Central venous catheterization (CVC) via the internal jugular vein (IJV) is a fundamental procedure in anesthesia and intensive care for hemodynamic monitoring, fluid resuscitation, and vasoactive drug administration. While modern clinical guidelines strongly advocate for ultrasound (USG) guidance, the traditional anatomical landmark technique remains widely utilized due to equipment availability or clinician habits. Proper positioning of the catheter tip is critical to prevent severe long-term complications; however, comparative data regarding catheter tip malposition between these two routine techniques-especially when confirmed by postprocedural bedside chest X-ray-require further prospective evaluation. Objective:

The primary objective of this prospective observational study is to compare ultrasound-guided versus landmark techniques for internal jugular vein catheterization with respect to catheter tip malposition, as determined by postprocedural bedside chest X-ray. Secondary objectives include the evaluation of the number of needle redirections, first-attempt success rate, total procedure time, and the incidence of mechanical complications (such as accidental arterial puncture or hematoma formation)

Inclusion Criteria:

• Patients aged 18-75 undergoing surgery requiring central venous (internal jugular) catheterization

Exclusion Criteria:

• Refusal to participate
• age <18 or >75
• emergency surgery
• coagulopathy
• infection, prior surgery, or prior cannulation at the insertion site
• allergy to ultrasound gel

Adult and elderly patients (18-75 years) undergoing elective or scheduled surgery in the general operating room unit of Dicle University Faculty of Medicine Hospital who require central venous catheterization via the internal jugular vein as part of routine perioperative care. The catheterization technique (ultrasound-guided or landmark) reflects the routine practice of the performing physician; no technique is assigned by the study for research purposes.