1. Cardiovascular and Respiratory Physiology Group, Technical Medical CentreUniversity of Twente Enschede The Netherlands
2. Department of Pulmonary Diseases/Home Mechanical Ventilation, University of GroningenUniversity Medical Center Groningen Groningen The Netherlands
3. Groningen Research Institute of Asthma and COPD (GRIAC)University of Groningen Groningen The Netherlands