1 Hôpitaux universitaires de Strasbourg, Nouvel hôpital civil, service d'anesthésie-réanimation chirurgicale, 1, place de l'Hôpital, BP 426, 67091 Strasbourg cedex, France. Electronic address: paul-michel.mertes@chru-strasbourg.fr.
2 Haukeland university hospital, regional centre for asthma, allergy and hypersensitivity, department of occupational medicine, 5021 Bergen, Norway. Electronic address: erik.florvaag@helse-bergen.no.