Decreases in Diffusing Lung Capacity for Carbon Monoxide (DLCO) in Occupational Divers and Their Impact on Decompression Sickness Risks

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Decreases in Diffusing Lung Capacity for Carbon Monoxide (DLCO) in Occupational Divers and Their Impact on Decompression Sickness Risks

Conditions
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Decompression Sickness

Intervention / Treatment
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* Other: 20 meters air dive


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 20 meters air dive<br> | Other: 20 meters air dive<br>* A dive in the depth of 20 m during 40 minutes. 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Venous bubbles will be detected by precordial Doppler | Venous bubbles will be detected by precordial Doppler | 30 minutes after the dive | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vascular abnormality | Assessement of microvascular reactivity by brachial artery flow mediated dilation | 60 minutes after the dive | 
| Coagulation activation | Assessment of blood coagulation factor after the dive | 60 minutes after the dive | 
| Inflammatory activation | Assessment of inflammatory factor after the dive | 60 minutes after the dive | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Alveolo-capillar membrane, decompression illness, diving, occupational