Many children with asthma use their inhaler device incorrectly even after comprehensive inhalation instruction. The aim of this study was to identify factors associated with correct inhalation technique. Two hundred children with asthma demonstrated their inhalation technique. Patient characteristics and the components of inhalation instructions they had received were compared for children demonstrating a correct or incorrect inhalation technique. In addition, the inhalation technique of 47 newly referred patients was followed-up prospectively after repeated comprehensive instruction sessions. Seventy-eight percent of all patients demonstrated a correct inhalation technique. Patients who had received repeated instruction sessions and patients who had previously been asked to demonstrate the use of their inhaler during an instruction session were more likely than other children to demonstrate a correct inhalation technique (p < 0.001 and p = 0.03, respectively). Multiple logistic regression analysis showed that repetition of instructions was significantly associated with a correct inhalation technique (odds ratio (OR) 8.2, 95% CI 3.2-21.5; p < 0.0001) irrespective of type of inhaler used. Demonstration of the inhaler use by the patient was significantly associated with a correct inhalation technique for patients using a metered dose inhaler plus spacer device (OR 3.5, 95% CI 1.0-12.6; p = 0.05). but not for patients using a dry powder inhaler (OR 1.6, 95% CI 0.4-6.4; p = 0.54). The number of newly referred patients demonstrating a correct inhalation technique improved from 57.4% to 97.9% after three comprehensive instruction sessions.
Conclusion: Inhalation instruction should be given repeatedly to achieve and maintain correct inhalation technique in asthmatic children.