Blood Processing Systems And Methods That Employ An In-Line Flexible Leukofilter

Abstract

Systems and methods separate pump the blood cells through an in-line leukofilter to a blood cell storage container. The leukofilter has a filtration medium enclosed within a flexile housing. The systems and methods can employ a fixture to restrain expansion of the flexible filter housing during operation of the pump.

1 - 8 . (canceled) 
     
     
         9 . A blood processing system comprising
 a blood processing set including a source of blood cells, and a blood component collection flow channel coupled to the source of blood cells including a blood cell storage container and an in-line filter to remove leukocytes from the blood cells before entering the blood cell storage container, the in-line filter including a leukocyte removal filter medium and first and second flexible housings, wherein the flexible housings are comprised of DEHP-free plastic material, and   a pump station adapted to be placed into communication with the blood component collection flow channel to pump blood into the blood cell storage container through the in-line filter.   
     
     
         10 . The blood processing system of  claim 9  wherein said leukocyte removal filter medium comprises a plurality of layers. 
     
     
         11 . The blood processing system of  claim 9  wherein said leukocyte removal filter medium comprises a leukocyte-exclusion filter medium including a membrane. 
     
     
         12 . The blood processing system of  claim 9  wherein said leukocyte removal filter medium comprises a depth filtration filter comprising a fibrous filter medium. 
     
     
         13 . In a method of filtering a liquid using a filter comprising a flexible housing having an inlet port and outlet port for the liquid and a sheet-like filter element for removing undesired components from the liquid, with the inlet port being separated from the outlet port by the filter element, a method characterized by maintaining the pressure at the outlet side of the filter at a positive pressure above atmospheric pressure by controlling a feed rate per unit time of a feed pump installed in an upstream flow channel of the filter. 
     
     
         14 . The method according to  claim 13 , wherein the filter does not comprise a spacer for securing a flow channel at the outlet side of the filter. 
     
     
         15 . The method according to  claim 13  or  claim 14  wherein a filter of which the outlet side flexible housing has not been processed to provide irregularity as a spacer for securing a flow channel at the filter outlet side and/or a filter in which a tube is not inserted between the outlet side flexible housing and the sheet-like filter as a spacer for securing a flow channel at the filter outlet side are/is used. 
     
     
         16 . The method according to  claim 13 , wherein the liquid to be filtered is blood. 
     
     
         17 . The method according to  claim 14 , wherein the liquid to be filtered is blood. 
     
     
         18 . The method according to  claim 15 , wherein the liquid to be filtered is blood. 
     
     
         19 . The method according to  claim 16 , wherein the liquid to be filtered is blood. 
     
     
         20 . The method according to  claim 17 , wherein the filter is used for removal of leukocytes. 
     
     
         21 . The method according to  claim 18 , wherein the filter is used for removal of leukocytes. 
     
     
         22 . In a filtering system for a liquid comprising a filter comprising a flexible housing having an inlet port and outlet port for the liquid, a sheet-like filter element for removing undesired components from the liquid, with the liquid inlet port and the outlet port separated from each other by the filter element, an upstream side flow channel connected to the filter inlet port, a filtered liquid recovery bag, a downstream side flow channel connecting the filter outlet port with the recovery bag, and a feed pump installed in the upstream side flow channel, a filtering system wherein the feed rate per unit time of a feed pump installed in an upstream flow channel of the filter can be controlled so that the pressure at the outlet side of the filter is maintained at a positive pressure above atmospheric pressure. 
     
     
         23 . The system according to  claim 22  comprising the filter without a spacer for securing a flow channel at the outlet side of the filter. 
     
     
         24 . The system according to  claim 22  or  claim 23 , wherein a filter of which the outlet side flexible housing has not been processed to provide irregularity as a spacer for securing a flow channel at the filter outlet port and/or a filter in which a tube is not inserted between the outlet side flexible housing and the sheet-like filter as a spacer for securing a flow channel at the filter outlet side are/is used. 
     
     
         25 . The system according to  claim 22 , wherein the liquid to be filtered is blood. 
     
     
         26 . The system according to  claim 23 , wherein the liquid to be filtered is blood. 
     
     
         27 . The system according to  claim 24 , wherein the liquid to be filtered is blood. 
     
     
         28 . The system according to  claim 25 , wherein the filter is used for removal of leukocytes. 
     
     
         29 . The system according to  claim 26 , wherein the filter is used for removal of leukocytes. 
     
     
         30 . The system according to  claim 27 , wherein the filter is used for removal of leukocytes. 
     
     
         31 . A liquid filtering method using the system according to  claim 22 . 
     
     
         32 . A liquid filtering method using the system according to  claim 23 . 
     
     
         33 . A liquid filtering method using the system according to  claim 24 . 
     
     
         34 . A liquid filtering method using the system according to  claim 25 . 
     
     
         35 . A liquid filtering method using the system according to  claim 26 . 
     
     
         36 . A liquid filtering method using the system according to  claim 27 . 
     
     
         37 . A liquid filtering method using the system according to  claim 28 . 
     
     
         38 . A liquid filtering method using the system according to  claim 29 . 
     
     
         39 . A liquid filtering method using the system according to  claim 30 . 
     
     
         40 . In a method of filtering blood or blood components using a filter comprising a flexible housing having an inlet port and outlet port, said inlet port being separated from the outlet port by a sheet-like filter element, said sheet-like filter element removing undesired elements from the blood, the method including:
 connecting the inlet port to a source of blood or blood components;   connecting the outlet port to a container;   pumping the blood from the source to the filter by a pump station communicating with a blood or blood component flow channel;   adjusting at least one filtration parameter so that a pressure at an outlet side of the filter is above atmospheric pressure;   maintaining a pressure at the outlet side of the filter above atmospheric pressure throughout filtration by adjusting said at least one filtration parameter; and   collecting filtered blood or blood components in the container.   
     
     
         41 . The method according to  claim 40  wherein the pressure at the outlet side of the filter is maintained above atmospheric pressure by controlling a feed rate per unit time of a feed pump installed in an upstream flow channel of the filter. 
     
     
         42 . The method according to  claim 40  wherein the pressure at the outlet side of the filter is maintained above atmospheric pressure by restraining expansion of the inlet side flexible housing and the outlet side flexible housing by contacting an outer surface of each of said flexible housings with a separate restraining structure to restrain the outward expansion of said flexible housings under pressure applied during operation of a feed pump. 
     
     
         43 . The method according to  claim 40 , wherein the filter does not comprise a spacer for securing a flow channel at the outlet side of the filter. 
     
     
         44 . The method according to  claim 40  wherein a filter of which the outlet side flexible housing has not been processed to provide irregularity as a spacer for securing a flow channel at the filter outlet side and/or a filter in which a tube is not inserted between the outlet side flexible housing and the sheet-like filter as a spacer for securing a flow channel at the filter outlet side are/is used. 
     
     
         45 . The method according to  claim 40 , wherein the filter is used for removal of leukocytes.