1 Critical Care Department, Hospital Universitari Vall d'Hebron, Institut de Recerca Vall d'Hebron, Barcelona, Spain; Ciber Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. Electronic address: [email protected].
2 Critical Care Department, Hospital Universitari Vall d'Hebron, Institut de Recerca Vall d'Hebron, Barcelona, Spain.
3 Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom.
4 Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom; Imperial College London, London, United Kingdom.