[The clinical tests used to determine the position of the central venous catheter]

Chest x-ray (Rx) is the standard test to assess correct placement of a central venous catheter (CVC). Our objective was to validate the use of four clinical measures (CMs) to assess the proper placement of the line.

During a period of eight month, at the Intensive Care Unit a prospective study was done. A chest Rx was always obtained to assess the position of the catheter. The CMs were: venous return; waveform of the central venous pressure (CVP); arrhythmias while advancing the guide wire and the difference between planned length in cm to be introduced and the length of the catheter introduced.

For each parameter alone the sensitivity and specificity found were: for venous return 97% and 22%, for CVP waveform changes 86% and 40%, for arrhythmias 97% and 60%, for difference between planned and real length introduced into the patient 97% and 50% respectively. According to chest x-ray, 78% of the catheters were located at a central position. Using the four CMs, we obtained 86% sensitivity and 90% specificity of the placement of the CVC.

The use of each parameter alone is highly sensitive but poorly specific.