Misplaced central venous catheters: applied anatomy and practical management.

Large numbers of central venous catheters (CVCs) are placed each year and misplacement occurs frequently. This review outlines the normal and abnormal anatomy of the central veins in relation to the placement of CVCs. An understanding of normal and variant anatomy enables identification of congenital and acquired abnormalities. Embryological variations such as a persistent left-sided superior vena cava are often diagnosed incidentally only after placement of a CVC, which is seen to take an abnormal course on X-ray. Acquired abnormalities such as stenosis or thrombosis of the central veins can be problematic and can present as a failure to pass a guidewire or catheter or complications after such attempts. Catheters can also be misplaced outside veins in a patient with otherwise normal anatomy with potentially disastrous consequences. We discuss the possible management options for these patients including the various imaging techniques used to verify correct or incorrect catheter placement and the limitations of each. If the course of a misplaced catheter can be correctly identified as not lying within a vulnerable structure then it can be safely removed. If the misplaced catheter is lying within or traversing large and incompressible arteries or veins, it should not be removed before consideration of what is likely to happen when it is removed. Advice and further imaging should be sought, typically in conjunction with interventional radiology or vascular surgery. With regard to misplaced CVCs, in the short term, a useful aide memoir is: 'if in doubt, don't take it out'.