Anesthetic face masks are usually cone-shaped, and their sizes vary depending on the size of the subject. Face masks selected should be of a snug fit and should not obstruct the mouth or nose of the subject. Small, transparent masks fitted with flexible rubber diaphragms prove to be useful in a large array of animals and birds. The snug fit ensures that the masks are not too large for the animal and prevent the re-inhalation of expired gases. Face masks that incorporate waste anesthetic gas removal (Hunter et al., 1984) are ideal for preventing exposure-related hazards to the personnel.
Breathing systems are used for the delivery of oxygen, removal of exhaled carbon dioxide, and ensuring sufficient anesthetic gases, meeting the animal’s requirements, are delivered. Although anesthetic chambers are useful when used for small animals that are difficult to restrain, they require the removal of the subject from the chamber to allow for surgical procedures. Thus, breathing systems make for a better option as opposed to the anesthetic chambers.