Bedside prediction of the central venous catheter insertion depth

The carina level has been shown to be near the pericardial reflection and can easily be identified as a landmark on a routine chest radiography. The purpose of this study was to reveal a simple method to predict the adequate central venous catheter (CVC) depth, hereby facilitating safe positioning of the CVC tip.

Central venous catheterization was performed via the right internal jugular vein (IJV) or the right subclavian vein (SCV). The CVC was placed at a depth derived by adding the length between the needle insertion point and the clavicular notch and the vertical length between the clavicular notch and the carina on the chest radiograph. The distance between the CVC tip and the carina was measured on the postoperative chest radiograph.

The tip position of 100 CVCs placed via the right IJV was 0.1 (1.1) cm [mean (SD)] below the carina (95% CI: 0.3 cm below carina-0.2 cm above carina) and the tip position of 153 CVCs placed via the right SCV was 0.0 (1.2) cm [mean (SD)] below the carina (95% CI: 0.2 cm below carina-0.2 cm above carina). There were nine outliers (two in IJV group and seven in SCV group).

When CVCs are inserted to a depth derived by adding the length between the needle insertion point and the clavicular notch and the vertical length between the clavicular notch and the carina, the CVC tip can be reliably placed near the carina level.