WO1997016214A1

WO1997016214A1 - Dialysis device

Info

Publication number: WO1997016214A1
Application number: PCT/NL1996/000427
Authority: WO
Inventors: Gerrit Wilhelmus Remkes
Original assignee: Cerato B.V.
Priority date: 1995-10-30
Filing date: 1996-10-30
Publication date: 1997-05-09
Also published as: AU7508096A; NL1001528C2

Abstract

The invention relates to a dialysis device (1) comprising a pump (8) having a pump chamber element (9) defining a pump chamber (9) with variable volume and drive means (11) engaging on the pump chamber element (9) for varying the volume of the pump chamber (9). The pump chamber (9) has an inlet and an outlet (14), connecting members (3) for a plurality of liquid lines, valve means (7) for selectively connecting the connecting members (3) to the inlet and the outlet (14), operating means (10) for the valve means (7) and a control device (13) for programmed control of the pump drive means (11) and the valve operating means (10). The pump chamber element (9), the connecting members (3) and the valve means (7) are herein embodied for once-only use and are releasably arranged in a permanent device comprising the drive means (11), valve operating means (10) and control device (13).

Description

DIALYSIS DEVICE

The invention relates to a dialysis device intended for use in dialysis of the type wherein the peritoneum of the patient functions as membrane for diffusing therethrough of substances for draining. In this dialysis system a liquid of a determined composition is introduced between the peritoneum and the abdominal wall of the patient. The waste products for removal from the blood of the patient subsequently diffuse for a determined time via the peritoneum to this liquid. Thereafter the liquid is removed and replaced by fresh liquid. Changing of the liquid usually occurs at night while the patient is asleep.

The invention has for its object to provide a device of the present type which is easy to use and compact . This object is achieved with the dialysis device as characterized in claim 1. The components coming into contact with the liquids can be packed in sterile manner and placed in the permanent device . After use these are thrown away. The patient is not therefore required to perform laborious cleaning operations.

The step according to claim 2 is preferably applied. The pump chamber element, the connecting members and the valve means can then be embodied as a type of cassette which can be placed into and removed from the permanent device with a simple operation.

A suitable embodiment is characterized in claim 3. By applying a peristaltic pump, wherein the pump chamber element is formed by a tube, no sealing problems can occur which could have an adverse effect on proper operation. The cost of the material for once-only use herein remains comparatively low. In a suitable manner a peristaltic pump can be used engaging two tubes used as pump chambers shifted in phase, such that a very even flow can be obtained.

A relatively simple construction leading to a compact unit can be obtained when the step of claim 4 is applied. A very suitable embodiment of the valve means is herein characterized in claim 5. A large plurality of connections and switching options can be realized in simple manner with valve means as according to this claim. In a further developed device according to the invention the step of claim 6 is applied. Using the plate-like heat exchanger the liquid supplied to the body of the patient is brought to body temperature. Due to the plate form a good contact can be obtained between the heat exchanger embodied for once-only use and the flat heating surface of the heating device, thus ensuring a reliable operation.

A very suitable further development is herein characterized in claim 7. By evacuating the chamber in which the heat exchanger is received the opposite walls are drawn against the heat exchanger and the heat exchanger itself is moreover drawn flat against the walls. A very good heat-exchanging contact hereby occurs between the liquid in the heat exchanger and the walls of the heating device.

According to a further development the step of claim 8 is applied. The liquid present between the walls of transparent material forms a liquid lens having a convexity depending on the liquid pressure. This liquid lens is placed in the path of the light from the light source to the light-sensitive element and the quantity of light incident upon the light-sensitive element depends on the convexity of the lens and thus on the liquid pressure. In this manner very simple but reliably operating pressure detection means are obtained, whereof the part embodied for once-only use can be manufactured at very low cost . The valve means can be embodied exceptionally simply when the step of claim 9 is applied. The valve means only have to connect the different connections selectively to one and the same inlet and outlet channel. A very suitable embodiment is herein characterized in claim 10.

The invention will be further elucidated in the following description with reference to the annexed figures .

Figure 1 shows schematically the dialysis device according to a preferred embodiment of the present invention during use. Figure 4 shows an embodiment of valve means for the dialysis device according to the invention.

Figure 5 shows a perspective view of a preferred embodiment of valve means. Figure 6 shows in partly sectional perspective view the part of the valve means of figure 5 embodied for once-only use.

Figure 7 shows in partly broken-away perspective view a heating device and heat exchanger for the device of figure 1. Figure 8 shows a cross section of the device of figure 7.

Figure 9 shows a preferred embodiment of pressure detection means for the device according to the invention.

The device 1 is intended for replacing in controlled manner cleaning liquid present in a patient 2. The patient has in his abdominal wall a connecting member 3 to which a line 4 for changing the liquids can be connected. Indicated schematically is that liquid introduced via connecting member 3 contributes to the kidney function of patient 2. Draining of the contaminated liquid and supplying of the clean liquid takes place by means of a pump 8 having a pump chamber element 9.

The pump 8 can be embodied such that it pumps a quantity of liquid into the pump chamber element 9 and thereafter pumps it out of this pump chamber 9 again into a drain line. Instead of such a reciprocating pump another type of pump can also be applied, for instance and in preference a peristaltic pump. A peristaltic pump has the advantage in the context of the present invention that the pump chamber element can comprise at least one tube, which is inexpensive. The pump chamber element can thus be embodied very suitably for once-only use.

The pump 8 has a combined inlet/outlet 14 which is connected to valve means 7. The valve means are embodied such that they can selectively connect a plurality of connecting members to inlet/outlet 14. The valve means are operated by a valve operating means 10.

The connecting members are connected to line 4, to a drain line 19 and to a plurality of feed lines from storage containers 15. In the shown embodiment the feed lines from storage containers 15 are guided via a heating element 16 so that the liquid for supplying to the patient has a suitable temperature, in particular is at body temperature.

The operation of the drive means 11 and the valve operating means 10 is adjusted by a control device 13, which is preferably a digital control device, in particular a computer. The drive means 11 and valve operating means 10 are in this case preferably stepping motors which can be controlled in simple manner by a digital control device 13.

By a suitable programming of control device 13 the valve operating means 10 are for instance activated at a given moment such that valve means 7 form a connection between line 4 and the inlet/outlet of pump means 8. The drive means 11 can subsequently be activated, whereafter a quantity of liquid is sucked out of line 4 and received in pump chamber 9. The control device 13 then controls valve operating means 10 such that the inlet/outlet 14 is placed into connection with drain line 19. The drive means 11 are subsequently activated and the liquid present in chamber 9 is pressed to the line 19 in a delivery stroke.

In another phase using a suitable control of the valve operating means 10, a mixture of the liquids in the storage containers 15 with a desired composition can be obtained by successively connecting the connecting members connected to the storage containers 15 to the inlet/outlet 14 of pump 8. As soon as a desired quantity of liquid with the desired composition has been collected in the pump chamber 9, the valve means 7 can be operated such that the inlet/outlet 14 is connected to the line 4 in order to feed the thus composed liquid to the patient.

The components of the device 1 which come into contact with the liquids are embodied for once-only use. In addition to the storage containers 15, lines 4 and 19, which are normally already embodied for once-only use, the components designated inside the box 6, i.e. the pump chamber element 9, the connecting members and the valve means 7, are also embodied for once-only use. The operating means 10, the drive means 11 and of course the control device 13 are included in a permanent device 5 suitable for frequent re-use.

In addition to the described components, other elements can be also incorporated in the device 1. Thus for instance a flow control valve 17 can be arranged in the line 4 which is operated by an operating element 18 which is controlled by the control device 13.

Fig. 4 shows a partly broken away view of valve means according to the invention in a first embodiment . These valve means comprise a connecting block 27 in which a valve member 28 is received which is here embodied as a rotatable valve member.

The connecting block 27 moreover carries the connecting members 29. Each connecting member 29 debouches via a channel at the port 32 on the periphery of valve member 28.

In the valve member 28 is formed a single channel containing a horizontal part and a connecting vertical part. On the underside the vertical part debouches into a line which can for instance be connected to the pump chamber. The channel 30 in valve member 28 thus forms the combined inlet/outlet of the pump chamber.

The valve means 50 shown in figure 5 form a variant of the valve means shown in detail in figure 5. Valve means 50 comprise a frame 51 having a stepping motor 52 and a transmission 53 at either end. The transmissions 53 have mutually facing output shafts 54 with flattened sides . This frame with drives forms a part of the permanent device. The disposable part 55 is placed in this permanent device. The disposable part 55 comprises a cylindrical housing 56 in which a valve member 57 is placed in this embodiment at both ends. The valve members 57 are rotatable in the cylindrical recess of valve housing 56.

The valve members 57 have an axial bore 60 and each a plurality of transverse bores 62 lying at axial distances. The transverse bores 62 correspond with ports such as for instance the ports 59 and 61. Formed on the end of valve member 57 which protrudes outside valve housing 56 is a slot 58 in which the shaft 54 with flattened side can engage. Depending on the rotational position of valve member 57 in valve housing 56 a connection is thus formed between one or more of the ports 59, 61. By a suitable placing of the transverse bores 62 a programmed cycle of changing connections can thus be effected during rotation of the drive shafts 54. A suitable embodiment of the heating device 16 is shown in figures 7 and 8. Here is shown that the device 16 has a chamber 65 with mutually opposite walls 66. In this embodiment the upper wall 66 is connected all around to a flexible membrane 67 so that walls 66 can move relatively toward each other. Into the walls 66 are integrated electric heating elements 68 which can be provided with electrical energy via electrical connections 69. Instead of one wall being embodied with a flexible membrane, it is also possible for both mutually opposite walls to be displaceable toward each other in that they at least comprise a flexible membrane all around.

On the front side the heating element 16 is provided with a slot 70 which provides access to the chamber 65. Through this slot 70 a schematically represented heat exchanger 71 can be placed into the chamber 65. An end part 72 herein falls into the slot 70 and is sealed therein by sealing means which are not further shown. Incorporated in heat exchanger 71 is a channel 73 through which liquid can flow.

After the heat exchanger 71 has been placed into chamber 65 through slot 70, air can be drawn out of the chamber 65 via the suction connection 74, whereby the walls 66 are moved toward each other, in particular the upper wall 66 moves downward into the situation shown in figure 9. The membrane 67 is herein stretched. Due to the underpressure in chamber 65 the walls 66 press firmly on heat exchanger 71, so that a good contact results and therefore a good heat transfer is obtained from the heating elements 68 in walls 66 to the liquid in heat exchanger 71.

The heat exchanger 71 is embodied as disposable component. It can be manufactured inexpensively from plastic, optionally in combination with cardboard. When the material of heat exchanger 71 is itself at least slightly flexible, it is moreover sucked flat against the walls 66 due to the effect of the vacuum. This improves the contact and the heat transfer. The device 1 is preferably further provided with pressure detection means 75, which are shown schematically in figure 9. In this embodiment these pressure detection means 75 comprise two holders 76, 77 through which flows the same liquid which is supplied through the line 81.

The holder 76 has two mutually opposite walls 78, 79 of flexible material, so that they bulge inward or outward to a greater or lesser degree according to the pressure of the liquid 80. The liquid 80 thus forms a liquid lens, the convexity of which varies with the liquid pressure.

According to another embodiment only one of the mutually opposite walls can be of flexible material and the other can be stiff. In this case also a liquid lens is formed of which the convexity varies with the liquid pressure.

Placed beneath this liquid lens 80 is a light source 82 which casts a divergent beam of light onto this liquid lens 80 via a concave lens 87. The light flows through the lens 80 and falls onto a light-sensitive element 83 placed above lens 80. In the shown situation the liquid lens 80 is convex, so that the light beam is converged and a relatively large quantity of the light emitted by light source 82 is received in the light-sensitive element 83. When the pressure is lower relative to this situation, less light will be directed onto the light- sensitive element 83, so that the light-sensitive element 83 will give a lower output signal. The output signal of the light-sensitive element 83 will thus be an indication for the convexity of the liquid lens 80 and thus of the liquid pressure.

The second holder 77 is arranged to compensate for possible differences in the translucency of the liquid. The holder 77 has transparent walls 86 which are not flexible. The light-sensitive element 85 thus always receives a determined part of the light emitted by light source 84, irrespective of the liquid pressure. Should the translucency of the liquid decrease, this would result in a reduced output signal of the light- sensitive element 83, which could be interpreted as a decrease in the liquid pressure. At the same time however, the output signal of the light-sensitive element 85 also decreases and this indicates that the translucency has decreased and not the pressure. The output signals of the light-sensitive elements 83 and 85 are connected to a processing device 88 which in principle divides the output signal of element 83 by the output signal of element 85, in order to obtain the desired compensation. The device 88 transmits the corrected signal to the control device 13 which adjusts for instance the pump 8 therewith.

The two holders 75, 77 can also be integrated into one element. At least one of the transparent walls of the holder is then given a partly stiff and partly flexible form. One of the light-sensitive elements is placed such that light incident through the flexible part falls thereon while another light-sensitive element is placed such that the light incident through the stiff part falls thereon.

In the case it is ensured that the translucency of the liquid will remain constant over a longer period, for instance because the relevant liquid contains a solution of a substance in water, wherein the substance has no effect on the translucency, a single element will of course suffice with one light-sensitive element which is illuminated via the flexible part of the wall.

Claims

1. Dialysis device comprising a pump having a pump chamber element defining a pump chamber with variable volume and drive means engaging on the pump chamber element for varying the volume of the pump chamber, wherein the pump chamber element has an inlet and an outlet, connecting members for a plurality of liquid lines, valve means for selectively connecting the connecting members to the inlet and the outlet, operating means for the valve means and a control device for programmed control of the pump drive means and the valve operating means, wherein the pump chamber element, the connecting members and the valve means are embodied for once-only use and are releasably arranged in a permanent device comprising the drive means, valve operating means and control device.

2. Device as claimed in claim 1, wherein the pump chamber element, the connecting members and the valve means are formed integrally.

3. Device as claimed in claim 1 or 2 , wherein the pump is a peristaltic pump and the pump chamber element comprising at least one tube.

4. Device as claimed in any of the foregoing claims, wherein the valve means comprise a rotatable valve member, the control device is a digital control device and the valve operating means comprise a stepping motor.

5. Device as claimed in claim 4, wherein the valve member is a member rotatable in a cylindrical recess of a valve housing, which member has an axial bore with a plurality of transverse bores at axial distances which co-act with ports arranged in the peripheral wall of the valve housing.

6. Device as claimed in any of the foregoing claims, comprising a plate-like heat exchanger embodied for once- only use and wherein the permanent device comprises a heating device with a flat heating surface.

7. Device as claimed in claim 6, wherein the heating surface is a wall of a chamber in the heating device which has on one side a slot-like insertion opening provided with sealing means for the heat exchanger and wherein opposite walls of the chamber are yieldably movable toward each other and means are arranged for extracting air out of the chamber.

8. Device as claimed in any of the foregoing claims, comprising pressure detection means which comprise a liquid holder embodied for once-only use and having mutually opposite walls of transparent material, at least one wall of which is flexible and wherein the permanent device comprises a light source and a light-sensitive element on either side of the mutually opposite walls.

9. Device as claimed in any of the foregoing claims, wherein the inlet and the outlet are alternatingly formed by one and the same channel .

10. Device as claimed in claim 9, wherein the channel is formed in the valve member.