Children are placed in a light head-down position. A standard sized towel roll is placed under the shoulders. The patient’s head is turned slightly to the side opposite to the cannulation. Positioning should enable the operator to see the entire US picture and the patient’s landmarks. Linear US probes are to be preferred. The US unit is settled on its highest resolution with a depth of 1.9 cm. Depending on the operator’s preference a 4 cm 21-gauge needle (Arrow; Arrow international, Inc.; Reading, PA) or 32 mm, 22-gauge i.v. cannula (Abbocath; Arnsino Medical (Shanghai) Co., Ltd; Shanghai, China) or 25 mm, 22-gauge i.v. cannula (Jelco; Smiths Medical International Ltd, Rossendale, Lancashire, UK) can be chosen. The i.v. cannula is slightly bent in its centre. The US probe is placed in the supraclavicular region so as to obtain a good longitudinal view of the SCV (SCV-Figure 1). The US probe is held in the one hand while the needle or i.v. cannula without attached syringe is maneuvered with the other hand. Using a strict in-plane technique the needle or i.v. cannula pierces the skin at the infraclavicular region (1). It is then guided from lateral to medial under direct US vision into the SCV (SCV-Figure 1; SCV-Clip 2). If there is a good spontaneous return of blood flow via the needle the US probe is withdrawn and a J-shaped 0.018 inch (0.46 mm) guide-wire (Arrow or Cook inc.; Bloomington, In, USA) is introduced into the vein. In the case of an i.v. cannula the needle is withdrawn as soon as a spontaneous return of blood flow is noted and the cannula advanced over the needle into the vein. If according to the US image the tip of the needle or i.v. cannula is believed to be inside the vein without a spontaneous return of blood flow, a syringe is attached in order to try to aspirate blood while slowly withdrawing the needle or i.v. cannula. After successful blood aspiration the guide-wire is introduced into the vein. If blood cannot be aspirated the US probe is replaced and the tip of the needle is redirected into the vein under direct US vision. Finally a 2-French single lumen catheter (Seldiflex; Plastimed; Saint-Leu-La-Foret, France) or 4-French double lumen catheter (Arrow) is threaded into the vein via the guide-wire and fixed on the patients’ shoulder.