Barotrauma of the Ear due to Diving

Definition

Barotrauma is the pain or damage done to bodily tissues due to the inability of pockets of air in certain tissues to equalize pressure with the pressure that is outside the body. There are three major areas in the body where air pockets are located: the middle ear, the sinuses, and the alveoli of the lungs where carbon dioxide is exchanged for oxygen. We will only cover barotrauma of the ear in this document.

The most common examples of barotrauma occur from diving below thirty feet (app. 10 Meters), ascending from below thirty foot depths,  or from high altitude exposure to low atmospheric pressure. 

How the middle ear works

The middle ear is very sensitive to changes in atmospheric pressure. Nerves in he middle ear chamber where the ossicles (the bones that transmit sound from the ear drum to the inner ear) are located, continually send messages to the Eustachian tube (located at the back of the throat) to open and close to keep the chamber pressure the same as outside the body. (For more details on how the ear works, please click here).

Types of Barotrauma Due to Diving

Water pressure outside the middle ear cavity greater than internal pressure

When the pressure in the middle ear varies too little from the outside pressure, then the outside pressure will push the eardrum in. If the Eustachian tube does not open to relieve the pressure and equalize it to the outside pressure, then the eardrum can be literally be pushed into the middle ear chamber and ripped open. If underwater, then water will flood the middle ear chamber and can cause damage to the middle ear bone or the inner ear permanent hearing loss.

With divers, barotrauma usually does not happen once they are at their destination under the water; it usually occurs either on the way down, or on the way back up. For example: As a descent is made, water pressure (inner ear squeeze) on the body (and the eardrum) accelerates quite fast. If there is a large pressure differential between the water pressure and the middle ear there will be extreme pain before the eardrum is penetrated.  Divers are taught that before pressure builds up on the eardrums, to immediately start swallowing or hold the nose and force air from the sinuses to the Eustachian tube to open it.  Once opened and the pressure equalized, the pressure on the eardrum is relieved. Pain means there’s a problem. It usually begins when the differential between the ambient and middle ear pressure reaches only 60 mmHg (millimeters of mercury). This is equal to a descent of only 2.5 feet (0.76 m). By the time the Eustachian tubes reach a pressure differential of 90 mmHg (equal to a descent of less than 4 feet [1.2 m]), they will “lock shut.” This means effective clearing must begin before descending a mere 4 feet (1.2 m). Waiting until one is deeper will require more force to be exerted to open the Eustachian tube and can cause additional damage.

Water pressure inside the middle ear greater than external water pressure

Sometimes the reverse can happen - an eardrum can be pushed out while diving. The most common cause is wearing earplugs while diving. Wearing an earplug creates an air space between the plug and the eardrum - an artificial air pocket. On a descent. the air inside the newly formed space has no way of equalizing so it becomes a vacuum. As a descent is made, the pressure from the higher water pressure create a low pressure pocket between the eardrum and the earplug. The external water pressure creates a greater vacuum in the space and forces the plug deeper inside the ear. If the descent continues, the eardrum will rupture, and the plug will have been driven deep within the ear. On very rare occasions this has happened as a result of excessive buildup of ear wax.

Minor Trauma to the Ear

Even with a sharp pain the the Eustachian tube opened, a diver may have damage to the middle ear, usually in the form of ruptured blood vessels in the inner ear as shown by the following images:

A healthy eardrum	A damaged eardrum due to water pressure. Note the indented middle of the eardrum, inflamed color, and the blood behind the eardrum.  However it has not ruptured.

This level of trauma to the eardrum will often heal on its own.

Major Trauma to the Ear

If the worst happens and a dive is too fast and a penetrated eardrum occurs and the middle ear is penetrated by water, a trip to the Emergency Room and then an ENT (Ear, Nose, Throat Specialist) is mandatory. Temporarily you will be in extreme pain. Take two ibuprofen to help relieve some of the pain until you get something stronger from a physician.

Chronic Ear Problems due to Water

Although not related to Barotrauma, swimmers, divers and surfers, who are continually in cold water can get growths of bony swellings in the outer ear canal known as exostoses. These growths are usually benign when small, but when larger, they can interfere with wax drainage and predispose to infections such as otitis externa (swimmers ear).