Dual, single needle blood treatment system and method

Abstract

A blood treatment system includes: (i) a dialysate circuit; (ii) a blood filter in fluid communication with the dialysate circuit; and (iii) an extracorporeal circuit in fluid communication with the blood filter, the extracorporeal circuit including a blood pump, a downstream line from the blood pump, an upstream line to the blood pump, a first patient access line, a second patient access line, a first valve arrangement fluidly communicating the first and second patient access lines to the downstream line, and a second valve arrangement fluidly communicating the first and second patient access lines to the upstream line.

The invention is claimed as follows: 
     
         1 . A blood treatment system comprising:
 a dialysate circuit;   a blood filter in fluid communication with the dialysate circuit; and   an extracorporeal circuit in fluid communication with the blood filter, the extracorporeal circuit including
 a blood pump, 
 a downstream line from the blood pump, 
 an upstream line to the blood pump, 
 a first patient access line, 
 a second patient access line, 
 a first valve arrangement fluidly communicating the first and second patient access lines to the downstream line, and 
 a second valve arrangement fluidly communicating the first and second patient access lines to the upstream line. 
   
     
     
         2 . The blood treatment system of  claim 1 , wherein at least one of the first and second valve arrangements includes a three-way valve. 
     
     
         3 . The blood treatment system of  claim 1 , which includes a control unit programmed to switch the first and second valve arrangements such that fluid is pumped: (i) down the downstream line and into the first patient access line during a first time period and (ii) down the downstream line and into the second patient access line during a second time period. 
     
     
         4 . The blood treatment system of  claim 3 , wherein the control unit is programmed to switch the first and second valve arrangements such that fluid is pumped: (i) up the second patient access line and into the upstream line during the first time period and (ii) up the first patient access line and into the upstream line during the second time period. 
     
     
         5 . The blood treatment system of  claim 1 , which includes first and second needles or cannulas connected to the first and second access lines, respectively. 
     
     
         6 . The blood treatment system of  claim 5 , which includes a control unit programmed to switch the first and second valve arrangements such that fluid is pumped: (i) downstream into the first needle or cannula during a first time period and (ii) upstream from the second needle or cannula during the first time period. 
     
     
         7 . The blood treatment system of  claim 6 , wherein the control unit is further programmed to switch the first and second valve arrangements such that fluid is pumped: (i) upstream from the first needle or cannula during a second time period, and (ii) downstream into the second needle or cannula during the second time period. 
     
     
         8 . The blood treatment system of  claim 7 , wherein fluid is pumped upstream from the first and second needles or cannulas alternatingly and virtually continuously. 
     
     
         9 . The blood treatment system of  claim 7 , wherein fluid is pumped downstream into the first and second needles or cannulas alternatingly and virtually continuously. 
     
     
         10 . The blood treatment system of  claim 7 , wherein an amount of fluid lost from the blood treatment system due to disconnection of one of the first or second needles or cannulas during therapy is less than or equal to an amount of fluid pumped during one of the first or second time periods. 
     
     
         11 . The blood treatment system of  claim 1 , wherein the first and second valve arrangements are located upstream of the blood pump. 
     
     
         12 . The blood treatment system of  claim 1 , wherein one of the first and second valve arrangements is dedicated to delivering blood to a patient, while the other of the first and second valve arrangements is dedicated to removing blood from the patient. 
     
     
         13 . The blood treatment system of  claim 1 , wherein the blood filter is of a type selected from the group consisting of: (i) a hemodialyzer or (ii) a hemofilter. 
     
     
         14 . The blood treatment system of  claim 1 , which performs a therapy selected from the group consisting of: (i) hemodialysis (“HD”), (ii) hemofiltration (“HF”) or (iii) hemodiafiltration (“HDF”). 
     
     
         15 . A blood treatment system comprising:
 a dialysate circuit;   a blood filter in fluid communication with the dialysate circuit; and   an extracorporeal circuit in fluid communication with the blood filter, the extracorporeal circuit including
 a blood pump, 
 an upstream line to the blood pump, 
 a downstream line from the blood pump, and 
 first and second needles or cannulas each in valved fluid communication with both of the upstream and downstream lines. 
   
     
     
         16 . The blood treatment system of  claim 15 , which includes first and second valve arrangements controlled so that fluid is pumped: (i) down the downstream line and into the first needle or cannula during a first time period and (ii) down the downstream line and into the second needle or cannula during a second time period. 
     
     
         17 . The blood treatment system of  claim 16 , wherein the first and second valve arrangements are further controlled so that fluid is pumped: (i) up the second needle or cannula and into the upstream line during the first time period and (ii) up the first needle or cannula and into the upstream line during the second time period. 
     
     
         18 . The blood treatment system of  claim 15 , wherein the blood pump pushes and pulls fluid through each needle or cannula. 
     
     
         19 . The blood treatment system of  claim 15 , wherein the first and second needles or cannulas are each placed in valved fluid communication with both of the upstream and downstream lines at locations upstream of the blood pump. 
     
     
         20 . A method for a blood treatment machine comprising:
 structuring the blood treatment machine so that the machine will
 (i) deliver blood to a patient via a first needle and remove blood from the patient via a second needle during a first time period; 
 (ii) deliver blood to the patient via the second needle and remove blood from the patient via the first needle during a second time period; and 
 (iii) repeat (i) and (ii) at least one time. 
   
     
     
         21 . The method of  claim 20 , which includes causing an amount of blood lost if one or the first or second needles or cannulas becomes dislodged from the patient to be less than or equal to an amount of blood pumped during one of the first or second time periods. 
     
     
         22 . The method of  claim 20 , which includes making the first and second time periods equal to each other.