Outcomes
Following barotrauma of the ears or lungs from diving the diver should not dive again until cleared by a diving doctor. After ear injury examination will include a hearing test and a demonstration that the middle ear can be autoinflated. Recovery can take weeks to months. Epidemiology
An estimate of in the order of 1000 dive injuries per year occur in the United States and Canada. Many of these involve barotrauma, with nearly 50% of reported injuries involving middle ear barotrauma. Diving injuries tend to correlate with trait anxiety and a tendency to panic, lack of experience, advancing age and reduction in fitness, alcohol usage, obesity, asthma, chronic sinusitis and otitis. Barotrauma in other animals
Whales and dolphins develop severely disabling barotrauma when exposed to excessive pressure changes induced by navy sonar, oil industry airguns, explosives, undersea earthquakes and volcanic eruptions.Injury and mortality of fish, marine mammals, including sea otters, seals, dolphins and whales, and birds by underwater explosions has been recorded in several studies. Bats can suffer fatal barotrauma in the low pressure zones behind the blades of wind turbines due to their more fragile mammalian lung structure in comparison with the more robust avian lungs, which are less affected by pressure change. Swim bladder overexpansion
Fish with isolated swim bladders are susceptible to barotrauma of ascent when brought to the surface by fishing. The swim bladder is an organ of buoyancy control which is filled with gas extracted from solution in the blood, and which is normally removed by the reverse process.
Rapid change of altitude
A rapid change of altitude can cause barotrauma when internal air spaces cannot be equalised. Self inflicted barotrauma
Excessively strenuous efforts to equalise the ears using the Valsalva manoeuvre can overpressurise the middle ear, and can cause middle ear and/or inner ear barotrauma. Blast-induced barotrauma
An explosive blast and explosive decompression create a pressure wave that can induce barotrauma. The difference in pressure between internal organs and the outer surface of the body causes injuries to internal organs that contain gas, such as the lungs, gastrointestinal tract, and ear.Lung injuries can also occur during rapid decompression, although the risk of injury is lower than with explosive decompression. Ventilator-induced barotrauma
Mechanical ventilation can lead to barotrauma of the lungs. This can be due to either:
absolute pressures used in order to ventilate non-compliant lungs. shearing forces, particularly associated with rapid changes in gas velocity.The resultant alveolar rupture can lead to pneumothorax, pulmonary interstitial emphysema (PIE) and pneumomediastinum.Barotrauma is a recognised complication of mechanical ventilation that can occur in any patient receiving mechanical ventilation, but is most commonly associated with acute respiratory distress syndrome. It used to be the most common complication of mechanical ventilation but can usually be avoided by limiting tidal volume and plateau pressure to less than 30 to 50 cm water column (30 to 50 mb). As an indicator of transalveolar pressure, which predicts alveolar distention, plateau pressure or peak airway pressure (PAP) may be the most effective predictor of risk, but there is no generally accepted safe pressure at which there is no risk.