Introduction: The aim was to investigate the prevalence of middle ear barotrauma (MEB) and to establish risk factors of MEB after repeated saltwater dives.
Methods: In this prospective observational cohort study 28 divers were examined over 6 consecutive days of diving in the Red Sea, Egypt. Participants underwent an otoscopic examination before the first dive, between each dive and after the last dive. In addition, they performed Valsalva maneuver (VM) and were questioned about dive-related complaints. Otoscopic findings were classified according to TEED classification for MEB (0 = normal otoscopy to 4 = perforation) separately for each ear. First examination was conducted before the first dive. Final examination, including a questionnaire, was conducted at least 12 h after the last dive.
Results: In total, 436 dives were performed and 1161 otoscopic findings were analyzed. All participants showed a normal eardrum and a positive VM during initial exam. MEB prevalence (TEED >0) was 36.5% at final examination. Prevalence increased significantly with number of dives per day (p < 0.001) as with number of diving days (p = 0.032). Neither depth nor duration of dives significantly influenced MEB prevalence (all p > 0.05). More experienced divers (>200 dives lifetime) showed significantly less barotrauma (p < 0.0001). Despite the high prevalence of MEB, 81.7% (316 of 387) of all dives were reported asymptomatic.
Conclusions: After 6 days of repetitive diving, MEB prevalence was high (36.5%). It was the most often cause of otalgia in divers. Cumulative pressure exposure during repetitive dives resulted in significant increase of MEB. Diving experience significantly reduced the MEB prevalence. Interestingly, the severity of MEB did not correlate with subjective complaints.