ABSTRACT
To confirm the possibility of middle ear barotrauma in Guinea Pigs even to safe, recomm-endable diving profiles to sports SCUBA divers and to study operating microscopic findings and progress of middle ear barotrauma, 16 Guinea Pigs were exposed to hyperbaric chamber for simulated diving. Simulated diving profiles were 20 meter sea water of maximum depth, 18 meter per minute of ascent, descent rates, 20 minutes of bottom time, 60 minutes of surface interval time and 2 repetitive dives in a day for 2 consecutive days. Then, tympanic membrane, middle ear and round membrane window were examined by operating microscope on 1 day, 7 days after simulated diving respectively. The experimental results showed that 26 of 32 ears(81.2%) disclosed findings of barotrauma in total, 23 ears(71.9%) in tympanic membrane, 25(78.1%) in middle ear, 7 ears(21.9%) in round window membrane respectively. The main operating microscopic findings of barotrauma were hyperemia of tympanic membrane in 23 ears(71.9%), hyperemia in 25 ears(78.1%), bleeding in 22 ears(68.8%) of middle ear, followed by bleeding, perforation of tympanic membrane, edema, effusion in middle ear, bleeding and rupture of round window membrane in order. Hyperemia of tympanic membrane and bleeding of middle ear in day 7 group showed significantly lower rate of barotrauma than those of day 1 group, that suggest spontaneous improvement in mild case of experimental middle ear barotrauma.