Untitled record

BACKGROUND OF THE INVENTION

<dl><dt>1. </dt><dd>Field of the Invention </dd></dl>

The present invention is about an apparatus for processing biological fluid by separating its therapeutically valuable components. More particularly, the present invention relates to an apparatus for processing donated blood by separating its therapeutically valuable components. More particularly, the present invention relates to an improved apparatus for processing donated blood, separating its therapeutically valuable components, which uses an improved open circuit system to substantially increase the recovery of all blood products from donated blood.

<dl><dt>2. </dt><dd>Presentation of the related technique </dd></dl>

p00002Procedures and apparatus for processing blood are well known in the prior art. US Patent No. 3,892,236 to Djerassi shows an apparatus for the continuous extraction of blood from a human donor, a forced extracorporeal circulation of the donor's blood with the separation of granulocytes, and the return of the whole blood impoverished in leukocytes to the donor through gravity.

p00003US Patent No. 5,126,054 to Matkovich shows a ventilation means for expelling gas from the transfer path of a liquid supply system comprising a housing, a first microporous membrane moistened by liquid carried in said housing, so that is in communication with the transfer path, and a second microporous membrane permeable to the non-wettable gas by liquid superimposed on said microporous membrane to the outer side of the housing. The gas in the supply system is expelled from the system while the first microporous membrane remains not humidified by the supply liquid.

p00004US Patent No. 5,451,321 to Matkovich shows biological fluid processing assemblies having a gas inlet and / or a gas outlet.

p00005Also known in the prior art (WO 95/23016) is a process for processing a biological fluid comprising obtaining a biological fluid from a source, separating at least one component of the biological fluid and returning the depleted biological fluid from the component to the source while that a portion of the separated component is impoverished in leukocytes by passing the component through a leukocyte impoverishment medium. In addition, a corresponding system is described in this document.

p00006Although these devices are generally satisfactory, some of the prior art methods and apparatus leave a large amount of biological fluid trapped in various elements of the fluid processing apparatus. Although the US patent No. 5,451,321 to Matkovich, mentioned above, allows the liquid trapped in various elements of the fluid processing system to be recovered either by causing a volume of gas behind the retained liquid to push the liquid through those elements and into the designated collection bag, or when removing the retained liquid inside the designated collection bag by means of a differential pressure (for example, gravity loading, pressure sleeve, suction and the like), the system still has several drawbacks. A drawback is that they require one or more non-wettable gas permeable membranes. This requirement may lead to higher costs with respect to wettable membranes.

p00007Therefore, those skilled in the art are still looking for a method and an apparatus to allow optimal recovery of the biological fluid from the biological fluid processing systems, cost reduction and ease of use, and have developed novel circuit systems. Open and closed circuit and procedures associated with them to achieve this goal.

SUMMARY OF THE INVENTION

p00009The problems of the prior art are solved by means of the present invention which uses a novel open circuit biological fluid processing system that shows the concept that gases transferred to the biological fluid processing system, outside or within it, They have the transfer paths arranged or configured so as to prevent the biological fluid from coming into contact at any time with the upstream and downstream ventilation openings or openings of the gas inlet and outlet. The gases are transferred to the biological fluid processing systems, and out of them, through a porous medium in the upstream and downstream ventilation openings or openings of gas inlet. Each housing or ventilation opening is separated from the biological fluid, and is in communication with it, by means of a gas column in the transfer paths. The upstream gas inlet housing or vent is in communication with the unfiltered biological fluid and the downstream vent or inlet is in communication with the filtered biological fluid.

p00010The present invention is described in independent claim 1. Advantageous embodiments are described in the corresponding dependent claims. Additional sections in the present summary of the invention now describe aspects of the present invention or features of the embodiments of the present invention.

p00011According to the present invention, a biological fluid filtration apparatus is provided which includes a fluid filtration or leukocyte depletion device having an inlet and an outlet, a fluid container upstream from said fluid or device filtration device. leukocyte impoverishment, and elevated above it, and has an outlet, a first conduit in fluid communication with the outlet of said fluid container and the inlet of said fluid filtration or leukocyte depletion device, a reception vessel downstream of said fluid filtration or leukocyte depletion device and that has an entrance, a second conduit in fluid communication with the inlet of said receiving vessel and the outlet of said fluid filtration or leukocyte depletion device, and the outlet of said fluid filtration or leukocyte depletion device, a current inlet above gas that is adapted to have one of its elevated ends above said fluid container, and which has its other end directly connected to said first conduit, and is in fluid communication with it. In addition, a downstream gas inlet can be provided which has one of its elevated ends above said fluid container, and which has its other end in fluid communication with said leukocyte depletion device or fluid filtration device.

p00012In yet another embodiment of the present invention, the downstream gas inlet may be connected to the receiving vessel instead of the fluid filtration or leukocyte depletion device.

p00013In the present invention, the downstream gas inlet is optional.

p00014In yet another modification of the present invention, the upstream gas inlet ventilation housing or opening and the downstream gas inlet ventilation housing or opening may be part of the same inlet device.

p00015Therefore, it is an object of the present invention to provide an improved apparatus for filtering biological fluid.

p00016It is a further object of the present invention to provide an open gas vent opening that prevents premature introduction of gas into the fluid stream in a biological fluid processing system.

p00017It is a further object of the present invention to provide an open circuit biological fluid processing system with transfer paths or conduits arranged or configured so as to prevent the biological fluid from coming into contact with the housings.

p00018or ventilation openings upstream and downstream of gas inlet.

p00019Another objective of the present invention is to offer a greater choice of materials that can be used in the gas inlet housings or in the gas outflow vents or openings of the biological fluid filtration systems. The present invention does not require wettable membranes. The choice of membranes for the present invention is not limited.

p00020Another object of the present invention is to provide a system of the above nature in which gas is transferred to the biological fluid processor, and is removed therefrom, through a porous medium in the upstream and downstream gas vent openings. .

p00021A further objective of the present invention is to provide an open circuit system of the above nature in which each gas vent opening is separated from the biological fluid, and is in communication with it, by means of a gas column in the tracks or transfer ducts.

p00022A further object of the present invention is to provide an open circuit biological fluid filtration system of the above nature in which the upstream gas inlet housing or aperture, and the inlet current inlet vent or housing Gas below may be a portion of the same input device.

p00023A further objective of the present invention is to provide an open circuit biological fluid filtration system that has a high upstream gas inlet above the level of the biological fluid container and that has a satellite bag connected to the fluid receiving container. biological.

p00024Further objectives and advantages of the present invention will be apparent from the following description and the appended claims, referring to the accompanying drawings that are part of the report, in which similar reference characters designate corresponding parts in the various views. .

BRIEF DESCRIPTION OF THE DRAWINGS

p00026Fig. 1 is an elevation view of a biological fluid filtration system of the prior art Fig. 2 is an elevation view of a construction that implements the present invention.

p00027Fig. 3 is an elevation view showing a modification of the construction shown in Fig. 2. Fig. 4 is an elevation view of an additional modification of the construction shown in Fig. 2, which does not show the invention but that provides useful information to understand the invention. Fig. 5 is an elevation view showing a further modification of the construction shown in Fig. 2. Fig. 6 it is an elevation view of a closed circuit construction that does not show the present invention but shows aspects of the present invention and provides useful information for understanding the present invention. Fig. 7 is an elevation view showing a modification of the construction shown in Fig. 6. Fig. 8 is an elevation view of an additional modification of the construction shown in Fig. 6. Fig. 9 it is an elevation view showing an additional modification of the construction shown in Fig. 6. Fig. 10 is an elevation view showing an additional modification of the construction shown in Fig. 6. Fig. 11 is a elevation view showing a further modification of the construction shown in Fig. 6. Fig. 12 is an elevation view of a construction that implements the present invention using a satellite bag.

DESCRIPTION OF THE PREFERRED EMBODIMENT

p00029US Patent No. 5,451,321 to Matkovich mentioned above shows a biological fluid processing assembly for biological filtration processes, such as blood. An example of the Matkovich apparatus is illustrated in Fig. 1. The apparatus has a blood collection bag 30 connected by means of a first conduit 31 to a leukocyte depletion device 32. The leukocyte depletion device 32 is connected through a second conduit 33 to a blood receiving bag 34. A gas inlet 35 is provided having a cover or a cover 36 in fluid communication with the first conduit 31 downstream of said collection bag 30, and a gas outlet 37 is provided in the second conduit 33 downstream of the device 32 depletion in leukocytes.

p00030In an embodiment of the prior art, a first compression clamp 38 is placed in the first conduit 31 downstream of the blood collection bag 30 and upstream of the gas inlet 35, and a second compression clamp 39 is placed in the second conduit 33 downstream of the gas outlet 37. In a typical operation, the blood collection bag 30 is sterile and is connected to the conduit 31 as illustrated. The gas inlet 35 comprises a housing 41 and a barrier 42 of porous medium in addition to a cover or cover 36. Additional details of the barrier 42 can be obtained with reference to US Patent No. 5,451,321.

p00031Before the start of the blood processing, the inlet compression clamp 38, the outlet compression clamp 39, and the gas inlet 35 are closed. The blood processing is started by opening the inlet compression clamp 38 and allowing the blood to drain from the blood collection bag 30. A column of blood flows through the first duct 31 into the leukocyte depletion device 32 showing any gas within the blood processing system. No blood enters the gas inlet device 35 since the gas inlet is closed. The displaced gas is expelled from the system through the gas outlet 37 since the second compression clamp 39 is closed. Since substantially all of the gas is expelled from the first conduit 31 and the portion of the second conduit 33 leading to the gas outlet 37, the blood moisturizes the porous medium, and the blood flow stops or stops at the antagonistic barrier of the liquids at gas outlet 37.

p00032Once the gas outlet 37 has been wetted, the second compression or outlet clamp 39 is opened, and the filtered blood flows into the blood receiving bag 34. The gas outlet 37 does not need to be closed before opening the outlet compression clamp since the gas outlet is sealed by the wetted porous medium. Blood flows from the blood bag or collapsible bag 30 through the leukocyte depletion device 32 and into the blood receiving bag 34 until a balance is reached in the system and the blood stops flowing. At this point, not all blood has been processed through leukocyte depletion device 32. The first conduit 31, the filter device 32 and the second conduit 33 are filled with blood.

p00033Removing the cover or lid 36 of the gas inlet 35 allows the gas to enter the processing system and propel the blood through the leukocyte depletion device 32. However, since the filter medium 32A in the leukocyte depletion device 32 is wetted, blood flow stops when the gas fills the chamber upstream of the filter. When the blood flow stops, the second compression or outlet clamp 39 is closed.

p00034It can be seen that, at this point, the downstream side of the leukocyte depletion device 32, and the second complete duct 33 are filled with blood. With a growing need for blood and blood products, those skilled in the art have struggled to increase blood recovery, and such a relatively large amount of blood left in the prior art device is no longer satisfactory.

p00035To solve the recovery problems present in prior art devices, the open circuit construction shown in Fig. 2 has been developed. A biological fluid filtration system 44 is shown having a leukocyte depletion device 45 with a filter means 46, an input 47, and an output 48. The leukocyte depletion device can be any suitable fluid filtration or leukocyte depletion device.

p00036A blood vessel 49 is provided upstream from said leukocyte depletion device 45, and is elevated above it. The blood vessel 49 is connected to said leukocyte depletion device 45, or is in fluid communication with it, through the first conduit 50.

p00037A container 52 for receiving blood downstream of said leukocyte depletion device 45 is also provided. The leukocyte impoverishment device 45 is connected to the blood receiving vessel 52 through the second conduit 54. An upstream gas inlet 56 is provided in fluid communication with said first conduit 50, and a downstream inlet gas 58 is provided in fluid communication with said leukocyte depletion device 45, downstream of said filter means 46 .

p00038An input compression clamp 60 and an output compression clamp 61 can be provided. It should be understood that one or more input compression pliers 60 and / or output compression pliers 61 may be provided, and be perfectly within the scope of the present invention.

p00039The upstream gas inlet 56 may take the form of a ventilation duct 62 that is connected to an upstream gas inlet housing 64. The ventilation path 62 may have a U-shaped portion 62A to prevent the introduction of gas into the biological fluid filtration system 44 until substantially all of the biological fluid has been drained from the biological fluid container 49. The other end of the ventilation path 62 should be at a sufficient height, so that it is always placed above the level of the fluid in the biological fluid container 49.

p00040The vent housing or vent 64 upstream of gas has an inlet 65 and an outlet 66. Interposed between the inlet 65 and the outlet 66 in a sealed relationship there is at least one layer of a porous medium 67. The porous medium can be such as a bacterial retention medium, a viral retention medium, or other suitable means.

p00041Similarly, the downstream gas inlet 58 may comprise a second ventilation path 70 connected to a downstream gas vent or opening 71 having an inlet 72 and an outlet 73. A cover or other closure may be used. 74 in connection with the opening and closing of the entrance 72. Interposed in the housing 71, between the entrance 72 and the exit 73 there is a second porous means 76. The second porous medium 76 may also be such as a bacterial retention medium, a viral retention medium, or other suitable means.

p00042As illustrated, the upstream gas inlet housing 64 and the downstream gas inlet housing 71 may be provided in a single novel inlet device 80 having a barrier or wall 81 that prevents fluid communication between the medium. porous 67 upstream of gas and the porous medium 67 downstream of gas. Then, the upstream medium 67 and the downstream medium 76 of a single sheet can be formed.

p00043The upstream gas inlet 56 and the downstream gas inlet 58 may be placed in any feasible location as long as they are located so that the blood product being filtered never comes into contact with the porous medium 67. In the preferred embodiment The porous medium 67 contained within the housing 64 is raised above the blood container 49, but other locations are perfectly within the scope of the present invention.

p00044In the blood processing method that implements the present invention, the inlet compression clamp 60 and the outlet compression clamp 61 are initially closed. Also in place is the lid or closure 74 that covers the inlet 72 of the downstream gas inlet device, the housing or housing portion 71.

p00045Blood processing is initiated by opening the inlet compression clamp 60 and allowing the biological fluid to flow through the first conduit 50. As the fluid flows through the fork 50A, some of the fluid will flow to the upstream gas inlet 56 through airway 62. A column of liquid of a desired predetermined length (shown as dimension A in Fig. 2), between the fork 50A and the lower part of the loop portion 62A, it prevents gas from entering the system until substantially all of the biological fluid has been emptied from the biological fluid container 49.

p00046The upstream gas vent can be considered as a pressure gauge that measures the pressure at fork 50A. As the level of fluid within the biological fluid container 49 decreases, the pressure in the fork 50A is reduced and, therefore, the height of the fluid in the ventilation path 62 is reduced. When substantially all of the biological fluid in the biological fluid container 49 has been emptied, the atmospheric pressure acting on the fluid column within the ventilation path 62 will cause all the fluid in the upstream gas inlet 56 to drain into the duct 50. The remaining fluid contained with the inlet path 62 upstream of gas in the duct 50 is emptied because the upstream inlet of gas is open to the atmosphere. Therefore, dimension A in Fig. 2 must have a sufficient distance for the sequence described above to occur. At this point, the leukocyte depletion device 45 is filled with filtered biological fluid downstream of the filter medium 46 and the second conduit 54 between the leukocyte depletion device 45 and the blood receiving vessel 52.

p00047The filtered biological fluid or blood downstream of the filter medium 46 in the leukocyte depletion device 45 can now be recovered by opening the lid or the closure 74 covering the inlet 72 of the downstream gas inlet device of the housing or of housing portion 71. Instead of the cover 74, a compression clamp (not shown) could be used in the second ventilation opening 70.

p00048After this stage all the blood not previously recovered by the prior art devices is in the blood receiving vessel 52. Any gas in the receiving vessel 52 and / or in the second conduit 54 downstream of the disconnection point of the blood receiving vessel 52 can be reintroduced into the second conduit 54 by carefully compressing the receiving vessel 52 , and then the output compression clamp 61 can be closed.

p00049As is now apparent, the construction shown in Fig. 2 provides a simple procedure of draining substantially all of the biological fluid from the receiving bag 52 through the leukocyte depletion device 45. Furthermore, in its preferred embodiment, the biological fluid filtration system 44 uses only a single housing in the inlet device 80, and a single layer of porous medium and substantially all of the filtered biological fluid is recovered. The system has a smaller number of parts, is easier to manufacture, and recovers more biological fluid at a lower processing cost per unit of biological fluid.

p00050Alternative embodiments of the invention shown in Fig. 2 are illustrated in Figures 3 and 5, which designate similar parts in similar views with similar numbers. Fig. 4 does not show an embodiment of the invention, but provides useful preliminary information. Its operation can be easily understood by those skilled in the art taking into account the above description.

p00051A modification of the present invention is shown in Fig. 12 using only the upstream gas inlet 56 and a satellite bag 83. The satellite bag 83 is connected in fluid communication with the blood receiving vessel 52 by means of the satellite conduit 84. The compression satellite clamp 85 opens and closes the satellite conduit 84. In this embodiment of the present invention, the satellite bag is used to expel the displaced gas from the receiving container 52. The volume of the satellite bag 83 should be sufficient to accept all displaced gas. After all the blood has flowed to the receiving container 52, the container is carefully compressed until all the gas is expelled by the compression satellite clamp 85, at which time the compression satellite clamp 85 is closed.

p00052Referring now to Fig. 6, a closed loop biological fluid filtration system 90 is shown which does not correspond to the present invention, but which shows aspects of the invention and provides useful preliminary information. As in the previous embodiments of the present invention, there is a leukocyte depletion device 45 having a filter means 46, an inlet 47, and an outlet 48. The filter means 46 is interposed in a tight relationship between the inlet 47 and the outlet 48. The system 90 also includes a blood vessel 49 connected by means of a first conduit 50 with the inlet 47 of the leukocyte depletion device 45. An input compression clamp 60 is provided as before.

p00053A blood receiving vessel 52 is provided downstream of the leukocyte depletion device 45. A second conduit 54 is connected between the outlet 48 of the leukocyte depletion device 45 and the inlet of the blood receiving vessel 52. Instead of the upstream gas inlet 56 and the downstream gas inlet 58 there is a bypass path 91, which can be opened or closed by means of the bypass compression clamp 92. A first end of the bypass line 91 is connected in fluid communication with the blood container 49 near the outlet thereof, and the other end of the bypass route 91 is connected in fluid communication with the container 52 of blood reception near the entrance of it. The loop portion 93 of the bypass path 91 is positioned such that when the blood vessel 49 is full of blood, the blood will not reach the loop portion 93 and, therefore, there can be no blood flow through the bypass route. A position such with the loop portion 93 raised above the blood vessel 49 is illustrated in Fig. 6.

p00054Instead of the loop portion 93, a unidirectional check valve or other device can be used, so that a gas column will always separate the unfiltered biological fluid upstream of the biological fluid filtration device filtered downstream of the device 45 of impoverishment in leukocytes. The placement of the loop portion 93, and the bypass path 91 can be varied to achieve this.

p00055The operation procedure of the closed circuit system differs in several aspects from the procedure used with the realization of open circuit according to the invention. As illustrated in Fig. 6, the additional bypass compression clamp 92 is needed because no gas inlet or gas outlet device is provided, as was necessary in the prior art. Before the start of the blood processing, the inlet compression clamp 60 is closed and the bypass compression clamp 92 is opened. The blood processing is initiated by opening the inlet compression clamp 60 and allowing the blood to drain from the blood vessel 49 through the first conduit 50 in the leukocyte depletion device 45 and, through it, in the blood receiving container 52. The blood does not circumvent the leukocyte depletion device 45 because the loop portion 93 of the bypass path 91 is elevated to a sufficient height. The gas within the closed circuit biological fluid filtration system 90 is displaced by the blood flow into the blood receiving vessel 52. As the blood vessel 49 approaches its near-empty condition, the gas stored in the receiving vessel 52 automatically flows through the bypass path 91 to the blood vessel 49 and allows substantially all of the blood to be processed through of the leukocyte impoverishment device 45. It is important to note that the chamber of the leukocyte depletion device 45 downstream of the filter medium 46 will be filled with blood at this point, as will the second duct 54 between the leukocyte depletion device and the container 52 of blood reception If there is still some gas in the receiving container 52, it can be moved to the bypass line 91 by closing the outlet compression clamp 61, carefully compressing the blood receiving container 52 and closing the compression clamp 92 bypass In this system comprising the closed circuit biological fluid filtration system, the chamber downstream of the filter medium 46 in the leukocyte depletion device 45, nor the second duct 54, is not drained of blood. However, they are removed the input device and the prior art output devices, and a simplified system is provided.

p00056Additional modifications of the closed circuit biological fluid filtration system 90 are shown in Figures 7-11. Its operation can be understood by those skilled in the art from the above description.

p00057Therefore, by carefully studying the problems present in the biological fluid filtration systems of the prior art, the inventor has developed a novel apparatus for the filtration of biological fluid.