normal human subjects ( n = 7 ) breathing 21 % o2 ( normoxia ) , 13 % o2 ( hypoxia ) , or 100 % o2 ( hyperoxia ) performed repeated maximal inspiratory maneuvers ( inspiratory duration = 1.5 s , total breath duration = 3.5 s ) on an `` '' isoflow '' '' system , which delivered a constant mouth flow ( 1.25 or 1 l/s ) while maintaining normocapnia ( 5.5 % end-tidal co2 ) .
C0035203
breathing
C0004048
inspiratory