Editorial Board: Andrew Bush (London, UK), Peter Calverley (Liverpool, UK), Martin Kolb (Hamilton, ON, Canada), Kjell Larsson (Stockholm, Sweden) Managing Editor: Rachel White European Respiratory Society, 442 Glossop Road, Sheffield, S10 2PX, UK Tel: 44 114 2672860 | E-mail: Monograph@ersj.org.uk Published by European Respiratory Society ©2014 September 2014 Print ISBN: 978-1-84984-052-1 Online ISBN: 978-1-84984-053-8 Print ISSN: 2312-508X Online ISSN: 2312-5098 Printed by Page Bros Ltd, Norwich, UK All material is copyright to European Respiratory Society. It may not be reproduced in any way including electronic means without the express permission of the company. Statements in the volume reflect the views of the authors, and not necessarily those of the European Respiratory Society, editors or publishers. C O P E C O M M I T T E E O N P U B L I C A T I O N E T H I C S This journal is a member of and subscribes to the principles of the Committee on Publication Ethics.