Background: It is well known that severe lung impairment in cystic fibrosis (CF) may compromise respiratory muscle function at rest. Even though patients with CF and severe obstructive lung disease exhibit an abnormal breathing pattern during exercise (due to expiratory flow limitation), patients with CF and normal lung function reportedly have a normal breathing pattern. Objectives: The aim of the study was to assess the precise characteristics of the ventilatory pattern adopted during exercise by children with CF and mild to moderate lung disease. Methods: Nine children diagnosed as having mild to moderate CF and 9 healthy children with a similar age distribution participated in this study. Both groups performed a continuous incremental cycling protocol. Breathing and timing components were assessed during exercise. Results: Differences in the breathing pattern between children with CF and controls during exercise are illustrated in Hey plot which described a rapid shallow breathing pattern in children with CF. During exercise, children with CF showed a significantly lower mean inspiratory flow than healthy children (p < 0.001), whereas the mean expiratory flow was higher (p < 0.001). Children with CF also showed a significant increase in the end-tidal carbon dioxide pressure, which may indicate the emergence of hypercapnia. Conclusions: During exercise, children with CF (even those not suffering from advanced disease) showed signs of rapid, shallow breathing and an increase in the ventilatory response. This was essentially due to an increase in the mean inspiratory flow, which in turn suggests an expiratory flow limitation. The children were also predisposed to hypercapnia.

Keywords:
Cystic fibrosis, Pulmonary impairment during exercise, Respiratory muscle function
1.
Nixon PA: Role of exercise in the evaluation and management of pulmonary disease in children and youth. Med Sci Sports Exerc 1996;28:414–420.
2.
Davis PB, Drumm M, Konstan MW: Cystic fibrosis. Am J Respir Crit Care Med 1996;154:1229–1256.
3.
Zach MS: Lung disease in cystic fibrosis – an updated concept. Pediatr Pulmonol 1990;8:188–202.
4.
Regnis JA, Alison JA, Henke KG, Donnelly PM, Bye PT: Changes in end-expiratory lung volume during exercise in cystic fibrosis relate to severity of lung disease. Am Rev Respir Dis 1991;144:507–512.
5.
Regnis JA, Donnelly PM, Robinson M, Alison JA, Bye PT: Ventilatory mechanics at rest and during exercise in patients with cystic fibrosis. Am J Respir Crit Care Med 1996;154:1418–1425.
6.
Coates AL, Canny G, Zinman R, Grisdale R, Desmond K, Roumeliotis D, Levison H: The effects of chronic airflow limitation, increased dead space, and the pattern of ventilation on gas exchange during maximal exercise in advanced cystic fibrosis. Am Rev Respir Dis 1988;138:1524–1531.
7.
Hayot M, Guillaumont S, Ramonatxo M, Voisin M, Prefaut C: Determinants of the tension-time index of inspiratory muscles in children with cystic fibrosis. Pediatr Pulmonol 1997;23:336–343.
8.
Pradal U, Polese G, Braggion C, Poggi R, Zanolla L, Mastella G, Rossi A: Determinants of maximal transdiaphragmatic pressure in adults with cystic fibrosis. Am J Respir Crit Care Med 1994;150:167–173.
9.
Rochester DF: Respiratory muscles and ventilatory failure: 1993 perspective. Am J Med Sci 1993;305:394–402.
10.
Hart N, Polkey MI, Clement A, Boule M, Moxham J, Lofaso F, Fauroux B: Changes in pulmonary mechanics with increasing disease severity in children and young adults with cystic fibrosis. Am J Respir Crit Care Med 2002;166:61–66.
11.
ATS: Standardization of spirometry, 1994 update. American Thoracic Society. Am J Respir Crit Care Med 1995;152:1107–1136.
12.
Zapletal A, Samanek M, Paul T: Lung function in children and adolescents; in Herzog H (ed): Progress in Respiratory Research. Basel, Karger, 1987, pp 32–52.
13.
Dempsey JA, Wagner PD: Exercise-induced arterial hypoxemia. J Appl Physiol 1999;87:1997–2006.
14.
Wasserman K: Principles of Exercise Testing and Interpretation: Including Pathophysiology and Clinical Applications, ed 4. Philadelphia, Lippincott Williams & Wilkins, 2005.
15.
Shepard R: Frontiers of Fitness. Springfield, Thomas, 1971.
16.
Astrand PO: Textbook of Work Physiology: Physiological Bases of Exercise, ed 4. Leeds, Human Kinetics, 2003.
17.
Hey EN, Lloyd BB, Cunningham DJ, Jukes MG, Bolton DP: Effects of various respiratory stimuli on the depth and frequency of breathing in man. Respir Physiol 1966;1:193–205.
18.
Bradley S, Solin P, Wilson J, Johns D, Walters EH, Naughton MT: Hypoxemia and hypercapnia during exercise and sleep in patients with cystic fibrosis. Chest 1999;116:647–654.
19.
Alison JA, Regnis JA, Donnelly PM, Adams RD, Sullivan CE, Bye PT: End-expiratory lung volume during arm and leg exercise in normal subjects and patients with cystic fibrosis. Am J Respir Crit Care Med 1998;158:1450–1458.
20.
Grassino AE, Derenne JP, Almirall J, Milic-Emili J, Whitelaw W: Configuration of the chest wall and occlusion pressures in awake humans. J Appl Physiol 1981;50:134–142.
21.
Grimby G, Goldman M, Mead J: Respiratory muscle action inferred from rib cage and abdominal V-P partitioning. J Appl Physiol 1976;41:739–751.
22.
Aliverti A, Macklem PT: How and why exercise is impaired in COPD. Respiration 2001;68:229–239.
23.
Schroeder CA, Balfe DL, Khan SS, Mohsenifar Z: Airflow limitation and breathing strategy in congestive heart failure patients during exercise. Respiration 2003;70:137–142.
24.
O’Donnell DE: Ventilatory limitations in chronic obstructive pulmonary disease. Med Sci Sports Exerc 2001;33:S647–S655.
25.
Younes M, Burks J: Breathing pattern during and after exercise of different intensities. J Appl Physiol 1985;59:898–908.
26.
Thin AG, Dodd JD, Gallagher CG, Fitzgerald MX, McLoughlin P: Effect of respiratory rate on airway deadspace ventilation during exercise in cystic fibrosis. Respir Med 2004;98:1063–1070.
27.
Dantzker DR, Patten GA, Bower JS: Gas exchange at rest and during exercise in adults with cystic fibrosis. Am Rev Respir Dis 1982;125:400–405.
28.
Wasserman K: Principles of Exercise Testing and Interpretation: Including Pathophysiology and Clinical Applications, ed 3. Philadelphia, Lippincott Williams & Wilkins, 1999.
29.
ATS/ACCP: ATS/ACCP statement on cardiopulmonary exercise testing. Am J Respir Crit Care Med 2003;167:211–277.
30.
ATS/ACCP statement on cardiopulmonary exercise testing. Am J Respir Crit Care Med 2003;167:211–277.
31.
Henke KG, Orenstein DM: Oxygen saturation during exercise in cystic fibrosis. Am Rev Respir Dis 1984;129:708–711.
32.
Lebecque P, Lapierre JG, Lamarre A, Coates AL: Diffusion capacity and oxygen desaturation effects on exercise in patients with cystic fibrosis. Chest 1987;91:693–697.
33.
Versteegh FG, Bogaard JM, Raatgever JW, Stam H, Neijens HJ, Kerrebijn KF: Relationship between airway obstruction, desaturation during exercise and nocturnal hypoxaemia in cystic fibrosis patients. Eur Respir J 1990;3:68–73.
© 2007 S. Karger AG, Basel
2006
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.