Ultrasound guidance in central venous catheterization has become the standard for clinical practice. Many approaches have been described in ultrasound guided catheterization procedures. The aim of this study is to compare the classical short axis out of plane (SAX-OOP) approach and the new anteroposterior short axis in plane (APSAX-IP approach in central jugular venous catheterization. The study was planned as prospective randomized and controlled. One hundred patients were planned to be included in this study.

Patients will be divided into two groups: Central jugular vein catheterization will be performed with the short axis out of plane group (ultrasound transducer will be positioned classically from medial to lateral in the neck) and anteroposterior short axis in plane group (ultrasound transducer will be positioned laterally from anterior to posterior on the neck). The two groups will be compared in terms of number of puncture attempts, duration of the procedure, ultrasound scan time before the procedure, number of needle redirection, overall success rate, complications, ease of catheterization and ultrasound visibility.

Central venous catheterization is a method frequently used in intensive care patients and patients to be operated. With classical methods, this central venous vascular access procedure in the landmark method can be performed or it can be successfully performed under ultrasound guidance.

Ultrasound-guided central venous catheterization is a safer and recommended approach. During venous catheterization with ultrasound the vein and its neighborhood can be easily visualized and it can be followed while the needle is directed to the target in vein puncture. Undesirable complications (hematoma, pneumothorax, arterial puncture) also decrease with the decrease in the number of punctures under ultrasound guidance. Ultrasound guided central catheterization which facilitates safer and faster procedures constitutes an important area for patient care. With the development of technology and the increase in accessibility it constitutes an important and useful area in the interventions made with ultrasound. The internal jugular vein is a frequently chosen central venous structure.

Many ultrasound-guided imaging and intervention methods have been described for catheterization of the internal jugular vein with the Seldinger method. These are described as longitudinal (long axis), transverse (short axis) and oblique methods for imaging and probe position. The image taken with the position of the needle relative to the ultrasound probe is described as in plane and out of plane.

Each method may have advantages over each other and can be preferred according to the patient's condition and the experience of the practitioner. Successful and safe catheterizations can be performed in the internal jugular vein with the short axis out-of-plane (SAX-OOP) method which is especially used in adults . Short axis out of plane is a successful method that can almost be called a classic that comes to mind first. Compared to other needle imaging methods out of plane tracking of the needle (as a point) seems to be a disadvantage in the user's imaging compared to the in-plane tracking method. Of course, it is easier and faster to capture the short axis when imaging the venous structure as long axis or short axis with ultrasound.

The " Anteroposterior short axis in plane" (APSAX-IP) technique is first reported by Aithal G. et al. in 2019. The use of both short axis and in-plane approaches has been described.The difference of the anteroposterior short axis in plane (APSAX-IP ) technique from the classical short axis out of plane (SAX-OOP) technique is that the location of the ultrasound is lateral to the neck, the needle is about 2-3 cm away from the ultrasound, the entry area from the skin, the needle is advanced subcutaneously in the anteroposterior direction, not medially, and the needle is not as a point in ultrasound that can be viewed longitudinally. It is thought that the APSAX-IP method has advantages such as easier follow-up of the needle, easier monitoring of the progression of the needle without damaging the posterior wall by seeing a large anterior posterior diameter of the vessel. It is stated that the APSAX-IP method will be more ergonomic in patients with short neck anatomy, obese and pediatric patients due to the location of the ultrasound probe. One method may be preferred over the other in patients. Although the definition of the method has been made, it has not been compared with any catheterization method. The aim of our study is to compare the classical SAX-OOP method and the newly defined APSAX-IP method in terms of difficulty, needle puncture time, needle procedure time and complications.

Inclusion Criteria:

• Patients that are planned a central venous catheter placement

Exclusion Criteria:

• Morbid obese patients (body mass index> 40)
• People with severe coagulopathy
• Severe deformity at the neck
• Skin deformity or infection at catheterization site
• Congenital anomalies of central veins
• Emergency operations