[Effects of ipratropium bromide and salbutamol on isolated lung hyperinflation in symptom-free intervals in asthmatic children].

To evaluate the effects of salbutamol and ipratropium bromide on the isolated hyperinflation, without central airways obstruction, during asymptomatic periods in asthmatic children, 31 children, out of ca. 500, were selected for a double-blind therapy trial, according to the following criteria: Thoracic gas volume greater than 140% predicted (mean +/- 1SD: 162 +/- 16%) and/or trapped-gas greater than 15% (21 +/- 5%); airways resistance less than 140% (105 +/- 25%) and forced expiratory volume in one second greater than 75% (91 +/- 11%). On 4 consecutive mornings spirometry, bodyplethesmography and measurement of functional residual capacity by helium-dilution were performed before and 20' after inhalation of 2 ml of each of 4 solutions respectively. The children received the solution which produced the largest fall of thoracic gas volume and/or trapped-gas, 4 times/day for 4-5 weeks: 1. five children received saline; 2. 13 salbutamol, 2.5 mg; 3. 6 ipratropium, 0.250 mg; 4. 7 both drugs. Clinical aspects and lung function differed not significantly between the 4 groups. Lung function values showed no correlations with duration, clinical severity and typ of asthma. At the beginning and after 4-5 weeks of treatment lung function improved significantly in the groups 2-4, compared with pretreatment values. At study end, the improvements of thoracic gas volume, trapped-gas and airways resistance differed significantly between the groups, salbutamol + ipratropium produced altogether the best effect. With time, the effect of salbutamol + ipratropium on thoracic gas volume and trapped-gas increased and that of salbutamol on airways resistance and forced expiratory volume in one second decreased.(ABSTRACT TRUNCATED AT 250 WORDS)