Comparison of Ultrasound-guided Central Venous Catherterization Via the Lower Internal Jugular Vein or the Subclavian Vein

The aim of this pilot study is to establish the success rate of catheterization of the lower jugular vein and the subclavian vein under ultrasound guidance in real time. The purpose is to compare the two techniques and to determine the best design for a full study (superiority, non-inferiority). This is a 2-arm randomized control study. The randomization ensures the comparability of the groups and allows evaluation of the feasibility and potential bias for further comparative studies.