5 minutes after anaesthesia induction, as well as 5 minutes after completion of Xenon wash-in, transpulmonary pressure will be measured from inspiratory plateau pressure and pleural pressure, which will be estimated from esophageal pressure. Esophageal pressure measurements will be facilitated via esophageal balloon catheters (Adult Esophageal Balloon Catheter Set 5 French, CooperSurgical, Trumbull, USA).