Objectives:~To study the validity and reliability of estimation of the central venous pressure by measurement of internal jugular vein size using 2-dimensional ultrasound.~To evaluate the correlation of internal jugular vein cross sectional area and central venous pressure.~Methods:~The study design is prospective observational study.~We will include all patients scheduled for cardiac surgery in Siriraj Hospital and record both internal jugular size using 2-dimensional ultrasound just before central venous catheter insertion. The central venous pressure will be recorded and the ultrasound picture will be measured.~The data will be analyzed.
To study the validity and reliability of estimation of the central venous pressure by measurement of internal jugular vein size using 2-dimensional ultrasound.