[Central venous catheters for haemodialysis and optimal blood flow]

Central venous catheters (CVC) have become and indispensable form of haemodialysis access and represent, in our centre, about 8,58 % of the permanent vascular access with a total number of more than 957 venous catheters in the past 8 years. We used double-lumen catheters.

The aim of this study was to identify the factors of the catheter dysfunction. We studied prospectively 23 chronic haemodialysed patients with CVC, 14 men and 9 women 63 +/- 14 (51-83), treated with haemodialysis for 3.7 +/- 4 (1-9) years. Catheters were inserted by percutaneous Seldinger techniques in right internal jugular vein. We studied the localization of the catheter tip: superior vena cava, right atrium, the blood pressure before and after haemodialysis, the interdialytic weight gain, and number of symptomatic episodes during 13 last dialysis (one month). The patients were divided into two groups: group I with usual adequate catheter function (n=17) and group II with frequent dysfunction (n=6).

In group I the catheters tip was in the right atrium, and in group II in the vena cava superior. Blood pressure was not different between the two groups. We found no correlation between central venous pressure, blood pressure, interdialytic weight gain and symptomatic hypotension, but there was a higher frequency of hypotension in the hypovolemic patients.

Optimal hemodynamic conditions will be provided by a catheters tip in the rights atrium and a central venous pressure over 5 mmHg, which can be provided with vascular filling or dry body weight.