Diving disorders and particularly Decompression sickness (DCS) represent a major concern in recreational and occupational pressure-related activities. As a result of decompression from higher to lower ambient pressure bubbles which are formed in vascular flow and in tissues take part in embolism then resulting in DCS. Individual factors such as vascular or respiratory defects are now considered to increase the risk of this dysbarism disease.

2 groups of occupational divers will be separated after a fitness medical examination by regarding DLCO decrease or not.

The divers will be evaluated before and 30, 60, 180 minutes after a 20 meters air dive. Venous bubbles will be detected by precordial Doppler 30 minutes after the dive.

In association with this Doppler, Flow Mediated Dilation, blood samples analysing inflammatory and thrombotic factors and other biomarkers will be explored before and after the dive in order to know how vascular and respiratory tracts in this environment react.

Inclusion Criteria:

• Be professional and voluntary diver
• Man or woman aged 18 years or older
• Diffusing Lung Capacity for Carbon Monoxide measured beforehand in the study
• No medical contraindication for hyperbaric
• No hyperbaric constraint in 3 days before the dive
• No prior Decompression sickness
• Not to follow medicinal treatment modifying the vascular endothelial and/or the coagulation and/or the respiratory function
• Patient affiliated to social security
• Informed and signed

Exclusion Criteria:

• Concomitant pathology identified by the Investigator, justifying a contraindication for hyperbaric
• Pregnant and nursing mothers
• Patient who refuse to sign consent form