Determining the Time to Maximal Bronchodilator Response in Asthmatic Children

• Published in: The Journal of asthma 2009-01, Vol.46 (1), p.25-29
• Main Authors: Stavreska, Vaska, Verheggen, Maureen, Oostryck, Jan, Stick, Stephen M., Hall, Graham L.
• Format: Article
• Language: English
• Subjects: Adolescent; Albuterol - administration & dosage; Albuterol - pharmacology; Asthma - diagnosis; Asthma - drug therapy; Asthma - physiopathology; Bronchodilator Agents - administration & dosage; Bronchodilator Agents - pharmacology; bronchodilator response; Child; children; Female; Forced Expiratory Volume - drug effects; Forced Expiratory Volume - physiology; Humans; lung function; Male; Maximal Midexpiratory Flow Rate - drug effects; Maximal Midexpiratory Flow Rate - physiology; Pulmonary Ventilation - drug effects; Pulmonary Ventilation - physiology; Respiratory Function Tests - methods; salbutamol; Spirometry; Time Factors; Vital Capacity - drug effects; Vital Capacity - physiology
• ISSN: 0277-0903; 1532-4303
• DOI: 10.1080/02770900802460555

Background. The interval between bronchodilator administration and post-bronchodilator lung function testing is critical for accurate interpretation of the bronchodilator response. The time course of this response in children is not well documented. We aimed to document the time taken to achieve maximal lung function following salbutamol inhalation. Methods. Eighteen asthmatic children between 7 and 18 years of age with a history of bronchodilator responsiveness were recruited. Spirometry was performed before and at 0, 10, 15, 20, 40, 60, and 90 minutes after salbutamol inhalation 600 μ g (Ventolin; GlaxoSmithKline) via a spacer (Volumatic; GlaxoSmithKline). Results. Spirometric indices significantly increased after salbutamol inhalation (p < 0.001). The group median time to maximal response in forced expiratory volume in 1 second (FEV1) was 17.5 (10-60: 10th-90th centiles) minutes after salbutamol. The magnitude of group response in FEV1 was significantly higher at 15 and 20 minutes than at 0 and 10 minutes post-salbutamol inhalation (repeat measures analysis of variance [ANOVA] on ranks; p < 0.05). Conclusion. We conclude that a minimal interval of 20 minutes, before re-testing spirometry, is required to document the maximal response to bronchodilators in the majority of asthmatic children.