Follow the outflow vein to the central veins to evaluate for which complication?

• A. Kinking
• B. Venous thrombus
• C. Extrinsic compression
• D. Arterial occlusion

Answer: (B)

This approach tests for venous patency and the presence of a thrombus by tracing the vein from its distal outflow toward the central veins. If a clot is present, the vein tends to become noncompressible and may show echogenic material within the lumen, with Doppler flow that is reduced or absent as you move toward the central veins. Following the outflow toward the heart helps determine both the existence of a thrombus and whether it extends centrally, which is the key concern when assessing for venous thrombus.

Kinking would show up as an abrupt change in the vessel’s course and flow pattern rather than a lumen filled with thrombus. Extrinsic compression would be suggested by external pressure distorting the vein and altering its caliber rather than intraluminal clot. Arterial occlusion involves arteries, not veins, so tracing venous flow wouldn’t evaluate arterial blockage.