Middle ear barotrauma is caused by the inability of the diver to clear the space in the middle ear through the Eustachian tube and has been described by MacFie and placed in TEED types I through IV. This diagnosis is made on the basis of pain on descent aand physical examination shows redness of the tympanic membrane due to hemorrhage and occasionally free blood in the middle ear cavity. MacFie has types I through V, Fred Pullen describes mild, moderate and severe.
TEED Classification of Middle Ear Barotrauma
Type I–congestion of umbra
Type II–entire drum red
Type III–hemorrhage and fluid
TypeIV–hemorrhage and perforation
Nature abhors a vacuum, so negative pressure in the middle ear retracts the ear drum and fills the middle ear with fluid.
To prevent middle ear squeeze, equalize frequently during descent by auto-inflation. The diver should dive feet first, which reduces venous engorgement of the head, sinuses and eustachian tube. The head down position produces a closure of the sinus ostia or eustachian tube.
During descent, unequal pressure causes an inward bulging of the tympanic membrane, which will continue unless the middle ear pressure is equalized. Fluid pressure within the inner ear equals that of the water surrounding the diver and with continued descent the pressure in the external auditory canal increases. Unless the pressure is equalized, round window rupture or tympanic membrane rupture may occur with as little as 100 millimeters of mercury difference between the external auditory canal and the middle ear. This change in pressure can be as little as 4 feet sea water.
Treatment
Try to achieve eustachian tube patency and function by autoinflation. The conductive hearing loss that is usually found is usually resolved by itself. Treatment with systemic decongestants (Sudafed, 60 mg orally three times a day. Topical nasal decongestants should be tried, (no longer than three days to avoid rhinitis medicamentosa).
Antibiotics are used only when there is fluid in the middle ear and there is the possibility of infection. If perforation is present, oral antibiotics definitely should be used. Eardrops are definitely contraindicated if there is perforation of the eardrum.
Return to diving
Divers with middle ear barotrauma should be discouraged from diving until all symptoms have cleared and the individual can autoinflate easily. If there has been perforation, diving should not be resumed for at least six weeks after the perforation has healed to allow for complete resolution of all edema and swelling. No ear drops should be used in the event of TM rupture, as damage can be done to the middle ear.
Reverse squeeze
A reverse squeeze occurs when the diver ascends with a blocked eustachian tube, causing increased pressure and pain within the tympanic cavity. This is most often due to congestion but can be due to other abnormalities around the opening of the Eustachian tube, succh as polyps, septal deviation or scarring. Frequently, descending to a comfortable level and then swallowing will clear the ears. If it is impossible to clear, the diver must ascend to the surface in spite of the pain, and round window or ear drum rupture can occur as a result of the hemorrhage and edema of the forced ascent. In this event–the diver must seek immediate ENT care for surgical repair of the round window.