[Asthma-tobacco interaction and alterations of maximal expiratory flow in air and in helium-oxygen (author's transl)].
The eventual interaction between tobacco and asthma and the sensitivity of different functional tests on small airways are compared in 4 groups of subjects (n = 49): non-smokers and control smokers, asthmatic non-smokers and smokers. All subjects have a normal vital capacity (VC) and a normal forced expiratory volume in one second (FEV1). The measurement of mid expiratory time (MET) and maximal flow at 50% (V Max 50) and at 25% (V Max 25) of the flow volume curve in air (FEMV) does not have any discriminating advantages over the simple measurement of the ratio FEV1/VC. The latter, although always normal, differentiates the controls from the asthmatic non-smokers. Besides, helium independency (characterized by an increase in the V Max 50 air-helium less than 20% and an increase of volume iso flow [V iso V] beyond 20% of VC) is mostly linked to tobacco addiction but is definitely worsened when associated to asthma.
D000388:Air; D001249:Asthma / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005540:Forced Expiratory Flow Rates; D005541:Forced Expiratory Volume; D006371:Helium; D006801:Humans; D008297:Male; D008448:Maximal Expiratory Flow Rate; D008449:Maximal Expiratory Flow-Volume Curves; D010100:Oxygen; D012907:Smoking; D014797:Vital Capacity
D006371:Helium; D010100:Oxygen
Interaction asthme-tabac et modifications des débits maximaux en air et en hélium-oxygène.