[Central venous access for hemodialysis. Dysfunctions: role of the nephrologist].

Central venous catheter for chronic hemodialysis can present primary or secondary dysfunctions. The first are related to malpositions or kinking, diagnosis is radiological. A postoperative chest radiography has to be done, but during the first session an initial evaluation of the catheter functioning is useful: a 'pressions test' (recording of arterial depression and venous counter-pression for progressively increasing blood flow) and recirculating test have to be performed. Later, clotting or thrombosis of catheter are often involved, detection and management are different according to the type of manifestations and to the moment of occurrence (when aspiration of residual heparin or when initiating dialysis). Fibrinolytics are often used. Catheter fissuration and leak are also frequent, often on the external extremity of adaptator, occasionally on the proximal extremity, exceptionally on the catheter itself. management is according to location of the fissuration, but there are always infectious and hemorrhagic risks during manipulations and changing of the external adaptor. Prevention of these dysfunctions is imperative, it depends on a strict follow-up and good practices.