Impact of constant and breath-synchronized nebulization on inhaled mass ofnebulized budesonide in infants and children

The aim of the present study was to compare the output of a breath-synchron ized jet nebulizer to a conventional constant output nebulizer over a fixed period of time in terms of inhaled mass of budesonide, i.e., the amount of budesonide deposited on a filter interposed between the nebulizer and the face mask, One hundred and sixty-five asthmatic children (103 boys) were en rolled in this open, randomized, crossover trial. Their age ranged from 6 m onths to 7.9 years, height from 69 to 132 cm, and weight from 8.2 to 31.3 k g. Their duration of asthma ranged from less than 1 to 7 years. Budesonide suspension, 0.5 mg mL(-1), 2 mL, was used. With 5 min of constant output nebulization, the mean inhaled mass of budeso nide in percent of the nominal dose was 11.4% in the youngest children and 14.9% in the 7-year-old children. Expressed in percent of the total output of budesonide, i.e., the amount that left the nebulizer as an aerosol, the inhaled mass ranged from 34.6-48.6%. Thus, 51.4-65.4% of the total output w as deposited on the expiratory filter. With 5 min of breath-synchronized ne bulization, the mean inhaled mass ranged from 10.5-14.9% of the nominal dos e. For the youngest patients less than 3-4 years of age, it was approximate ly 80-90% of the total output. For the older patients the inhaled mass was approximately 95% of the total output, i.e., only small amounts of budesoni de were deposited on the expiratory filter. For both modes of nebulization the between-subject variation in inhaled mass was large: up to 6-fold in th e young children, and 3-4-fold in the older ones. The results of the present study showed that the inhaled mass of budesonide was significantly age-dependent with both modes of nebulization, i.e., the inhaled mass was less in younger children. Breath-synchronized nebulizatio n resulted in reduced waste of drug during expiration. (C) 1999 Wiley-Liss, Inc.