FIELD OF INVENTION

The present invention relates to an apparatus for peritoneal ultrafiltration of a patient in need thereof, for example due to congestive heart failure or for a patient under dialysis.

BACKGROUND

The patent document WO 95/20985 discloses an apparatus for carrying out peritoneal dialysis. The apparatus comprises a heat bag and a discharge bag positioned in an airtight space, said bags being connected with a catheter arranged at the patient, who is to perform peritoneal dialysis. The apparatus comprises a pump arrangement connected with the space for producing overpressure and underpressure, respectively, in the space. Valve arrangements are adapted to connect either the discharge bag or the heat bag with the patient's catheter. By providing an underpressure in the space, fresh dialysis solution is provided to the heat bag from supply bags, whereupon used dialysis fluid is extracted from a patient to the discharge bag. By causing an overpressure in the space, a fresh and heated dialysis solution is supplied from the heat bag to the patient, whereupon the discharge bag is drained to a waste or to collection bags.

The patent document WO 2016/080883 Al discloses an apparatus for ultrafiltration of a patient, comprising a tube set including a connector for connection to a patient line for access to the peritoneal cavity of the patient. A flow pump is arranged for circulation of fluid from/to the peritoneal cavity. An osmotic agent peristaltic pump is arranged for replenishment of glucose solution to the fluid added to the peritoneal cavity for promoting ultrafiltration. The glucose is replenished for keeping a concentration of glucose substantially constant in the peritoneal cavity. The flow pump comprises a pressure chamber with rigid walls and a flexible pump bag arranged therein. An air pump pressurizes the chamber for removal of fluid from the peritoneal cavity by a sub-pressure and supply of fluid to the peritoneal cavity by an overpressure, which pressures are maintained within safe limits.

Said apparatuses work well in most situations. However, the introduction and removal of the flexible pump bag in the rigid wall pressure chamber may be difficult and it may be desired to be able to access the air chamber from several directions.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages singly or in any combination. Additional objects appear from the specification below. In an aspect, there is provided an apparatus for ultrafiltration of a patient in need thereof, for example a patient which is overhydrated, comprising a patient tube for access to a peritoneal cavity of the patient; a flow pump for removal of a fluid via said patient tube from the peritoneal cavity and to a flexible pump bag and for filling of the fluid from the pump bag to the peritoneal cavity; a glucose bag connector for connection to a glucose bag comprising concentrated glucose solution; a glucose pump for addition of concentrated glucose to said fluid; whereby the glucose is diluted in said fluid and replenished intermittently for keeping a concentration of the osmotic agent substantially constant in the peritoneal cavity. The flow pump comprises a pneumatic pump chamber having rigid walls and said flexible pump bag is constructed to be inserted in said pump chamber, whereby the exterior of the flexible pump bag is exposed to a positive or negative pressure inside said pump chamber by means of an air pump generating a positive pressure or a negative pressure inside said pneumatic pump chamber. The pneumatic pump chamber comprises a cylindrical tube with a first open end and a second open end at opposite sides of said cylindrical tube; an end cap arranged at said first open end of said pump chamber, said end cap being removable and being sealed to the cylindrical tube by a first radial sealing member; a lid, which is constructed to be inserted at the second open end of said pump chamber, said lid being sealed to the cylindrical tube by a second radial sealing member; a flow tube for connection of said flexible pump bag to said patient tube, whereby said flow tube extends through said lid so that the flow tube is arranged outside the cylindrical tube and the flexible pump bag is arranged inside said cylindrical tube when the lid is inserted at the second open end of said pump chamber.

In an embodiment, the sealing member is arranged at the open end of said cylindrical tube and is constructed for cooperation with a mating cylindrical surface of said end cap or said lid. The pump chamber may comprise an overpressure when the lid and/or the cap is to be removed for overcoming friction forces of the radial sealing member. Similarly, the pump chamber may comprise a sub pressure when the lid and/or the cap is to be inserted for overcoming friction forces of the radial sealing member.

In another embodiment, the flexible pump bag may be provided with a reinforcement member extending from the lid to the other end of the pump chamber for enabling insertion of the flexible bag in the cylindrical tube. The reinforcement member may be a longitudinal thickening of the material of the flexible pump bag. Alternatively, the reinforcement member may be a longitudinal pocket which may be inflated by a fluid pressure, such as an air pressure. Still alternatively, the reinforcement member may be an elongation of a tube through the flexible pump bag lid, said tube being provided with several holes, which open to the interior of the flexible pump bag.

In a still further embodiment, the apparatus may further comprise at least one magnet and at least one magnet detector, such as a reed relay, for indicating that the lid is arranged in a locked position. BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages of the invention will become apparent from the following detailed description of embodiments of the invention with reference to the drawings, in which:

Fig. 1 is a schematic plan view of an embodiment of an apparatus for providing ultrafiltration fluid to a patient.

Fig. 2 is a schematic diagram of the apparatus according to Fig. 1 provided with a tube set.

Figs. 3 and 4 are cross-sectional views of a pressure chamber of the apparatus taken according to line III-III according to Fig. 1 and showing reinforcement members.

Fig. 5 is a side view of the apparatus taken as indicated by line V-V.

Fig. 6 is a side view of the apparatus taken as indicated by line VI- VI and showing a cover lid in an intermediate position.

Fig. 7 is a bottom view of the apparatus according to Fig. 1 with a battery partially inserted.

Fig. 8 is a view similar to Fig. 7 with the battery further inserted.

Fig. 9 is an enlarged view similar to Figs. 7 and 8 with the battery fully inserted.

DETAILED DESCRIPTION OF EMBODIMENTS

Below, several embodiments of the invention will be described. These embodiments are described in illustrating purpose in order to enable a skilled person to carry out the invention and to disclose the best mode. However, such embodiments do not limit the scope of the invention. Moreover, certain combinations of features are shown and discussed.

However, other combinations of the different features are possible within the scope of the invention.

The apparatus according to the embodiment according to Fig. 1 is arranged for providing a peritoneal fluid to a peritoneal cavity and for replenishment of the fluid by an agent such as glucose. More specifically, the apparatus is arranged to remove a portion of the fluid installed in the peritoneal cavity and to replenish the removed fluid portion with glucose and finally to fill the replenished fluid back to the peritoneal cavity for compensating for glucose absorbed by the body. Thus, the glucose concentration in the peritoneal cavity is maintained substantially constant over a long time, such as 12 hours. In this manner a persistent ultrafiltration is provided, which may be tailored to the need of a patient, for example an overhydrated patient. The patient may be a congestive heart failure patient being overhydrated. The patient may be a dialysis patient on hemodialysis or peritoneal dialysis, needing dehydration or ultrafiltration.

Fig. 1 discloses the apparatus in a top plan view. The apparatus comprises a base unit 11 comprising a pump chamber 43 with rigid walls and a glucose pump 16, which is of the peristaltic type. Other types of pumps may be used. The base unit is provided with recesses or channels intended to encompass a tube set, which will be described below in connection with Fig. 2. The channels comprise several pinch valves 17 and 18 as will be described below. Furthermore, the base unit comprises an air pump and electronic circuits (not visible). A battery 82 is included in the base unit, see Figs. 7 to 9. Moreover, the base unit comprises a base unit lid 81, which is not shown in Fig. 1 but is shown in Fig. 6. A remote control unit 14 is connected to the base unit via a wire 15.

As shown in Fig. 2, a tube set 20 is intended to be inserted in the channels of the base unit. The tube set comprises an end connector 21, which mates with a connector to a catheter arranged at the patient for access to the peritoneal cavity of the patient. The end connector 21 is arranged at a distal end of a patient tube 22. A proximal end of the patient tube 22 is connected to a cassette 25 via a patient valve 18. Thus, the interior of the cassette 25 is connected to the end connector 21. The tube set further comprises a connector 26 intended to be connected to a glucose bag. The connector 26 is connected to the cassette 25 via a glucose tube 27. The glucose tube 27 is connected to a pump segment 29 passing through the glucose pump 16 and further to the cassette 25. The glucose bag is connected to the cassette 25, via glucose pump 16. The tube set further comprises a connector 30 intended to be connected to a drain bag. The connector 30 is connected to a drain tube 31. The drain tube 31 is connected to the cassette 25. A drain valve 17 acts upon the drain tube 31 for occluding the drain tube when activated. Thus, the drain bag is connected to the cassette 25. The tube set further comprises a flexible pump bag 64, see Fig. 3, connected to a pump tube 42. The pump tube 42 is connected to the cassette 25. Thus, the pump bag 64 is connected to the cassette 25. The pump bag 64 is intended to be inserted into a closed pump chamber 43 having rigid walls and a constant inner volume, as described in further detail below. The pump chamber 43 is, via an air tube, connected to an air pump, which is operated by an electric motor. The cassette 25 is, in addition, connected to a fluid pressure meter 51 via a pressure meter tube 52.

Fig. 3 discloses the pump chamber 43, which is arranged in the base unit. The pump is of a pneumatic type. The pump chamber has rigid walls and a constant inner volume. The pump chamber may be cylindrical with a circular or oval cross-section. The pump chamber 43 is connected to an air pump 60 via an opening 63. The air pump is operated by an electric motor. When the motor is driven in a forward direction, air is pumped into chamber 43 and when the motor is driven in a backward direction, air is pumped out of chamber 43.

Alternatively, there is a valve system providing the mentioned air flow from the air pump driven by the motor. The pump may be able to produce a maximum overpressure or positive pressure, which may be for example about +0.2 Bar and a minimum sub pressure or negative pressure, which may be for example about -0.2 Bar in relation to ambient pressure. The pressure inside the pump bag 64 is, consequently, always between about +0.2 Bar and about - 0.2 Bar. Thus, when the air pump delivers an overpressure, pump bag 64 is exposed to an external overpressure of maximum +0.2 Bar (between 0 Bar and +0.2 Bar), which results in that fluid inside pump bag 64 is expelled out of pump bag 64 to the cassette 25. When, the air pump 60 delivers a sub pressure, pump bag 64 is exposed to an external sub pressure of minimum -0.2 Bar (between 0 Bar and -0.2 Bar), which results in that fluid inside pump bag 64 is sucked into pump bag 64 from the cassette 25. Thus, pump bag 64 operates as a fluid pump having controlled and restricted maximum and minimum pressures.

So far the apparatus is substantially as disclosed in the above-mentioned patent publication WO 2016/080883.

Pump chamber 43 as shown in the embodiment according to Fig. 3 comprises a cylindrical tube with openings at each end. A lower opening in Fig. 3 is closed by a removable cap 61. An upper opening of the pump chamber in Fig. 3 is closed by a lid 62, through which the pump tube 42 passes. The pump tube 42 ends in a flexible bag 64. The flexible bag is arranged inside the pump chamber 43 when the removable lid 62 is positioned as shown in Fig. 3. The cap 61 and the lid 62 are sealed in relation to the opening of the pump chamber 43 by a sealing member 65.

The sealing member 65 comprises a radial sealing body which mates with an axial and cylindrical surface of the lid 62 and of the cap 61. Thus, the lid 62 and the cap 61 may move a short distance without loosing the sealing property.

However, the sealing member exerts a substantial force on the axial cylindrical surface of the lid (and cap), which makes it difficult to remove the lid unintentionally.

An embodiment of the sealing member is shown in more detail in Fig. 10. The sealing member comprises a sealing body 86 of rubber, comprising an upper surface 87 which is arranged in recesses in the walls of the cylindrical tube as shown in Figs. 3 and 4. A lower rubber portion 88 is constructed for engagement with the lid and the cap respectively. A steel band 90 extends along the upper surface for providing stability. A spring member 89 is arranged at the lower rubber body for providing a substantial sealing force between the lid (cap) surface and the rubber body. Thus, sealing action is obtained also when the interior of the pump chamber is exposed to a subpressure. As shown, the sealing member is ring-shaped.

The flexible bag 64 may be provided with a reinforcement member 66, which makes it more easy to introduce the flexible bag 64 into the pump chamber 43 without jamming. The reinforcement member may extend from the lid 62 to the interior end of the flexible bag 64.

An embodiment of the reinforcement member may be a longitudinal area of the flexible bag 64 having increased thickness in relation to the rest of the flexible bag.

Another embodiment of the reinforcement member may be a further foil of the flexible bag which forms a longitudinal pocket. The pocket may be connected to a fluid under pressure, such as air, whereby the pocket is inflated and forms said reinforcement member. The pressure inside the pocket may be kept during the treatment or be relieved as soon as the flexible bag 64 has been inserted in the pump chamber 43. Alternatively, the pocket may comprise granules of a friction material, for example polystyrene granules of a diameter of about 1 mm. When the pocket is exposed to a subpressure, the granules are compressed towards each other and form a stiff body with the shape it had when the subpressure was applied inside the pocket. The subpressure may be arranged during the manufacturing, but may alternatively be applied during or shortly before the assembly of the device.

A further embodiment of the reinforcement member is shown in Fig. 4, whereby the pump tube 42 has an extension 67 passing beyond the lid 62 and being provided with several side holes 68 towards the inside or interior of the flexible bag 64. In this manner, the pump tube extension 67 forms said reinforcement member.

The flexible bag 64 may be provided with a ring 70 at the end. If the flexible bag 64 does not enter smoothly into the pump chamber, the cap 61 may be removed and the flexible bag may be manipulated by a tool pulling the ring 70 downward and thus pulling the flexible bag to a desired position. The ring 70 may be replaced by holes in the bottom portion of the flexible bag, as shown by broken lines in Fig. 4.

Fig. 5 discloses the removable cap 61 and base unit in a side view. The base unit is provided with three screws 71, 72, 73, which cooperate with tabs 74, 75, 76 arranged in the cap 61 for retaining the cap. If the removable cap 61 is rotated a few degrees, the screws will mate with recesses 77, 78, 79 in the cap 61, whereby the cap 61 may be removed. The cap is sealed by sealing members 69 as shown in Fig. 3. When the cap 61 and the lid 62 at the other end of the pump chamber 43 are removed, the interior of the pump chamber 43 is available. Thus, it is enabled that the interior surface of the pump chamber may be kept clean so that the flexible pump bag 64 does not stick to the surface.

The cap 61 may also be removed during use or set-up of the device, for example if the flexible bag does not enter the pump chamber 43 smoothly. In this case, the cap 61 may be removed and the position of the flexible bag 64 position may be corrected.

The base unit is provided with a base unit lid 81 shown in Fig. 6. The base unit lid 81 is pivotable around a screw 82 and is shown in an intermediate position in Fig. 6. The base unit lid 81 is provided with a protrusion 83 which passes beyond the flexible bag lid 62 when the base unit lid is rotated counterclockwise for locking the flexible bag lid 62 in position, so that it cannot be removed. In this manner, the flexible bag lid 62 does not require a separate locking device, which may interfere with the sealing function. When the base unit lid 81 is pivoted 90 degrees in the clockwise direction, the flexible bag lid 62 is free to be removed. As mentioned above, a small axial movement of the lid 62 is permitted without loosing the sealing property of the sealing member.

The base unit lid 81 may be provided with a magnet 84 and the base unit may be provided with a magnet detector 85, such as a reed relay, which indicates when the base unit lid 81 is in a locked position. In order to make removal of the flexible bag lid 62 more easy after a treatment, the air pump may generate a positive pressure inside the pump chamber when the reed relay 85 indicated that the base unit lid 81 is opened, and the system computer indicates that a treatment has been performed. In this manner, the flexible bag lid 62 is exposed to an air pressure which effectively releases the flexible bag lid 62, and counteracts the retaining force of the sealing member.

During insertion of the flexible bag before a treatment, the air pump may generate a negative pressure inside the pump chamber so that the flexible bag lid 62 is forced to sealing engagement with the pump chamber entrance. In this manner, at least the final insertion of the flexible bag is facilitated.

Similarly, an overpressure and a subpressure may be used for removing or adding the removable cap 61.

Fig. 7 discloses the under side of the base unit. As shown in Fig. 5, there is a side opening 91 into which a battery 92 may be inserted. The interior end of the opening 91 comprises connectors 93 for cooperation with mating connectors of the battery. Opposite the connectors 93, there is arranged a bottom opening 94 in the base unit, through which the battery interior end is visible.

In Fig. 7, the battery is only partially inserted. In Fig. 8, the battery is almost fully inserted and in Fig. 9, the battery is fully inserted. When the battery should be removed, it may be difficult to get it out from the opening 81. The bottom opening 94 is provided with three recesses 95, which are clearly visible in Fig. 9. By entering three fingers or a tool in these recesses 95, the user may push the battery out of the opening 91.

The base unit may be arranged in a cover having straps for being worn by a patient over the shoulder or like a backpack.

In the claims, the term "comprises/comprising" does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit. Additionally, although individual features may be included in different claims or embodiments, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. The terms "a", "an", "first", "second" etc. do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.

Although the present invention has been described above with reference to specific embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims and other embodiments than those specified above are equally possible within the scope of these appended claims.