Catheter malpositions

Imaging description Catheter malpositions are found by identifying the tip of the venous or arterial catheter in the incorrect position, either within the incorrect vessel, or advanced too far or too short for acceptable use (Figures 92.1 to 92.4). Malpositions can occasionally be challenging to identify on radiographs due to overlying structures; however, they can typically be resolved with adjustments to brightness and contrast. Catheter malpositions are easily identified by cross-sectional imaging but are not uncommonly missed due to reader oversight. Importance Central venous catheterization is commonly used in modern medicine for various purposes; however, more than 15% of patients who receive thesecatheters have complications. These complications include mechanical and chemical injury to the vessel wall with thrombus formation, development of a fibrin sheath, infection, and misplacement into other vessels. Malposition of central venous catheter placement may occur when advancing a catheter into an incorrect vein, or extending a catheter too far distally within a vessel. Malposition of a central venous catheter can result in complications including thrombosis, and vascular perforation or even cardiac perforation and pericardial tamponade. Positioning a catheter tip into the right atrium is thought to increase the likelihood of cardiac arrhythmias. It is important to detect malposition ofa central venous catheter on imaging studies. Typical clinical scenario There is controversy regarding the correct position for the tip of a central venous catheter. When a catheter is placed from the internal jugular vein or upper extremity veins, the traditional approach has been to place the tip of the central venous catheter within the superior vena cava; however, many believe that the performance and durability of the catheter will be improved by positioning the catheter tip within the upper right atrium. Catheter malposition may occur in the azygos vein, hemiazygos vein, internal mammary vein, or contralateral innominate vein. Positioning of the catheter in an anomalous vein or a venous collateral may occur, including persistent left superior vena cava, dominant supreme intercostal vein, and pericardiophrenic vein. In patients with central vein occlusion due to thrombus or external compression, a central venous catheter may be advanced to an unintended position.