A:Hemodialysis achieves solute clearance by diffusion across a semipermeable membrane from a higher concentration (in the patient’s blood) to a lower concentration (in the dialysis fluid).B:Hemofiltration (which is the mechanism used in continuous venovenous hemofiltration [CVVH]) achieves solute clearance by convection across a semipermeable membrane from a higher hydrostatic pressure (in a patient’s blood) to a lower hydrostatic pressure (in the hemofiltrate).