Decompression sickness lessen the pressure reduction, and hence the risk of DCS. All cases of decompression sickness should be treated initially with 100% oxygen until hyperbaric oxygen therapy (100% oxygen delivered in a high-pressure chamber) can be provided. Mild cases of the "bends" and some skin symptoms may disappear during descent from high altitude; however, it is recommended that these cases still be evaluated. Neurological symptoms, pulmonary symptoms, and mottled or marbled skin lesions should be treated with hyperbaric oxygen therapy if seen within 10 to 14 days of development. Recompression on air was shown to be an effective treatment for minor
Ratio decompression Ratio decompression Ratio decompression (usually referred to in abbreviated form as ratio deco) is a technique for calculating decompression schedules for scuba divers engaged in deep diving without using dive tables, decompression software or a dive computer. It is generally taught as part of the "DIR" philosophy of diving promoted by organisations such Global Underwater Explorers (GUE) and Unified Team Diving (UTD) at the advanced technical diving level. It is designed for decompression diving executed deeper than standard recreational diving depth limits using trimix as a "bottom mix" breathing gas. The physiology behind the off-gassing of nitrogen or helium absorbed