<P> Recompression on air was shown to be an effective treatment for minor DCS symptoms by Keays in 1909 . Evidence of the effectiveness of recompression therapy utilizing oxygen was first shown by Yarbrough and Behnke, and has since become the standard of care for treatment of DCS . Recompression is normally carried out in a recompression chamber . At a dive site, a riskier alternative is in - water recompression . </P> <P> Oxygen first aid has been used as an emergency treatment for diving injuries for years . If given within the first four hours of surfacing, it increases the success of recompression therapy as well as decreasing the number of recompression treatments required . Most fully closed - circuit rebreathers can deliver sustained high concentrations of oxygen - rich breathing gas and could be used as a means of supplying oxygen if dedicated equipment is not available . </P> <P> It is beneficial to give fluids, as this helps reduce dehydration . It is no longer recommended to administer aspirin, unless advised to do so by medical personnel, as analgesics may mask symptoms . People should be made comfortable and placed in the supine position (horizontal), or the recovery position if vomiting occurs . In the past, both the Trendelenburg position and the left lateral decubitus position (Durant's maneuver) have been suggested as beneficial where air emboli are suspected, but are no longer recommended for extended periods, owing to concerns regarding cerebral edema . </P> <P> The duration of recompression treatment depends on the severity of symptoms, the dive history, the type of recompression therapy used and the patient's response to the treatment . One of the more frequently used treatment schedules is the US Navy Table 6, which provides hyperbaric oxygen therapy with a maximum pressure equivalent to 60 feet (18 m) of seawater for a total time under pressure of 288 minutes, of which 240 minutes are on oxygen and the balance are air breaks to minimise the possibility of oxygen toxicity . </P>

Two scuba divers are 50 m below the surface of the water