Delayed onset, fluctuation and progressive deterioration of deafness point toward perilymph fistula. Dizziness, hearing impairment and tinnitus after scuba diving indicate likely injury of inner ear but the cause may be either decompression sickness or barotrauma. The perilymphatic fistula is most severe form of IEBt but it diagnosis is not always obvious. Morvan and co-authors presented a series of 11 cases of perilymphatic fistula due to IEBt in scuba divers. Authors suspect that excessive pressure caused by forceful Valsalva may have been the cause of IEBt in some divers and especially in those with normal opening pressures but who became impatient with equalization and blew to strongly. Divers with IEBt and perilymph fistula had more severe ET dysfunction. However, some divers with IEBt had normal ET function at the time of measurement. Among divers with IEBt, most had dysfunctional ET requiring either greater pressure differential to open it and/or it took longer time to equalize. They avoided IEBt so far, probably by practicing slow ascent but they often experienced alternobaric vertigo. In healthy divers without a history of IEBt, one third had slow equalizing ET but the pressure differential required was within normal range. The stenotic ET takes larger pressure (up to 1200 daPa/120 cm H 2O measured) to open it or it fills and empties very slowly. Normal ET is collapsed but it takes less than 650 daPa to open it and it fills or empties instantaneously. The patulous ET is open permanently or it takes pressure differential of less than 200 daPa to open it. The paper describes three main type of ET based on the equalization characteristics: patulous (open) ET, normal ET and stenotic (narrowed) ET. The maximum volume of air in middle ear varies from 0.2 to 0.9 ml. In the ideal conditions, the pressure differential needed to open the ET in either direction is 200 to 650 daPa which corresponds to a pressure gradient caused by depth change of 20-65 cm or 8-26 inches. ![]() They measured the opening pressure for ET, the maximum volume of the air in the middle ear and the speed at which the equalization occurs. They correlated the function of Eustachian tube to the incidence of IEBt. Kitayima and co-authors studied Eustachian tube function in 16 divers who experienced IEBt and in 20 healthy divers without history of IEBt. 2 June 2016 brings three articles addressing these issues. ![]() The Diving and Hyperbaric Medicine Volume 46 No. While middle-ear barotrauma usually heals well, inner ear barotrauma may cause permanent damage if not recognized and treated on time and thus, the prevention of IEBt is very important. The most common diving injury related to Eustachian tube dysfunction is middle ear barotrauma, and less common but more grave is inner-ear barotrauma (IEBt). Eustachian tube dysfunction may result with ear injury during diving. We recommend you take good care of your ears and be aware of the risks to your hearing health in summer.Normal Eustachian tube (ET) function is important for fitness to dive. On the other hand, tympanostomy or pressure equalization (PE) tubes can be inserted in the eardrum to drain the ear if none of the solutions above are successful in improving the symptoms. ![]() On the one hand, certain medicines, such as nasal decongestants, antihistamines and steroid treatments may be helpful and can be taken in combination with antibiotics if there is a risk of infection due to a blockage in the eustachian tubes. Two treatments can be used to relieve ear barotrauma if none of the techniques above improve the situation. This helps to push air into the eustachian tubes and counterbalance the negative air pressure in the middle ear. Recommended techniques for preventing ear barotrauma include chewing gum, yawning or carrying out the Valsalva manoeuvre, which involves closing the glottis, pinching the nose shut and exhaling forcefully.
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