AN21 - Health Research and Developmental Services; Health Research and Training; Basic Research

The Naval Submarine Medical Research Laboratory (NSMRL) is interested in understanding the physiological responses to decompression stress. To that end, NSMRL plans to conduct dry hyperbaric experiments with up to 14 U.S. Navy divers as test subjects during which they will be exposed to a dive profile that is expected to produce venous gas emboli (VGE).

As VGE are filtered by the lungs, it is possible that biomarkers of this decompression stress may be evident in the exhaled breath of the divers following decompression. Thus, one of the primary aims of the NSMRL study entitled Applied Biomarkers of Decompression Stress is to identify substances in exhaled breath that are associated with decompression stress. To do this, NSMRL researchers will collect exhaled breath condensate (EBC) immediately before the dive and at two time points post-dive.

These EBC samples will be compared to a control condition in which the same divers breathe a normobaric nitrox gas mixture (with the PiO2 matched to the decompression dive) that will not produce any VGE. During both the decompression dive and the control condition, will also collect breath samples on thermal desorption tubes pre- and post-dive at the same time points, as well as gas sample controls to allow for analysis of the volatile organic compounds in exhaled breath.

NSMRL will be responsible for securing human use approval prior to conducting the study and will supply all EBC and VOC samples to the awarded contractor as de-identified coded samples. Description of tasks in attached synopsis.