[Performance of central catheters on the filtration yield measured by ionic dialysance ]. / Performances des cathéters centraux sur les débits d'épuration mesurés par la dialysance ionique.

Certain number of dysfunctions, particularly decline of blood flow or, recirculation, can decrease the adequacy of depuration, when central catheters are used. Ionic dialysance is available on some monitors (Integra), and reflects perfectly the effective urea clearance, permits to watch any variation in the effective clearance of the depuration system due to these dysfunctions. We report on our experience in a retrospective study from 01/01/2000 to 30/11/2000 where we compared the effective clearance of depuration measured by the ionic dialysance of all the sessions of dialysis made on central catheters in our center, with the forecast clearance of sessions made in the same conditions of dialysis but with a non pathologic fistula. The mean of dialysances decreases of 12% on Dual Cath, of 15% on Ash Split Cath, and 28% on Silicone single lumen femoral catheter, and further analysis makes appear that respectively 60, 65 and 92% of these sessions have a mean of dialysance--10% with regard to the threshold value. The recirculation is certainly the major factor of this decline of the ionic dialysance as well as the decline of blood flow due to partial clotting or relative low venous central pressure due to hypovolaemia. Our data incite to more vigilance for a possible sub dialysis during the use of the central catheters, and prove the utility of the ionic dialysance to watch the technical conditions of the session of dialysis.