Possible mechanism: The muscle tone keeping the intraoral parotid gland orifice closed is reduced, either by (a) drugs used during anesthesia or (b) parasympathetic response caused by stimulation of the pharynx. This makes it easier for a transient increase in oropharyngeal pressure to let air enter the parotid duct and then the parotid gland.
Risk factors:
(1) use of an endotracheal tube, endoscopy, bronchoscopy or rigid esophagoscopy
(2) use of muscle relaxants or paralyzing agents
(3) increased oropharyngeal pressure (mask ventilation, violent coughing)
Clinical findings:
(1) unilateral or bilateral swelling of the parotid glands during or shortly after surgery
(2) painless
(3) crepitus felt on palpation
(4) frothy and bubbly saliva which can be produced by pressing on the parotid gland
(5) spontaneous regression over the next few days
Because the process is often only an isolated event it is unlikely to be complicated by infection.
