DE102014008546B4 - Haemofiltration device, hose set and its use and method for operating a hemofiltration device - Google Patents

Abstract

Haemofiltration system with a haemofilter (3), with a supply line (1) for supplying a blood flow from a patient to the haemofilter (3), and with a return line (6) for returning the blood flow to the patient, with upstream of the haemofilter (3) a first addition point for a substitution agent is arranged to the blood stream, and wherein downstream of the hemofilter (3) a second addition point for a substitution agent is arranged to the blood stream, and with a supply device for supplying the substitution agent from a supply (9) to the first and / or to the second addition point, wherein the feed device has a Y-shaped branched hose line (13) with a first line section (10) running from the store (9) to a branch point and with a first and second branch line (from the branch point) ( 7, 8), with a hose pump (11) for pumping the S. ubstitutionmittel is arranged, and wherein the first line branch (7) runs from the junction to the first, upstream addition point, and wherein the second line branch (8) runs from the branch to the second, downstream addition point, characterized in that only in a check valve (18) is arranged in one of the two line branches (7, 8) of the hose line (13), and that a shut-off valve (316) is arranged only in the other of the two line branches (7, 8) of the hose line (13).

Description

The invention relates to a haemofiltration system with a haemofilter, with a supply line for supplying a blood flow from a patient to the haemofilter and a return line for returning the blood flow to the patient, a first addition point for a substitution agent to the blood flow being provided upstream of the haemofilter, and wherein a second addition point for a substitution agent to the blood stream is provided downstream of the haemofilter, and with a supply device for supplying the substitution agent from a supply to the first and / or to the second addition point, the supply device having a Y-shaped branched hose line with a Line section running up to a branch point and with a first and second line branch running from the branch point, a hose pump for conveying the substitution agent being arranged on the first line section, and the first Line branch runs from the junction to the first, upstream addition point, and wherein the second line branch runs from the branch to the second, downstream addition point.

The invention further relates to a hose set for a haemofiltration system consisting of a Y-shaped branched hose line made of flexible material, and its use.

Extracorporeal therapy methods, which work according to the basic principle of hemofiltration, filter off part of the blood and thus eliminate urinary substances or toxins dissolved in it in the broadest sense, while the cellular blood components remain in the bloodstream. In order not to cause unwanted volume losses, a sterile substitution agent with a suitable electrolyte composition and with the desired volume is fed back into the extracorporeal blood circulation during the course of the treatment. The medically required balancing accuracy for this substitution drug addition is mostly achieved by electronic regulating devices using monitoring and control systems such as gravimetric or volumetric measuring devices and processor-controlled pumps. If such a therapy method is used in patients with kidney failure, in addition to the elimination of urinary substances, the required volume reduction can also be achieved by withdrawing more fluid from the circulation than substituting it. Such devices for renal replacement therapy are known as artificial kidneys, for example from US Pat DE 25 52 304 A1 .

The substitution agent can be supplied to the extracorporeal blood circuit using a conventional drip chamber downstream behind the haemofilter. The filtered blood and the substitution agent are then returned to the patient via the return line. Since the blood that is concentrated when it passes through the haemofilter is only diluted again after the filter, this admixing process is known as post-dilution.

In the course of a hemofiltration treatment, usually lasting several hours, the percentage of cellular components in the blood increases due to the filtration of fluid. This increase in hematocrit causes an increase in the viscosity of the blood and often leads to a reduction in the effectiveness of the haemofilter or even to a complete blockage of the filter membrane. This effect is also known as clotting. By using anticoagulant substances such as heparin or citrate solution, the undesired coagulation effect can be reduced, but for medical reasons the anticoagulation thus effected cannot be increased at will.

An alternative to post-dilution is to add the substitution agent before the haemofilter. This admixture process is known as predilution. It has advantages and disadvantages compared to classic post-dilution. It is advantageous that, due to the thinning of the blood before entry into the haemofilter, the clotting effects can be significantly reduced or avoided entirely. A disadvantage is that a large part of the substitution agent supplied is immediately lost again in the filtration process. On the one hand, this reduces the effectiveness of the entire filtration process, and on the other hand, the treatment costs increase significantly because there can be a significant increase in the need for expensive substitution agents.

A combined procedure that enables both post- and predilution is often medically and technically sensible as well as economically justifiable. In the course of the treatment, which lasts several hours, the initial post-dilution is usually switched to predilution when a measurably increased hematocrit value is reached or based on empirical values.

The simplest form of switching between post-dilution and predilution is to manually shut off the substitution agent's hose connection, which is typically used, using temporarily effective shut-off elements, to detach it from the port for post-dilution and to connect it to a port provided for predilution. This manual intervention disrupts the operational process and harbors an additional risk of contamination. In addition, this method can only be used to choose between 100% post-dilution or 100% Predilution can be changed. A short-term change between the operating modes is therefore not possible.

Also known are technical arrangements in which the hose line for the transport of the substitution agent is divided into two branches in a Y-shape, each of which leads to the point of addition for post dilution or for predilution. Several commercially available hemofiltration devices offer such a solution, two hose pumps for independent, defined liquid transport being connected in the two line branches according to the Y-shaped division, see 1 . These two peristaltic pumps arranged in the branch lines cause a selectively controllable ratio of post- and predilution, as well as a desired closure of an individual of the line branches or both line branches in the event of a standstill. Such a principle is used, among other things, in the devices Multifiltrate ^® from Fresenius, Aquarius ^® from Edwards Lifeschiences, Accura ^® from Baxter and HF 400 ^® from Infomed.

the DE 42 40 681 A1 describes a hemofiltration system with lines for postdilution and for predilution. For the function of this system it is necessary that a hose clamp valve is arranged in each line, see 2 of the present application.

the WO 2005/044339 A2 describes an extracorporeal blood treatment device that also enables hemofiltration to be used. Alternatively, pre-dilution and post-dilution are possible.

the DE 10 2009 037 917 A1 describes a tubing set for a blood treatment device.

Another technical possibility uses only a hose pump in front of the Y-shaped hose branch and two separate hose clamp valves downstream of the branch for the selective closure of one of the two line branches after the branch, siege 2 . Post- or predilution is made possible by opening or closing the typically electrically controllable shut-off valves. Since in this embodiment variant there is in principle the possibility that blood flows past the haemofilter through the hose line when the hose clamp valves are open at the same time, non-return valves must be provided in both line branches. A defined relation of pre- to post-dilution with simultaneous opening of both shut-off valves is not possible because the delivery rates in the two transport branches are dependent on back pressure and this back pressure is influenced by the changing filter status and the blood flow rate. The synchronization of the opening and closing processes requires careful timing and is fraught with the risk of undesired pressure peaks. Since the hose pump usually runs continuously, the pressure in the hose increases immediately when the first shut-off valve is already closed and the second shut-off valve is not yet open. Such an arrangement with correspondingly complex pressure sensors and controls is, for example, in US 7 744 553 B2 described. This principle is also used in the Piasauto ^® hemofiltration device from Asahi Kasei.

The object of the invention is to provide a hemofiltration system and a corresponding hose set which enable the addition of a substitution agent to be switched between pre- and post-dilution in a simple and reliable manner. Furthermore, an improved method for operating a hemofiltration system is described.

The object is achieved according to the invention by a hemofiltration system with a hemofilter, a supply line for supplying a blood flow from a patient to the hemofilter, and a return line for returning the blood flow to the patient, with a first addition point for a substitution agent upstream of the hemofilter the blood flow is arranged, and downstream of the hemofilter a second addition point for a substitution agent is arranged to the blood flow, and with a supply device for supplying the substitution agent from a supply to the first and / or the second addition point, wherein the supply device is Y-shaped has branched hose line with a line section running up to a branch point and with a first and second line branch running from the branch point, a hose pump for conveying the substitution agent being arranged on the first line section is, and wherein the first line branch runs from the junction to the first addition point, and wherein the second line branch runs from the junction to the second addition point, which is further developed in that a check valve is arranged in only one of the two line branches, and that only a shut-off valve, in particular a hose clamp valve, is arranged in the other of the two line branches.

In this embodiment of the hemofiltration system according to the invention, manual intervention on the system is no longer necessary to switch between pre- and post-dilution. At the same time, only one shut-off valve has to be switched, while the check valve opens or closes automatically by switching the shut-off valve from the open to the closed state and vice versa. The control and sensor costs are low. In addition, the equipment required is reduced, since only one check valve and only one shut-off valve are required. Compared to embodiments with two hose pumps, a significant size reduction can also be achieved.

In the context of the invention, a hose line branched in a Y-shape is understood to mean any hose line whose lumen splits from a lumen leading to the branch into two lumen leading away from the branch. The branching can also be T-shaped or asymmetrical without deviating from the invention.

In an advantageous development of the invention, a heating device is arranged along the first line section of the hose line. This enables the substitution agent to be preheated to body temperature in order to avoid thermal stress on the blood circulation.

In a particularly advantageous embodiment of the invention, the hose line has a higher elasticity in the area of the hose pump and / or the shut-off valve than in the rest of the hose area. As a result, the hose can be designed specifically optimized for the stress in its particularly stressed area, without the entire hose being made of a material that is adapted to the stresses that are only required in certain areas. The increased elasticity can be achieved, for example, by using a silicone material and / or by changing the wall thickness of the hose line. The particularly stressed areas are, for example, the area where the peristaltic pump acts. There the hose must be walkable and reliably withstand the stress of several hours until the hose set is replaced. This also applies to the effective area of the shut-off valve, e.g. a clamp valve.

According to a particularly advantageous development of the invention, the check valve is spring-loaded, i.e. the closed position is only left after an opening force that exceeds the spring force has been applied, and the valve automatically returns to the closed position when the spring force is higher than the applied opening force. This ensures that the check valve is not opened unintentionally by the back pressure of the substitution agent flowing through the open shut-off valve. The spring load is preferably set so that the hose pump can easily open the check valve against the pressure in the filtration circuit when the shut-off valve is closed. Typical opening pressures at which the check valve should open are, for example, in the range of 200 - 300 mbar.

The first branch of the hose, which is connected to the first addition point, is provided with the shut-off valve in a preferred embodiment of the invention. In this embodiment, the predominant post-dilution in the typical course of treatment takes place through the shut-off valve, which preferably opens in the de-energized state, while only the rarer pre-dilution takes place through the check valve, which is arranged in the second branch of the line that leads to the second addition point.

In a particularly advantageous embodiment of the invention, the first addition point and / or the second addition point are designed as drip chambers. This enables bubble-free and optically verifiable addition of the substitution agent.

The set object is further achieved by a hose set for a haemofiltration system according to one of the embodiments described above, consisting of a Y-shaped branched hose line made of flexible material, with an in particular spring-loaded check valve being arranged in only one of the line branches behind the branching of the hose line.

In a particularly advantageous embodiment of the hose set according to the invention, the first line section of the hose line and / or the line branch in which the check valve is not arranged has an area with increased hose elasticity in this area.

According to a further aspect of the invention, the object set is achieved by the use of a hose set according to the invention in a hemofiltration system.

A method for operating a hemofiltration system involves the following steps: providing a hemofiltration system according to the invention, performing the hemofiltration with the addition of a substitution agent through the Y-shaped branched hose line at the first addition point or at the second addition point, and switching the addition of the substitution agent between the first addition point and the second addition point by opening or closing the shut-off valve.

• 1: ein Haemofiltrationsgerät gemäß dem Stand der Technik,
• 2: ein weiteres Haemofiltrationsgerät gemäß dem Stand der Technik, und
• 3: ein Haemofiltrationsgerät gemäß der Erfindung.

The invention is explained below with reference to exemplary embodiments which are shown in the schematic drawings. Show it:

• 1 : a haemofiltration device according to the state of the art,
• 2 : another prior art hemofiltration device, and
• 3 : a hemofiltration device according to the invention.

1 shows a hemofiltration device 100 according to the state of the art. A feed line 1 directs a flow of blood from the patient, not shown, through a first drip chamber 2 through to a haemofilter 3 , in which unwanted blood components are filtered out and via a filtrate line 4th be discharged. The purified blood stream is through a second drip chamber 5 through and via a return line 6th fed back to the patient.

The transport of the bloodstream through the hemofiltration device 100 typically takes place using a blood pump (not shown here), the blood being taken from a vein and also being fed back into a vein.

To compensate for the volume removed by filtration, a substituate is added to the blood stream. This is taken from a supply 9 via a Y-shaped branched hose line 13th by means of two peristaltic pumps 14th , 15 of the first drip chamber 2 or the second drip chamber 5 and added to the bloodstream there. The drip chambers 2 , 5 serve for bubble-free mixing and visual inspection by the treatment staff.

On a first line section 10 the hose line 13th that from the supply 9 runs to the branching point is an infusion heater 12th arranged to preheat the substituate. The infusion heater 12th can, for example, be designed as a biocompatible heat exchanger, infrared heater or as a combination of heating plates and heating bags.

A first branch of the line 7th the hose line 13th leads from the branch point to the first drip chamber 2 . A first peristaltic pump 15 is arranged on this first line branch in order to convey the substituate via the first drip chamber 2 to be added to the bloodstream. The first peristaltic pump 15 is put into operation when predilution is desired and put out of operation when post-dilution is required. When the first hose pump 15 is put out of operation, the first line branch is 7th the hose line 13th locked.

A second branch of the line 8th the hose line 13th leads from the branch point to the second drip chamber 5 . On this second branch of the line 8th is a second peristaltic pump 14th arranged to the substituate via the second drip chamber 5 to be added to the bloodstream. The second peristaltic pump 14th is activated when post-dilution is desired and deactivated when predilution is required. When the second hose pump is out of operation 14th is the second branch of the line 8th the hose line 13th locked.

2 shows another hemofiltration device 200 according to another prior art, which is similar to the hemofiltration device 100 according to 1 is constructed. A repeated description of the same components is therefore dispensed with here.

Unlike in the embodiment according to 1 is in the first line section 10 the hose line 13th a peristaltic pump 11th arranged, the promotion of the substituate from the supply both with postdilution and with predilution 9 causes.

Both in the first branch of the line 7th as well as in the second branch of the line 8th the hose line 13th are shut-off valves 16 , 17th arranged, which to avoid an unwanted bypass flow of the blood at the filter 3 are executed over each with associated check valves. The shut-off valves 16 , 17th so leave the substituate in the open state only in the direction of the drip chambers 2 , 5 flow, but not in the opposite direction.

In operation of the hemofiltration device 200 the shut-off valve is used first when working with post-dilution 17th closed and the shut-off valve 16 open. The substituate is created by the peristaltic pump 11th from stock 9 through the pipe sections 10 and 8th the hose line 13th to the second drip chamber 5 where it mixes with the bloodstream.

If a switch to predilution is required due to an increased hematocrit value, the shut-off valve is activated 16 closed and the shut-off valve 17th open. The substituate is then passed through the line sections 10 and 7th the hose line to the first drip chamber 2 promoted and mixed there with the bloodstream.

Switching the shut-off valves 16 and 17th must be synchronized. For example, the shut-off valve 17th opened too late after the shut-off valve 16 is already closed, it builds up in the hose line between the hose pump 11th and the shut-off valves 16 , 17th a pressure peak, which after opening the shut-off valve 17th on the feed line 1 and the Haemofilter 3 acts and damage the haemofilter 3 can lead. If, however, the shut-off valve 17th opened before the shut-off valve 16 is closed, both shut-off valves are briefly off 16 , 17th opened and there can be a short-term bypass flow through the pipe branches 7th and 8th on the haemofilter 3 that only arise through the shut-off valves 16 , 17th provided check valves is interrupted.

In 3 is a hemofiltration device 300 shown according to the invention. The haemofiltration device 300 again comprises a feed line 1 , which a flow of blood from the patient, not shown, through a first drip chamber 2 to a haemofilter 3 conducts, in which unwanted blood components are filtered out and via a filtrate line 4th be discharged. The purified blood stream is through a second drip chamber 5 via a return line 6th fed back to the patient.

The transport of the bloodstream through the hemofiltration device 300 takes place again typically by a separate blood pump, not shown, the blood being taken from a vein and returned to a vein.

The substituate is taken from the supply 9 via a Y-shaped branched hose line 13th by means of a peristaltic pump 11th the first drip chamber 2 or the second drip chamber 5 and added to the bloodstream there.

On the first line section 10 the hose line 13th that from the supply 9 runs to the branching point, is, as already described for the previous figures, an infusion heater 12th arranged to preheat the substituate.

A first branch of the line 7th the hose line 13th leads from the branch point to the first drip chamber 2 . In this first branch of the line 7th is a check valve 18th arranged. A second branch of the line 8th the hose line 13th leads from the branch point to the second drip chamber 5 . On this second branch of the line 8th is a shut-off valve 316 arranged, which in this illustrated embodiment of the invention does not have to have a non-return function and is therefore designed as a simple hose clamp valve.

• Zu Beginn der Haemofiltrationsbehandlung weist das Blut des Patienten einen normalen Haematokritwert auf, so dass wegen einer geringen Clottinggefahr mit Postdilution gearbeitet werden kann. Dazu ist das Absperrventil 316 geöffnet. Da dies der überwiegend vorliegende Betriebszustand ist, ist das Absperrventil 316 als passiv öffnendes Ventil ausgeführt, welches bei Bestromung schließt.

The mode of action of this haemofiltration device according to the invention 300 is as follows:

• At the beginning of the hemofiltration treatment, the patient's blood has a normal hematocrit value, so that post-dilution can be used because of the low risk of clotting. This is the shut-off valve 316 open. Since this is the predominant operating state, it is the shut-off valve 316 designed as a passively opening valve which closes when energized.

In this operating state, the peristaltic pump delivers 11th the substituate at low pressure and with a delivery rate monitored by a control (not shown) through the second branch of the line 8th and the second drip chamber 5 through into the blood flowing back to the patient. Because of the low delivery pressure and because of the same over the haemofilter 3 the prevailing pressure gradient remains the check valve 18th safely closed. By using a spring-loaded check valve 18th the security against unintentional opening is additionally increased.

If the hematocrit value of the blood increases as a result of hemofiltration, the risk of clotting increases, so that after a certain point in time a switch should be made from postdilution to predilution. At this point the shut-off valve will open 316 closed by energizing.

Since the substituate is no longer through the second branch 8th which can flow through the shut-off valve 316 is closed, builds up in the hose line 13th behind the peristaltic pump 11th successively an increasing delivery pressure, for example from approx. 200-500 mbar. This pressure is sufficient to open the check valve 18th to open against the spring tension, so that the substituate is now through the first branch 7th the hose line 13th through to the first drip chamber 2 is promoted and mixed there with the bloodstream.

This described arrangement manages without additional pressure sensors and associated software control. However, sensors can be provided, e.g. to provide additional pressure monitoring and safety precautions,

By electrically actuating the shut-off valve 316 Quasi-simultaneous predilution and post-dilution with a variable duty cycle can also be achieved in sufficiently short time intervals. Reversing the positions of the check valve 18th and the shut-off valve 316 is possible and can be useful for technical reasons. However, since in practice the post-dilution usually outweighs the pre-dilution in terms of time and volume, the arrangement shown is to be preferred for energetic reasons, because the shut-off valve, which is typically electromagnetically actuated 316 consumes no energy in the currentless open state and therefore does not generate any heat due to power loss.

The advantage of the invention described lies in particular in its particular technical simplicity. In particular, only one peristaltic pump is used to control the dilution 11th and only one shut-off valve 316 required as machine components. As a result, the hemofiltration device equipped in this way 300 can be produced more cost-effectively than conventionally equipped devices due to the reduced number of components. Furthermore, there is a significant weight and volume reduction, which contributes to the desired downsizing of the devices. From the omission of a pump segment in the hose line 13th This also results in easier handling of the device, since only one pump segment is inserted into the associated hose pump 11th is to be inserted, while in the prior art there were two pump segments. Another advantage is that existing devices that only allow post-dilution, for example, can easily be retrofitted.

The hose line, which is typically designed as a disposable item, is also technically simpler and therefore more cost-effective. Instead of a second pump segment, only a miniaturized check valve is used in one of the two line branches 18th integrated. Such components are available in the field of medical technology as industrial mass-produced articles and as inexpensive, sterilizable disposable articles.

The dilution control according to the invention has the additional advantage over the previously known arrangements that it can work independently and can thus be implemented as a separate retrofit unit for hemofiltration devices that were originally designed only for post-dilution. Since, in particular, the safety-relevant fluid balance of the devices is not influenced, no changes to the device software and no electrical control intervention are required. Only the hose line, which is usually designed as a disposable item anyway, has to be integrated with the non-return valve 18th be modified.

List of reference symbols

1

Feed line

2.5

Drip chamber

3

Haemofilter

4th

Filtrate line

6th

Return line

7.8.10

Line sections, first and second line branches

9

stock

11,13,14

Peristaltic pump

12th

Infusion heater

13th

Hose line

16,17,316

Shut-off valve

18th

check valve

100,200,300

Haemofiltration device

Claims (13)

Haemofiltration system with a haemofilter (3), with a supply line (1) for supplying a blood flow from a patient to the haemofilter (3), and with a return line (6) for returning the blood flow to the patient, with upstream of the haemofilter (3) a first addition point for a substitution agent is arranged to the blood stream, and wherein downstream of the hemofilter (3) a second addition point for a substitution agent is arranged to the blood stream, and with a supply device for supplying the substitution agent from a supply (9) to the first and / or to the second addition point, wherein the feed device has a Y-shaped branched hose line (13) with a first line section (10) running from the store (9) to a branch point and with a first and second branch line (from the branch point) ( 7, 8), with a hose pump (11) for pumping the S. ubstitutionmittel is arranged, and wherein the first line branch (7) runs from the junction to the first, upstream addition point, and wherein the second line branch (8) runs from the branch to the second, downstream addition point, characterized in that only in A check valve (18) is arranged in one of the two line branches (7, 8) of the hose line (13), and that a shut-off valve (316) is arranged only in the other of the two line branches (7, 8) of the hose line (13). Haemofiltration system according to Claim 1 , characterized in that the shut-off valve (316) is designed as a hose clamp valve. Haemofiltration system according to Claim 1 or 2 , characterized in that a heating device (12) is arranged along the first line section (10) of the hose line (13). Haemofiltration system according to one of the preceding claims, characterized in that the hose line (13) has a higher elasticity in the area of the hose pump (11) and / or the shut-off valve (316) than in the rest of the hose area. Haemofiltration system according to one of the preceding claims, characterized in that the check valve (18) is spring-loaded. Haemofiltration system according to one of the preceding claims, characterized in that the shut-off valve (316) is arranged in the first line branch (7) of the hose line (13). Haemofiltration system according to Claim 6 , characterized in that the shut-off valve is designed to switch when current is applied. Haemofiltration system according to Claim 7 , characterized in that the shut-off valve is designed so that it is in the open position without current. Haemofiltration system according to one of the preceding claims, characterized in that the first addition point and / or the second addition point is or are designed as a drip chamber (2, 5). Hose set for a haemofiltration system according to one of the preceding claims, consisting of a Y-shaped branching hose line (13) made of flexible material, the hose line (13) having a first line section (10) extending up to a branching point and first and leading from the branching point second line branches (7, 8), wherein a hose pump (11) for conveying the substitution agent can be arranged on the first line section (10), and only in the first or only in the second line branch (7, 8) of the hose line ( 13) a check valve (18) is arranged. Hose set for a haemofiltration system according to Claim 10 , characterized in that the check valve is a spring-loaded check valve. Hose set according to Claim 10 or 11th , characterized in that at least one line area of the hose line (13) in which the check valve (18) is not arranged has a higher elasticity than the rest of the hose area, namely the hose area provided for the action of a hose pump and / or a shut-off valve. Use of a hose set according to one of the Claims 10 until 12th in a haemofiltration plant.

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