Background: In this study we sought to determine whether the topographical measurement along the course of the central veins can estimate the approximate insertion depths of central venous catheters (CVC).
Methods: Two hundred central venous catheterizations were performed via the right and left internal jugular vein (IJV) or subclavian vein (SCV). The anterior approach, using the sternocleidomastoid muscle as a landmark, was used for IJV catheterization and the infraclavicular approach for SCV. Topographical measurement was performed by placing the catheter with its own curvature over the draped skin starting from the insertion point of the needle through the ipsilateral clavicular notch, and to the insertion point of the second right costal cartilage to the manubriosternal joint. The CVC was inserted and secured to a depth determined topographically. The distance between the CVC tip and the carina and the angle of the left-sided CVC tip to the vertical were measured on the postoperative chest radiograph.
Results: The mean (SD) tip position of 50 CVCs placed via the right IJV was 0.1 (1.1) cm above the carina; right SCV, 0.0 (0.9) cm; left IJV, 0.3 (1.0) cm above the carina, and left SCV, 0.2 (0.9) cm below the carina. CVC locations could be predicted with a margin of error between 2.2 cm below the carina and 2.3 cm above the carina in 95% of patients. There were steeper (≥ 40°) angles to the vertical in the left-sided CVCs whose tips were above the carina (17 out of 54) than below the carina (2 out of 46).
Conclusions: The approximate insertion depth of a CVC can be estimated using measurement of surface landmarks along the pathway of central veins.