DRIP CHAMBER ARRANGEMENT FOR A MEDICAL INFUSION SYSTEM

Description

[0001] The invention relates to a drip chamber arrangement having the features of the preamble of claim 1.

[0002] From DE 38 00 319 A1, a drip chamber arrangement with the features of claim 1 is known. The known drip chamber arrangement has a floating valve that is visible through a transparent drip chamber housing and allows, in principle, monitoring of the liquid level present in the drip chamber housing. The valve is extremely soft and therefore particularly compliant with its shape. If the liquid level rises, the valve floats up and enters an area above a pump section of the drip chamber housing.

[0003] Furthermore, WO 2012 / 057602 A1 discloses a drip chamber arrangement with a valve body designed as a buoyancy element, which is movable by way of buoyancy within a drip chamber housing. The drip chamber housing itself is not movable by pumping. Instead, a compressible body is provided, which is fluid-conducting and movable by pumping. The compressible body is located away from the drip chamber housing. Therefore, the valve body cannot be tactilely perceived by the compressible body, nor can its pumping movement be reduced.

[0004] Another drip chamber arrangement is well-known in the field of medical technology and is intended for use in infusion therapy as a component of an infusion system, which can also be called a transfer system. This well-known drip chamber arrangement has a housing that encloses a drip chamber for receiving a medical fluid to be administered. The housing is provided with an inlet and an outlet. The inlet is for introducing the medical fluid drop by drop into the drip chamber, and the outlet is for draining it from the drip chamber. During infusion therapy, a certain fluid level of the medical fluid is established in the drip chamber, which should be neither too high nor too low. A fluid level that is too low can cause air, entering the drip chamber through the inlet, to be flushed into a tubing line of the infusion system downstream of the drip chamber.An excessively high fluid level can lead to the formation of so-called germ pathways. Both of these factors are detrimental to patient safety. Therefore, to allow visual monitoring of the fluid level, the housing of the known drip chamber arrangement is made of transparent plastic. For improved visual monitoring, the known drip chamber arrangement features a level indicator in the form of a static fill line, which is applied to a wall of the transparent housing.

[0005] Furthermore, from US 6 213 986 B1 a drip chamber arrangement with a first fluid chamber and a second fluid chamber is known, wherein a float valve is arranged in the first fluid chamber.

[0006] Furthermore, US patent 4,096,879 A discloses a flow control device comprising an upper fluid chamber and a separate lower fluid chamber. The upper fluid chamber has a float valve that, depending on the fluid level, either closes or opens an inlet or outlet of the upper fluid chamber.

[0007] Furthermore, WO 2004 / 064904 A1 discloses an infusion set with a fluid chamber and a float, wherein the float is arranged in the fluid chamber.

[0008] Furthermore, a drip chamber arrangement with a float for flow control is known from US 2015 / 374909 A1.

[0009] The object of the invention is to provide a drip chamber arrangement of the type mentioned above which enables improved patient safety compared to the prior art.

[0010] This problem is solved by providing the level indicator as a functional element movably arranged within the drip chamber. This element is designed to float on the medical fluid and, depending on the fluid level, can be moved between different floating positions in the axial direction of the drip chamber. At least in one floating position corresponding to a desired fluid level, the level indicator is visible through the housing, which is at least partially transparent, for monitoring purposes. The solution according to the invention allows for significantly improved visual monitoring of the fluid level, particularly during the initial filling of the drip chamber with medical fluid to initiate the infusion. This is because the functional element changes its floating position within the drip chamber during such an initial filling process.This change is relatively easy and clearly perceptible to medical personnel. This offers significant advantages, particularly compared to prior art drip chamber arrangements with fill lines for monitoring the liquid level. The solution according to the invention eliminates the need for a visual comparison between the actual liquid level and the fill line. Such a check is comparatively time-consuming, subject to error-prone parallax, and particularly difficult to perform from a distance. The functional element is designed to be buoyant, with its density correspondingly matched to the density of the medical fluid being administered. To ensure the buoyancy of the functional element for as many different medical fluids as possible, it is advantageous if its density is lower than that of water.The functional element is preferably made of a plastic. It can be designed as a solid structural element. Alternatively, it can have a material structure that generates and / or supports buoyancy, for example, a foam, honeycomb, and / or porous structure. The functional element is freely movable in the axial direction of the drip chamber. To this end, the radial outer diameter of the functional element is matched to and smaller than the radial inner diameter of the drip chamber, thus ensuring its free movement in the axial direction. In a standard operating state, the axial direction of the drip chamber is oriented parallel to the direction in which medical fluid drips into the chamber. The housing can be made of one or more parts.Preferably, the housing is a housing consisting of at least two parts and accordingly comprises a drip chamber upper part and a drip chamber lower part. If such a design is provided, it is advantageous if the functional element is movably arranged in the drip chamber lower part.

[0011] In this embodiment of the invention, the functional element is visible in all floating positions. This means that the functional element is always visible, regardless of the liquid level, and particularly even when the drip chamber is empty. This allows for even better visual monitoring of the liquid level. Accordingly, the housing is designed to be transparent, so that the functional element is visible in all positions achievable within the drip chamber.

[0012] In a further embodiment of the invention, the functional element has a density of less than 1.05 g / cm³, preferably less than 0.50 g / cm³, and particularly preferably less than 0.10 g / cm³. If the density of the functional element is less than 1.05 g / cm³, buoyancy on isotonic saline solution is ensured, which may be sufficient for some applications of the drip chamber arrangement. To ensure the buoyancy of the functional element for all commonly relevant and / or suitable medical fluids for administration, it is particularly advantageous if the density of the functional element is less than 0.50 g / cm³. With a density of the functional element less than 0.10 g / cm³, it is particularly advantageous that the functional element floats very easily.This is particularly advantageous for visually monitoring the fluid level during the initial filling of the drip chamber with medical fluid. The density of the functional element is not necessarily identical to the material density of the material from which the functional element is manufactured. This is especially true if the functional element has at least one cavity, pore, honeycomb, and / or helical structure.

[0013] Furthermore, according to the invention, the housing has a pump section which is elastically conformable in the radial direction of the drip chamber and is arranged in the axial direction of the drip chamber between the inlet and the outlet, wherein the pump section can be moved between a radially compressed pump state and a non-manually compressed rest state for the initial aspiration of the medical fluid through the inlet by means of a manual radial pumping movement, and wherein the functional element is dimensionally stable compared to the pump section and is tactilely perceptible through the pump section in the compressed pump state of the pump section in the level-floating position and is not tactilely perceptible in a further floating position which is associated with a lower fluid level.This embodiment of the invention provides the person handling the drip chamber assembly with tactile feedback during the initial filling of the drip chamber or when starting the infusion, as soon as the float position and thus the desired fluid level in the drip chamber is reached. This further improves patient safety. The pump section serves to initiate an infusion to be administered. For this purpose, the pump section can be manually and elastically pressed in radially through the inlet of the drip chamber to draw in the medical fluid. This manual pumping action moves the pump section between the pressed-in pumping state and the unpressed resting state. This manual pumping action can be repeated until the desired fluid level is reached.Since the functional element is tactilely perceptible in the level-floating position corresponding to the desired fluid level, the operator receives immediate feedback. This prevents unintentional overfilling or underfilling of the drip chamber when initiating the infusion. This is a particularly advantageous embodiment of the invention. To ensure tactile perceptibility, the functional element is dimensionally stable, meaning it is at least less deformable than the pump section. The pump section is preferably softly elastic and deformable. The functional element is preferably dimensionally stable. If the drip chamber assembly has a multi-part housing design, the pump section is preferably assigned to a lower drip chamber section of the housing. The pump section defines a partial volume of the drip chamber.The functional element can always be located within the partial volume or only be displaced into the partial volume, and thus into the pump section, as a result of floating on the medical fluid. Conversely, if the fluid level is lower than the target level, the functional element is not tactilely perceptible. "Not tactilely perceptible" also includes a reduced degree of tactile perceptibility compared to the level-floating position. Accordingly, the functional element does not have to be completely tactilely imperceptible in at least one other floating position, which can, however, be advantageous.

[0014] Furthermore, according to the invention, the radial compliance of the pump section in the level-floating position is reduced, preferably at least substantially completely blocked, by means of the functional element. This embodiment of the invention reliably prevents the drip chamber from initially filling above the desired liquid level. As soon as the functional element reaches the level-floating position and thus the liquid level reaches the desired height, the functional element reduces the radial compliance of the pump section and thus impairs the pump's movement. Even greater patient safety can be achieved if the functional element at least substantially completely, preferably completely, blocks the pump's movement in the level-floating position.In order to achieve a corresponding reduction or even blockage of the pump's movement, the radial outer diameter of the functional element and the radial inner diameter of the pump section in the rest state are accordingly matched.

[0015] In a further embodiment of the invention, the radial outer diameter of the functional element is more than 75%, preferably more than 85%, and particularly preferably more than 95% of the inner diameter of the pump section in its resting state. A reduction in pump movement sufficient for most applications can already be achieved if the outer diameter is 25% of the inner diameter. A more significant reduction can be achieved if the outer diameter is more than 85% of the inner diameter. At least substantially complete blockage of the pump movement can be achieved if the outer diameter is more than 95% of the inner diameter.

[0016] In a further embodiment of the invention, the functional element is designed in the form of a disc, a sphere, a drop, or a polyhedron, preferably an octahedron. In principle, any shape of the functional element is advantageous that ensures, on the one hand, adequate visual perceptibility for monitoring the liquid level and, on the other hand, adequate tactile perceptibility for providing feedback on the liquid level when the pump section is actuated. A disc-, sphere-, drop-, or polyhedral shape has proven particularly advantageous. If the functional element is designed in the form of an octahedron, particularly advantageous tactile perceptibility is achieved while simultaneously providing adequate visual perceptibility.

[0017] Further advantages and features of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are illustrated with reference to the drawings. Fig. 1 shows, in a highly simplified and partially truncated schematic representation, a medical infusion system with an embodiment of a drip chamber arrangement according to the invention; Fig. 2 shows, in a truncated and partially cut-away enlarged detail view, the drip chamber arrangement according to Fig. 1 , Fig. 3 in one of the Fig. 2 corresponding representation of the drip chamber arrangement according to the Fig. 1 and 2 in a state filled with a medical fluid up to a desired fluid level and Figs. 4, 5, 6 each in a highly simplified schematic representation alternative embodiments of a drip chamber arrangement according to the Fig. 1 bis 3 movable functional element.

[0018] According to Fig. 1 is a medical infusion system 1, which can also be referred to as a transfer system 1, intended for use in gravity-driven infusion therapy.

[0019] The infusion system 1 comprises an infusion container 2, which is filled with a medical fluid F (not otherwise specified) to be administered to a patient as part of infusion therapy. The infusion container is designed in the form of an infusion bag 2 and has a generally known function and design, so that further details of the infusion bag 2 need not be discussed here.

[0020] The infusion system 1 also includes a drip chamber arrangement 3 according to the invention with a housing 4. The housing 4 encloses a drip chamber K and has an inlet 5 and an outlet 6. The inlet 5 is provided for introducing the medical fluid F into the drip chamber K. The outlet 6, on the other hand, is provided for draining the medical fluid F from the drip chamber K and is connected for this purpose, in a fluid-conducting manner, to a hose line 7 downstream of the drip chamber arrangement 3. The hose line 7 has a connector at its end (not shown in the drawing) opposite the drip chamber arrangement 3, which can be provided, in particular, for a fluid-conducting connection to a patient-side access or another fluid-conducting system.The drip chamber assembly 3 is fluid-conductingly connected at its inlet side to a piercing element 8, which has a generally known structure and function. In this case, the piercing element 8 is directly connected to the housing 4 of the drip chamber assembly 3 and can, in particular, be formed integrally with it. The piercing element 8 has a hollow piercing mandrel 9 through which a lumen, not shown in detail, extends, opening at one end into the inlet 5.

[0021] To transfer the medical fluid F from the infusion bag 2 into the aforementioned patient access or fluid-conducting system, the drip chamber assembly 3, together with the piercing element 8, is inserted into a piercing section 10 of the infusion bag 2, starting from a configuration not shown in the drawing and not connected to the infusion bag 2, with the piercing pin 9 leading the way in the axial direction A of the drip chamber K. This allows the infusion system 1 to receive the fluid F. Fig. 1 The configuration shown is as follows. Infusion bag 2 is attached in a generally known manner to an IV stand or similar device (not shown), hanging vertically downwards. That is to say, in the configuration shown... Fig. 1 In the configuration shown, the axial direction A extends parallel to the Earth's gravity vector g. In this configuration, the medical fluid F can pass through the lumen of the piercing spike 9 to the inlet 5 of the drip chamber K and from there fall drop by drop into the drip chamber K. A liquid level P of the medical fluid F is established in the drip chamber K in a generally known manner. That is, the drip chamber K is filled with medical fluid up to a certain height in the axial direction A. Above the liquid level P and below the inlet 5, an air cushion or air space (not specified in detail) is formed, through which the drops of the medical fluid F fall due to gravity.

[0022] For visual monitoring of the liquid level P, the housing 4 is at least partially transparent. In this design, the housing 4 is constructed in two parts, comprising a drip chamber upper part 11 and a drip chamber lower part 12, although this is not mandatory. The housing 4 can also be constructed in one part or in more than two parts. In this design, the drip chamber upper part 11 and the drip chamber lower part 12 are each made of plastic and, to create a fluid-tight connection, are overmolded with plastic at their opposing end faces, forming a radial flange 13. This is also not mandatory. In an embodiment not shown in the drawing, the drip chamber upper part 11 and the drip chamber lower part 12 can be inserted into one another without forming a radial flange or butt-jointed.

[0023] To improve visual control of the liquid level P, a functional element 14 is provided according to the invention, which is movably arranged in the drip chamber K (see Figure 1). Fig. 2, 3 The functional element 14 is designed to float on the medical fluid F. Accordingly, the density of the functional element 14 is matched to the density of the medical fluid F and is lower than it. Depending on the fluid level P, the functional element 14 can be moved between different floating positions in the axial direction A of the drip chamber. Fig. 2 The functional element 14 is shown in a state in the drip chamber K in which it is not filled with medical fluid F, whereby the position of the functional element 14 assumed there shall nevertheless also be referred to as a floating position. Based on Fig. 3 The functional element 14 is shown in a float position corresponding to a target liquid level P' in the drip chamber K. The target liquid level P' can also be referred to as the setpoint liquid level. From a medical perspective, the target liquid level P' is neither too high nor too low. When the drip chamber K is filled with the target liquid level P, a sufficient air cushion between the inlet 5 and the outlet 6 is ensured, which counteracts the formation of so-called germ lines. Furthermore, it is ensured that the medical fluid F does not flow directly from the inlet 5 into the outlet 6, which could lead to an undesirable introduction of air into the tubing 7. For visual monitoring of the liquid level, the functional element 14 is positioned at least in the position shown. Fig. 3 The visible float position of the functional element 14 is visible through the housing 4, which is at least partially transparent. To ensure this visibility of the functional element 14, the housing 4 is at least partially transparent in a housing section V corresponding to the desired liquid level P' (see Figure 1). Fig. 3 ) is designed to be transparent. In the present case, the housing 4 is not merely transparent in housing section V, but instead is essentially completely transparent. Accordingly, both the drip chamber lower part 12 and the drip chamber upper part 11 are made of transparent plastic.

[0024] To ensure the highest possible buoyancy and thus smooth floating of the functional element 14, the functional element 14 has a density of less than 0.10 g / cm³. However, this is not strictly necessary. A density of less than 1.05 g / cm³ may be sufficient for many medical applications and a variety of relevant medical fluids. Practically unrestricted buoyancy of the functional element 14 can be achieved with a density of 0.50 g / cm³.

[0025] For the initial filling of the drip chamber K with the medical fluid F, the housing 4 has a pump section, which in this case is formed by the drip chamber lower part 12. The drip chamber lower part 12 is elastically conformable in the radial direction R of the drip chamber K. For the initial aspiration of the medical fluid F through the inlet 5 into the drip chamber K, the drip chamber lower part 12 can be moved between a radially compressed pump state and a non-compressed rest state by means of a manual radial pumping motion. This is shown by Fig. 2 The radially compressed pump state of the drip chamber lower part 12 is illustrated by the dashed lines present there. The rest state of the drip chamber lower part 12 refers to the primarily visible sectional view of the Fig. 2 . In order to ensure this pumping function, the drip chamber base 12 is made of a soft elastic plastic.

[0026] To initially fill the drip chamber K with the medical fluid F, the drip chamber base 12, with the piercing part 8 inserted into the infusion bag 2, is grasped between the thumb and forefinger of one hand approximately midway between the outlet 6 and the radial collar 13 in the axial direction A and repeatedly pressed radially. This causes the medical fluid F to enter the drip chamber K under negative pressure as described above, thereby increasing the fluid level from the level indicated by the Fig. 2 apparent unfilled state in the direction of the desired liquid level P' (cf. Fig. 3 ) increases.

[0027] To prevent excessive manual pumping and thus overfilling of the drip chamber K beyond the desired liquid level P', the functional element 14 is dimensionally stable compared to the drip chamber base 12 and, in the level-floating position, i.e., when the desired liquid level P' is reached, is tactilely perceptible through the pump section 12 in the depressed pump state. This is evident from Fig. 2 This is illustrated. The dashed outline shown there identifies the functional element 14 in the level-floating position. Due to the dimensionally stable design of the functional element 14, the otherwise elastically compliant drip chamber lower part 12 can only be compressed radially to a reduced extent in the direction of the pump state. This provides personnel handling the infusion system 2 with immediate feedback if overfilling of the drip chamber K is imminent during the initial filling. In contrast, the functional element 14 is further characterized by Fig. 2 The apparent floating position, which is associated with a lower liquid level or an unfilled state of the drip chamber K, is not tactilely perceptible or at least to a lesser extent.

[0028] In this case, the radial outer diameter D1 of the functional element 14 is matched to the radial inner diameter D2 of the drip chamber base 12 in the pumped state such that the pumping movement of the drip chamber base 12 in the level-floating position is essentially completely blocked. The outer diameter D1 of the functional element 14 is only slightly smaller than an unspecified inner diameter of the drip chamber base 12 in the resting state.

[0029] The housing 4 has a hollow cylindrical shape with an annular axial cross-sectional area. The functional element 14 of the embodiment according to the Fig. 1 bis 3 It has a circular disk shape and is accordingly designed in the form of a disk. However, such a shape for the functional element 14 is not mandatory.

[0030] Alternative designs of the functional element are based on the Fig. 4 bis 6 clarifies. This shows Fig. 4 a functional element 14a in the form of a sphere. Another alternative embodiment according to Fig. 5 The functional element 14b is in the form of a polyhedron, which in this case is designed as an octahedron. Fig. 6 A functional element 14c in the form of a drop is visible. Based on the Fig. 4 bis 6 The visible shapes are purely exemplary, whereby in particular a dimensional coordination between the functional elements 14a to 14c and the ones in the Fig. 4 bis 6 The respective visible housing sections are not shown to scale in the drawing.

[0031] In an embodiment not shown in the drawing, the functional element may only be provided for visual control of the level P. In this respect, this embodiment does not provide for tactile perception of the functional element in the level-floating position for improved control of the liquid level P during the initial filling of the drip chamber K. In other words, the functional element is not tactilely perceptible in the level-floating position based on the Fig. 1 bis 3The illustrated combination of features is not mandatory; the functional element may, by contrast, be intended solely for visual inspection. In another embodiment not shown in the drawing, the functional element is provided solely for tactile perception in the float position. In this embodiment of the invention, a partially transparent design of the housing and / or a level indicator associated with the housing and provided for monitoring the liquid level of the medical fluid in the drip chamber are not strictly necessary.

Claims

1. Drip chamber assembly (3) for a medical infusion system (1), having a housing (4, 11, 12), which is at least partially transparent and delimits a drip chamber (K) for receiving a medical liquid (F), an inlet (5), which is arranged on the housing (4, 11) and is provided for the introduction of the medical liquid (F) into the drip chamber (K), and an outlet (6), which is arranged on the housing (4, 12) and is provided for the discharging of the medical liquid (F) from the drip chamber (K), and having a level indicator, which is assigned to the housing (4, 11, 12) and is provided to allow visual monitoring of a liquid level (P) of the medical liquid (F) in the drip chamber (K), wherein the level indicator is a functional element (14, 14a to 14c) which is arranged movably in the drip chamber and which is designed to float on the medical liquid (F) and, depending on the liquid level (P), is displaceable in the axial direction (A) of the drip chamber (K) between different floating positions and, at least in one floating position which is assigned to a desired liquid level (P'), can be seen through the at least partially transparent housing (4, 11, 12) in order to allow monitoring of the liquid level (P), wherein the housing (4, 11, 12) has a pump section (12) which is elastically resilient in the radial direction (R) of the drip chamber (K) and is arranged in the axial direction (A) of the drip chamber (K) between the inlet (5) and the outlet (6), wherein the pump section (12), for the initial suction of the medical liquid (F) through the inlet (5), can be transferred, by means of a manual radial pumping movement, between a pump state in which it is pressed inwards in the radial direction (R) and a resting state in which it is not manually pressed inwards, characterized in that the functional element (14, 14a to 14c) is dimensionally stable compared to the pump section and, in the floating position in the inwardly pressed state of the pump section (12), is perceptible to touch through the pump section (12), and, in at least one further floating position, which is assigned to a lower liquid level, is not perceptible to touch, and wherein the radial resiliency of the pump section (12) in the floating position is reduced by means of the functional element (14, 14a to 14c), preferably at least substantially completely blocked.

2. Drip chamber assembly (3) according to Claim 1, characterized in that the functional element (14, 14a to 14c) is visible in all floating positions.

3. Drip chamber assembly (3) according to Claim 1 or 2, characterized in that the functional element (14, 14a to 14c) has a density of less than 1.05 g / cm3, preferably less than 0.50 g / cm3, and particularly preferably less than 0.10 g / cm3.

4. Drip chamber assembly (3) according to any one of the preceding claims, characterized in that a radial outer diameter (D1) of the functional element (14, 14a to 14c) is more than 75%, preferably more than 85%, and particularly preferably more than 95%, of an inner diameter of the pump section (12) in the resting state.

5. Drip chamber assembly (3) according to any one of the preceding claims, characterized in that the functional element is in the form of a disc (14), a sphere (14a), a drop (14c) or a polyhedron (14b), preferably an octahedron.