Dialysis machine including ultrafiltration and backfiltration means

A dialysis machine making it possible to treat a body fluid, said machine comprising:

• a dialyzer including an enclosure housing a dialysis membrane that subdivides the enclosure into a body fluid compartment for passing said body fluid, and a dialysate compartment for passing dialysate;
• said body fluid compartment having a body fluid inlet and a body fluid outlet, and said dialysate compartment having a dialysate inlet and a dialysate outlet;
• a dialysate feed system comprising a dialysate feed line connected to the inlet of the dialysate compartment;
• and a dialysate discharge system comprising a dialysate discharge line connected to the outlet of the dialysate compartment;
• a control unit that comprises:
• ultrafiltration control means that sends an aqueous quantity of the body fluid to pass through a portion of the membrane from the body fluid compartment into the dialysate compartment;
• and back-filtration control means configured to make the dialysate pass through at least a portion of the membrane, from the dialysate compartment into the body fluid compartment;
• wherein the dialysate feed line is provided with a flow constriction, and said machine further comprises means for measuring the pressure difference across the terminals of said flow constriction;
• in that said dialysate feed system further comprises:
• at least one ventricle flexible bag designed to contain the dialysate and connected to said feed line upstream from said flow constriction, said ventricle bag being contained in an enclosure;
• and pressurizer means for putting the ventricle bag under pressure by pressurizing said enclosure;
• and in that said machine further comprises an open/close system for opening/closing the dialysate discharge line, which system, when in the open state, allows the dialysate present at the outlet of the dialysate compartment to flow through said discharge line, and, when in the closed state, prevents the dialysate present at the outlet of said dialysate compartment from flowing through said discharge line said back-filtration control means being configured to:
• control said open/close system so as to close the discharge line;
• and when said discharge line is in the closed state, control the pressure applied to said ventricle bag as a function of the pressure difference measured across the terminals of the constriction, so as to obtain a given flow rate of dialysate.