Pressure at airway opening (Pao) will be monitored using a transducer for invasive blood pressure monitoring and attached to a cuffed endotracheal tube. Invasive systemic arterial pressure (SAP) will be measured by the same transducers attached to intra-arterial line placed in left or right radial artery. The central venous catheter for central venous pressure (CVP) and Swan-Ganz catheter (Swan-Ganz CCOmbo Pulmonary Artery Catheter and Vigilance II Monitor, Edwards Inc., USA) for continuous cardiac output and pulmonary artery pressure (PAP) measurements will be inserted after the induction into general anesthesia via right jugular internal vein.