FI59724B - DUALFILTER ANVAENDBART VID BLODTRANSFUSIONER - Google Patents

Description

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Patents and Registration Documents An «ekan utiagd och uti.tkriften public · red 30.06.8l (32) (33) (31) Requested atuolkaut— Begird prlorltet 31.07 · 72 USA (US) 276623 (71) Pall Corporation, Glen Cove, New York, USA (US) (72) David J. Rosenberg, Glen Cove, New York, USA (US) (7 * 0 Oy Kolster Ab (5U) Dualfilter for blood transfusions -Dualfilter användbart vid blodtransfusioner

There are usually two types of blood filters available on the market for transfusions in humans. The most common is made of metal wire or nylon or polyester fiber mesh with an orifice size of about 125 to 400 microns (Surgioal Advances, Vol. II, No. 6, September 1933-) · Wedding filters are called blood strainers. They are very rough in aperture size because they tend to clog quickly if the aperture size is any finer.

Another type of blood filter that can be used in blood transfusions is made of a fairly thick nonwoven nonwoven mat and is called a dacron wool filter. This filter is described in U.S. Patent No. 3,448,041 to R.L. Swank, registered 3 * 6.1969 »as a destination. Commercially available filters have an orifice size of several hundred microns and are made of very fine fibers.

The principle on which the Svank filter is built is described in column 3 * of the patent, starting at line 33- and continuing in column 4 * at line 38. Swank wanted a fine-grained subdivided material with surface properties and size that selectively collect storage-modified components from transfusion blood. . The purpose of the filter is to act as a platform to which platelets and white blood cells that have changed during storage adhere to 2,59724. The other components are assumed to pass freely through a filter with a large absorbent surface area in order to achieve a high filtration efficiency with the smallest possible size of the device. Swank also wanted a material that could be used for a long time without collapsing or clogging, and that would not be adversely affected by repeated exposure to heat and chemical sterilization.

The problem with known blood strainers is that they do not remove enough small, fines due to their large orifice size. On the other hand, nonwoven fiber mats represent another extreme. Despite their large orifice size, over 100 microns, these filters remove too much material and have a very bad tendency to clog. Large numbers of platelets and white blood cells, as well as particles of their size in the blood, tend to strain, causing rapid clogging as well as compression of the mat due to increasing differences in fluid pressure in its transverse direction. These results have been reported by Egeblad, Osbom, Burns, Hill, and Gerbode in The Journal of Thoraric and Cardiovascular Surgery, Vol. 63, No. 3, March 1972, p. 384-390, and McNamara, Burra, and Suehiro in a study entitled "Effective Filtration of Preserved Blood" (a copy of this study is included in HS Application No. 88 356, registered November 10, 1970).

Egeblad et al. reported good results when using a dacron filter during drainage in open heart surgery, where the filter was placed in a line between the conical atom reservoir and the main vessel, with a large part of the bloodstream passing the filter. results obtained, however, within a shorter period of time. When the filter was in the arterial line so that all the blood from the oxidizer was filtered, the pressure in the filter increased so that it was necessary to connect to a second filter connected in parallel with the first, air was also left in the filter during initial filling and found to be later may have entered the arteries directly. Blood platelet counts dropped to very low during the first ten minutes of filter use and this situation continued throughout the side cycle. The number of white blood cells also decreased and the decrease in both was much more pronounced than is usually seen in the pulmonary-cardiac circulation, indicating that the filter was rich in platelets and some white blood cells. The pressure rise in the filter was considered to be due in part to this large amount of aeolus and in part to intravenous coagulation, with fibrin formations adhering to the filter. In addition, the red blood cells adhering to the filter later tended to break down and the broken down substances got into the filtered blood.

U.S. Patent No. 88,356, filed November 10, 1970, relates to a disposable filter element comprising a square woven nonwoven plastic web of polyester fibers having an aperture size of about 25 to 50 microns in which the fibers are locked in place at their intersections; with a fiber diameter of about 25-50 microns.Such filter elements are capable of separating micro-clots from human blood in human circulatory systems, requiring blood circulation in large «SSr without separating the normal and desired components of the blood * The filter removes not only microcytes but also grease and waste the resistance at high flow is also low and its flow power is high and it does not tend to clog even during long periods of operation.

However, this filter is not entirely satisfactory for use in blood transfusions. The blood used in transfusions tends to contain blood clots that are not normally found in the human circulatory system when the patient's own blood circulates in the system. Blood clots are sticky groups of substances, and if they are abundant, a woven square-bonded plastic mesh can become clogged very quickly.

According to the invention, there is provided a two-part stem filtration element for use in blood transfusions which is capable of removing not only large particles such as blood clots but also small particles up to about 20 microns in size, while passing through red blood cells and at least a substantial portion of white blood cells. The blood filter according to the invention comprises two filter plates arranged so that their orifice size continuously decreases as it goes downstream from coarse to finer.

The first filter plate is a coarse open plastic wire mesh with an orifice size of 800-4000 microns. This orifice size is small enough to separate blood clots that are 500-1000 microns in diameter and large enough not to become clogged due to filtered blood clots.

The second filter plate is an open or square woven sieve fabric made of plastic fibers with an opening size of about 20 to 50 microns. This filter plate removes microcytes, fats, debris, and gas plugs, virtually all of the particles that pass through the first filter element except platelets, white blood cells, erythrocytes, and the like.

This combination of filter plates can be called a series, because each successive filter plate removes some of the particles that the previous filter plate has passed through. The distribution of the relative amount of particles separated by each filter plate is significant in that neither filter plate tends to clog during the transfusion given to the patient. For hygienic reasons, blood transfusion filters are not reused, not even when a second blood transfusion is performed later on the same patient, and because the filter element sets of the invention are completely interchangeable to eliminate the clogging problem common to blood filters. platelets.

The first filter plate is an open-mesh mesh. It is made by extruding, molding or compressing plastic into an open mesh fabric with a uniform fibrous structure.

Used plastic material Bopii together with blood. Typical are polypropylene, polyethylene, polyester, polyamide and polycarbonate.

One form corresponds to an open four-fabric woven filter mesh, although it is not made by a weaving method from a fibrous material. Extruded open-mesh plastic fiber polypropylene mesh is commercially available under the trademark "Vexar".

Other mesh shapes are available that do not correspond to an open square-woven fabric. In these, the fibrous plastic material can be arranged to form round elliptical openings or polygonal openings, which can be, for example, triangles, squares, rectangles, pentagons, hexagons, heptagons, octagons individually or in pattern combinations. For example, one model has triangular openings separated by a plastic fiber material and grouped in groups of six to form a hexagon, and another has triangular openings in groups of two that form a diamond. The shape of the openings in the network is by no means critical, but it is important that the size of the opening be in the range of 600-4000 microns, given the largest and smallest dimension of the opening if it is not circular or symmetrical but e.g. square.

The second filter plate is a woven open mesh square woven fabric that can be made of any monofilament plastic compatible with blood, such as polypropylene, polyethylene, polyester, polyamide, and polycarbonate, and has an aperture size in the range of about 20 to 50 microns.

Polyester monofilaments are preferred. Most of the monofilament polyesters available are polyesters of ethylene glycol and terephthalic acid, available under the trademark "Dacron". Monofilament polyester yarns can also be made from other polymers of alkene glycols and dicarboxylic acids, usually aromatic acids, but also eycloaliphatic and aliphatic acids, of which propylene glycol-1,2, butylene glycol-2,3 and -1,2 and pentylene glycol-1,2 and -2, and - 1,3 are exemplified esterified with terephthalic acid or alkyl-substituted terephthalic acids or adipic or suberic acids or cyclohexane-1,4-dicarboxylic acid.

Ethylene glycol terephthalic acid polyester monofilaments are preferred because they are readily available and low in cost. However, polyesters of other glycols and acids may be used. Typical monofilament polyester screen fabrics that can be used in the present invention are made of monofilament polyester having a diameter of 20, 25, and 40 microns with an aperture of (a) 53 microns, with an aperture area of 33 (¾) 44 microns, with an aperture area of 5 59724 is 27 (c) 37 microns with an aperture area of $ 23 and (d) 21 microns with an aperture area of 14 * 5 # · Similar screen fabrics are available made of polyamide fibers, polyvinylidene chloride fibers, and polypropylene fibers.

It is also preferred that the individual fibers of the woven square woven screen be locked in place at the intersections. The lock not only increases strength and rigidity, but also ensures that the dimensions of the openings do not change during use, which is very important.

The dual filter set of the invention can be placed in a filter element of any type and shape. In order to maximize the open area and flow rate within the available space, the two filter plates are preferably arranged close to each other, although they can also be separated by spacers, and both surfaces are preferably corrugated or corrugated to form the largest possible flow area with spacers.

The spacer or support material is stiffer than the filter plates and is preferably flexible and also preferably plastic so that it can be attached to the same end cover or filter bag of the filter element. The aperture size of the spacer is at least equal to the first filter plate and preferably larger, ranging from about 800 to 10,000 microns.

Any plate with an uneven ridge, such as a bumpy ridge or a raised surface with large through holes, can be used as a spacer. Extruded, cast and extruded nets are useful, as are perforated sheets made of polypropylene, polyethylene, polyester, polycarbonate and polyamide. The surface of the spacer or support is uneven enough to dry and prevent the support plate from clogging a medium or fine filter plate. The preferred support material is a Vexar sieve (extruded polypropylene mesh).

The spacers can also help to keep the set of filter plates in the desired, in particular, for example, corrugated form. The spacer, if used, is usually very close to or in contact with the second filter plate in the series. Due to its large opening size, the open mesh first filter plate does not need any spacers at the front or rear *

In a suitable element form, the filter plates are folded into a corrugated cylinder, the open ends of which are closed by lids which limit the connection to the filter flow to pass through the filter set, the filter flow being in operative communication with at least the second end cover. The end caps are preferably made of plastic and may be, for example, polyester, polypropylene or polycarbonate. The end caps can be connected to the corrugated filter plate element with sealing compound or conventional adhesive. However, in order to ensure a tight seam, the lids are preferably formed in a series of filter plates, and for this purpose a polyolefin, such as polyethylene or polypropylene, is preferably used as the cover material. Other plastic materials that can be used in the end caps include polyamides, polycarbonates, and polyester as well as Teflon polytetrafluoroethylene and Kel-ef polytrifluorochloroethylene, but these are more difficult to solder. which may be, for example, conduit connections, such as tubes, that open to opposite sides of the filter plate array.

This type is particularly useful for attachment to transfusion bags and can be provided with a piercing tube attachment if desired.

The series filter element of the invention can be used in filter jets for simple blood transfusions which do not require large flow rates as well as for dripping or draining from blood bags by gravity, which can be assisted by a pump if desired. The serial filter reagent can thus be provided with a fastener or cable connection which makes it suitable for connection to the cables of any type of blood transfusion system.

Preferred embodiments of the invention are illustrated in the drawings, in which Figure 1 is a sectional side view of a box-shaped filter element with a dual filter set according to the invention, Figure 2 is a second, partially sectioned side view of the filter element of Figure 1 showing filter housing side covers, Figure 3 is a detail view of part Fig. 4 is an isometric view of a bag-shaped filter element embodiment with a dual filter set according to the invention, Fig. 5 is a longitudinal section taken along line 5-5 of Fig. 4 in the direction of arrows, and Fig. 6 is a cross-sectional view taken along line 6 * 6 of Fig. 4. view.

The filter element of Figures 1-3 consists of a housing 1 having first and second housing parts 2 and 3 defining a fluid space 4 between them. The liquid opening 5 is at the end of the housing part 2 and the liquid opening 6 is at the end of the housing part 3, these openings are concentric. The opening 3 acts as a liquid inlet and the flow takes place only from the opening 5 towards the opening 6 and the opening 6 acts as a liquid outlet due to the arrangement of the two filter plates in series.

The inflow opening 3 is in a pointed tube 7t intended to pierce the stopper of a blood bag used for transfusion. The housing part 2 has a 7 59724 internal reinforcing protrusion 8 extending from one side 9 to the other side 10 and the housing part 3 has a similar internal protrusion 11 extending from one side 12 to the other side 13 · These act as supports extending over the corrugation of the three-part filter plate set and spacer combination 40, which acts as a filter.

Each of the housing parts 2 and 3 is generally groove-shaped, with the opposite sides 9 and 10 extending outwards from the bottom of the part 2 and the opposite sides 12 and 13 outwards from the bottom of the part 3. The bottoms of each housing part 2 and 3 are provided with grooves 14 for the flow of liquid. Part 2 has two guide fingers 13 on each side and part 3 has four guide fingers 16 on each side, with a groove 17 in between which the fingers 13 fit into. These guide parts 2 and 3 during installation. The sides 12 and 13 rest on the sides 9 and 10 at the ends and are soldered to them, so that the housing parts are joined in one piece. The two parallel projections 20, 21 in the part 3 extend parallel to the sides 12 and 13 inside them up to the inner wall of the housing part 2.

The two-piece filter plate and spacer assembly 40 protrudes at the edges 22 and 23 into recesses 24, 23 defined by the sides 12, 13 and the projections 20,21, where the three-layer combination wraps around the tips of the projections 20,21 and presses tightly against the inner wall of the part 2 at 27. Closed. The connection is made by fusing the parts 20 and 21 to the housing part 2, through the open pores of the two filter plates 41-42 and the spacer plate 44, whereby a non-sealing seam is formed along those sides of the combination and all three plates are connected at those points. Such a joint can be made, for example, by ultrasonic welding, solvent softening or heat melting.

The filter plate-spacer plate assembly 40 »best seen in Figure 3» comprises a first coarse, extruded polypropylene mesh (Vexar) filter plate 41 »with an orifice size of about 1500 microns. The spacer plate 44 is also made of extruded polypropylene mesh (Vexar) and has the same orifice size, about 1300 microns. The second filter plate 42 is made of an open-mesh square-bonded monofilament polyester fabric having an aperture size of about 40 microns, a fiber diameter of 40 microns, and an aperture surface 27.

The filter plates 41, 42 of the filter set are corrugated in shape so that their surface in the confined space of the liquid chamber 4 is larger and the ends of the waves are against the protruding parts Θ and 11 of the housing parts 2 and 3, which at the same time hold them in place. The edges 32,33 of the filter plate set extend to the ends of the sides 12,13.

The U-shaped portions 2, 3 of the housing are open at their sides and, as best seen in Figure 2, form openings 28 and 29 leading to the liquid chamber 59724 4 in the housing 1. The openings are closed by side covers 30, 31 attached to the housing parts 2 and 3. , and to the edges 52,33 »of the filter plate set and spacer assembly 40 extending from end to end between the interconnected edges 9.10.12 and 13 of the housing parts * This closes the two edges of the filter plate set from the flow, limiting the flow between the parts 34 of the housing 1 Through the holes in the filter plate in the Irish filter plate set 40. Thus, the flow between the liquid openings 5 and 6 of the housing 1 must pass through both filter plates in the direction 41.42, as can be clearly seen in Fig. 3 ·

The configuration of the box filter element shown in Figures 1-3 is as follows: it can be seen from the figure that the side portions 9 »10.12 and 13 of each housing part 2 and 5 are of special construction so that when the housing parts are joined together a liquid-tight seam is formed between them. end with similar sides 12,13 of the second housing part 3. Part 2 has two guide soxes 15 on each side which guide it laterally and part 3 has a guide finger 16 on each side 4, between which the fingers 15 go to make sure that the parts fit snugly together and are in the correct position to hold the filter plate set 40. in place.

Pages 9, 10, 12, and 13 are slightly longer than their combined length after being joined together. When the parts 2 and 3 are joined together, the sides 9,10 are easily fused to the corresponding sides 12,13 », forming a unitary structure at the seam 36: Figures 1 and 2. The housing part 3 has projections 20 inside the sides 12,13. , 21, which extend at points 26 and 27 of the housing part 2 up to the inner wall.

In the assembly, the corrugated edges 22, 23 of the filter plate set-flake plate assembly 40 are folded around the protrusions 20, 21 of the housing part 3 into recesses between the sides 12.13 and the protrusions 20,21, where they remain securely. The housing part 2 is then fitted on the part 3 and pressed down firmly against the combined set of filter plates and spacer, the three plates squeezing against the tips of the projections 20,21 at 26,27 and staying firmly in place due to the tight seam between the housing part 2 and the parts 20,21. The projections 20,21 are then connected through holes in the spacer plate 44 and the two filter elements 41,42 to the wall of the housing part 2 at 26,27 so that a liquid-tight seam is formed between them and both sides of the filter plate set are closed by flow. The sides 9,10 in the housing part 2 can also be fused together with the sides 12,13 of the housing part 3, for example by ultrasonic welding simultaneously or afterwards, so that the two housing parts 2,3 are sealed relative to each other, so that no liquid can escape outside the filter assembly.

The chip covers 30,31 are then attached through the openings 28,29 to the housing parts 2, 3 and the edges 32,33 of the filter plate set-spacer assembly by joining the sides and spacer plates of the filter plate to the side covers and completing the fixing of the filter plate set and spacer 40 in the liquid chamber 4. as well as the seal between the filter plate set and the four side walls of the housing. This can be done, for example, by using an adhesive, glue or resin or some other sealing mixture, or by melting the end caps. The filter element is now complete and can be used *

In practice, the filter element works as follows: the sharp tip is inserted into the blood bag closure, whereby blood begins to flow from the bag through the inlet 5 through the channel 7 to the chamber part 34 * Blood then flows through the filter plate set 40 through the filter plate 41 and the spacer plate 44 exits the housing down the channel 14 through the opening 6.

Cable connections to openings 5 and. 6 can be done in any desired manner. Luer syringes can also be used if desired.

The filter element 50 shown in Figures 4-6 has a two-part filter-plate assembly 60 (plates 41 »42 and spacer plate 44)» which is corrugated in a curved shape such that the corrugations 51 are in the plane of the filter element extending on top of each other. The two filter plates 41,42 and the spacer plate 44 are positioned exactly as shown in Figure 3, the filter plate 41 being the outermost and the spacer plate 44 the innermost in a closed form, as shown in Figures 4-6. The corrugated curved assembly 60 is heat sealed at 32 along all four sides (or three sides if it is itself pleated). The set of filter plates 60 encased in this way has an outflow connection through a pipe 33 which extends into its open interior 34 and terminates in a net-tipped tip 33 · The interior 34 can only be accessed through the set of filter plates 60. This type of filter element is particularly useful in a flexible bag-type filter unit, which bag 36 is shown as dotted lines in Figures 4 and 3. The other end of the bag 56, which may be a blood bag per se, may have an inlet tube 37 for blood. It is also possible that it has a pointed tip outside the assembly 60 in the bag 56, whereby it can be heat-sealed in the bag 5 in the same way as in the filter element. This combination can then be connected to a blood bag, as was the case with the filter elements of Figures 1 and 2, with the filter plate 41 being the outermost and the spacer plate 44 being the innermost.

The type of filter element shown in Figures 4-6 is particularly suitable for filtering blood during transfusion, allowing it to be incorporated into a normal blood bag, but can also be attached to any blood container or container.

Thanks to the filter plate series waveform, the surface area is large and the placement of the waves makes a flat bag possible without internal support, as the spaces between the waves act as wires while the waves extending over each other provide 10,59724 waves of structural support. The support or spacer plate 44 of the double filter set is a heat-softening agent, which softens at a lower temperature than either of the two plates forming the series, so that the plates 41 and 42 are not affected by the conditions under which the spacers soften so that the latter can be melted into a dense moon. through the openings in the filter plate without damaging the filter plates. Heat sealing can be performed by large period heating and all hot seams including pipe seams can be done simultaneously.

Claims (9)

1. Blood filter element series used in blood transfusions without blocking and which can remove Large particles, such as blood clots, and even small particles down to a size of about 20 microns, while allowing platelets, red blood cells and at least a substantial portion of white blood cells to pass through , characterized in that it comprises two filter discs arranged downstream of one another with progressively increased fineness in the flow direction, the first filter disc (1 + 1) being made of a coarse open plastic filament network with a heel size of approx. 800-1 + 000 microns, which heel size is small enough to remove blood clots and coarse enough that the filtered blood clots do not cause blockage, and the second filter disc (1 + 2) is made of an open sieve of monofilaments with a heel size of about 20-50 microns, which can remove microembolies, lipids and residues as well as gas embolisms that pass through the first filter element, while platelets, white blood cells and red blood cells were allowed to pass. Blood filter element series according to claim 1, characterized in that the first filter disc (1 * 1) is an open mesh made by extrusion, casting or compression molding of plastic and has a uniform filament-like structure. Blood filter element series according to claim 2, characterized in that the plastic material is polypropylene, polyethylene, polyester, polyamide or polycarbonate. h. Blood filter element series according to claim 1, characterized in that the second filter disc (1 + 2) is a woven square mesh of plastic monofilaments having a heel size of about, 20-50 microns and whose filaments are fixed to plastic at their intersection points. Blood filter element series according to claim 1+, characterized in that the diameter of the monofilaments is approx. 25 ~ 50 microns, Blood filter element series according to claim 1+, characterized in that the monofilaments are polyester plastic, 7 · Blood filter element series according to claim 1, characterized in that the filaments are read in place by thermosetting; 8, Blood filter element series according to claim 1, characterized in that the two filter discs (1 + 1, 1 + 2) are adjacent to each other and are road shaped or grooved to provide large surface area for flow.