Patent Application
20180036480
The present invention relates to a device for the administration of fluids to a human or animal body, comprising a housing with a first inlet, at least one second inlet, one outlet and a collecting point, wherein the first inlet communicates with the collecting point through a first channel and the outlet communicates with the collecting point.
Such devices are known from prior art and serve the purpose of administering medicaments to humans, in particular infants, or, in some cases, to animals. There are some medicaments which need to be administered with a precise dose, as they have toxic properties and negative side effects. A patient should be exposed to such medicaments only as much as is necessary. Too high a dosage of such medicaments can cause serious damage to a patient and can even cause the death of the same. On the other hand, a dosage too low leads to an insufficient treatment of the respective medical indication, while nevertheless exposing the patient to such medicaments, and thus, causing negative side effects.
An apparatus for administering multiple fluid medicaments to a patient is known from U.S. Pat. No. 3,941,126 A. The apparatus allows for an independent adjustment of the dilution of the individual medicaments fed to it. The dilutor is fed from a storage vessel into cylindrical containers through valves, where the amount of the dilutor can be adjusted for each container. Subsequently, the medicaments are added to the individual containers with the aid of syringes. By means of additional valves the diluted medicaments flow into a drip chamber through separate tubes where they converge. The mixture of diluted medicaments then flows to a point of administration, e.g. an infusion needle, through another tube.
US 2009/0137951 A1 discloses an apparatus for transferring several fluid medicaments into a tube with several channels. The tube ends in a mixing chamber arranged in the proximity of a patient. The medicaments converge within the mixing chamber. The medicament mixture then flows from the mixing chamber to an administration point that can be embodied as an infusion needle, e.g. Thus, owing to the said tube featuring several channels, the medicaments converge shortly before the administration point.
The present invention relates to a device 2 for the administration of fluids to a human or animal body comprising a housing 3 with a first inlet 28, at least one second inlet 29, 30, one outlet 31 and a collecting point, wherein the first inlet 28 communicates with the collecting point through a first channel and the outlet 31 communicates with the collecting point. The device is characterized in that the second inlet 29, 30 communicates with the collecting point or an indicator chamber 24, 25 through a second channel 21, 22 in which a valve 26, 27 is arranged, the valve 26, 27 being adjustable between a first position and a second position, wherein, in the first position of the valve 26, 27, the second channel 26, 27 communicates with the indicator chamber 24, 25 and, in the second position of the valve 26, 27, the second channel 21, 22 communicates with the collecting point. With the device 2 according to the invention, flow rate irregularities are eliminated (over shoot) or at least minimized (time delay, flow rate fluctuations due to changing flow rates), such that the device 2 allows for a more precise dosage.
It is an object of the present invention to provide a device for administering fluid medicaments to a patient with a more precise dosage with respect to devices known from prior art, especially with low flow rates in the range of 0.5 ml/h to 20 ml/h.
This is achieved by a device with the features of claim 1. The device according to the invention is characterized in that the second inlet communicates with the collecting point or an indicator chamber through a second channel, in which a valve is arranged, while said valve is adjustable between a first position and a second position, wherein the second channel communicates with the indicator chamber in the first position of the valve, and the second channel communicates with the collecting point in the second position of the valve.
First of all, it should be noted that the expressions fluid and medicament are used interchangeably throughout the present description of the invention, since the medicaments that are to be administered to a patient by means of the device according to the invention are in the form of a fluid, i.e. fluid substances or solutions of originally solid substances. In the latter case, the solvent is in most cases water, which might already contain sodium chloride. Furthermore, a solution without a physiological effect on a patient, in particular a sodium chloride solution, can be fed to one of the inlets serving as a transportation medium for the medicaments which are to be administered and which are fed to the second inlet. Furthermore, a nutritive solution can be fed to the device. The fluids fed to the first and second inlets are collected in the collecting point that is therefore denominated as such.
In addition to the collecting point, the device comprises an indicator chamber whose purpose is to indicate, in particular making visible, that the flow path between the second inlet and the valve, including the volume of the valve which is exposed to the fluid fed to the second inlet, is filled with fluid. Once this is ensured, the valve is adjusted from its first position to its second position, in which the second channel communicates with the collecting point. Since the second channel and the fluid guiding volume of the valve is already filled with fluid, converging of the fluid fed to the second inlet and the fluid fed to the first inlet occurs immediately after the valve is switched in its second position, and thus, the delay between adjusting the valve and administering the mixture of fluids to a patient is minimized. This allows for a precise setting of the point in time at which the administration of medicaments starts and therefore, for a more precise calculation of the dose (dose=[volume of medicament/time unit]×administration period) actually administered to a patient. For these reasons, the indicator chamber is an essential feature of the device according to the invention.
When employing the device according to the invention, tubes are connected to the first inlet, to the at least one second inlet and to the outlet, respectively. The tube connected to the outlet is connected with an infusion needle on its proximal end. Then, pumps are activated feeding a first fluid to the first inlet through a first tube and a second fluid to the second inlet through a second tube. This first fluid is generally a sodium chloride solution or a nutritive solution. The second fluid is regularly a medicament. The valve of the device is in its first position and provides thus a fluid connection between the second inlet and the indicator chamber via the second channel. After a short while, the indicator chamber is filled with the second fluid which is at least detectable electronically, e.g. by means of a detector, but preferably visible. In the next step, the valve is adjusted to its second position, in which state the valve provides a fluid connection between the second inlet and the collecting point via the second channel. Now, the second fluid being fed through the second channel and the first fluid being fed through the first channel converge at the collecting point. The mixture of the fluids is then fed to the outlet communicating with the collecting point. If administration of the second fluid, normally a medicament, shall end, the valve is switched back to its first position so as to block the fluid connection between the second inlet and the collecting point. On the other hand, the fluid connection between the first inlet and the collecting point is still existent, and the first fluid, normally a sodium chloride solution or a nutritive solution, is still administered to the patient. The valve can later be adjusted to its second position again in order to further administer the second fluid to the patient if desired or necessary. In the latter case, there is again almost no delay between adjusting the valve and the administration of the second fluid, since the flow path is already filled with the second fluid.
It is pointed out, that a device comprising one first inlet and one second inlet is merely a basic embodiment of the device according to the invention. Preferably, there are two second inlets and, correspondingly, two second channels, two valves and two indicator chambers. However, more than two second inlets and, correspondingly, more than two second channels, two second valves and two indicator chambers can be provided as well.
Further advantageous embodiments of the device according to the invention result from the sub-claims.
According to such an advantageous embodiment, the indicator chamber and/or the housing is at least in part transparent or translucent for visible electromagnetic radiation, i.e. for visible light. This feature allows for a simple detection of whether the indicator chamber is filled with the fluid fed to the second inlet, namely by means of a human eye.
According to a further embodiment of the invention, the indicator chamber comprises a hydrophobic filter element. However, according to a preferred embodiment, the indicator chamber comprises an indicator element which changes its color in case of fluid contact. Obviously, there can be both a hydrophobic filter element and an indicator element arranged within the indicator chamber. A hydrophobic filter element allows air or gas bubbles to escape, which must not enter a patient's blood circuit. This is due to the well-known fact that air or other gases within the blood circuit can lead to a failure of the heard or other organs, since all organs need a blood supply for the supply with oxygen and nutritive substances. Blood also serves for temperature control of the organs and for the transport of products of metabolism. Correspondingly, the indicator chamber must comprise a wall with at least one opening communicating with the ambience air of the device and against which the hydrophobic filter element abuts in order to allow gas bubbles to escape.
A wall or a section of a wall of the indicator chamber, that is transparent for visible light, might already allow for the observation whether a fluid is present in the indicator chamber. However, according to a preferred embodiment, there is an indicator element arranged in the indicator chamber, which changes its color in case of fluid contact, such that the presence of a fluid in the indicator chamber is easily observable by the human eye and accordingly without further technical equipment. Of course, being observable by the human eye requires that a wall or a section of a wall of the indicator chamber is transparent or translucent for visible light.
The indicator element can be made of a sintered plastic material. Such a sintered plastic material combines the functionalities of a hydrophobic filter element on the one hand, and of an indicator element on the other hand. Such sintered plastic materials are porous before fluid contact and change their density in case of fluid contact, whereat the small channels of the previously porous plastic material get sealed. This might not be true for all plastic materials, but there are some plastic materials available which have this property in the sintered state. By means of at least one additive, a color transition in case of fluid contact can be achieved as well, in which case the indicator element serves as hydrophobic filter and as color changing indicator. Due to this synergy effect, the embodiment just described is the particularly preferred embodiment of the device according to the invention. A suitable plastic material having said property, i.e. the said synergy effect, is sintered polyethylene (PEL), which is already available on the market.
As is the case with the hydrophobic filter element, the indicator element with such a property abuts on a wall of the indicator chamber with at least one opening communicating with the ambience air of the device, in order to allow gas bubbles to escape from the indicator chamber and thus, from the fluid fed to the second inlet.
Furthermore, it can be provided that an inlet opening of the indicator chamber is covered by an elastic sealing element acting as a check valve which is closed in a pressureless state, whereat the term pressureless refers to atmospheric pressure, i.e. pressure not exceeding atmospheric pressure. The sealing element serves as a check valve and can be provided in addition to check valves arranged in the first or second channel or without the latter check valves. It covers the inlet opening of the indicator chamber, extends marginally over the circumference of the inlet opening and can be held in position by a support which contacts the sealing element in its center, for instance, and exerts an initial tension on the sealing element such that the outer edge of the sealing element acts as sealing lip being raisable in only one direction.
Such support can be realized in that the indicator chamber comprises at least one insertion element which holds the sealing element in its position by contacting the sealing element and/or which receives the hydrophobic filter element and/or the indicator element. The insertion element can serve both purposes or only one of them. Correspondingly, a plurality of insertion elements can be provided, which serve different purposes and are possibly fixed together by frictional connections, tongue and groove connections, welding, gluing or in similar ways. For example, the wall of the indicator chamber with at least one opening can be embodied as a wall element that is fixed on the insertion element or on one or more of the insertion elements. The housing of the device might comprise a clearance forming the indicator chamber and into which the at least one insertion element is, together with the sealing element and/or the hydrophobic filter element and/or the indicator element, inserted and fixed to the circumferential surface of the clearance by means of, e.g., a frictional connection, a tongue and groove connection, welding, gluing or the like.
As an alternative to the indicator element, an indicator mechanism can be arranged within the indicator chamber, comprising at least one movable part which moves with respect to the indicator chamber, preferably out of the same, when the latter is filled with fluid, i.e. the pressure within the indicator chamber leads to a movement of the movable part. Such indicator mechanism can be embodied as a pin, which is the movable part, and a resilient member, in the form of a spring, e.g. In this case, the pin moves against the restoring force of the resilient member due to the pressure within the indicator chamber, or the pin moves through the restoring force of the resilient member after the pressure within the indicator chamber has released a retainer that held the resilient member in a tensioned, i.e. compressed, state. Of course, a plurality of indicator mechanisms is conceivable by a skilled person and is considered to be within the scope of the present invention. The mentioned indicator mechanisms comprising a pin and a resilient member are merely chosen as an example. The indicator mechanism serves the same purpose as the indicator element referred to hereinbefore, namely, indicating wether the indicator chamber is filled with the fluid fed to the respective second channel.
The movable part can additionally feature a color mark, by means of which can be observed more easily that the movable part moved.
With a further embodiment of the device the second channel and/or the first channel comprise a filter chamber in which a hydrophilic filter member is arranged, wherein the filter member separates the filter chamber into to sub-chambers. This hydrophilic filter member allows for a removal of solid particles contained as contaminants in the medicament fed to the second inlet. Such contaminants can get into medicaments during the manufacturing process of the same, or by absorption from the air in non-decontaminated environments. However, they shall not reach the patient's blood, as agglomerates of such particles can block blood vessels or such particles can contain toxic ingredients like heavy metals. It is assumed that the hydrophilic filter members also contribute to an increased independency of flow rates within the single channels of the device, i.e. an adjustment of the flow rate within one channel has a lower effect on the flow rates within the other channels, since the hydrophilic filter members are flow resistances.
Furthermore, a hydrophobic filter member can be arranged in the filter chamber, which covers an opening of the filter chamber being in communication with the ambience air of the device. In this case, an opening is located in the filter chamber that communicates with the ambience air of the device, which means that the opening extends through the housing of the device. The opening is covered by the hydrophobic filter member allowing gas bubbles, in particular air bubbles, possibly contained in the fluid, which is fed to the second inlet, to escape. Air bubbles must be prevented from reaching the patient's blood circuit as set forth above.
The hydrophilic filter member and the hydrophobic filter member are preferably fixed to the filter chamber by welding, in particular ultra sonic welding, wherein the welding seam extends along the outer edge of the filter members. However, a fixation by means of gluing is also possible.
The hydrophilic filter member can be supported by protrusions extending from at least one wall of the filter chamber. The protrusions of this embodiment ensure that the hydrophilic filter member does not lose its flat shape. Moreover, the hydrophilic filter member can be fixed on some or all of the protrusions, in order to provide a stronger fixation of the hydrophilic filter member.
In order to prevent back flow of the fluids, a check valve can be arranged in the first channel and/or in the second channel. Preferably, one check valve is arranged in the first channel in the vicinity of the collecting point and one check valve is arranged in each second channel in the vicinity of the respective valve.
It is important that the dead volume of the device is comparatively small, since a larger dead volume leads to a longer delay between a switching of the valve and the administration of the fluid fed to the second inlet to a patient. It is assumed that the dead volume contributes to a dependency of flow rates, causing fluctuations of other flow rates if one flow rate is changed. It is assumed that a small dead volume minimizes this effect. The volume of the collecting point should therefore be small, which is why the denomination “collecting point” was chosen. However, the collecting point can be embodied as a collecting chamber with a larger dead volume due to design purposes, and in particular due to the fact that very small structural elements of the device lead to higher manufacturing costs, as it is difficult to manufacture small plastic components with the prescribed design, to assemble them and to fix them to each other by means of, for instance, welding or gluing.
In one particular embodiment the collecting chamber has a ring shape, i.e. a ring-like structure, whereat the fluids enter the collecting chamber at different points on its outer circumference. For instance, two second channels are provided, being arranged in the housing in such way that a second channel is positioned on each side of a centrally arranged first channel, whereat the second channels end in the ring-shaped collecting chamber at angle differences of +90° and −90° with respect to the end point of the first channel (0°). In this case, the exit point of the fluid or fluid mixture within the collecting chamber communicating with the outlet can be arranged opposite to the end point of the first channel, i.e. there is an angle difference of 180° between the end point of the first channel and the exit point of the collecting chamber.
Regarding the at least one valve of the device according to the invention, it can be provided that at least one section of the valve has a cylindrical shape, the radial surface of which comprises a recess extending over the circumference of the radial surface, wherein the recess provides a communication between the second channel and the indicator chamber in the first position of the valve, and between the second channel and the collecting point in the second position of the valve. By means of such a valve, the adjustment between the first and second position, and vice versa, can be carried out by turning its cylindrical section about the axial direction of the same. On the cylindrical section a grip portion can be formed, allowing for an easy manual adjustment of the valve. The cylindrical section of the valve can moreover be inserted into the housing, in which case there is a clearance formed within the housing of the device into which the cylindrical section of the valve is inserted and fixed in such a manner, that the cylindrical section is still turnable, e.g., by means of a tongue and groove connection. On the radial surface of the cylindrical section, a recess is formed that extends over the circumference of the radial surface allowing thus for an adjustable fluid connection between the second channel and the indicator chamber or the collecting point, whereat the adjustment can be conducted by turning the cylindrical section of the valve about its axial direction from the first position to the second position, or vice versa. The length of the recess formed on the radial surface of the cylindrical section depends on the angle difference between the location of the points of the second channel, which adjoin the cylindrical section and communicate with the second inlet, the collecting point or the indicator chamber.
A particular preferred embodiment of the device according to the invention is described hereinafter with reference to figures, whereat
The first channel 20 extends through the housing starting from the first inlet 28 and ending at the collecting chamber 23. Within the first channel 28 check valve 33 is arranged in the vicinity of the collecting chamber 23, preventing back flow from the collecting chamber 23 into the first channel 20.
The collecting chamber 23 is essentially ring-shaped. There is a protrusion 38 formed on the inner wall of the ring-shaped collecting chamber 23, which protrusion 38 extends marginally into the first channel 20. The protrusion 38 results in the fluid fed to the first channel 20 being separated into two half streams, flowing through the collecting chamber 23 in different directions, i.e. clockwise and counterclockwise, when it enters the collecting chamber 23. The end of outlet channel 32 and protrusion 38 have an angle difference of 180°. The collecting chamber 23 is realized by providing a clearance in the housing 3, into which a cylindrical-shaped insertion member 64 with a recess 65 formed on its radial surface is inserted. The collecting chamber 23 is formed by the recess of insertion member 64 and the circumferential surface of the clearance.
The second channels 21, 22 extend through the housing 3, starting from the second inlets 29, 30 and ending at the indicator chambers 24, 25, or at the collecting chamber 23. The second channels 21, 22 each have a branched structure, wherein one of the valves 26, 27 is arranged at the branching point such that an adjustable fluid connection between the second channels 21, 22 and the indicator chambers 24, 25 or between the second channels 21, 22 and the collecting chamber 23 can be provided there. In each second channel, one of the check valves 34, 35 is arranged preventing backflow from the collecting chamber 23 or the indicator chambers 24, 25 towards the second inlets 29, 30. In order to minimize the dead volume of the device 2 the branches 39, 40, 41, 42 of the second channels 21, 22 are designed to be very short and extend merely through the walls separating the valves 26, 27 from the indicator chambers 24, 25 and the walls separating the valves 26, 27 from the collecting chamber 23. The minimal thickness of these walls depend on the desired mechanical stability of the device 2. The second channels 21, 22 further comprise filter chambers 36, 37, in which a hydrophilic filter member (not shown) or, in the present embodiment, a respective hydrophobic filter member (not shown) are arranged. In the sectional view of
Each of the valves 26, 27 comprise a cylindrical section. On the radial surface of the cylindrical sections a corresponding recess 43, 44 is formed. The recesses 43, 44 extend over the radial surface of the cylindrical sections of the valves 26, 27 in order to provide an adjustable fluid connection between the second channels 21, 22 and the indicator chambers 24, 25 (first position of the valves 26, 27) or the collecting chamber 23 (second position of the valves 26, 27), whereat the adjustment is carried out by turning the cylindrical sections about their axial directions, moving the recesses 43, 44 at the same time. The grip portions 13, 14 shown in
Indicator chambers 24, 25 communicate with the second channels 21, 22 in the first position of the valves 26, 27, which is the starting adjustment during employment of the device 2. The indicator chambers 24, 25 comprise each an inlet opening 50, 51, a sealing element 52, 53, an insertion element 54, 55, a wall element 56, 57 with an opening 58, 59 and an indicator element 60, 61. The inlet openings 50, 51 have a protruded edge against which the sealing elements 52, 53 rest. Sealing elements 52, 53 are supported by protrusions 62, 63 formed on the insertions elements 54, 55. Protrusions 62, 63 exert an initial tension on sealing elements 52, 53 such that they seal inlet openings 50, 51 in a pressure-less state. The sealing elements 52, 53 can be fixed on the protrusions 62, 63, by welding, gluing or the like, in order to simplify the assembly of the device 2 during manufacturing. The sealing elements 52, 53 act as check valves, as their outer edges can only be raised in the inflow direction.
The insertion elements 54, 55 are of cylindrical shape. They are each inserted into a corresponding clearance provided on the housing 3 and fixed on the circumferential surfaces of the clearance by, for instance, a frictional connection, tongue and groove connection, welding or gluing. The wall elements 56, 57 are adapted to the cross sectional shape of the insertion elements 54, 55 and are fixed on the wall elements 56, 57. They, furthermore, are transparent or translucent for visible light. The insertion elements 54, 55 receive indicator elements 60, 61 which consist in the present embodiment of sintered polyethylene (PEL). Indicator elements 60, 61 abut on the wall elements 56, 57 and cover the openings 58, 59. As mentioned hereinbefore, sintered polyethylene is a porous plastic material such that air can pass through it. However, if the material is in contact with a fluid, it gets densified to an impervious state. Therefore, the openings 58, 59 are sealed by indicator element 60, 61, if a fluid enters the indicator chambers 24, 25 and gets in contact with indicator elements 60, 61. So, the air located within the second channels 21, 22 before employment of the device 2 is driven to indicator chambers 24, 25 by the fluids entering the second inlets 29, 30 and escapes via the openings 58, 59, provided that the valves 26, 27 are in their first positions. When the fluids reach the indicator elements 60, 61, the latter are densified and seal openings 58, 59.
Indicator elements 60, 61 furthermore feature the property of a change in colour in case of fluid contact, which property can be achieved by additives. This allows for an easy observation whether a fluid has reached not only the respective indicator chamber 24, 25, but the indicator element 60, 61 as well, i.e. that the air contained in the second channel 21, 22 upstream the indicator element 60, 61 was removed, and that the second channel 21, 22 and the recess 43, 44 of the valve 26, 27 are filled with the fluid fed to the respective second inlet 29, 30. If administration of the fluid fed to one of the second inlets 29, 30 is to be started, the respective valve 26, 27 is switched from its first position to its second position, in which the respective second channel 21, 22 communicates with the collecting chamber 23. Switching of both valves 26, 27 can occur at the same time or at different points in time, depending on the administration schedule set for a patient. Due to the fact, that the respective second channel 21, 22 and the respective recess 43, 44 are already filled with fluid, the delay between switching of the valve 26, 27 and administration of the fluid to a patient is shortened, which allows for a more precise dosage. In the second positions of the valves 26, 27, the fluids fed to the second inlets 29, 30 flow to the collecting chamber 23 via recesses 43, 44 and enter the collecting chamber 23 at locations with an angle difference with respect the protrusion 38 and thus, with respect to the end portion of the first channel 20, of ±90°. The fluids fed to the second inlet 29, 30 converge with the fluid fed to the first inlet 28 at these locations. The mixture of said fluids flows from there to the outlet channel 32 and to the outlet 31 of the device 2.
The check valves 33, 34, 35 comprise each a cylindrical body with a protruding edge on one side and an elastic cover being fixed on the other side and having a slit formed therein. The elastic cover is formed such that it is openable by a fluid flowing in the inflow direction and closable by fluid flowing in the outflow direction. The protruding edge rests against a corresponding contact surface of the housing 3 to which the protruding edge can be fixed, e.g., by means of welding or gluing.
The upper sub-chamber of the filter chamber 37 communicates with the downstream portion of the second channel 22 via an outlet 46, which is formed on the insertion member 76. Within the downstream portion of the second channel 22, a check valve 35 is arranged. Downstream the check valve 35, the second channel 22 leads to a recess 44 located on the radial surface of the cylindrical section 73 of the valve 27. The valve 27 is fixed on the housing by means of a tongue 74 and groove 75 connection, whereat the groove 75 is formed on the radial surface of the cylindrical section 73. By means of the grip portion 14, the valve 27 is manually turnable in an easy manner. The lower sub-chamber of the filter chamber 37 communicates with the second inlet 30.
Referring to
A second effect observable with prior art infusion systems is the so-called over shoot occurring with the flow rate 112 between 0.5 h and 1 h and between 3.25 h and 3.5 h. This problem is remedied with the device 2, as can be seen on the course of flow rate 110.
A third effect observable with prior art infusion systems are flow rate fluctuations occurring if one of two or more flow rates is set to another value by means of a pump. Such fluctuations occur with the flow rate 112 between 5.0 h and 5.25 h, where the pump setting is set from 0.5 ml/h to 1.0 ml/h, and between 6.0 h and 6.25 h, where the pump setting 115 is set from 1.0 ml/h to 0.5 ml/h. With the flow rate 113 such fluctuations occur between 3.0 h and 3.25 h, where the pump setting 114 is set from 6.0 ml/h to 10 ml/h, and between 4.0 and 4.25 h, where the pump setting 114 is set from 10 ml/h to 6 ml/h. These fluctuations are remarkably minimized with the device 2, as can be seen on the course of flow rates 110, 111.
The courses of flow rates 110, 111 are in general remarkably closer to the courses of the respective pump settings 114, 115, i.e. a more precise dosage is achieved.
While the invention has been described with reference to a specific embodiment, the description is merely explanatory and is not to be construed as limiting the scope of the invention. Various modifications may be conceived by those skilled in the art without departing from the scope of the invention as defined by the claims.
This application is the U.S. national stage of International Application No. PCT/EP2015/000365, filed on 2015 Feb. 19.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/000365 | 2/19/2015 | WO | 00 |
