Application and efficacy of the multi-dose powder inhaler, Easyhaler, in children with asthma.

With powder inhalers, optimal performance is dependent on the inspiratory flow produced by the patient through the devices. The objective of this open, non-randomized study was to evaluate the suitability of a new, multidose, dry powder inhaler, the Easyhaler, for children with asthma. The peak inspiratory flow (PIF) through the Easyhaler (PIF(EH)) was measured with a pneumotachograph in 120 asthmatic children aged 4-16 yr. The bronchodilatory effect of 0.2 mg salbutamol through the Easyhaler was compared with that of 0.2 mg salbutamol through a metered dose inhaler (MDI) with a spacer, in 15 children with obstruction. The mean PIF(EH) was 56 l/min (range 22-83 l/min). The PIF(EH) correlated significantly with age, height, and absolute peak expiratory flow (PEF), but not with the level of obstruction (PEF percentage of predicted, range 45-146%). Only four children (aged 5, 6, 10, and 16 yr) had PIF(EH) values below 28 l/min, which has been shown in in vitro studies to be the threshold for effective use of the Easyhaler. In 15 children with PEF, < 85% of predicted bronchodilatory effects of 0.2 mg salbutamol through the Easyhaler and from an MDI-cum-spacer were equal. Most children aged 6-16 yr produce PIF values sufficient for the use of the Easyhaler. The gain of 0.2 mg salbutamol from the Easyhaler was equal to that from a new, unprimed, MDI with a spacer in children with asthma.