Intervention description {11a}
tCDC
All CDC-inserting physicians employed at the participating departments who have performed at least 100 ultrasound-guided central vein catheterisations (whereof at least 10 in the subclavian vein using the in-plane needling technique) will be asked to participate in the study as enrolling and inserting physicians. All participating physicians will certify that they fulfil these criteria in a signed curriculum vitae. To promote standardisation of the insertion procedure, all enrolling physicians must participate in an educational session on subclavian and internal jugular vein tCDC insertion.