Vertigo Due To Barotrauma

Abstract

This vertigo is associated with exposure to alterations in ambient pressure, either an increase (diving) or a decrease (flying). The atmosphere exerts an absolute pressure of 760 mm Hg at sea level, the standard one atmosphere absolute (1 ATA) pressure. Changes of pressure in water increase linearly with increasing depth: one atmosphere is added for each 33 ft. This increased pressure is balanced by breathing air delivered at the new ambient pressure and by equalising the pressure in all gas-containing body cavities to ambient (Farmer and Thomas 1976; Margulies 1987). The volume of gas varies inversely with ambient pressure and this pressure–volume relationship mostly causes the barotrauma. The likelihood of damage to the Eustachian tube and middle and inner ear increases as the rate of change of external pressure increases, because it is in these areas that large pressure differentials are produced.