pulmonary function including maximal expiratory flow-volume curve breathing of room air and of a gas mixture containing 80 % helium and 20 % oxygen ( he-o2 ) was measured at each incremental plasma theophylline concentration plateau ( 5 , 10 , and 15 micrograms/ml ) in 12 acutely ill asthmatic patients .
C0039771
theophylline
C0004096
asthmatic