Estimation of the bronchodilatory effect of deep inhalation after a free run in children

¹ Service d'Explorations Fonctionnelles Pédiatriques, Hôpital d'Enfants, Centre Hospitalier Universitaire de Nancy
² Laboratoire de Physiologie, Faculté de Médecine, Vandoeuvre les Nancy, France
³ Service d'Explorations Fonctionnelles Pédiatriques, Hôpital d'Enfants, Centre Hospitalier Universitaire de Nancy; and Laboratoire de Physiologie, Faculté de Médecine, Vandoeuvre les Nancy, France

^* To whom correspondence should be addressed. E-mail: f.marchal{at}chu-nancy.fr.

	Abstract

The bronchomotor effects of a deep inhalation (DI) may provide relevant information on the mechanisms of exercise induced airway obstruction in children and may be assessed by respiratory conductance (Grs) measured by the forced oscillation technique. The aims of the study were to assess the effect of DI on Grs after exercise, in relationship with the lung function response to exercise. Grs at 12 Hz using a head generator and spirometry were measured in 62 children suspect of asthma, before and 5 min after a 6 min free run. After exercise, Grs was significantly increased by DI in 38 subjects who had also larger Grs (p=0.002) and FEV₁/FVC (p=0.008) responses to exercise than the 24 non responders. Stepwise regression indicated significant correlation between Grs_DI and both Grs and FEV₁/FVC responses to exercise. The data are consistent with exercise induced bronchoconstriction being reversed by DI.