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The response of salbutamol (Ventolin, Glaxo), topically administered from a metered dose inhaler (MDI) through a new baby-spacer-device (Babyhaler, Glaxo) was studied in 14 infants (8 wheezy infants, 3 infants with cystic fibrosis and 3 infants after respiratory distress syndrome), age 2.9-18.8 months. Changes in thoracic gas volume (TGV) as an estimate of pulmonary hyperinflation and changes in airway conductance (Gaw) as an estimate of bronchial obstruction were assessed by whole-body plethysmography. After baseline measurements, 1 puff of 100 micrograms salbutamol was given repeatedly at 5 min intervals until 600 micrograms have been inhaled and TGV and Gaw were measured after each inhalation at 5, 10, 15, 20, 25 and 30 min. Significant improvement in lung function was achieved in 57.1% of infants after 400 micrograms and in 92.9% of infants after 600 micrograms salbutamol. The study shows usefulness of bronchodilator treatment in infants with bronchopulmonary disease by a system with a MDI and baby-spacer-device. However a special dose-time relationship must be respected.

Functional disorders and efficacy of treatment with a beta-2-agonist salbutamol (Ventolin), 0.225 mg/kg bodyweight, systemically given, were evaluated by infant whole-body plethysmography in 60 infants (64 data sets) with broncho-pulmonary disease belonging to three diagnostic groups: 24 survivors after respiratory distress syndrome, 21 patients with recurrent wheezing, and 15 infants with cystic fibrosis. The values of thoracic gas volume (IGV) and airway resistance (Raw) prior to the drug administration showed a scattered distribution, which was unrelated to the 3 diagnostic groups. Therefore, stratification into 4 functional groups was performed. In 25 tests (22 infants) normal lung function (TGV less than 130% pred., Raw less than 130% pred.); in 16 tests pulmonary hyperinflation (TGV greater than 130% pred., Raw less than 130% pred.); in 10 tests hyperinflation and bronchial obstruction (TGV and Raw greater than 130% pred.); and in 13 tests (12 patients) bronchial obstruction (TGV less than 130% pred; Raw greater than 130% pred.) were found. The response to beta-2-agonists was evaluated by vector analysis (circular statistics) revealing different response groups. With respect to the initial lung function abnormality and due to a stratification into different "response groups", beta adrenoreceptor agonists showed a volume-response (decrease in end-expiratory level) in 63% of infants with pulmonary hyperinflation, a flow response (improvement of airway resistance) in 54% of infants with predominantly bronchial obstruction and a mixed-response (decrease of TGV and Raw) in 70% of infants with mixed functional abnormalities, at least if the drug is given systemically. However, distinction into functional groups and its response to a sympathomimetic agent is only possible when both, changes in TGV and concomitant changes in Raw are accurately assessed.

The effects of salbutamol 0.225 mg/kg given systemically on lung function in infants have been measured by whole-body plethysmography in 60 children with broncho-pulmonary diseases (24 after respiratory distress syndrome, 21 with wheezy bronchitis and 15 with cystic fibrosis). A therapeutic action was demonstrated in 74% of the tests, taking into account changes in end-expiratory resting level (state of inflation) and associated changes in airway resistance. There was a significant decrease in thoracic gas volume as an estimate of pulmonary hyperinflation, which was due to improved alveolar ventilation and to a consequential decrease in end-expiratory resting level. The improvement in airway resistance, as an estimate of airway obstruction, reflects a substantial relaxation of bronchial smooth muscle increasing the diameter of the airways. The extent to which similar results may be achieved by topical administration of nebulised beta agonists remains to be determined.

In infants paradoxical bronchoconstriction instead of dilatation was observed after beta-2-agonist inhalation and was thought to be due to an osmolality and pH change of the inhalation mixture in the nebuliser cup. Therefore, we measured lung function in 11 asthmatic children and adolescents, and in a healthy control group, after inhalation of a hyperosmolar beta-2-NaCl mixture. 0.5 ml salbutamol in 1.5 ml physiological saline (2 ml total) or 1.0 ml salbutamol in 3 ml NaCl, respectively, were nebulised for 10 minutes. Following nebulisation the patients were asked to inhale for 5 minutes from the residue in the cup. Before and after this procedure lung function was measured. All the patients were symptom-free and were tested on two days at the same time after being off medication for at least 24 hours. Baseline osmolality of the mixtures at the start of nebulisation was 235 +/- 5.0 mmol/kg and increased in the cup after 10 minutes to 322 +/- 7.5 mmol/kg for the low initial volume (2 ml) and to 261 +/- 2.0 mmol/kg for the high initial volume (4 ml). After the 5 minutes' inhalation session osmolality rose further to 460 +/- 25.0 mmol/kg (2 ml) and 278 +/- 1.0 mmol/kg (4 ml), respectively. In all asthmatic children significant changes (p less than 0.01, paired t-test) before and after inhalation occurred (decrease of airway resistance, increase of FEV1, increase of maximal expiratory flows at 75%, 50% and 25% of vital capacity, increase of peak expiratory flow. Thoracic gas volume, residual volume and vital capacity remained unchanged). No changes were seen in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

The lung function response to three doses of salbutamol 0.075 mg/kg given at 10 minute intervals by gastric tube was studied in 31 infants aged 2-22 months with bronchopulmonary disease (eight after the respiratory distress syndrome, 15 with wheezy bronchitis, and eight with cystic fibrosis). Lung function was measured by whole body plethysmography. Seven of 31 infants had normal lung function and 10 of the remaining 24 had an increase in thoracic gas volume (TGV), 10 an increase in airway resistance (Raw), and four an increase in both the TGV and Raw. The response of TGV and Raw to salbutamol was analysed by circular statistics, enabling analysis of coupled, directional data. Thirty minutes after administration of the first dose of salbutamol there was a reduction in TGV or Raw in 21 of the 24 infants, 11 showing a decrease in TGV ("volume responder") and 10 a fall in Raw ("flow responder"). These results indicate that in most infants with bronchopulmonary disease an improvement in lung function can be documented after systemic administration of beta agonists if both TGV and Raw are measured.