[Guidewire knot formation during insertion of a central venous catheter].

A knot was formed on the guidewire during the procedure of inserting a central venous catheter through the right subclavian vein. The diameter of the knot was 3 mm after it had been pulled as tight as possible. Fortunately, there was no sign of severe haemothorax, though the knot must have caused considerable damage to the vessel.