Monday, September 14, 2009

Decompression Sickness

Decompression sickness (DCS; also historically or colloquially known as divers' disease, the bends or caisson disease) describes a condition arising from the precipitation of dissolved gasses into bubbles inside the body on depressurisation. DCS most commonly refers to a specific type of scuba diving hazard but may be experienced in other depressurisation events such as caisson working, flying in unpressurised aircraft and extra-vehicular activity from spacecraft.

Although DCS is not a common event, its potential severity is such that much research has gone into preventing it and scuba divers use dive tables or dive computers to set limits to their exposure to pressure. Its effects may vary from joint pain and rash to paralysis and death. Treatment is by hyperbaric oxygen therapy in a recompression chamber. If treated early, there is a significantly higher chance of success.

The original name for DCS was caisson disease; this term was used in the 19th century, in large engineering excavations below the water table, such as with the piers of bridges and with tunnels, where caissons under pressure were used to keep water from flooding the excavations. Workers who spend time in high-pressure atmospheric pressure conditions are at risk when they return to the lower pressure outside the caisson without slowly reducing the surrounding pressure.

DCS was a major factor in the during construction of Eads Bridge, when 15 workers died from what was then a mysterious illness, and later during construction of the Brooklyn Bridge, where it incapacitated the project leader Washington Roebling.

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