Evaluation of predive parameters related to eustachian tube dysfunction for symptomatic middle ear barotrauma in divers.
Eustachian tube dysfunction plays an important role in the pathogenesis of middle ear barotrauma. This investigation evaluates the predictive value of several parameters related to tubal dysfunction, in relation to symptomatic middle ear barotrauma in divers. Prospective and blinded. Thirty-one sport scuba divers with normal predive audiometry, tympanometry, and general and otorhinolaryngologic examination. After an occurrence of middle ear barotrauma, the individual diver predive data on smoking, mild septal deviation, otitis media history, rhinosinusitis history, Valsalva, Toynbee, and nine-step inflation/deflation tympanometric test, as well as degree of mastoid pneumatization were registered for calculation of predictive value in relation to the barotrauma. All symptomatic ears were examined within 24 hours of diving by the investigator, who was blinded to the predive findings. Barotraumas that occurred during an upper respiratory tract infection were excluded. Divers completed a total of 774 dives (median, 25; range, 3-100). Symptomatic middle ear barotrauma occurred in 19 ears (31%) of 14 divers (45%) at one time or another. The rate of tubal dysfunction measured by the nine-step test and a mastoid pneumatization below average were significantly higher in divers (p <0.05) as well as in ears (p <0.005) with barotrauma. Positive and negative predictive values of both parameters for subsequent barotrauma were between 69% and 76%. Combining the results into a two-test battery in a strict approach (positive on both) increased the positive predictive value to 86%. Eustachian tube dysfunction measured by the nine-step test and a small size of the mastoid cell system seem to be risk factors for symptomatic middle ear barotrauma in otherwise healthy sport scuba divers. Evaluation of these factors in the predive examination of diving candidates may be useful in the determination of fitness to dive.