GB2097285A

GB2097285A - Method and apparatus for the production of dialysate

Info

Publication number: GB2097285A
Application number: GB8209515A
Authority: GB
Original assignee: TERSTEEGEN BERNDT
Current assignee: TERSTEEGEN BERNDT
Priority date: 1981-03-31
Filing date: 1982-03-31
Publication date: 1982-11-03
Also published as: IT8204813A0; JPS57188261A; FR2502960A1

Abstract

A method and apparatus for the production of a prescribed charge of dialysate is disclosed. With the present invention it is possible to easily and safely produce a dialysate meeting the requirements for the particular condition or illness of each patient. A metered quantity of water is supplied tangentially (6) to a mixing chamber (5) having a filter (9) associated with its outlet (8), and dissolves therein a charge of dialysate precursor powder added via a filling opening (7). Means (10)-(13) may be provided to add liquid components to the mixing chamber. <IMAGE>

Description

SPECIFICATION Method and apparatus for the production of dialysate Technical Field of the Invention The present invention relates to a process for the production of dialysate for use in hemodialysis.

Background of the Invention Hemodialysis, the use of an artificial kidney device, requires about 80 to 180 liters of dialyzing fluid, dialysate, per treatment. The preparation of such large volume of fluid demands considerable attention and the overall treatment method and it execution require considerable technical expenditure. Strict demands are placed on the properties of the dialysate, which, being a medicinal agent must meet physiological requirements and be substantially free from germs and pyrogens.

The problems of preparing a suitable composition adapted to the requirements of the dialysate can be found in the book Replacement of Renal Function by Dialysis, (editors: W. Drukker, F.M. Parsons, J.F. Maher; Verlag Martinus Nijhoff Medical Division, the Hague 1978) in the main section "The Composition of Dialysis Fluid" (authors: F.M. Parsons, A.M. Davison). It is well-known, and evident from the publication that adapting the composition of the dialysate to the condition or illness of a particular patient is one of the essential medical requirements.

In the past this goal has been pursued many times, but for predominantly technical reasons no permanent, practical solution has been found. In one procedure a patient's entire dialysate supply was prepared in a tank having the necessary total amount of water dissolving the requisite components (salts, glucose etc.) for the individual prescription. This process has not proved successful because of the high amoount of work and time as well as the necessity for careful monitoring. Problems have ocasionally occurred because of incomplete dissolving of components.

It was a substantial advance, therefore, when industrially prefabricated concdntrates became available from which dialysate could be produced by diluting with water. Handling was substantially simplified, because, inter alia, the use of proportional mixing pumps made possible a continuous generation of the dialysate from the liquid concentrate and water. However, this partial advance also involves considerable concessions. The degree of adaption available for the individual condition or illness of a patient is reduced, since in the interest of a efficient production and storage, only a limited selection of standard concentrates can be kept available. Still more serious, however, are the concessions on the basis of pharmaceutical technical requirements, especially for the stability and storability of the concentrates.In particular, the more compatible bicarbonate was replaced by acetate for these pharmaceutical reasons. The same is also true for other desirable components.

The present invention attempts to solve these problems by providing suitable means for the production of an individually adapted, physiologically high-quality dialysate.

Accordingly, the invention proposes a system for the production of a charge of dialysate comprising: a) a mixing chamber having an interior and communicating with the interior, an inlet, outlet and filling opening having a cover; the inlet for connection to a liquid source and communicating with the interior such that a turbulence is created within the chamber as liquid passes through the inlet; b) a filter within the chamber and associated with the outlet for filtering fluid leaving the chamber through the outlet; c) control means operably associated with the inlet for apportioning the volume of water introduced into the chamber; whereby the predescribed components to prepare a charge of dialysate can be placed into the chamber and the control means activated to introduce a predetermined amount of liquid into the chamber through the inlet to mix with and disssolve the components to produce a solution which can then pass through the filter and outlet to a hemodialysis unit with any undissolved components being retained by the filter.

The invention also provides a mixing unit for use in the production of dialysate for a hemodialysis apparatus, the unit including a chamber having a generally cylindrical interior, and communicating with the interior, an inlet, an outlet on the bottom, a filling opening and cover; the inlet passing tangentially into the chamber such that liquid introduced through the inlet generates a turbulence within the chamber, the unit also inlcuding a filter within the chamber and over the outlet such that the generated turbulence removes undissolved dialysate components which may collect on the filter.

According to a further aspect, the invention comprises a method for producing a charge of dialysate according to the prescription of a particular patient, comprising the steps of: a) providing a mixing chamber having a filtered outlet; b) placing into the chamber components which when mixed with a predetermined amount of water form a dialysate according to the prescription; c) introducing into the chamber a flow of water of the predetermined amount to mix with and dissolve the components into a solution which passes through the filter and out of the outlet; and d) collecting the produced solution in a tank, the collected solution serving as the predescribed dialysate.

The dialysate thus prepared is supplied to the particular hemodialysis apparatus. A central supply unit can be used to supply several hemodialysis apparatuses as at a hospital station by filling the tank of each apparatus with dialysate prepared according to each patient's requirements. The usual prior arrangements with individual hemodialysis apparatuses for the generation, of dialysate can be eliminated.

In particular proportional-mixing pumps for the dosing of concentrate and water and the arrangements for monitoring the concentration of the dialysate fluid are not needed.

The present invention is also advantageous compared to known central supply units in which the dialysate is generated by mixing water and industrially prefabricated concentrates. These prior systems do not permit the individualization of the dialysate composition for each patient. Since such installations treat all patients at the same time, there must be accepted into the bargain a uniform standard composition for the dialysate.

A further advantage of the present invention is that the cost of the components used to produce the dialysate are clearly lower in comparison to the use of industrially prefabricated concentrates. The additional expenditures from the individual adaptation of the dialysate to the patient's condition are therefore at least partially compensated.

Further details and features of the invention are apparent from the following description of an example, drawings, and the appended claims.

Figure 1 shows a diagram representation of a central supply unit having a chamber for disssolving solid components and for the filtration of the solution; Figure 2 is a schematic longitudinal section through the chamber of the supply unit; Figure 3 is a plan view of the arrangement of Fig. 2.

In the arrangement shown in Fig. 1, the water required for the production of the dialysate is supplied over line 1. Line 1 is provided a block-off valve 2. To ensure a uniform water inflow it is expedient to provide an adjustable pressure regulator 3 and a water-dosing device 4 for measuring out a certain amount of water. A predetermined amount of water is automatically supplied in each working cycle by the water-dosing device 4 controlling the block-off valve 2.

The water passes into the interior of a chamber 5, through a water intake 6 passing tangentially into the chamber 5. The chamber is sustantially a standing cylinder. The chamber 5 has a filling opening 7 at the top, through which the solid (powder) components to be dissolved are supplied before the water enters. At the bottom of the chamber 5 there is an outlet 8 for the produced solution.

With suitable selection of the chamber dimensions and inflow rate, the tangential inflow of the water produces a very intensive circular flow within the chamber 5, which sets the solid components placed into the chamber in turbulence so that in a short time they dissolved. This process is promoted by baffle plates (not represented) arranged within the chamber. A substantially cylindrically formed filter inset 9, which is placed upright within the chamber over the outlet 8, also contributes to the process described. The outer surface of the filter material prevents still undissolved components from flowing through the outlet and limits the circular flow to an approximately annular space. The surface of the filter cylinder is steadily washed tangentially, automatically reducing the danger of a clogging of the filter.The filter inset into limits the flow of the solution through the outlet 8 allowing adjustment of an optimun staying time of the circulating fluid within the chamber. The turbulence process is still further heightened by the eccentric arrangements of the outlet 8 and of the filter inset 9.

A further advantage of the filter arangement lies in its easy accessibility, greatly simplifying the checking and possibly necessary changing of the filter. For this, the outlet connecting piece inside the chamber 5 is expediently provided with a threaded or tapered section.

The filter cylinder is similarly provided with a counterpart which fits into the threaded or tapered section of the outlet.

Fig. 2 shows a preferred formation of the chamber 5 in the longitudinal section. A filling opening occupying the entire upper surface together with a lockable cover is provided so the substances to be dissolved can be placed in the chamber. The filter inset 9 is fastened by a tapered plug connection over the outlet connecting piece 8.

Where certain components of the dialysate are required to be supplied in liquid form, they can be supplied through the same filling opening as the solid components. It is also possible, in the interest of a simpler handling to provide a separate feed for these components into the chamber 5, as is represented in the diagram of Fig. 1. The corresponding line 10 communicates through a valve 11 with a dosing vessel 12, which can be filled over a line 13 through a valve 14 from a supply vessel (not represented). The filling of the dosing vessel with a predescribed amount can be automated by using a filling level meter 15 in conjunction with a control unit 16 for the operation of the valves 1 1 and 14.

The operation of the above described supply unit is discontinuous. The dialysate for supplying the hemodialysis apparatuses is generated in charges as prescribed in each case. A supply unit of the type described is especially suited, therefore, for use as a central filling station for so-called tank kidneys, i.e., hemodialysis apparatus that have a holding container for the entire liquid volume of dialysate required for a treatment.

In movable hemodialysis apparatus of the type mentioned, there is the further advantage that distribution lines between the supply unit to the individual hemodialysis apparatuses are eliminated. This not only means a reduction in expenditure, but also avoidance of the hygienic problems normally associated with the use of dialysate distribution lines.

Claims

1. A system for the production of a charge of dialysate comprising: a) a mixing a chamber having an interior and communicating with the interior, an inlet, outlet and filling opening having a cover; the inlet for connection to a liquid source and communicating with the interior such that a turbulence is created within the chamber as liquid passes through the inlet; b) a filter within the chamber and assoicated with the oulet for filtering fluid leaving the chamber through the outlet; c) control means operably associated with the inlet for apportioning the volume of water introduced into the chamber; whereby the predescribed components to prepare a charge of dialysate can be placed into the chamber and the control means activated to introduce a predetermined amount of liquid into the chamber through the inlet to mix with and dissolve the components to produce a solution which can then pass through the filter and outlet to a hemodialysis unit with any undissolved components being retained by the filter.

2. The system of claim 1 wherein the inlet communicates tangentially with the interior of the chamber to create the turbulence.

3. The system of claim 1 wherein the interior of the chamber is generally cylindrical and the filter is defined by a filter cylinder having a filter material on its surface.

4. The system of claim 3 wherein the outlet is on the bottom of the chamber and filter cylinder extends over and upward from the outlet into the interior of the chamber.

5. The system of claim 4 wherein the filter cylinder is positioned eccentrically within the interior of the chamber.

6. The system of claim 1 further including at least one liquid connection communicating with the interior of the chamber for introducing liquid dialysate components into the chamber.

7. The system of claim 6 further including liquid dosing means in fluid communication with the liquid connection for controlling the amount of liquid dialysate components introduced.

8. A mixing unit for use in the production of dialysate for a hemodialysis apparatus, the unit including a chamber having a generally cylindrical interior, and communicating with the interior, an inlet, an outlet on the bottom, a filling opening and cover; the inlet passing tangentially into the chamber such that liquid introduced through the inlet generates a turbulence within the chamber, the unit also including a filter within the chamber and over the outlet such that the generated turbulence removes undissolved dialysate compound which may collect on the filter.

9. The mixing unit of claim 8 wherein the filter comprises a filter cylinder having a filter material on its exterior surface.

10. The mixing unit of claim 9 wherein the filter cylinder extends from the outlet upward into the interior of the chamber to define an annular flow region about the filter.

11. A method for producing a charge of dialysate according to the prescription of a particular patient, comprising the steps of: a) providing a mixing chamber having a filtered outlet; b) placing into the chamber components which when mixed with a predetermined amount of water form a dialysate according to the prescription; c) introducing into the chamber a flow of water of the predetermined amount to mix with and dissolve the components into a solution which passes through the filter and out the outlet; and d) collecting the produced solution in a tank, the collected solution as the prescribed dialysate.

12. The method according to claim 11 wherein the flow of water is introduced into the interior of the chamber tangentially to create a turbulent annular flow within the chamber.

13. The method according to claim 12 wherein the filter comprises a filter cylinder and the solution within the chamber is directed to flow annularly about the filter cylinder to remove any undissolved components which may collect on the surface of the filter cylinder.

14. Apparatus for preparing dialysate substantially as herein described with reference to the accompanying drawings.

15. A method of preparing dialysate substantially as herein described with refence to the accompanying drawings.