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Diving disorders are medical conditions specifically arising from underwater diving. The signs and symptoms of these may present during a dive, on surfacing, or up to several hours after a dive. The principal conditions are decompression illness (which covers decompression sickness and arterial gas embolism ), nitrogen narcosis , high pressure ...
Generalized hypoxia occurs when breathing mixtures of gases with a low oxygen content, e.g. while diving underwater especially when using closed-circuit rebreather systems that control the amount of oxygen in the supplied air, or when breathing gas mixtures blended to prevent oxygen toxicity at depths below about 60 m near or at the surface ...
Typically an oxygen rebreather for attack swimmers, and a mixed gas rebreather for clearance diving work, and this simplifies the training and logistical requirements. [50] Rebreather diving for recreational purposes is generally classed as technical diving, and the training is provided by the technical diver certification agencies.
Nitrox and drysuit use, greater frequency of diving in the past year, increasing age, and years since certification were associated with lower risk, possibly as indicators of more extensive training and experience. [1] Statistics show diving fatalities comparable to motor vehicle accidents of 16.4 per 100,000 divers and 16 per 100,000 drivers.
Breathing mixtures for diving must limit partial pressure of oxygen to avoid the risk of acute oxygen toxicity, Recreational technical divers generally limit partial pressure of oxygen at the maximum planned depth of a dive to approximately 1.4 bar. When diving to depths below 57 m this requires the use of breathing gases with less than 21% oxygen.
Gas injection system failure is also mainly a problem of mixed gas diving rebreathers. Oxygen rebreathers gas injection systems are generally robust and reliable and can be manually overridden if they fail, and this form of failure is identifiable by an inappropriate volume of gas in the ambient pressure volume of the rebreather.
Severe hypercapnia is more likely to be a problem in rebreather diving. [23] Scrubber failure is the most common cause at moderate to shallow depths. Excessive work of breathing (WoB), when extreme, can exceed the capacity of the diver to eliminate carbon dioxide and eventually cause a hypocapnic blackout, which is likely to be followed by ...
A Diving rebreather is an underwater breathing apparatus that absorbs the carbon dioxide of a diver's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. Oxygen is added to replenish the amount metabolised by the diver.