Description

• Barotrauma of the middle or inner ear, most commonly caused by flying in an airplane or scuba diving but also caused by travel in elevators and travel to high altitudes
• May also be seen in those who have used a hyperbaric oxygen chamber and in people involved in explosions—blast injuries
• Referred to as “middle ear squeeze” by scuba divers

Epidemiology

• Severe disease is uncommon in commercial aircraft because of pressurization.
• Significant disease is more common in scuba divers, in those who fly military aircraft, and during use of hyperbaric oxygen chambers.
• There is wide variation, with studies reporting an incidence of 8–55% for children after a single flight.
• Most studies agree that the incidence is ~20% in adults after a single flight.
• 40% frequency in scuba diving

Risk Factors

• Age: Infants or toddlers are at higher risk because of small eustachian tubes.
• Disease states that impede normal eustachian tube function: otitis media, upper respiratory tract infection (URI), allergic rhinitis
• Smoking
• Vigorous use of Valsalva maneuver

General Prevention

• Gradual descent during scuba diving—never rapid
• When ascending, divers should avoid rising more quickly than their air bubbles.
• Yawning, swallowing, chewing, or doing Valsalva maneuver during takeoff and landing in planes and during ascent and descent when scuba diving
• Gentle Valsalva—never vigorous
• Avoid flying or diving when you have a URI or allergic rhinitis.
• Avoid sleeping on plane during takeoff and landing.
• Break seal of wet suit hood to allow water to fill external canal before descent.
• Avoid use of earplugs.

Pathophysiology

• Boyle’s law states that as pressure of a gas decreases, volume increases, and as pressure of a gas increases, volume decreases.
• Ambient pressure decreases during airplane/scuba diving ascent and increases during descent.
• During ascent, the tympanic membrane (TM) bulges outward and the eustachian tube vents the excess middle ear pressure. Pressure is easily equalized.
• During descent, the TM bulges inward and the eustachian tube resists inward flow of air. Pressure equalization is difficult.
• At a pressure differential of 60 mm Hg (greater ambient to middle ear pressure), subjective discomfort is reported.
• At a pressure differential of 90 mm Hg, the eustachian tube collapses and becomes obstructed. Autoinflation is unsuccessful.
• TM can rupture at pressure differentials >100 to 400 mm Hg.
• Barotitis is sometimes classified using Teed classification of disease severity (see “Physical Exam”).

Etiology

Differences in the atmospheric pressure between the inner ear, middle ear, and environment result in injury to the middle and/or inner ear.