Exercise-induced Asthma In Children Research Articles

Incidence of exercise-induced asthma in children

The incidence of exercise-induced asthma (EIA) was studied in 134 asthmatic and 102 nonasthmatic atopic children and compared to that in 56 nonatopic children. Pulmonary function tests measuring forced vital capacity (FVC) and 1-sec forced expiratory volume (FEV 1) were performed on each child prior to and serially for 20 min following free running exercise. The incidences of EIA among the asthmatic and atopic nonasthmatic children were 63% and 41%, respectively. This phenomenon is widespread among allergic children and cannot be accurately predicted from the history. A simple and easily performed outpatient procedure is described for the diagnosis of EIA.

Salmefamol and salbutamol in exercise-induced asthma in children

A double-blind controlled study is reported of salmefamol 200 μg and salbutamol 200 μg administered by aerosol before exercise tests in asthmatic children. Both drugs prevented exercise-induced asthma. There was no significant difference between them.

Incidence of Exercise-Induced Asthma in Children

The incidence of exercise-induced asthma (EIA) was studied in 134 asthmatic, 102 nonasthmatic atopic, and 56 nonatopic children. Pulmonary function tests measuring forced vital capacity (FVC) and one-second forced expiratory volume (FEV1) were performed on each child prior to and serially for 20 minutes following free running exercise. The incidence of EIA among the asthmatic and atopic nonasthmatic children was 63% and 41% respectively, and 7% among control subjects. Airway function was studied prior to and after a standardized free running exercise test. Forty-one percent of the nonasthmatic and 63% of the asthmatic atopic children had a significant decrease in airway function as compared to 5% of the nonallergic subjects.

Maximal expiratory flow and lung volume changes associated with exercise-induced asthma in children and the effect of breathing a low-density gas mixture.

1. Lung volumes and maximum expiratory flow volume (MEFV) curves were measured before and after exercise and after a bronchodilator in eight asthmatic children. 2. Exercise produced significant changes in all volumes and flow rates measured, but the most sensitive measurement was of flow rate at an absolute volume in the terminal portion of the forced vital capacity. Of the more simply obtained measurements maximal flow at 50% of the exhaled vital capacity was the most sensitive, but reductions in forced expiratory volume at 1 s and peak flow rate were almost as marked. 3. The marked reductions in flow rates at low lung volumes after exercise were accompanied by large increases in residual volume and a reduction in the slope of the MEFV curve. These changes suggest functional closure of some lung units and an increase in the time-constant of emptying of other units. 4. The response of flow to breathing helium—oxygen (79:21, v/v) was assessed in the dilated state (before exercise or after bronchodilator) and the constricted state (after exercise) in five of the subjects. 5. An increase in density-dependence of flow rates at all lung volumes during constriction is evidence that, despite the reduction in flow rates, convective acceleration and turbulent flow constitute a greater proportion of the total upstream resistance after exercise than before exercise. The implication is that the cross-sectional area at equal pressure points (EPP) is smaller after exercise than before exercise. This could result from either bronchoconstriction with no change in the location of EPP, or from progression of the EPP further upstream to a region where loss of airways or reduction in their diameter has rendered the total cross-sectional area considerably smaller than under normal circumstances.