The risks may not be justified for case of mild symptoms likely to resolve spontaneously, or for cases where the diver is likely to be unsafe in the water, but in-water recompression may be justified in cases where severe outcomes are likely, if conducted by a competent and suitably equipped team.Carrying out in-water recompression when there is a nearby recompression chamber or without suitable equipment and training is never a desirable option. The risk of the procedure is due to the diver suffering from DCS being seriously ill and may become paralysed, unconscious or stop breathing while under water. Any one of these events is likely to result in the diver drowning or asphyxiating or suffering further injury during a subsequent rescue to the surface. This risk can be reduced by improving airway security by using surface supplied gas and a helmet or full-face mask.Several schedules have been published for in-water recompression treatment, but little data on their efficacy is available.The decision of whether or not to attempt IWR is dependent on identifying the diver whose condition is serious enough to justify the risk, but whose clinical condition does not indicate that the risk is unacceptable. The risk may not be justified for mild DCI, if spontaneous recovery is probable whether the diver is recompressed or not, and surface oxygen is indicated for these cases. However, in these cases the risk of the recompression is also low, and early abandonment is also unlikely to cause further harm.
Although it is possible that this may have other causes, such as an injured intervertebral disk, these symptoms indicate an urgent need for medical assessment. In combination with weakness, paralysis or loss of bowel or bladder control, they indicate a medical emergency. Prevention
Underwater diving
To prevent the excess formation of bubbles that can lead to decompression sickness, divers limit their ascent rate—the recommended ascent rate used by popular decompression models is about 10 metres (33 ft) per minute—and follow a decompression schedule as necessary. This schedule may require the diver to ascend to a particular depth, and remain at that depth until sufficient inert gas has been eliminated from the body to allow further ascent. Each of these is termed a "decompression stop", and a schedule for a given bottom time and depth may contain one or more stops, or none at all. Dives that contain no decompression stops are called "no-stop dives", but divers usually schedule a short "safety stop" at 3 to 6 m (10 to 20 ft),  depending on the training agency or dive computer.The decompression schedule may be derived from decompression tables, decompression software, or from dive computers, and these are generally based upon a mathematical model of the bodys uptake and release of inert gas as pressure changes.