So, a descent from the surface to 10 metres (33 feet) underwater results in a doubling of the pressure on the diver. This pressure change will reduce the volume of a flexible gas-filled space by half. Boyles law describes the relationship between the volume of the gas space and the pressure in the gas.Barotraumas of descent are caused by preventing the free change of volume of the gas in a closed space in contact with the diver, resulting in a pressure difference between the tissues and the gas space, and the unbalanced force due to this pressure difference causes deformation of the tissues resulting in cell rupture.Barotraumas of ascent are also caused when the free change of volume of the gas in a closed space in contact with the diver is prevented. In this case the pressure difference causes a resultant tension in the surrounding tissues which exceeds their tensile strength. Use of a hyperbaric chamber
Patients undergoing hyperbaric oxygen therapy must equalize their ears to avoid barotrauma. High risk of otic barotrauma is associated with unconscious patients. Rapid decompression of a pressurised artificial environment
Explosive decompression of a hyperbaric environment can produce severe barotrauma, followed by severe decompression bubble formation and other related injury. The Byford Dolphin incident is an example. Rapid uncontrolled decomression from caissons, airlocks, pressurised aircraft, spacecraft, and pressure suits can have similar effects of decompression barotrauma. Rapid pressurisation of an artificial environment
Collapse of a pressure resistant structure such as a submarine, submersible, or atmospheric diving suit can cause rapid compression barotrauma.
A variety of injuries may be present, which may include inner ear haemorrhage, intralabyrinthine membrane tear, perilymph fistula, and other pathologies.Divers who develop cochlear and/or vestibular symptoms during descent to any depth, or during shallow diving in which decompression sickness is unlikely, should be treated with bed rest with head elevation, and should avoid any activity which could cause raised cerebrospinal fluid and intralabyrinthine pressure. If there is no improvement in symptoms after 48 hours, exploratory tympanotomy may be considered to investigate possible repair of a labyrinthine window fistula. Recompression therapy is contraindicated in these cases, but is the definitive treatment for inner ear decompression sickness, making an early and accurate differential diagnosis important for deciding on appropriate treatment. IEBt in divers may be difficult to distinguish from inner ear decompression sickness (IEDCS), and as a dive profile alone cannot always eliminate either of the possibilities, the detailed dive history may be necessary to diagnose the more likely injury. It is also possible for both to occur at the same time, and IEDCS is more likely to affect the semicircular canals, causing severe vertigo, while IEBt is more likely to affect the cochlea, causing hearing loss, but these are just statistical probabilities, and in reality it can go either way or both. It is accepted practice to assume that if any symptom typical of DCS is present, that the diver has DCS and will be treated accordingly with recompression.