A reverse squeeze is barotrauma due to an inability to release pressure from the middle ear on ascent.
Pressure must be released from the middle ear as the diver ascends, or the expanding air will bulge and even rupture the eardrum. Expanding air normally escapes down the Eustachian tubes, but if the tubes are blocked with mucus at depth (usually the result of poor equalization on descent, diving while congested or relying on decongestants that wear off at depth), barotrauma can result.
- Pressure, fullness in ear
- Ear pain
While diving: Sometimes one of the equalizing techniques used on descent will clear your ears on ascent. Pointing the affected ear toward the bottom may help, too. Ascend as slowly as your air supply allows. Increasing pressure usually opens the Eustachian tube and relieves overpressure. However, in rare cases it may persist all the way up. In that case, you will have to endure the pain to reach the surface. Notify your buddy, and stay in close proximity.
First aid: Nasal decongestant spray may help open the Eustachian tube. A physician evaluation is advised if you experience vertigo, protracted pain and fullness of the ears.
Prior to diving, try equalizing on the surface to ensure Eustachian tube function