[New elements in the interpretation of flow-volume curves]. / Nouveaux éléments d'interprétation de la courbe débit-volume.

We have measured flow-volume curves (FV) in 167 normal individuals of both sexes aged 20 to 89. All were non-smokers and none had cardio-respiratory disease. The flows at 25, 50 and 75 per cent of vital capacity (VC) as well as flows normalized by VC or total lung capacity (TLC) gave, in general, good correlation coefficients with age. The parameters V25/TLC and especially V50/TLC gave for the best correlations with age and we suggest these parameters in future when flow volume curves are used to assess respiratory pathophysiology. Normal values as well as regression equations of these parameters with age are proposed for various age groups in the 20-89 years age range.

Plethysmography study and pulmonary function in well-trained adolescents.

The values of lung volumes (VC, FRC, TGV, FEV1.0, etc.) and airway resistances (Raw, Raw) were measured by the spirometry and plethysmography method in 35 physically well trained, healthy adolescents, aged 14 to 20 years, boys and girls coming from various schools from the Grenoble area. The data were correlated with body height and some also with age or weight through linear, exponential or power law relationships. All volumes increased with height (Ht), which was the best independent variable, with some preference for a linear representation. However the increase of lung volumes with height was also well reproduced by an exponential function proportional for all volumes to e0.020Ht in good agreement with recent results obtained for young children. Some significant sex differences were observed for lung volumes. Airway resistance measured by two different methods (Raw and Raw) decreased with height with some preference for a linear relationship. The mean airway resistance (Raw) obtained from a complete inspiration-expiration curve while the subject breathed at his own spontaneous breathing rate was systematically smaller (from 0.5 to 1 cmH2O/l/s) than Raw measured by a technique similar to the panting method. No sex differences for airway resistances or conductances were observed. Specific airway conductance was found to be age and height independent.