Decompression sickness Decompression sickness Decompression sickness (DCS; also known as divers' disease, the bends, aerobullosis, or caisson disease) describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurisation. DCS most commonly refers to problems arising from underwater diving decompression (i.e., during ascent), but may be experienced in other depressurisation events such as emerging from a caisson, flying in an unpressurised aircraft at altitude, and extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness. Since bubbles can form in or migrate to any part of the body, DCS
Scuba set pressure gauge, and in the looser sense it has been used to refer to any diving equipment used by the scuba diver, though this would more commonly and accurately be termed scuba equipment or scuba gear. Scuba is overwhelmingly the most common underwater breathing system used by recreational divers and is also used in professional diving when it provides advantages, usually of mobility and range, over surface supplied diving systems, and is allowed by the relevant code of practice. Two basic functional systems of scuba are in general use: open-circuit-demand, and rebreather. In open-circuit demand scuba, the diver expels exhaled