Main Article Content
Exercise induced bronchoconstriction (EIB) is a frequent and specific symptom of childhood asthma featured by expiratory flow limitation. A recent study showed that exercise can also induce inspiratory flow limitation, independent of EIB. The aim of this study was to investigate whether salbutamol protects against exercise induced inspiratory flow limitation in asthmatic children.
Methods: The study had a prospective double-blind placebo-controlled randomized cross-over design with two exercise challenge tests preceded by the inhalation of 200µg salbutamol or placebo. Children 8-16 years old with documented exercise induced inspiratory flow limitation performed two exercise challenge tests (ECT’s) to assess EIB. EIB was defined as a fall in forced expiratory volume in 1 second (FEV1) ≥ 13% whereas inspiratory flow limitation was defined as a fall in mid inspiratory flow (MIF50) ≥ 25%.
Results: 63% of the children (19/30) with exercise induced flow limitation showed an inspiratory flow limitation. Salbutamol significantly reduced the mean exercise induced fall in MIF50 in children with exercise induced inspiratory flow limitation compared to placebo (17.6% versus 24.9%, p=0.004).
Conclusions: We observed a significant but inconsistent, individually variable protection of salbutamol against exercise induced inspiratory flow limitation in contrast to the consistent protective effect of salbutamol against EIB. We confirmed that a substantial number of the children with exercise induced flow limitation have an inspiratory flow limitation. Asthmatic children who experience persistent exercise induced asthmatic symptoms despite the use of (prophylactic) salbutamol, may suffer from an inspiratory flow limitation as a component of their asthma.
The Medical Research Archives grants authors the right to publish and reproduce the unrevised contribution in whole or in part at any time and in any form for any scholarly non-commercial purpose with the condition that all publications of the contribution include a full citation to the journal as published by the Medical Research Archives.
2. Croft D, Lloyd B. Asthma spoils sport for too many children. Practitioner. 1989;233:969, 971.
3. Merikallio VJ, Mustalahti K, Remes ST, Valovirta EJ, Kaila M. Comparison of quality of life between asthmatic and healthy school children. Pediatr Allergy Immunol. 2005;16:332-340.
4. Bucca C, Rolla G, Brussino L, De R, V, Bugiani M. Are asthma-like symptoms due to bronchial or extrathoracic airway dysfunction? Lancet. 1995;346:791-795.
5. Driessen JM, van der Palen J, van Aalderen WM, de Jongh FH, Thio BJ. Inspiratory airflow limitation after exercise challenge in cold air in asthmatic children. Respir Med. 2012;106:1362-1368.
6. Joos GF, O'Connor B, Anderson SD, Chung F, Cockcroft DW, Dahlen B, et al. Indirect airway challenges. Eur Respir J. 2003;21:1050-1068.
7. Kelso JM, Enright PL, Scanlon PD, O'Connell EJ, Sachs MI. Effect of inhaled methacholine on inspiratory flow. Chest. 1990;98:1426-1429.
8. Turktas I, Dalgic N, Bostanci I, Cengizlier R. Extrathoracic airway responsiveness in children with asthma-like symptoms, including chronic persistent cough. Pediatr Pulmonol. 2002;34:172-180.
9. Russo C, Zeng D, Prosperini G, Spicuzza L, Guarino F, Polosa R. Effect of salbutamol on nasal symptoms and mast cell degranulation induced by adenosine 5' monophosphate nasal challenge. Clin Exp Allergy. 2005;35:1192-1196.
10. Vilozni D, Bentur L, Efrati O, Barak A, Szeinberg A, Shoseyov D, et al. Exercise challenge test in 3- to 6-year-old asthmatic children. Chest. 2007;132:497-503.
11. van Leeuwen JC, Driessen JM, de Jongh FH, Anderson SD, Thio BJ. Measuring breakthrough exercise-induced bronchoconstriction in young asthmatic children using a jumping castle. J Allergy Clin Immunol. 2013;131:1427-1429.
12. Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al. Standardisation of spirometry. Eur Respir J. 2005;26:319-338.
13. Koopman M, Zanen P, Kruitwagen CL, van der Ent CK, Arets HG. Reference values for paediatric pulmonary function testing: The Utrecht dataset. Respir Med. 2011;105:15-23.
14. Liu AH, Zeiger R, Sorkness C, Mahr T, Ostrom N, Burgess S, et al. Development and cross-sectional validation of the Childhood Asthma Control Test. J Allergy Clin Immunol. 2007;119:817-825.
15. Nathan RA, Sorkness CA, Kosinski M, Schatz M, Li JT, Marcus P, et al. Development of the asthma control test: a survey for assessing asthma control. J Allergy Clin Immunol. 2004;113:59-65.
16. Anderson SD. Exercise-induced bronchoconstriction in the 21st century. J Am Osteopath Assoc. 2011;111:S3-10.
17. Kenn K, Balkissoon R. Vocal cord dysfunction: what do we know? Eur Respir J. 2011;37:194-200.
18. McFadden ER, Jr., Zawadski DK. Vocal cord dysfunction masquerading as exercise-induced asthma. a physiologic cause for "choking" during athletic activities. Am J Respir Crit Care Med. 1996;153:942-947.
19. Rundell KW, Spiering BA. Inspiratory stridor in elite athletes. Chest. 2003;123:468-474.
20. Watson MA, King CS, Holley AB, Greenburg DL, Mikita JA. Clinical and lung-function variables associated with vocal cord dysfunction. Respir Care. 2009;54:467-473.
21. Tomalak W, Radlinski J, Pogorzelski A, Doniec Z. Reference values for forced inspiratory flows in children aged 7-15 years. Pediatr Pulmonol. 2004;38:246-249.