1Chairman, Department of Anesthesiology, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
2Staff Anesthesiologist, Department of Anesthesiology, Hospital del Mar, Institut Municipal d'Investigació Mèdica, Universitat Autònoma de Barcelona, Barcelona, Spain.
3Professor, Department of Anesthesiology, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
4Head of Department of Hospital Medical Records, Corporació de Salut del Maresme i La Selva, Calella, Barcelona, Spain.
5Staff Anesthesiologist, Department of Anesthesiology, Fundació Puigvert, Barcelona, Spain.
6Staff Anesthesiologist, Department of Anesthesiology Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain.
7Research Fellow, Department of Anesthesiology, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.
8Professor, Department of Pneumology, Hospital Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain, ‡‡ See appendix.