Method and apparatus for ultrafiltration in hemodialysis

A method for ultrafiltration in hemodialysis for use with an ultrafiltrate balancing device having an ultrafiltrate balance chamber having a first and a second ultrafiltrate balance chamber portion comprising the steps of:

• dialyzing blood using a dialyzer, a fresh dialysis fluid entering the dialyzer and a spent dialysis fluid exiting the dialyzer;
• balancing the fresh dialysis fluid and the spent dialysis fluid in a dialysis fluid balancing device, the balanced fresh dialysis fluid being sent to the dialyzer;
• during a first cycle, sending spent dialysis fluid into the first ultrafiltrate balance chamber portion, so that substituate is diverted from the second ultrafiltrate balance chamber portion;
• during a second cycle, sending substituate into the second ultrafiltrate balance chamber portion, so that spent dialysis fluid from the first ultrafiltrate balance chamber portion is removed.

An apparatus for ultrafiltration in hemodialysis comprising:

• a dialyzer subdivided by a semipermeable membrane into a blood chamber and a dialysis fluid chamber, the blood chamber being part of a blood circulation;
• a dialysis fluid source;
• an inlet and an outlet line connected to the dialysis fluid chamber, the inlet line supplying a fresh dialysis fluid from the dialysis fluid source into the dialysis fluid chamber and the outlet line removing spent dialysis fluid from the dialysis fluid chamber into a drain;
• a dialysis fluid balancing device connected to the inlet and outlet lines for balancing the fresh and spent dialysis fluid, the dialysis fluid balancing device including a balance chamber subdivided into first and second balance chamber portions by a movable partition, with an inlet and an outlet cutoff element arranged in the inlet and the outlet lines connected to the balance chamber portions;
• a control unit connected to the inlet and outlet cutoff elements;
• a device for removing an ultrafiltrate from the dialysis fluid path;
• and
• a substituate source for supplying a substituate;
• the device for removing ultrafiltrate including an ultrafiltrate balancing device having an ultrafiltrate balance chamber subdivided by another movable partition into first and second ultrafiltrate chamber portions, wherein the first ultrafiltrate chamber portion is connected by a filtrate inlet line to the dialysis fluid path and by a filtrate outlet line to the drain, and the second ultrafiltrate chamber portion is connected by a substituate inlet line to the substituate source and is also connected to a substituate outlet line;
• an ultrafiltrate cutoff element being provided in the ultrafiltrate outlet and ultrafiltrate inlet lines and a substituate cutoff element being provided in the substituate inlet and substituate outlet lines, the control unit connected to the ultrafiltrate and substituate cutoff elements;
• and
• the control unit operating during a first cycle so that the first ultrafiltrate chamber portion is filled with ultrafiltrate, so as to divert substituate from the second ultrafiltrate chamber portion, and during a second cycle so that the second ultrafiltrate chamber portion may be filled with substituate, so as to divert ultrafiltrate from the first ultrafiltrate chamber portion into an outlet.

An apparatus for ultrafiltration in hemodialysis comprising:

• a dialysis fluid source;
• a dialyzer having an inlet line for supplying a fresh dialysis fluid from the dialysis fluid source and an outlet line for spent dialysis fluid;
• a dialysis fluid balancing device connected to the dialyzer for balancing the fresh and spent dialysis fluids;
• and
• an ultrafiltrate balancing device having an ultrafiltrate balance chamber subdivided by a movable partition into a first ultrafiltrate chamber portion and a second ultrafiltrate chamber portion, the first ultrafiltrate chamber portion being connected to the outlet line, the second ultrafiltrate chamber portion being connected to the dialysis fluid source and to at least one of a blood circulation and a return line to the dialysis fluid source.