Internal jugular vein cannulation can be performed with the blind technique under ultrasound (USG) guidance or using classical marker points. It has been shown that USG-guided interventions reduce the complication rate compared to the method performed with the blind technique (4%/13.5%). In addition, the initial entry success rate in the USG supported group is 65%. , this rate remained at 45% with the blind technique.

Although Pleth variability index monitoring is a noninvasive method, it is a technique that consistently predicts fluid sensitivity in patients under mechanical ventilation.

The aim of study is before applying USG guided catheterization; We think that by revealing the factors of the patient that are effective on the number of interventions, necessary measures can be taken for the success of catheterization as a result.

Inclusion Criteria:

• aged 18-75
• underwent coronary artery bypass surgery

Exclusion Criteria:

• <18 years old
• Hemodynamic instability
• Use of inotropic agents