Spirometric modifications in a population that initiates scuba diving with compressed air

Abstract

Objective. This study aimed to observe spirometric modifications in a population of scuba diving student who initiated it for the first time and continuously in the hyperbaric setting with compressed air.

Methods. Ninety-two healthy, male, military subjects who were taking an 8-week scuba diving course at 50 meters deep with compressed air were studied. We measured forced vital capacity (FVC), forced expired volume in the 1st second (FEV1), FEV1/FVC, and forced expiratory flow at 25-75% and 75-85% of FVC (FEF 25-75%, FEF 75-85%). Lung function was measured with portable spirometry Vitalograph COMPACT. A pulmonary function test was performed in all subjects on the first day of the course and weekly.

Results. No differences were found in FVC values during the time of the diving course. There were significant differences in the decline of FEV1 (102.72 ± 12.91 and 96.73 ± 15.83; p < 0.001), FEV1/FVC (78.75 ± 7.73 and 74.25 ± 9.91; p < 0.001), FEF 25-75% (95.83 ± 22.36 and 84.33 ± 18.94; p < 0.001) and FEF 75-85% (105.08 ± 35.86 and 86.27 ± 29.44; p < 0.001).

Conclusions. A decreasing evolution of flow parameters, that was not linked to either depth or time of exposure to the hyperbaric setting, was observed. Combined effects of diving equipment and breathing compressed air could contribute to the fall of flow parameters.