Claude Thayse

Adsorption of ß2-microglobulin on dialysis membranes: comparison of different dialyzers and effects of reuse procedures

In order to measure ß2-microglobulin adsorption on dialysis membranes, uremic plasma was passed through different dialyzers in a simulated hemodialysis circuit in which both plasma and dialysate compartments were organized as closed loops, the ultrafiltration pressure being adjusted to minimize water shifts. Under these conditions, comparison of the amounts of ß2-m in the plasma and dialysate compartments allowed us to calculate the binding of ß2-m to the membrane at different times of the procedure. Whereas cuprophane membrane (Gambro gf 180m, 1.8m2) did not bind ß2-m, AN69 (Filtral, 1.1 m2), high flux polysulfone (F60, 1.2m2) and modified polyamide (Polyflux 130, Gambro, 1.3m2) were found to adsorb 49 ± 8 mg (mean ± SEM), 17 ± 5 mg and 38 ± 4 mg of 82-m, respectively. These data were confirmed in trace labeling experiments with 125I-ß2-m. Adsorption was a saturable phenomenon occurring during the first 90 min of in vitro dialysis. After reuse with peracetic acid, the adsorption capacity of AN69 membrane was lowered to 20 ± 4 mg of ß2-m, contrasting with the unchanged adsorption after reuse with sodium hypochlorite. These data indicate that adsorption significantly contributes to ß2-m removal during hemodialysis with certain dialyzers and that reuse procedures may affect the propensity of dialysis membranes to bind 82-m.

Infections Associated with Subclavian Dialysis Catheters: The Key Role of Nurse Training

Two hundred subclavian dialysis catheters were placed in 148 patients who kept them in place for a total of 2,798 days. Catheterization time ranged from 1 to 79 days with an average of 14.0 +/- 1.0 days per catheter and 18.9 +/- 1.0 days per patient. Twenty nine catheters were infected, 17 of which were the source of bacteremias due to Staphylococcus epidermidis in 13 cases and to Staphylococcus aureus in 4 cases. The incidence of sepsis was not significantly greater in diabetic patients, in patients with corticotherapy or in patients presenting an underlying systemic disease. On the contrary, the incidence was greater in hospitalized patients (15 bacteremias during 1,948 catheter days) than in ambulatory patients (2 bacteremias during 850 catheters-days) as well as during a period corresponding to a greater number of untrained nurses enrolled in the dialysis team. During this period, 6 sepsies occurred in 19 catheters (other periods: 7 sepsies/116 catheters, p less than 0.01). 6 of 28 nurses had less than 3 months of professional experience (other periods: 1 of 25, p less than 0.01). These data underline the key role of nurse training in the prevention of catheter-related infections.