What action would increase diffusion during dialysis?

Increasing diffusion during dialysis relies heavily on the concentration gradient between the dialysate and the blood. When a bath provides a greater concentration gradient, it enhances the movement of solutes from an area of higher concentration to an area of lower concentration, which is essentially how diffusion works.

In dialysis, the dialysate is used to draw impurities and excess solutes from the blood. If the concentration of a waste product, such as urea, is higher in the blood than in the dialysate, diffusion will occur, transporting the waste from the blood into the dialysate for removal. By utilizing a bath that has a greater concentration of a solute compared to what's in the blood, the rate at which that solute diffuses from the blood into the dialysate is increased, effectively enhancing the overall removal of wastes and toxins during treatment.

The other actions listed don't focus on altering the concentration gradient, which is the primary mechanism driving diffusion. For instance, decreasing the ultrafiltration rate or giving saline adjusts fluid balance but does not impact solute movement directly. Similarly, administering erythropoietin (EPO) influences hematocrit levels but does not augment the diffusion process itself, as it does not affect the concentration gradients present