesthetic machine, rather they are for direct pressure monitoring in patients.