Method and a device for preparing a medical liquid

Abstract

A method for preparing a medical liquid from a liquid, such as water, and two concentrated solutions comprises the following steps: circulating the liquid in a conduit ( 15 ), at a flowrate Q 0; injecting into the conduit ( 15 ), at a flowrate Q 1, a first concentrated solution containing a first ionic substance A and a second ionic substance B, the ionic substances A and B having, respectively, in the first concentrated solution, a concentration [Asol] and a first concentration [B1sol]; injecting into the conduit ( 15 ), at a flowrate Q 2, a second concentrated solution containing the first ionic substance A and the second ionic substance B, the first ionic substance A having, in the second concentrated solution, the same concentration [Asol] as in the first concentrated solution, and the second ionic substance B having, in the second concentrated solution, a second concentration [B2sol] different than the first concentration [B1sol] in the first concentrated solution; regulating the injection flowrate Q 1 and the injection flowrate Q 2 of the first and second concentrated solutions in such a way that at any given time the diluted solution resulting from the mixing of the liquid and the concentrated solutions has a desired concentration [Ades] of first substance A and a desired concentration [Bdes] of second substance B.

1 - 17 . (canceled)  
   
   
       18 . An extracorporeal blood treatment apparatus comprising: 
 a preparation conduit with a first end configured to receive a liquid and a second end for delivering a treatment liquid;    a circulation device for circulating the liquid in the preparation conduit;    a first concentrated solution containing at least sodium, potassium, and calcium and/or magnesium;    a first injection means for injecting into the preparation conduit, at a first injection flowrate Q 1 , the first concentrated solution;    a second concentrated solution having, with respect to the first concentrated solution, the same concentration of sodium and of calcium and/or magnesium and a different concentration of potassium;    a second injection means for injecting into the preparation conduit, at a second injection flowrate Q 2 , the second concentrated solution;    a control means for adjusting the first injection flowrate Q 1  and the second injection flowrate Q 2  such that at any given time a diluted solution resulting from a mixing of the liquid and the first and second concentrated solutions has a desired concentration of sodium and of calcium and/or magnesium and a desired concentration of potassium; and    a supply conduit connected to the second end of the preparation conduit and to an inlet of a membrane exchanger.    
   
   
       19 . An apparatus according to  claim 18 , further comprising a removal conduit for removing spent liquid, the removal conduit being connected to an outlet of the membrane exchanger.  
   
   
       20 . An apparatus according to  claim 18 , wherein the control means controls, over the course of time, the first injection flowrate Q 1  and the second injection flowrate Q 2  of the first and second concentrated solutions, respectively, such that the concentration of potassium in the diluted solution varies over the course of time in accordance with a predetermined profile.  
   
   
       21 . An apparatus according to  claim 18 , wherein the control means controls, over the course of time, the first injection flowrate Q 1  and the second injection flowrate Q 2  of the first and second concentrated solutions, respectively, in such a way that the concentration of sodium in the diluted solution varies over the course of time in accordance with a predetermined profile.  
   
   
       22 . An apparatus according to  claim 21 , wherein the control means maintains a sum of the injection flowrates Q 1  and Q 2  of the first and second concentrated solutions, respectively, constant such that, for a constant flowrate of the liquid in the preparation conduit, the concentration of sodium in the diluted solution remains substantially constant.  
   
   
       23 . An apparatus according to  claim 18 , further comprising an infusion device configured to infuse a patient with a third solution containing at least bicarbonate, which is absent from the treatment liquid.  
   
   
       24 . An apparatus according to  claim 18 , wherein said control means comprises a control unit.  
   
   
       25 . An apparatus according to  claim 18 , wherein said first injection means further comprises a first pump arranged on a first subsidiary conduit connecting the first concentrated solution with the preparation conduit.  
   
   
       26 . An apparatus according to  claim 18  or  25 , wherein said second injection means further comprises a second pump arranged on a second subsidiary conduit connecting the second concentrated solution with the preparation conduit.