Comparison of the Needle Tip Location by the Position of the Operator During Ultrasound Guided LIJV Catheterization.

Comparison of the Needle Tip Location According to the Position of the Operator During Short Axis Ultrasound Guided Central Venous Catheterization in the Left Internal Jugular Vein

When the left internal jugular vein catheterization under short-axis ultrasound guided, an operator should be stand around the lying patient's head. The investigators are going to evaluate to effects of the operator's location.

When placing the central line catheter in the left internal jugular vein under short-axis ultrasound guided, an operator should be stand around the lying patient's head. The investigators are going to evaluate to effects of the operator's location. (Above the midline of patient's head versus above the left extended axillary line)

Inclusion Criteria:

• Central venous catheterization required on lt. IJV

Exclusion Criteria:

• History of cervical spine surgery
• Abnormal structure of cervical spine, carotid artery or jugular vein
• Disease of carotid artery
• Immobilization due to cervical spine fracture or other diseases.