Unintended arterial puncture and local hematoma formation are the most common complications during internal jugular vein central venous catheterization. Other serious complications like pseudoaneurysm, arteriovenous fistula, arterial dissection, thrombosis, embolism are also possible. These complications mostly occur by mechanical trauma or injury when advancing needle back and forth to puncture internal jugular vein. Placement of guidewire or dilator can also cause mechanical trauma or injury around the vessel.~Because internal jugular vein collapses easily during needle advance, anterior and posterior wall of the vessel can be punctured simultaneously. Posterior wall puncture can increase the risk of complications of the catheterization. Delicate puncture of the vessel and stable fixation of the needle after puncture are important to reduce overall number of catheterization attempts, increase success rate, reduce complications.~Seldinger technique(thin-wall needle technique) is commonly used procedure to obtain safe access to central vein. The desired vessel is punctured with a sharp hollow needle, syringe is detached and guidewire is advanced through the lumen of the needle, and then the needle is withdrawn. Central catheter is then passed over the guidewire into the vessel. Contrarily, modified Seldinger technique(guiding sheath-over-the-needle technique) use needle that is covered with guiding sheath. After desired vessel puncture, guiding sheath is instantly slid over the needle into the vessel. The needle is withdrawn, guidewire is advanced through the guiding sheath, central catheter is placed into the vessel.~When using Seldinger technique, it is important to fix the needle firmly with hand until the guidewire is placed into the vessel lumen. If hand fixation is not stable, needle tip can migrate from the lumen, can pierce the vessel wall, and carotid artery puncture, and local hematoma formation might occur. Even if there is no evidence of complications, when blood regurgitation fails, overall number of vessel puncture attempts would increase and it is expected that rate of complications of the catheterization would increase.~When using modified Seldinger technique, guiding sheath is easily slid over the needle, providing stable route into the vessel lumen relatively in early step of the catheterization. Therefore, it is expected that stability of the fixation improves, success rate of the catheterization increase, and complications of the catheterization decrease. But there is no high level of evidence yet, and still decision to use which technique is based on experience of the operator.~The investigators are going to compare the Seldinger technique and modified Seldinger technique on success rate and complications during central venous catheterization by prospective, randomized, controlled study.~In addition, any difference in success rate and complications between the two techniques may be different depending on the experience of the practitioners. Therefore, the investigators also plan to compare the two techniques between experienced and non-experienced practitioners.~The success rate and complications between the two techniques may also be different depending on the long and short-axis techniques. As subgroup analyses, we intend to investigate whether there is a difference between Seldinger and modified Seldinger technique according to the experience of the operator or long or short axis approach.
The investigators intend to compare the Seldinger technique and modified Seldinger technique on success rate and complications during central venous catheterization by a prospective, randomized, controlled study. The investigators are planning to compare both techniques in both experienced (anesthesiologist board member) and non-experienced practitioners (first and second-grade resident).