Optimal insertion depth of central venous catheters--is a formula required? A prospective cohort study.

INTRODUCTION: To determine the optimal length for initial insertion of central venous catheters (CVCs) and to evaluate whether a recommended depth predicted optimal positioning of CVCs.

MATERIALS AND METHODS: All patients who were CVC-cannulated and who underwent chest computed tomography (CT) during a 10-month period were included. We measured the distance from catheter insertion to the superior vena cava/right atrium (SVC/RA) junction and calculated a recommended insertion depth. We compared the accuracy of the recommended depth with that suggested by the formula of Peres for predicting optimal positioning of a CVC.

RESULTS: Of the 1238 patients who were CVC-cannulated over 10 months, 106 underwent chest CT. Based on the mean distance from the CVC insertion point to the distal SVC, we determined that the recommended depth of insertion should be 14 cm for the right subclavian vein, 15 cm for the right internal jugular vein, 17 cm for the left subclavian vein and 18 cm for left internal jugular vein. Using these guidelines, initial placement of a CVC in the distal SVC was more accurate than when the Peres formula was used (91.5% vs. 77.4%, p<0.05).

CONCLUSIONS: For Asian populations, we found that these guidelines are more accurate than those derived from the Peres formulae and more simple to use, thus increasing the likelihood of optimal tip location within the SVC on the first attempt and eliminating the need for later repositioning.