Straining or a forceful Valsalva can cause rupture of the round or oval window , as first described by Fred Pullen in 1971. This results in a fistula with drainage of fluid into the middle ear, sensineural hearing loss, vertigo, or tinnitus and should be operated upon immediately to correct the fistula. They should not be recompressed if the above symptoms occur during a dive that has not required decompression.
Inner Ear Decompression Sickness
Here are two references to this entity:
1. Inner Ear Decompression Sickness (IEDCS)--manifested by tinnitus, vertigo, nausea, vomiting, and hearing loss--is usually associated with deep air or mixed gas dives, and accompanied by other CNS symptoms of decompression sickness (DCS). Early recompression treatment is required in order to avoid permanent inner ear damage. They present an unusual case of a scuba diver suffering from IEDCS as the only manifestation of DCS following a short shallow scuba dive, successfully treated by U.S. Navy treatment table 6 and tranquilizers. This case suggests that diving medical personnel should be more aware of the possible occurrence of IEDCS among the wide population of sport scuba divers. Aviat Space Environ Med 61 (6): 563-566 (Jun 1990)
2. Inner ear decompression sickness (IEDCS) is one form of Type II decompression sickness. Most cases of IEDCS have been associated with saturation dives, so there are very few reports of occurrence following shallow scuba dives. They present a case of a diver who suffered from IEDCS following a shallow scuba dive (30m), and was successfully treated by the protocol outlined in U.S. Navy treatment table 6. This case suggests that there is the possibility of occurrence of IEDCS, even following a shallow scuba dive, if proper decompression procedures are not adhered to. In addition, detailed analysis of diving profiles should be used to distinguish the inner ear dysfunction seen in some divers from inner ear barotrauma which may be attributable to IEDCS. Nippon Jibiinkoka Gakkai Kaiho 95 (4): 499-504 (Apr 1992).