Comparison of four dialyzer-dialysate combinations: effects on blood gases, cell counts, complement contact factors and fibrinolytic system

Continuous registration of blood oxygen tension during hemodialysis

Continuous monitoring of blood oxygen tension was carried out during 45 hemodialyses sessions. The oxygen tension curves displayed different appearances. Some curves presented with a periodicity like sinus curves (type 1), while others (type 2) fluctuated with other appearances, or displayed straight lines. Blood pressure variations during dialysis were significantly greater during dialyses displaying type 1 curves than during those displaying type 2 curves (p values < 0.02). Due to a greater descend of S-urea during dialyses with type 1 curves than during dialyses with type 2 curves (p < 0.05) it is hypothesized, that the intensity of the dialysis treatment could be of some importance to the observed fluctuations in oxygen tension.

Proteins adsorbed on hemodialysis membranes modulate neutrophil activation

The rapid adsorption of plasma proteins is one of the initial events that occur when blood enters into contact with an artificial surface. This study investigates adsorption of plasma proteins in vitro by different types of dialysis membranes and how it influences neutrophil oxygen radical production. The recovery of proteins varied between the membranes and was by far the largest on polysulfone. Electrophoresis of the proteins removed indicated that albumin was present on all of the membranes. A specific band at 45 kD was observed on polysulfone, whereas a band at 12-14 kD was seen on polysulfone and polyacrilonitrile. The adsorbed proteins enhanced or reduced the ability of the membranes to stimulate neutrophil superoxide production, as measured by cytochrome-C reduction. The complement system was involved in this stimulation only on some membranes. Therefore, protein adsorption and neutrophil activation appear to take part in the membrane bioincompatibility process.

Dialysis hypoxemia. Role of dialyzer membrane and dialysate delivery system

Arterial blood gas values, carbon monoxide diffusion capacity, oxygen consumption, carbon dioxide production, respiratory quotient, minute ventilation, and pulmonary capillary blood flow were determined before and during hemodialysis. In addition, the effect of single passage through the dialyzer on blood carbon dioxide tension, pH, and bicarbonate concentration was evaluated. Acetate-based dialysate was used in all experiments. Cellulosic dialyzer with single-pass dialysate delivery system was used in one group, and polyacrylonitrile dialyzers with recirculating delivery system in another. Although hypoxemia occurred in both groups, it was more severe in the former group. Dialyzer carbon dioxide loss was significantly greater with single-pass dialysate delivery system and cellulosic dialyzers than with recirculating delivery system and polyacrylonitrile dialyzer. To differentiate the role of dialysate delivery system from that of the membrane, the experiments were repeated using recirculating delivery system and cellulosic dialyzer. This resulted in marked attenuation of hypoxemia and dialyzer carbon dioxide tension losses. Since other experimental conditions were the same, the observed differences were thought to be due to the difference in the mode of dialysate delivery. It thus appears that the mode of dialysate delivery per se can modify the changes in arterial oxygen tension during hemodialysis and should be added to the list of factors implicated in the genesis of dialysis hypoxemia.