In 50 Patients who are undergoing a planned surgical procedure which require a central venous catheter the diameter of the subclavian vein is measured by ultrasound under 6 different conditions. The conditions are~neutral positioning, PEEP 0 cm H2O,~neutral positioning, PEEP 5cm H2O,~neutral positioning, PEEP 10cm H2O,~Trendelenburg positioning -20°, PEEP 0 cmH2O,~Trendelenburg positioning -20°, PEEP 5 cmH2O,~Trendelenburg positioning -20°, PEEP 10 cmH2O After these measurements a central venous catheter is used to measure the central venous pressure.
In 50 Patients who are undergoing a planned surgical procedure which require a central venous catheter the diameter of the subclavian vein is measured by ultrasound under 6 different conditions.