To remove mucus that may be building up in the throat to avoid the person from chocking and becoming ill this will help to improve the flow of air into the lungs resulting in patient being able to breathe better on their own (RCH).
Oral suctioning is also used in order to maintain a patients airway if they are to have a blockage such as having a build up of mucus or if their chocking on food or if they have add a allergic reaction and just needs to keep the airway open; oral suctioning will help to keep them breathing on their own. It is also important to watch for any respiratory distress so that you know that oral suctioning is needed and that there isn't another reason why they may be out of breath or having trouble with their breathing (RCH.).