No abstract

In 377 children, the commercially available Siregnost FD-5 was used to measure respiratory system resistance (Rrs) by forced oscillation at 10 Hz. The children were between 3 and 18 years of age and, by a detailed questionnaire and conventional pulmonary function testing in 335, they were shown to be representative of the normal pediatric population. There was a linear relationship between Rrs and height (Rrs = 13.9-0.064 x ht (cm), r = -0.87). Children less than 6 years of age had no trouble with using the forced oscillation technique. The smoking of tobacco in the house, the presence of carpets in the child's bedroom, or an atopic family history, alone or in combination, had no influence on Rrs or on any spirometric measure. Forced oscillation is useful in children too young to be able to cooperate with conventional pulmonary function testing.

No abstract

Chronic obstructive hypercapnic patients were monitored for blood gases and breathing pattern, before, during and after a 7-day treatment with 75 mg/day of medroxyprogesterone (MPA). In 9 out of the 15 patients the P_aCO₂ level decreased ( ± 8 mm Hg) significantly with return to nearly control values at stop. 4 subjects still continued to improve after cessation of therapy and were considered as not being stable. In 2 patients P_aCO₂ did not change. We were unable to find any significant difference between the control values of these three categories. The study of the breathing pattern in responsive subjects showed an increase in minute ventilation and tidal volume, with a small increase in mean inspiratory flow and no change in inspiratory time as a function of total respiratory cycle time. We conclude that MPA lowers the P_aCO₂ of hypercapnic chronic obstructive pulmonary disease patients through an increased tidal volume, which could result from an increased central nervous inspiratory output, or from better mechanical performance of the respiratory muscles due to the same central stimulation.

The bronchodilating effects of a metered aerosol dose of 40 μg ipratropium bromide and of 200 μg oxitropium bromide are similar 15 min after administration. The bronchodilating activity of ipratropium bromide appears earlier (i.e. 75–90 s after administration) than that of oxitropium bromide but later than that of ibuterol, a β₂-agonist. Ipratropium bromide administered at the dose of 80 μg provokes a bronchodilation about double of that obtained with 40 μg. An adaptation of the usual dosage should be considered.