Is the correct use of a dry powder inhaler (Turbohaler) age dependent?
BACKGROUND
The metered-dose inhalers are the most commonly used devices in the treatment of asthma, but dry powder inhalers (eg, Turbohaler) are being increasingly used. Studies evaluating how well children can use a Turbohaler are lacking.


OBJECTIVE
We assessed whether the correct use of a Turbohaler could be easily taught to unselected stable asthmatic children.


METHODS
One hundred sixty-one asthmatic children aged 5 to 17 years (mean, 9.8 years) consecutively attending the outpatient clinic were included in study. After a demonstration and 10 minutes of training, the inhalation technique was checked in a standardized way (yes/no response). Keeping the device upright, proper preparation of the drug dose and inspiratory flow on inhalation were measured by the Turbohaler trainer.


RESULTS
One hundred thirty-three children (83%) performed every step correctly (ie, 96% of children older than 8 years but only 55% of children between 5 and 8 years; P <.001). Of 28 children incorrectly using the Turbuhaler-trainer, 20 generated insufficient inspiratory flow through the device. There was no significant difference in airway obstruction (expressed as percent of predicted forced vital capacity, FEV1, and Tiffeneau index) between correct and incorrect users, but when measured through the pneumotachograph, mean peak inspiratory flow (expressed as percent predicted) was significantly lower in those children incorrectly using the device. Turbohaler use was reevaluated after 4.7 +/- 2.0 months in a subset of 64 patients. Fifty-three of 64 (83%) children again used the device correctly. Only 3 of 13 who used the device incorrectly at the first evaluation used it correctly at the second evaluation.


CONCLUSIONS
We conclude that the correct use of the Turbohaler can be easily taught to asthmatic children older than 8 years. Those who use the device correctly after initial instructions continue to do so afterwards.
D001249:Asthma / Q000188:drug therapy; D002648:Child; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D009330:Nebulizers and Vaporizers / Q000706:statistics & numerical data*; D011208:Powders; D012984:Software; D013223:Statistics as Topic