PUBLISHED BY THE EUROPEAN RESPIRATORY SOCIETY CHIEF EDITORS Leo Heunks and Marcus J. Schultz (Amsterdam, the Netherlands) ERS STAFF Caroline Ashford-Bentley, Alice Bartlett, Matt Broadhead, Alyson Cann, Sarah Cleveland, Rachel Gozzard, Jonathan Hansen, Catherine Pumphrey, Elin Reeves, Claire Marchant, Ben Watson ©2019 European Respiratory Society Cover image: Tyler Olson, shutterstock Design by Claire Marchant and Ben Watson, ERS Typeset by Nova Techset Printed in the UK by Page Bros (Norwich) Ltd. Indexed by Merrall-Ross International All material is copyright to the European Respiratory Society. It may not be reproduced in any way including electronically without the express permission of the society. CONTACT, PERMISSIONS AND SALES REQUESTS: European Respiratory Society, 442 Glossop Road, Sheffield, S10 2PX, UK Tel: +44 114 2672860 Fax: +44 114 2665064 e-mail: books@ersnet.org Print: ISBN: 978-1-84984-121-4 Online ISBN: 978-1-84984-122-1