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Influence of repetitive diving in freshwater on pressure equalization and Eustachian tube function in recreational scuba divers: a prospective observational trial
18 April 2018 (online)
The objective was to investigate the effect of repetitive pressure exposure during freshwater dives on Eustachian tube function and the middle ear, assessed by Eustachian tube function test (ETFT).
This prospective observational cohort study included 23 participants, which dived during three consecutive days in freshwater lakes in Nordhausen, Germany. All participants underwent otoscopy and ETFT before the first dive, between each dive and after the last dive. ETFT included regular tympanometry (R-tymp), tympanometry after Valsalva (V-tymp) and after swallowing (S-tymp). Peak pressure difference R-V-tymp and V-S-tymp defined the pressure equalization after Valsalva and after swallowing maneuvers, respectively. We evaluated the change of compliance and peak pressure and correlated the results to the otoscopic findings.
Altogether, 46 ears were analyzed after 144 dives. In the ETFT, the R-tymp peak pressure displayed a negative shift from day one to three (p =.001) and differed significantly between the experiences groups (p =.010). Peak pressure difference during equalization maneuvers (R-V-tymp and V-S-tymp) increased on day one (all p>.05) but did not change equivalently to the shift of the R-tymp peak pressure on days two and three (all p>.05). Participants without barotrauma showed significantly lower R-tymp values than with barotrauma (p =.019).
Repetitive pressure exposure during three consecutive days of diving led to negative shift of the peak pressure in the middle ear. Less experienced divers showed significantly higher middle ear peak pressure and higher pressure difference after equalization maneuvers. Higher middle ear peak pressure was also associated with higher barotrauma prevalence.