Barotrauma of the Middle Ear
Barotrauma of the middle ear manifests at the level of the eardrum, a membrane that stifls the ear canal (external ear) from the middle ear.
The middle ear is in communication with the throat through the Eustace Tube, through which the balance between the pressure of the air contained in the middle ear and the pressure of the breathed air is made.
Under normal physiological conditions, during diving, any variation in ambient pressure (hydrostatic pressure) will thus be compensated by the air pressure we breathe through the regulator.
If, for any reason (anatomical, pathophysiological, or temporary changes), the Eustace Tube is obstructed and does not allow free air circulation, the balance is not done, creating an imbalance of pressures. The air inside the middle ear maintains initial pressure and reduces its volume, causing distension (curvature) of the tympanum membrane in the direction of the middle ear.
The first symptom of this situation is hearing loss and pain, which will become increasingly intense if the diver insists on the descent.
Pressure compensation maneuvers
In principle this situation will not happen if the diver is careful to, from the beginning of the descent, perform pressure compensation maneuvers, which can be the simple act of swallowing or chewing by moving the jaw from side to side. These maneuvers facilitate the clearance of the Eustace tube allowing air to enter the ambient pressure into the middle ear.
Valsalva maneuver
This maneuver consists of trying to exhale through the nose, with a tight nose. As the air cannot come out, the pressure will increase enough to make its way through the Eustace tube in order to restore the balance of pressures between the middle ear and throat. In this way, the ear is compensated.
The Valsalva maneuver must be made as soon as the descent begins, very gentlely and again and again. If this does not work, the descent should be suspended immediately to avoid more serious situations, such as the rupture of the eardrum, with all the resulting consequences.
TO THE SLIGHTEST HINT OF PAIN, THE DESCENT MUST BE IMMEDIATELY INTERRUPTED
The diver must climb a few meters, until the painful symptom disappears completely, and restart the compensation maneuver and the descent .
In the long run the individual who does not spare his ears, may suffer from chronic otitis and early deafness.
Other manoeuvres may be carried out for the same purpose, but because they are more difficult to perform, they are not mentioned here.
Usually, during the ascent the Eustace tube opens passively. However, although it is less frequent, during the ascent there may also be difficulty in compensating the ear. In this case there is the reverse situation of the descent, that is, by lowering the ambient pressure, the air inside the middle ear increases in volume and if the eardrum cannot escape, it is obliged to distend itself, in this case from the inside out. This distension of the eardrum causes acute pain and has the same implications described above.
As soon as it enters the water, the diver should remove the hood from the suit in the ear site, so that the water will see a water in the outside ear, so that there is no air bubble inside. If this happens, the release of the bubble during the dive by simply tilting the head may cause a vertigo situation by the sudden contact of the water with the tympanum membrane.
The use of earplugs creates an air zone at atmospheric pressure, between the cap and the tympanum membrane.
If the Eustace tube is permeable and allows air to pass through the ambient pressure into the middle ear, an imbalance of pressures between the middle ear and the blister retained by the cap will be created, which will lead to distension of the tympanum membrane from the inside out, with the above consequences. The presence of wax in the ears can also cause an effect identical to that of the tampons.
THE USE OF EARPLUGS IS ABSOLUTELY FORBIDDEN WHEN DIVING
The use of vasoconstrictor drugs is highly ill-advised. Its time of effect is reduced and may end during the dive and cause problems to the diver when the climb begins.
In this situation, by lowering the ambient pressure, the air in the middle ear increases in volume. If you can’t get out because the horn is no longer permeable, you’ll push the tympanum membrane out, causing the barotrauma.
Summarizing
If after the onset of the painful symptom (because the pressures between the middle ear and the environment cannot be balanced) the diver insists on descent or ascent, other disturbances will arise, which will constitute the clinical pictures of barotraumatic otitis.
Depending on the intensity of the aggression, the effects of barotrauma may be congestion of the eardrum, bleeding and shedding in the eardrum box, and may even cause rupture of the eardrum.
After a barotraumatic accident of the ear, the diver should immediately go to the specialist doctor, limiting himself to taking an analgesic drug (aspirin, saridon, etc.) to reduce discomfort. Never put ear drops before being observed, so that a correct assessment of the extent of the damage caused can be made.
EAR BAROTRAUMA CAN HAPPEN BOTH ON DESCENT AND DURING ASCENT