Apparatus for extracorporeal blood treatment

Patent metadata

Field	Value
Publication number	US-11426501-B2
Application number	US-201716463781-A
Country	US
Kind code	B2
Filing date	Oct 27, 2017
Priority date	Nov 25, 2016
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

An extracorporeal blood treatment apparatus is provided comprising a filtration unit (2) connected to a blood circuit (17) and to a dialysate circuit (32), a preparation device (9) for preparing and regulating the composition of the dialysis fluid, and a sensor (11) for measuring conductivity of the dialysate (i.e. spent dialysis fluid); a control unit (12) configured for setting a sodium concentration in the dialysis fluid and after setting the dialysis fluid at the initial set point, circulating the dialysis fluid and/or the substitution fluid, measuring an initial conductivity value of the dialysate at the beginning of the treatment, and calculating, based on the measured initial conductivity value of the spent dialysis fluid and on the corresponding conductivity value of the dialysis fluid, the value of the initial plasma conductivity, said circulating the dialysis fluid up to the calculating of the initial plasma conductivity being performed maintaining the dialysis fluid conductivity substantially constant.

First claim

The invention claimed is:

1. An apparatus for extracorporeal blood treatment comprising:
a filtration unit having a primary chamber and a secondary chamber separated by a semi-permeable membrane;
a blood circuit including a blood withdrawal line connected to an inlet of the primary chamber and a blood return line connected to an outlet of the primary chamber, said blood lines being configured for connection to a patient cardiovascular system;
a dialysis supply line including at least an infusion line connected to said blood circuit;
a dialysis effluent line connected to an outlet of the secondary chamber;
a preparation device for preparing a dialysis fluid connected to said dialysis supply line and comprising a regulator for regulating the composition of the dialysis fluid;
a sensor for measuring a parameter value of a dialysate in the dialysis effluent line, said parameter of the dialysate being at least one chosen from a group consisting of conductivity of the dialysate, a conductivity-related parameter of the dialysate, concentration of at least a substance in the dialysate, and a concentration-related parameter of at least a substance in the dialysate; and
a control unit configured to run at least one of a hemofiltration (HF) treatment or a hemodiafiltration (HDF) treatment, each of said treatments including an infusion of substitution fluid through said infusion line, the control unit being connected to the sensor for receiving said parameter value of the dialysate, said control unit being also connected to the regulator and programmed for calculating a value representative of an initial plasma conductivity, wherein said control unit is configured for:
setting a parameter value for the dialysis fluid in the dialysis supply line at an initial set point, said parameter of the dialysis fluid being at least one chosen from a group consisting of conductivity of the dialysis fluid, a conductivity-related parameter of the dialysis fluid, concentration of at least a substance in the dialysis fluid, and a concentration-related parameter of at least a substance in the dialysis fluid;
after setting the dialysis fluid parameter value at the initial set point, circulating the dialysis fluid through the infusion line so as to inject fluid in the blood;
circulating blood through the primary chamber of the filtration unit;
measuring at least an initial value of said parameter of the dialysate downstream of said secondary chamber at the beginning of the treatment; and
calculating the value representative of the initial plasma conductivity, based on a sum of (i) the measured initial parameter value of the dialysate and (ii) a weighted difference between the measured initial parameter value of the dialysate and the corresponding parameter value of the dialysis fluid in the infusion line.

2. The apparatus according to claim 1 , wherein the regulator modifies the dialysis fluid composition by changing conductivity of the dialysis fluid or by changing the concentration of at least one substance in the dialysis fluid and wherein the preparation device prepares a dialysis fluid containing at least a substance, said substance being present in the blood, said regulator regulating the concentration of at least said substance in the dialysis fluid.

3. The apparatus according to claim 1 , wherein the parameter of the dialysis fluid is the concentration of at least the substance in the dialysis fluid, wherein the control unit is configured to set the parameter value for the dialysis fluid at the initial set point so that a dialysis fluid conductivity matches a first estimate of the plasma conductivity of the blood, the control unit being configured for calculating the initial set point of the substance concentration in the dialysis fluid, and a regulation of the dialysis fluid conductivity in the supply line deriving from said calculated set point of said substance concentration,
wherein the control unit is configured to calculate the initial set point of the substance concentration in the dialysis fluid as a function of the concentration of at least a further substance in the dialysis fluid, and wherein the substance whose concentration is to be set is different from the further substance.

4. The apparatus according to claim 3 , wherein the further substance is chosen from a group consisting of bicarbonate, potassium, calcium, magnesium, acetate, lactate, citrate, phosphate, and sulphate, and wherein the control unit is configured to calculate the initial set point of the substance concentration in the dialysis fluid as a function of the concentration of bicarbonate, potassium, acetate, and/or citrate, in the dialysis fluid.

5. The apparatus according to claim 3 , wherein the control unit is configured to calculate the initial set point of the substance concentration in the dialysis fluid as a function of an estimated plasma concentration of at least two substances chosen from a group consisting of sodium, bicarbonate, potassium, and acetate, and
wherein, for HDF pre-dilution treatment and HF pre-dilution treatment, said estimated plasma concentration is a diluted plasma concentration, the diluted plasma concentration being function of the blood flow rate and of the infusion flow rate.

6. The apparatus according to claim 3 , wherein the control unit is configured to calculate the initial set point of the substance concentration in the dialysis fluid as a function of a weighted difference in concentration of at least a further substance in the dialysis fluid and in plasma of the patient, the substance, whose concentration is to be set, being different from the further substance, said further substance being chosen from a group consisting of bicarbonate, potassium, calcium, magnesium, acetate, lactate, citrate, phosphate, and sulphate, and
wherein, for HDF pre-dilution treatment and HF pre-dilution treatment, said plasma concentration is a diluted plasma concentration, the diluted plasma concentration being function of the blood flow rate and of the infusion flow rate.

7. The apparatus according to claim 3 , wherein the control unit is configured to calculate the initial set point of the substance concentration in the dialysis fluid as a function of the molar conductivities of at least three substances in the dialysis fluid chosen from a group consisting of acids and salts of (i) bicarbonate (HCO 3 − ), (ii) chloride (Cl − ), (iii) acetate (CH 3 COO − ), (iv) lactate (C 3 H 5 O 3 − ), (v) citrate (C 6 H 5 O 7 3− ), (vi) phosphate (PO 4 3− ), and (vii) sulphate (SO 4 2− ), wherein the salts are formed with sodium, potassium, calcium, and/or magnesium.

8. The apparatus according to claim 3 , wherein the control unit is configured to calculate the initial set point of the substance concentration in the dialysis fluid as a function of at least a dialysate flow rate at the outlet of the secondary chamber.

9. The apparatus according to claim 3 , wherein the control unit is configured to calculate the initial set point of the substance concentration in the dialysis fluid as a function of at least an efficiency parameter of the filtration unit.

10. The apparatus according to claim 1 , wherein, after calculating the initial plasma conductivity, the control unit is configured to drive the regulator to change the content of a substance in the dialysis fluid to reach a set point for the substance, the set point being a function of the calculated initial plasma conductivity.

11. The apparatus according to claim 1 , wherein the control unit is configured to measure at least the initial value of the parameter value of the dialysate in the dialysis effluent line downstream of the secondary chamber as soon as an exchange proces

Assignees

• Gambro Lundia Ab

Inventors

• Wallenborg Anders
• Nilsson Anders
• Solem Kristian
• Hertz Thomas
• Rovatti Paolo
• Lodi Carlo Alberto
• Surace Alessandro
• Sternby Jan

Classifications

• A61M1/1656 Primary

  Apparatus for preparing dialysates · CPC title

• A61M1/3406

  Physical characteristics of the filtrate, e.g. urea · CPC title

• A61M1/16 Primary

  with membranes · CPC title

• A61M1/3465

  using dialysate as substitution fluid · CPC title

• A61M1/3621

  Extra-corporeal blood circuits (single-needle circuits A61M1/30) · CPC title