Maximal Airway Response in Adolescents With Long-term Asthma Remission and Persisting Airway Hypersensitivity: Asthma
Considering the fact that mild asthma patients were chosen for the symptomatic group in order to provide a matching degree of airway sensitivity to the remission group and to minimize the risks inherent in producing an excessive fall in FEV1, it is likely that a more balanced group of symptomatic asthmatics would have greater maximal airway response than the adolescents with asthma remission.
No published data are available on the maximal airway response to pharmacologic agents in adolescents with long-term clinical remission. The relatively mild degree of maximal airway response in adolescents with asthma remission, compared to that in adolescents with symptomatic asthma to a similar degree of airway sensitivity to methacholine, was not unexpected since the maximal airway response reflects the potential degree of airways obstruction in the individual patient irrespective of the level of sensitivity.” Indeed, it has been demonstrated that the maximal degree of airway narrowing is associated with the severity of asthma symptoms. Our observation suggests that the level of maximal airway response, rather than airway sensitivity, is a more important determinant of whether asthmatic symptoms occur, and supports the hypothesis that maximal airway response is an important con-founder in the relationship between airway sensitivity and the clinical expression of asthma. There are indications that the maximal airway narrowing response may be determined by mechanical factors, such as smooth-muscle contractility, airway wall thickness, and elastic loads from the surrounding parenchyma. The factors that normally limit airway narrowing are assumed to be operative in nonasthmatic subjects. It is possible that airway mechanical properties involved with maximal airway response are modified in adolescents with asthma remission.