The Effect of the M17A2 Mask on Spirometry Values in Healthy Subjects
NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA
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The effects of the M17A2 gas mask on respiratory function was evaluated using standard pulmonary function test measurements. Marine volunteers 58 males, 8 females performed forced vital capacity FVC and maximum voluntary ventilation MVV maneuvers with and without the mask. The subjects were randomly assigned to be tested in the mask or the control condition first. The mask had significant effects on almost all the volumes and flows measured. There was a decrement of 200 ml in the mean FVC p.002 and in the forced expiratory volume in 1 second FEV2, p.001. The forced expiratory volume in .5 second FEV.5 dropped from 58 to 54 of the total FVC p.007, but the other proportional relationships were not changed. Higher baseline flows were correlated with greater drops in flow when the mask was worn r.64, p.001. Mean MVV dropped by 24 liters 15 p.001 in the masked condition. Females dropped their FEV1s by 17, while males dropped by only 4 p.003, with similar nonsignificant trends on other measures. Unlike the overall group, smokers did not show a significant drop in FEV.5, FEV1, the enforced expiratory volume in 3 seconds or the forced expiratory flow rate during the middle half of the breath. Keywords Operational effectiveness.
- Anatomy and Physiology
- Command, Control and Communications Systems