The main intention of this study is to compare two ultrasound-guided central venous catheterization procedures namely: real-time, ultrasound-guided, in plane axillary vein catheterization and real-time, ultrasound-guided, out of plane jugular vein catheterization in terms of venipuncture, catheterization success, early mechanical complication and catheter-related infection rate in mechanically ventilated patients admitted to the intensive care unit.

Inclusion Criteria:

• mechanically ventilated intensive care patients with clinical indications for central venous line placement

Exclusion Criteria:

• trauma and hematoma at the catheterization site
• major blood coagulation disorders coincided with active bleeding
• anatomical abnormalities at the catheterization site
• infection at the catheterization site
• age less than 18 years
• lack of patients or closest relatives consent