1. Pulmonary Division, Department of Internal Medicine, University Hospital of Zurich and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
2. Medical Intensive Care Unit, Department of Internal Medicine, University Hospital of Zurich and Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland.
3. Pulmonary Division, Department of Internal Medicine, Cantonal Hospital Winterthur, Switzerland.
4. Department of Intensive Care Medicine, University Hospital Berne, Berne, Switzerland.
5. Department of Ophthalmology, University Hospital, Zurich, Switzerland.
6. Department of Surgery, Cantonal Hospital Aarau, Switzerland.
7. Pulmonary Division, Department of Internal Medicine, Cantonal Hospital St. Gallen, Switzerland.