007 - Relationships between specific airway resistance and forced expiratory flows in asthmatic children - 05/12/08
B. Mahut [1, 2, 3, 4 et 7],
L. Trinquart [5 et 7],
P. Bokov [2, 6 et 7],
M. Le Bourgeois [3],
S. Waernessyckle [3],
C. Peiffer [2 et 7],
C. Delclaux [2, 4 et 7]
Ver las filiacionesBackground: The nature and strength of the relationships between specific airway resistance (sRaw) and forced expiratory flows have poorly been described.
Methods and patients: We determined the mathematical relationships between resistance and forced expiratory flows based on a two-compartment lung model. Pulmonary function tests (sRaw0.5, FEV1, FVC, FEF25-75%, FEF50%) of 2193 asthmatic children were selected from two databases for a transversal analysis. Subsequently, 365 children were selected for longitudinal assessment from preschool to school age.
Results: The mathematical analysis and the observed data demonstrated that sRaw is differently linked with FEF50% (-1/sRaw) and FEV1 (near linearly). A statistically higher correlation between sRaw0.5 and FEF50% than with FEV1 was evidenced. In asthmatic children suspected for small airway disease (FEF25-75% / FEV1 ratio < 0.80 and FEV1 > 80% predicted, n=968), the relationship between sRaw and flow rates was linear, a 10% reduction of FEF25- 75% or FEF50% corresponded to a mean increase in sRaw of ˜ 0.50 kPa.s. In the longitudinal part of the study, sRaw0.5 at preschool age was better correlated with FEF50% than FEV1 at school age.
Conclusion: Specific Raw is better linked to FEF50% than to FEV1 and can detect airway obstruction from preschool to school age.
© 2008 Elsevier Masson SAS. Tous droits réservés.