Intermittent urinary catheter assembly including a sensor element

Abstract

An intermittent catheterization assembly (1) for self-catheterization includes an intermittent catheter (5), which includes an insertion tube. The insertion tube further includes a catheter (4) that extends longitudinally within the insertion tube and defines at least a portion of a flow path from the distal insertion end of the insertion tube to its proximal outlet end; a measurement system for determining at least one fluid parameter in the flow path. The measurement system includes at least one sensor element (35) and signal processing means, the at least one sensor element being configured to determine at least one fluid parameter in the catheter and / or in a space in communication with the catheter. In one aspect, the signal processing means is removably fixed relative to a connecting portion of the intermittent catheter. In another aspect, the measurement system is fixedly connected to or integrated with a non-insertable portion of the insertion tube.

Description

Technical Field

[0001] The present invention relates to the field of alleviating urinary retention and intermittent catheterization. Summary of the Invention

[0002] An embodiment provides an intermittent catheterization assembly for self-catheterization. The intermittent catheterization system includes an intermittent catheter, which includes an insertion tube. The insertion tube includes an insertable portion intended to be inserted into the urethra of a user, a non-insertable portion not intended to be inserted into the urethra of the user, and a connection portion integral with or mounted to the non-insertable portion. The intermittent catheter further includes a catheter that extends longitudinally within the insertion tube and defines at least a portion of a flow path from a distal insertion end of the insertion tube to its proximal outlet end. The assembly further includes a measurement system for determining at least one fluid parameter in the flow path. The measurement system includes at least one sensor element and signal processing means, the at least one sensor element being configured to determine the at least one fluid parameter in the catheter and / or in a space in communication with the catheter. In one aspect, the signal processing means includes a housing having engagement means for removably securing the signal processing means relative to the connection portion of the intermittent catheter, in which case the assembly includes an interface for connecting the signal processing means to the at least one sensor element. In another aspect, the measurement system is fixedly connected to or integrated with the non-insertable portion of the insertion tube without the need for an insertion tube connection portion. Also disclosed is an intermittent catheterization system and an intermittent catheterization method. Brief Description of the Drawings

[0003] The drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments and, together with the description, are used to explain the principles of the embodiments. Many other embodiments and many of the intended advantages of the embodiments will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals indicate corresponding like parts.

[0004] Figures 1 to 12 Schematic cross-sectional views showing different embodiments of an intermittent catheterization assembly having an intermittent catheter and a measurement system are shown.

[0005] Figure 13 Schematic cross-sectional views showing an implemented flow limiter are shown.

[0006] Figures 14 to 15 Schematic cross-sectional views showing an implemented measurement sub-structure and signal processing means are shown.

[0007] Figure 16Shows a schematic cross-sectional view of the implemented intermittent catheter.

[0008] Figure 17 Shows a graph of the measured voiding time of the implemented intermittent catheter assembly 1. Detailed implementation

[0009] Intermittent catheters are typically inserted by the user themselves and remain in the urethra and bladder only for the time it takes to empty the bladder, e.g., about 5 - 10 minutes. Intermittent catheters are typically used every 4 - 6 hours to empty the bladder, which roughly corresponds to the time intervals at which people without urinary problems would typically visit the restroom. Intermittent catheters are generally more rigid than indwelling catheters because they must be inserted by the user themselves and because they do not need to remain in the urethra for days or weeks. An important feature of intermittent catheters is ease of insertion into the urethra. This is achieved by providing a low-friction surface to the intermittent catheter. Non-limiting examples of such are hydrophilic-coated catheters, which are subsequently wetted with a swelling medium to form a low-friction surface, or wetted with an oil- or water-based gel applied to the catheter before insertion into the urethra.

[0010] Intermittent catheters can be provided with a hydrophilic coating that needs to be wetted before use and thereby absorbs a large amount of liquid. Such a hydrophilic coating will provide a very smooth surface that has very low friction when the catheter is inserted. Hydrophilic-coated catheters (where the coating absorbs a large amount of liquid to obtain a low-friction surface) (swelling degree > 100%) are not suitable for use as indwelling catheters because if left in the body for a longer period of time, the hydrophilic surface coating will stick within the urethral mucosa due to the hydrophilic coating transitioning from a highly lubricated state when fully wetted to a sticky state when the hydration level of the coating decreases.

[0011] The present invention relates to an intermittent catheter that can be provided with such a hydrophilic coating that is wetted before use to absorb a large amount of liquid and provide a very lubricated surface.

[0012] Typically, catheters used as voiding devices are in the range of 8FR to 18FR. FR (or French size or Charriere (Ch)) is the standard specification of the catheter and roughly corresponds to the outer circumference (in mm). More precisely, the outer diameter of the catheter (in mm) corresponds to the FR divided by 3. Thus, 8FR corresponds to a catheter with an outer diameter of 2.7 mm and 18FR corresponds to a catheter with an outer diameter of 6 mm.

[0013] Intermittent catheters are typically in the range from CH 8 to CH 16.

[0014] Intermittent catheters are mainly used to enable the user to perform self-catheterization.

[0015] Embodiments provide an intermittent catheter assembly and an intermittent catheter that can measure fluid parameters to improve the usability and convenience for the user. The intermittent catheter assembly and the intermittent catheter provide a sensor element configured to determine the fluid parameter.

[0016] In a first aspect, embodiments provide an intermittent catheterization assembly for self-catheterization, the intermittent catheterization assembly comprising:

[0017] - An intermittent catheter, the intermittent catheter comprising:

[0018] o An intubation tube, the intubation tube comprising an insertable portion intended to be inserted into the urethra of the user, a non-insertable portion not intended to be inserted into the urethra of the user, and a connection portion integral with or mounted on the non-insertable portion;

[0019] o A catheter, the catheter extending longitudinally within the intubation tube and defining at least a portion of a flow path from a distal insertion end of the intubation tube to its proximal outlet end;

[0020] - A measurement system for determining at least one fluid parameter in the flow path, the measurement system comprising

[0021] o At least one sensor element configured to determine the at least one fluid parameter in the catheter and / or in a space in communication with the catheter;

[0022] o Signal processing means, the signal processing means comprising

[0023] · A housing having engagement means for removably fixing the signal processing means relative to the connection portion of the intermittent catheter; and

[0024] · An interface for connecting the signal processing means to the at least one sensor element.

[0025] In a second aspect, embodiments provide an intermittent catheter for use in an intermittent catheterization assembly according to the first aspect, the intermittent catheter comprising:

[0026] - An intubation tube, the intubation tube comprising an insertable portion intended to be inserted into the urethra of the user and a non-insertable portion not intended to be inserted into the urethra of the user, wherein the non-insertable portion defines a connection portion integral with or mounted on the non-insertable portion;

[0027] - A catheter, the catheter extending longitudinally within the intubation tube and defining at least a portion of a flow path from a distal insertion end of the intermittent catheter to its proximal outlet end,

[0028] Wherein, the connecting portion is configured to cooperate with the engaging mechanism of the component.

[0029] Due to the provision of the at least one sensor element and the signal processing device, the user of the implemented intermittent catheter assembly can determine at least one fluid parameter in the catheter of the intermittent catheter and / or in the space communicating with the catheter. The at least one fluid parameter can be related to several aspects of intermittent catheterization and provide information about, for example, the fluid flow rate and / or urine volume discharged during intermittent catheterization; the degree of bladder filling before intermittent catheterization, the user's hydration level, and / or the presence and / or concentration of one or more analytes. Accordingly, an improved utility of the intermittent catheter assembly is provided to the user and may be able to make informed choices based on the information determined by the at least one sensor element and the signal processing device.

[0030] At least one of the at least one sensor element can be embedded in or integral with the catheter. Alternatively or additionally, at least one of the at least one sensor element can be included in the housing of the signal processing device. In each case, the interface allows the signal processing device to establish a data connection with the at least one sensor element inside the housing of the signal processing device or externally between the catheter and the signal processing device.

[0031] In an embodiment, the intermittent catheter is disposable.

[0032] The connection portion of the intermittent catheter combined with the engaging mechanism can detachably fix the signal processing device relative to the catheter. Accordingly, the intermittent catheter can be discarded after each intermittent catheterization, while the signal processing device can be used multiple times to more effectively utilize resources.

[0033] In an embodiment, when the connection portion and the engaging mechanism are properly fixed relative to each other, fluid communication can be achieved between the catheter and the at least one sensor element.

[0034] In an embodiment, the connection portion of the catheter and the engaging mechanism of the measuring device include corresponding mating connection elements. In one embodiment, the engaging mechanism includes elastic members configured to engage and at least partially surround a groove, for example, at the outer circumference of the connection portion of the catheter, which can provide improved tactile feedback for users with, for example, physical impairments. The engaging mechanism and the connection portion can also be implemented as, for example, a detachable snap-lock pair for ease of manufacturing; mutually attracting magnets for ease of attachment (by the attraction of magnets working at a distance); or a friction coupling, where the protruding connection portion of the catheter is forced into the receiving portion of the engaging mechanism (or vice versa).

[0035] In an embodiment, the at least one fluid parameter includes at least one of the following: pressure, fluid flow rate, particle size, particle count, particle distribution, particle concentration, particle characteristics, analyte concentration, refractive index, conductivity, temperature, absorption spectrum, refractive spectrum, viscosity, pH. Each parameter can be used to determine information related to the user. The sensed pressure and / or fluid flow rate can be used to determine, for example, urine fluid flow rate, pressure within the bladder, initial pressure within the bladder before urine excretion, a measure of the degree of bladder distension, the amount of urine excreted during intermittent catheterization, and / or whether urine excretion suddenly stops. Different particle characteristics allow derivation of information related to the user's condition. For example, certain particle size / count / distribution / concentration may indicate a disorder or disease. For example, a relatively high protein content in urine may be a sign of damaged glomeruli. Fluid parameters such as analyte concentration, absorption spectrum (color), and conductivity can be used to determine the user's hydration level, which in turn can help the user prevent or mitigate dehydration, thereby helping to prevent bladder and / or urinary tract infections. Particle characteristics and spectra can also be used to determine the presence and concentration of cells (such as white blood cells) in urine. Any white blood cells in urine above trace amounts may indicate a urinary tract or bladder infection. For users of intermittent catheters, detection of such conditions is particularly relevant as they are generally relatively exposed to such infections due to the repeated introduction of the intermittent catheter into the urethra.

[0036] In an embodiment, the signal processing device includes a wired or wireless connection device for connecting to and transmitting data to another electronic device, such as a portable electronic device (such as a smartphone or tablet) or a stationary computer or server for further data analysis and / or output.

[0037] In an embodiment, the measurement system includes a data output device. The data output device may include a visual output unit that may have color resolution. The visual output unit may be integrated in the housing of the signal processing device or in an external device that is in data connection with the signal processing device. In an embodiment, the data output device includes a haptic feedback device. The haptic feedback device may particularly include a vibrator. Haptic feedback can provide feedback to the user without visual contact with the intermittent catheterization assembly. Such feedback is particularly advantageous for intermittent catheterization as it is typically performed by the user themselves and visual inspection of the intermittent catheterization assembly may be difficult and / or inconvenient. In one embodiment, the measurement system is configured to provide haptic feedback to the user in response to detecting a fluid flow rate below a first threshold and / or its derivative in the catheter, and / or in response to detecting a fluid flow rate above a second threshold or its derivative in the catheter, to enhance user convenience.

[0038] In an embodiment, the intermittent catheter is configured to remain in the user's urethra for a period of no more than 15 minutes. This allows the intermittent catheter to include, for example, a coating that does not permit the long catheterization durations required for indwelling catheters.

[0039] In an embodiment, at least the outer surface of the insertable portion of the cannula includes a hydrophilic surface coating. Such a hydrophilic coating allows for particularly convenient intermittent catheterization.

[0040] The hydrophilic coating may be provided only on the insertable portion of the cannula. The hydrophilic surface coating is such that when hydrated or swollen using a swelling medium, it will reduce the friction on the surface area of the cannula (corresponding to the insertable portion of the cannula) intended to be inserted into the user's urinary tract.

[0041] The intermittent hydrophilic cannula also differs from an indwelling cannula in that the hydrophilic surface coating of such a cannula is not suitable for indwelling use because if left in the body for more than a period of 5 - 20 minutes, the surface coating is prone to sticking within the urethral mucosa due to the hydrophilic coating transitioning from highly lubricated when fully wetted (95% by weight water) to sticky when the hydration level of the coating decreases (<75% by weight water).

[0042] In an embodiment, the cannula is a single - lumen tube and the catheter constitutes the only passage between the distal insertion end and the proximal outlet end of the intermittent catheter. Such a single - lumen cannula is generally not suitable for indwelling use because there is no passage for introducing air into an indwelling catheter balloon or a Foley catheter balloon.

[0043] In an embodiment, at least one of the at least one sensor elements is included in the signal - processing device. This allows the at least one sensor element in the signal - processing device to be reused while the intermittent catheter is conveniently discarded. In one embodiment, the signal - processing device includes a wired or wireless connection device for connecting to and transmitting data to another electronic device, such as a portable electronic device (such as a smartphone or a tablet) or a stationary computer or server. In one embodiment, the signal - processing device includes a data output device as described above.

[0044] In an embodiment, the measurement system includes a measurement sub-structure embedded in or integral with the cannula, the measurement sub-structure being configured to allow measurement of the at least one fluid parameter in combination with the at least one sensor element. Accordingly, a measurement sub-structure may be required to measure the at least one fluid parameter without forming part of the at least one sensor element. In some embodiments, the at least one sensor element is contained within the housing of a signal processing device and is configured to interact with the measurement sub-structure. Accordingly, the measurement sub-structure may be exposed to the flow path and be capable of measuring the at least one fluid parameter, while the at least one sensor element is not exposed to the flow path and determines the at least one fluid parameter by interacting with the measurement sub-structure.

[0045] In an embodiment, the measurement sub-structure includes one or more conductive elements, and the at least one sensor element includes a voltmeter and / or an ammeter or is in electrical communication therewith to measure fluid parameters such as electric potential or current. Such measurement results can be used to derive information related to fluid flow rate and / or fluid charge (ionic charge and concentration).

[0046] In an embodiment, the measurement sub-structure includes a flow restrictor in the catheter and at least one pressure communication path, and the at least one sensor element includes a pressure sensor configured to measure the pressure in the at least one pressure communication path. Accordingly, the flow restrictor exposed to urine can be conveniently discarded, while the pressure sensor, which may be protected from contact with urine, can be reused.

[0047] In an embodiment, the measurement sub-structure includes a window defined by a high optical transparency relative to the surrounding cannula for interaction with at least one sensor element in the form of a light emitter and / or an optical sensor.

[0048] In an embodiment, the measurement sub-structure includes an optical reflection element, and the at least one sensor element includes a light emitter and an optical sensor for determining at least one fluid parameter in the form of a spectrum.

[0049] In an embodiment, the measurement sub-structure includes an assay device having at least one predefined molecular probe, the at least one molecular probe being predefined based on its binding properties and / or chemical reactivity with one or more substances or biomolecules that may be present in urine. In some embodiments, the assay device emits light having a characteristic spectrum in response to binding and / or chemical reaction with the at least one predefined molecular probe. In some embodiments, the binding and / or chemical reaction with the at least one predefined molecular probe causes a characteristic change in the recorded spectrum. As an example, one or more substances or biomolecules to be detected may be nitrite or white blood cells.

[0050] In an embodiment, the measurement sub-structure includes an elastic member configured to deflect with the fluid flow rate in the catheter, and the at least one sensor element includes a camera adapted to image the deflection of the elastic member.

[0051] In an embodiment, the measurement system includes:

[0052] - A first part including the at least one sensor element in the housing of the signal processing device, the at least one sensor element being configured to determine at least one fluid parameter in and / or in a space in communication with the catheter when the signal processing device is fixed relative to the intermittent catheter;

[0053] - A second part for contacting the intermittent catheter and / or its catheter;

[0054] - A barrier element between the first part and the second part for preventing liquid in the catheter from contacting the at least one sensor element.

[0055] In such an embodiment, the at least one sensor element in the housing of the signal processing device is not exposed to the liquid in the catheter, thereby allowing the at least one sensor element to be stored and reused without the need to specially clean the at least one sensor element.

[0056] In an embodiment, the barrier element is embedded in the cannula, allowing for convenient disposal after the barrier element may have come into contact with urine in the catheter.

[0057] In an embodiment, the barrier element includes a liquid-impermeable flexible barrier. The advantage of such a liquid-impermeable flexible barrier is that it allows pressure to be transmitted across the barrier element without allowing liquid to pass through the barrier. Accordingly, a pressure sensor can detect the pressure in the catheter without being in liquid communication with the catheter. The liquid-impermeable flexible barrier can be made of natural or artificial rubber, Gore-Tex(R), or a polymer (e.g., technical plastic (TP) or thermoplastic elastomer).

[0058] In an embodiment, the barrier element includes a gas conduit configured to establish a gaseous buffer between the flow path and the signal processing device so as to effectively transmit pressure between the flow path and the at least one sensor element of the signal processing device. In one embodiment, the gaseous buffer is the atmosphere.

[0059] In an embodiment, at least one of the at least one sensor element is embedded in or integrally formed with the catheter. In this case, the interface for connecting the signal processing device to the at least one sensor element is configured to connect the signal processing device to the catheter. The interface may include, for example, corresponding conductive elements on each of the signal processing device and the catheter, which are arranged to establish electrical contact when the housing of the signal processing device is detachably fixed to the intermittent catheter.

[0060] By embedding or integrally forming the at least one sensor element with the catheter, a higher accuracy determination of the at least one fluid parameter can be obtained when determining the catheter arrangement of the at least one sensor element relative to the catheter at the production level. In some embodiments, a first relatively simple sensor element is embedded in or integrally formed with the catheter, while a second relatively complex sensor element is arranged in the housing of the signal processing device, allowing the relatively simple sensor to be discarded together with the catheter, and the relatively complex sensor to be reused together with the signal processing device.

[0061] In an embodiment, the at least one fluid parameter includes pressure, wherein:

[0062] - The assembly includes a flow restrictor that is in or adapted to be in fluid communication with the flow path and forms a through-passage, and the flow restrictor is configured to restrict the flow therethrough; and wherein,

[0063] - The measurement system includes at least one pressure gauge in fluid communication with the flow path.

[0064] The combination of a flow restrictor and at least one pressure gauge in fluid communication with the flow path can allow the signal processing device or other devices connected to the signal processing device to determine the fluid flow rate in a relatively simple and more accurate manner compared to other ways of determining the fluid flow rate in the flow path. Additionally, the fluid flow rate in the flow path is particularly useful for intermittent catheterization. One reason is that a sudden change in the liquid flow rate can indicate, for example, that the tissue of the bladder has blocked the liquid from entering the catheter at the distal insertion end, and repositioning the intermittent catheter will help continue urination and empty the bladder. Such considerations generally do not apply to indwelling catheters or Foley catheters, which typically include a balloon at the distal insertion end for holding the indwelling catheter or Foley catheter in the patient's bladder, and the balloon prevents tissue from blocking the liquid entry.

[0065] The fluid flow rate can be determined based at least on the pressure measured by the at least one pressure sensor and the predetermined pressure / fluid flow rate correlation of the flow restrictor. Additionally or alternatively, the flow rate can be derived using the overall predetermined pressure / fluid flow rate correlation of the catheter. Further, if the flow path is cut off downstream of the pressure gauge, the at least one pressure sensor of the present embodiment is capable of measuring the static pressure in the catheter or in a space in communication with the catheter (e.g., the user's bladder). The flow path can be cut off by, for example, a valve in communication with the flow path, or by the user's finger at the outlet of the intermittent catheter assembly. The flow restrictor can be embedded in or integrally formed with the catheter, or it can be included in the signal processing device.

[0066] In an embodiment:

[0067] - The through-passage defines an inner surface having at least a third liquid friction coefficient;

[0068] - At least a portion of the outer periphery of the flow path upstream of the flow restrictor has a fourth liquid friction coefficient; and wherein,

[0069] - The third liquid friction coefficient is at least greater than the fourth liquid friction coefficient.

[0070] In this context, the terms 'upstream' and 'downstream' relate to the flow path in the direction from the distal insertion end of the intermittent catheter towards the proximal outlet end of the intermittent catheter. These terms similarly apply to flow path extensions in fluid communication with the flow path. Accordingly, "upstream" refers to the flow direction towards the distal insertion end of the intermittent catheter, while "downstream" refers to the flow direction away from the distal insertion end of the intermittent catheter.

[0071] Different surface roughnesses can provide different liquid friction coefficients. In this context, the term 'liquid friction coefficient' should be understood as the friction coefficient defined between a given surface and liquid water (or urine). In the present embodiment, the flow restrictor includes a region with increased liquid friction, thereby causing a pressure drop across the flow restrictor. The third and fourth liquid friction coefficients are preferably predefined to obtain a predefined pressure drop / fluid flow rate correlation.

[0072] In an embodiment, the third liquid friction coefficient is created by forming protrusions and / or ribs on the inner surface of the through-passage, for simply manufacturing a flow restriction portion. In an embodiment, the third liquid friction coefficient is created by a hydrophilic adhesive layer such that when liquid flows through the flow restriction portion, turbulence is generated. In one embodiment, the third liquid friction coefficient is created by a change in the cross-sectional area along the through-passage. The cross-sectional area of the through-passage can be greater than or less than the first maximum cross-sectional area of the catheter. If the cross-sectional area of the through-passage is greater than the first maximum cross-sectional area of the catheter, this will result in a more defined resistance along the through-passage, and / or due to a decrease in the Reynolds number, a more defined pressure drop across the flow restriction portion.

[0073] In an embodiment:

[0074] - The catheter defines a lumen having a first maximum cross-sectional area; and

[0075] - The through-passage has a second minimum cross-sectional area that is different from, such as less than, the first maximum cross-sectional area.

[0076] These different cross-sectional areas enable a predefined pressure / fluid flow correlation of the flow restrictor. In some embodiments, the size of the second minimum cross-sectional area of the through-passage of the flow restrictor is in the range of 5 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

[0077] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the flow restrictor is in the range of 17 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter to achieve a pressure / fluid flow correlation such that a relatively large pressure change is provided depending on the flow rate to facilitate measurement.

[0078] In an embodiment, the flow restrictor includes an orifice plate or an orifice tube. In this case, the flow restrictor creates a pressure drop across the orifice plate or orifice tube, which is relatively simple to implement. The pressure drop / fluid flow correlation is at least partially defined by the difference between the first and second cross-sectional areas, i.e., the greater the difference in cross-sectional areas, the greater the change in pressure drop in response to a change in flow rate.

[0079] In the present context, the term 'orifice tube' should be understood as an orifice plate that is elongated in a direction parallel to the general flow direction through the orifice. In this way, the orifice tube forms a flow restrictor that extends further than the orifice plate.

[0080] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the orifice plate or orifice tube is in the range of 30 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter. Although the difference between the first and second cross-sectional areas creates a pressure drop for determining the fluid flow rate, it is also found that it generally reduces the fluid flow rate in the flow path, resulting in an extended urination time. The current embodiment provides a favorable compromise between measurement accuracy and the amount of extended urination time.

[0081] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the orifice plate or orifice tube is in the range of 60 - 90% of the size of the first maximum cross-sectional area of the inner lumen of the intermittent catheter, so as to improve the optimization between the measurement accuracy and the extended urination time.

[0082] In an embodiment, the flow restrictor includes a Venturi tube. The Venturi tube generally generates a relatively low pressure drop across the flow restrictor, so that the increase in urination time is relatively small compared to an orifice plate or orifice tube, etc., while the pressure drop related to the fluid flow can be measured at the second minimum cross-sectional area of the Venturi tube. The Venturi tube is also called a Venturi meter.

[0083] In an embodiment, as further described above, the flow restrictor in the form of, for example, an orifice plate, an orifice tube or a Venturi tube is a measurement sub-structure embedded in or integral with the catheter.

[0084] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the Venturi tube is in the range of 17 - 80% of the size of the first maximum cross-sectional area of the inner lumen of the intermittent catheter. For the Venturi flow restrictor, the current interval of the difference between the first cross-sectional area and the second cross-sectional area has been proven to be an improved compromise between the measurement accuracy and the increase in urination time.

[0085] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the Venturi tube is in the range of 17 - 60% of the size of the first maximum cross-sectional area of the inner lumen of the intermittent catheter. For the Venturi flow restrictor, the implemented interval has been proven to be a further improved compromise between the measurement accuracy and the increase in urination time.

[0086] In an embodiment, the Venturi tube has a second liquid friction coefficient at least at the circumference of the second minimum cross-sectional area of the through-passage of the Venturi tube, at least a part of the inner lumen of the intermittent catheter has a first liquid friction coefficient, and the second liquid friction coefficient is less than the first liquid friction coefficient. The difference in liquid friction coefficients may be caused by the difference in surface roughness. The relatively small second liquid friction coefficient in the through-passage of the Venturi tube reduces the resistance and pressure drop of the Venturi tube without sacrificing the measurement accuracy. Accordingly, for the same measurement accuracy, a smaller increase in urination time can be achieved.

[0087] In an embodiment, the at least one pressure gauge includes:

[0088] - A first pressure gauge, which is arranged in the flow path of the catheter or is adapted to be in fluid communication with the flow path upstream of the flow restrictor; and

[0089] - A third pressure gauge arranged in the through-passage,

[0090] Wherein, the signal processing device is configured to determine the fluid flow rate based on the difference between the first pressure determined by the first pressure gauge and the third pressure determined by the third pressure gauge. The current embodiment is particularly advantageous when combined with a flow restrictor that increases the fluid flow rate in a through-passage (e.g., a Venturi tube), and allows the determination of the fluid flow rate for a relatively wide range of fluid flow rates.

[0091] In an embodiment, the at least one pressure gauge includes:

[0092] - A first pressure gauge arranged in the flow path of the conduit or adapted to be in fluid communication with the flow path upstream of the flow restrictor; and

[0093] - A second pressure gauge arranged in the flow path downstream of the flow restrictor or adapted to be in fluid communication with the flow path downstream of the flow restrictor,

[0094] Wherein, the signal processing device is configured to determine the fluid flow rate based on the difference between the first pressure determined by the first pressure gauge and the second pressure determined by the second pressure gauge. The current embodiment is particularly advantageous when combined with a flow restrictor that mainly generates a pressure drop across the flow restrictor (such as an orifice plate or an orifice tube), and allows the determination of the fluid flow rate for a relatively wide range of fluid flow rates.

[0095] In an embodiment, at least one fluid parameter includes the fluid flow rate, and the signal processing device is configured to determine the static pressure in the conduit or in a space in fluid communication with the conduit based on the flow rate, thereby allowing the simultaneous determination of the fluid flow rate and the static pressure. Accordingly, the initial static pressure in, for example, the user's bladder can be determined based on the initial flow rate, and there is no need to cut off the flow path.

[0096] In an embodiment, the measurement system is configured to continuously determine the pressure loss in the fluid flow along a predetermined length of the conduit and determine the fluid flow rate based on the pressure loss, thereby facilitating the determination of the fluid flow rate.

[0097] In an embodiment, the measurement system is configured to continuously determine the fluid flow rate of the fluid passing through the conduit and integrate the flow rate over time to obtain a measurement of the total volume of urine discharged from the bladder. For users of intermittent catheters, knowing the total volume of urine discharged is particularly useful, and this provides an indication of whether further urination is required. The total volume of urine discharged can also be an indication of the user's health.

[0098] In an embodiment, the at least one fluid parameter includes pressure, and wherein at least the catheter of the intermittent catheter has a predefined characteristic pressure drop, the measuring device includes at least one pressure gauge in fluid communication with the flow path, and wherein the signal processing device is configured to determine the fluid flow rate based at least on the predefined characteristic pressure drop and the pressure determined by the at least one pressure gauge. The predefined characteristic pressure drop is used to determine the characteristic pressure drop / fluid flow rate correlation and allows the determination of the fluid flow rate. The predefined characteristic pressure drop can be pre-determined based on reference measurements on the implemented intermittent catheter, or the implemented intermittent catheter can be a standardized intermittent catheter, where the predefined characteristic pressure drop is based on reference measurements on another standardized intermittent catheter.

[0099] In an embodiment, the measuring device includes a valve configured to allow obtaining a variable fluid flow cross-sectional area in fluid communication with the flow path. This allows the user to change the fluid flow rate in the flow path by adjusting the valve. In one embodiment, the valve can vary between a set of different predefined cross-sectional areas. In this embodiment, the valve can be used as a combination of a flow restrictor and a pressure gauge. In this case, the fluid flow rate can be determined based at least on the predefined cross-sectional area of the valve and the pressure measured by the pressure gauge. Accordingly, if higher measurement accuracy is desired, the user can reduce the predefined cross-sectional area, and if a greater fluid flow rate is desired, the user can increase the predefined cross-sectional area.

[0100] In an embodiment, the valve is configured to automatically change the fluid flow cross-sectional area based on the determined fluid flow rate or the pressure in the flow path. In this case, the valve can be used as a flow restrictor, and the valve can automatically increase the cross-sectional area to increase the fluid flow rate in response to a measured fluid flow rate or pressure below a first threshold and automatically reduce the cross-sectional area to improve the measurement accuracy in response to a measured fluid flow rate or pressure above a second threshold. This allows the automatic optimization of the relationship between measurement accuracy and urination time.

[0101] In a third aspect, an embodiment provides an intubation system, the intubation system includes a disposable intermittent catheter according to any one of the embodiments of the second aspect and a bag for accommodating the intermittent catheter therein under sterile conditions to reduce the need for sterilization after removing the intermittent catheter from the bag.

[0102] In an embodiment, at least the insertable portion of the cannula includes a hydrophilic surface coating, wherein the pouch contains a certain amount of liquid swelling medium. Accordingly, the liquid swelling medium is capable of activating the hydrophilic surface coating to obtain a very lubricious surface that has very low friction when the catheter has been inserted into the pouch. In an embodiment, the pouch includes a gas-impermeable barrier to extend the service life of the catheterization system, and the barrier encloses a lumen for receiving an intermittent catheter. In one embodiment, the liquid swelling medium is a water-based substance, such as sterile water, saline solution, or any water-based liquid.

[0103] In a fourth aspect, an embodiment provides an intermittent catheterization assembly that includes:

[0104] - An intermittent catheter that includes:

[0105] o A cannula that includes an insertable portion intended to be inserted into the urethra of a user and a non-insertable portion not intended to be inserted into the urethra of the user;

[0106] o A catheter that extends longitudinally within the cannula and defines at least a portion of a flow path from a distal insertion end of the intermittent catheter to its proximal outlet end;

[0107] - A measurement system fixedly connected to or integral with the non-insertable portion of the cannula to determine at least one fluid parameter in the flow path, the measurement system including:

[0108] o At least one sensor element configured to determine the at least one fluid parameter in the catheter and / or in a space in communication with the catheter;

[0109] o Signal processing means that includes a data communication interface.

[0110] Attributable to providing the at least one sensor element and the signal processing device, a user of the implemented intermittent catheter assembly is enabled to determine at least one fluid parameter in the catheter of the intermittent catheter and / or in a space in communication with the catheter. The at least one fluid parameter may be related to several aspects of intermittent catheterization and provide information about, for example, the flow rate and / or urine volume discharged during intermittent catheterization; the degree of bladder filling before intermittent catheterization, the user's hydration level, and / or the presence and / or concentration of one or more analytes. Accordingly, an improved utility of the intermittent catheter assembly is provided to the user and may be able to make informed choices based on the information determined by the at least one sensor element and the signal processing device. Additionally, attributable to providing a measurement system fixedly connected to or integral with the non-insertable portion of the cannula, the user is able to determine the at least one fluid parameter without establishing a connection between the cannula and the measurement system.

[0111] At least one of the at least one sensor element may be embedded in or integral with the cannula. Alternatively or additionally, at least one of the at least one sensor element may be included in the housing of the signal processing device.

[0112] In an embodiment, the at least one fluid parameter includes at least one of the following: pressure, fluid flow rate, particle size, particle count, particle distribution, particle concentration, particle characteristics, analyte concentration, refractive index, conductivity, temperature, absorption spectrum, refractive spectrum, viscosity, pH. Each parameter can be used to determine information related to the user. The sensed pressure and / or fluid flow rate can be used to determine, for example, the urine fluid flow rate, the pressure within the bladder, the initial pressure within the bladder before urine discharge, a measure of the degree of bladder distension, the volume of urine discharged during intermittent catheterization, and / or whether urine discharge suddenly stops. Different particle characteristics allow for the derivation of information related to the user's condition. For example, certain particle sizes / counts / distributions / concentrations / characteristics may indicate a disorder or disease. For example, a relatively high protein content in urine may be a sign of glomerular damage. Fluid parameters such as analyte concentration, absorption spectrum (color), and conductivity can be used to determine the user's hydration level, which in turn can help the user prevent or alleviate dehydration, thereby helping to prevent bladder and / or urinary tract infections. Particle characteristics and spectra can also be used to determine the presence and concentration of cells (such as white blood cells) in urine. Any white blood cells in urine above trace amounts may indicate a urinary tract or bladder infection. For users of intermittent catheters, detecting such conditions is particularly relevant as they are generally relatively exposed to such infections due to the repeated introduction of the intermittent catheter into the urethra.

[0113] In an embodiment, the signal processing device includes a wired or wireless connection device for connecting to and transmitting data to another electronic device, such as a portable electronic device (such as a smartphone or a tablet) or a stationary computer or server for further data analysis and / or output.

[0114] In an embodiment, the measurement system includes a data output device. The data output device may include a visual output unit that may have color resolution. In an embodiment, the data output device includes a haptic feedback device. The haptic feedback device may particularly include a vibrator. The haptic feedback can provide feedback to the user without visual contact with the intermittent catheterization assembly. Such feedback is particularly advantageous for intermittent catheterization since it is typically performed by the user himself / herself, and a visual inspection of the intermittent catheterization assembly may be difficult and / or inconvenient. In one embodiment, the measurement system is configured to provide haptic feedback to the user in response to detecting a fluid flow rate below a first threshold and / or its derivative in the catheter, and / or in response to detecting a fluid flow rate above a second threshold or its derivative in the catheter, to improve user convenience.

[0115] In an embodiment, the intermittent catheter assembly further includes a pouch assembly for accommodating the intermittent catheter and the signal processing device, wherein, when the pouch assembly is in a closed state, within the pouch assembly, the signal processing device is operatively connected to or operatively integrated with the intermittent catheter. In this case, the intermittent catheter assembly can determine the at least one fluid parameter without establishing an operative connection between the intermittent catheter and the signal processing device after opening the pouch. In one embodiment, the intermittent catheter is stored in the pouch assembly in a ready-to-use state to allow insertion of the intermittent catheter and direct determination of the at least one fluid parameter when the assembly is removed from the pouch, thereby requiring less manipulation before insertion.

[0116] In an embodiment, the intermittent catheter is configured to remain in the user's urethra for a period of no more than 15 minutes. This allows the intermittent catheter to include, for example, a coating that does not allow the long catheterization duration required for an indwelling catheter.

[0117] In an embodiment, at least the outer surface of the insertable portion of the catheter includes a hydrophilic surface coating. Such a hydrophilic coating allows for particularly convenient intermittent catheterization. In an embodiment, the pouch assembly includes a quantity of swelling medium to activate the hydrophilic surface, thereby providing an intermittent catheter assembly in a ready-to-use state when the pouch assembly is in a closed state.

[0118] The hydrophilic coating may be provided only on the insertable portion of the cannula. A hydrophilic surface coating is one that, when hydrated or swollen using a swelling medium, reduces the friction on the surface area of the cannula (corresponding to the insertable portion of the cannula) intended to be inserted into the urinary tract of a user.

[0119] An intermittent hydrophilic cannula differs from an indwelling cannula in that the hydrophilic surface coating of such a cannula is not suitable for indwelling use because if left in the body for a period exceeding 5 - 20 minutes, the surface coating is prone to sticking within the urethral mucosa due to the hydrophilic coating transitioning from highly lubricated when fully wetted (95% by weight water) to sticky when the hydration level of the coating decreases (<75% by weight water).

[0120] In some embodiments of the fourth aspect, at least the outer surface of the insertable portion of the cannula includes a hydrophilic surface coating, and the catheter assembly includes a pouch assembly that includes an outer pouch for accommodating an intermittent catheter, a signal processing device, a quantity of liquid swelling medium, and a gas - and / or liquid - impermeable inner barrier, wherein the inner barrier is arranged to prevent the liquid swelling medium from reaching the signal processing device when the outer pouch is in a closed state. Accordingly, when the pouch assembly is in a closed state, it is possible to provide the hydrophilic coating of the intermittent catheter assembly in a ready - to - use state without exposing the signal processing device to the liquid swelling medium.

[0121] In an embodiment, the cannula is a single - lumen tube, and the catheter constitutes the only passage between the distal insertion end and the proximal outlet end of the intermittent catheter. Such a single - lumen cannula is generally not suitable for indwelling use because there is no passage for introducing air into an indwelling catheter balloon or a Foley catheter balloon.

[0122] In an embodiment, the measurement system includes a measurement sub - structure embedded in or integral with the cannula, the measurement sub - structure being configured to allow the measurement of the at least one fluid parameter in combination with the at least one sensor element. Accordingly, a measurement sub - structure may be required to measure the at least one fluid parameter without forming part of the at least one sensor element. In some embodiments, the at least one sensor element is contained within the signal processing device and is configured to interact with the measurement sub - structure. Accordingly, the measurement sub - structure can be exposed to the flow path and be capable of measuring the at least one fluid parameter, while the at least one sensor element is not exposed to the flow path and determines the at least one fluid parameter by interacting with the measurement sub - structure.

[0123] In an embodiment, the measurement sub-structure includes one or more conductive elements, and the at least one sensor element includes a voltmeter and / or an ammeter or is in electrical communication therewith to measure fluid parameters such as electric potential or current. Such measurement results can be used to derive information related to fluid flow rate, fluid charge (ionic charge and concentration).

[0124] In an embodiment, the measurement sub-structure includes a flow restrictor in a catheter and at least one pressure communication path, and the at least one sensor element includes a pressure sensor configured to measure the pressure in the at least one pressure communication path.

[0125] In an embodiment, the measurement sub-structure includes a window defined by a high optical transparency relative to the surrounding cannula for interaction with at least one sensor element in the form of a light emitter and / or an optical sensor.

[0126] In an embodiment, the measurement sub-structure includes an optical reflection element, and the at least one sensor element includes a light emitter and an optical sensor for determining at least one fluid parameter in the form of a spectrum.

[0127] In an embodiment, the measurement sub-structure includes an assay device having at least one predefined molecular probe predefined based on its binding properties and / or chemical reactivity with one or more substances or biomolecules that may be present in urine. In some embodiments, the assay device emits light having a characteristic spectrum in response to binding and / or chemical reaction with the at least one predefined molecular probe. In some embodiments, the binding and / or chemical reaction with the at least one predefined molecular probe causes a characteristic change in the recorded spectrum. By way of example, one or more substances or biomolecules to be detected may be nitrite or white blood cells.

[0128] In an embodiment, the measurement sub-structure includes an elastic member configured to deflect with the fluid flow rate in the catheter, and the at least one sensor element includes a camera adapted to image the deflection of the elastic member.

[0129] In an embodiment, at least one of the at least one sensor elements is embedded in or integrally formed with the cannula. By embedding at least one of the at least one sensor elements in or integrally forming it with the cannula, a higher accuracy determination of the at least one fluid parameter can be obtained when determining the catheter arrangement of the at least one sensor element relative to the cannula at the production level.

[0130] In an embodiment, the at least one fluid parameter includes pressure, and:

[0131] - The component includes a flow restrictor that is in or adapted to be in fluid communication with the flow path and forms a through-passage, the flow restrictor being configured to restrict the flow therethrough; and

[0132] - The measurement system includes at least one pressure gauge in fluid communication with the flow path.

[0133] The combination of a flow restrictor and at least one pressure gauge in fluid communication with the flow path can allow a signal processing device or other device connected to the signal processing device to determine the fluid flow rate in a relatively simple manner and with increased accuracy compared to other ways of determining the fluid flow rate in the flow path. Additionally, the fluid flow rate in the flow path is particularly useful for intermittent catheterization. One reason is that a sudden change in the liquid flow rate can indicate, for example, that tissue in the bladder has blocked the entry of liquid at the distal insertion end, and repositioning the intermittent catheter will help continue urination and empty the bladder. Such considerations generally do not apply to indwelling catheters or Foley catheters, which typically include a balloon at the distal insertion end for holding the indwelling catheter or Foley catheter in the patient's bladder, and the balloon prevents tissue from blocking the entry of liquid.

[0134] The fluid flow rate can be determined based at least on the pressure measured by the at least one pressure sensor and the predetermined pressure / fluid flow rate correlation of the flow restrictor. Additionally or alternatively, the flow rate can be derived using the overall predetermined pressure / fluid flow rate correlation of the catheter. Further, if the flow path is cut off downstream of the pressure gauge, the at least one pressure sensor of the present embodiment is capable of measuring the static pressure in the catheter or in a space (e.g., the user's bladder) in fluid communication with the catheter. The flow path can be cut off, for example, by a valve in fluid communication with the flow path or by the user's finger at the outlet of the intermittent catheter assembly. The flow restrictor can be embedded in or integrally formed with the catheter, or it can be included in the signal processing device.

[0135] In an embodiment:

[0136] - The through-passage defines an inner surface having at least a third liquid friction coefficient;

[0137] - At least a portion of the outer periphery of the flow path upstream of the flow restrictor has a fourth liquid friction coefficient; and wherein,

[0138] - The third liquid friction coefficient is at least greater than the fourth liquid friction coefficient.

[0139] Different surface roughnesses can provide different coefficients of liquid friction. In this context, the term 'coefficient of liquid friction' should be understood as the coefficient of friction defined between a given surface and liquid water (or urine). In the present embodiment, the flow restrictor includes regions with increased liquid friction, thereby causing a pressure drop in the flow path. The third and fourth coefficients of liquid friction are preferably predefined so as to obtain a predefined pressure drop / fluid flow correlation.

[0140] In an embodiment, the third coefficient of liquid friction is created by forming protrusions and / or ribs on the inner surface of the through-passage for simply manufacturing the flow restriction. In an embodiment, the third coefficient of liquid friction is produced by a hydrophilic adhesive layer such that turbulence is generated when the liquid flows through the flow restriction. In one embodiment, the third coefficient of liquid friction is created by a change in the cross-sectional area along the through-passage. The cross-sectional area of the through-passage can be greater than or less than the first maximum cross-sectional area of the catheter. If the cross-sectional area of the through-passage is greater than the first maximum cross-sectional area of the catheter, this will result in a more defined resistance along the through-passage and / or a more defined pressure drop across the flow restriction due to a decrease in the Reynolds number.

[0141] In an embodiment:

[0142] - the catheter defines a lumen having a first maximum cross-sectional area; and wherein,

[0143] - the through-passage has a second minimum cross-sectional area.

[0144] These different cross-sectional areas enable a predefined pressure / fluid flow correlation of the flow restrictor. In some embodiments, the size of the second minimum cross-sectional area of the through-passage of the flow restrictor is in the range of 5 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

[0145] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the flow restrictor is in the range of 17 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter to achieve a pressure / fluid flow correlation such that a relatively large pressure change is provided depending on the flow rate to facilitate measurement.

[0146] In an embodiment, the flow restrictor includes an orifice plate or an orifice tube. In this case, the flow restrictor produces a pressure drop across the orifice plate or orifice tube, which is relatively simple to implement. The pressure drop / fluid flow correlation is at least partially defined by the difference between the first and second cross-sectional areas, i.e., the greater the difference in cross-sectional areas, the greater the change in pressure drop in response to a change in flow rate.

[0147] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the orifice plate or orifice tube is in the range of 30 - 95% of the size of the first maximum cross-sectional area of the inner lumen of the intermittent catheter. Although the difference between the first cross-sectional area and the second cross-sectional area creates a pressure drop for determining the fluid flow rate, it has also been found that it generally reduces the fluid flow rate in the flow path, resulting in an extended urination time. The current embodiment provides a favorable compromise between measurement accuracy and the amount of extended urination time.

[0148] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the orifice plate or orifice tube is in the range of 60 - 90% of the size of the first maximum cross-sectional area of the inner lumen of the intermittent catheter to improve the optimization between measurement accuracy and the amount of extended urination time.

[0149] In an embodiment, the flow limiter includes a Venturi tube. A Venturi tube generally produces a relatively low pressure drop across the flow limiter, such that the increase in urination time is relatively small compared to an orifice plate or orifice tube, etc., while the pressure drop related to the fluid flow rate can be measured at the second minimum cross-sectional area of the Venturi tube. A Venturi tube is also referred to as a Venturi.

[0150] In an embodiment, as further described above, the flow limiter in the form of, for example, an orifice plate, an orifice tube, or a Venturi tube is a measurement sub-structure embedded in or integral with the catheter.

[0151] In an embodiment, the size of the second minimum cross-sectional area of the through-passage of the Venturi tube is in the range of 17 - 80% of the size of the first maximum cross-sectional area of the inner lumen of the intermittent catheter. For a Venturi flow limiter, the current range of the difference between the first cross-sectional area and the second cross-sectional area has proven to be an improved compromise between measurement accuracy and the increase in urination time.

[0152] In an embodiment, for a Venturi flow limiter, the size of the second minimum cross-sectional area of the through-passage of the Venturi tube is in the range of 30 - 60% of the size of the first maximum cross-sectional area of the inner lumen of the intermittent catheter to obtain an even better compromise between measurement accuracy and the increase in urination time.

[0153] In an embodiment, the Venturi tube has a second liquid friction coefficient at least at the circumference of the second minimum cross-sectional area of the through-passage of the Venturi tube, wherein at least a part of the inner lumen of the intermittent catheter has a first liquid friction coefficient, and wherein the second liquid friction coefficient is less than the first liquid friction coefficient. The difference in liquid friction coefficients may be caused by differences in surface roughness. The relatively small second liquid friction coefficient in the through-passage of the Venturi tube reduces the resistance and pressure drop of the Venturi tube without sacrificing measurement accuracy. Accordingly, for the same measurement accuracy, a smaller increase in urination time can be achieved.

[0154] In an embodiment, the at least one pressure gauge includes:

[0155] - a first pressure gauge, which is arranged in the flow path of the conduit or is adapted to be in fluid communication with the flow path upstream of the flow restrictor; and

[0156] - a third pressure gauge arranged in the through-passage,

[0157] and wherein the signal processing device is configured to determine the fluid flow rate based on the difference between the first pressure determined by the first pressure gauge and the third pressure determined by the third pressure gauge. The current embodiment is particularly advantageous when combined with a flow restrictor that increases the fluid flow rate in a through-passage (such as a Venturi tube), and allows the determination of the fluid flow rate for a relatively wide range of fluid flow rates.

[0158] In an embodiment, the at least one pressure gauge includes:

[0159] - a first pressure gauge, which is arranged in the flow path of the conduit or is adapted to be in fluid communication with the flow path upstream of the flow restrictor; and

[0160] - a second pressure gauge, which is arranged in the flow path downstream of the flow restrictor or is adapted to be in fluid communication with the flow path downstream of the flow restrictor,

[0161] and wherein the signal processing device is configured to determine the fluid flow rate based on the difference between the first pressure determined by the first pressure gauge and the second pressure determined by the second pressure gauge. The current embodiment is particularly advantageous when combined with a flow restrictor that mainly generates a pressure drop across the flow restrictor (such as an orifice plate or an orifice tube), and allows the determination of the fluid flow rate for a relatively wide range of fluid flow rates.

[0162] In an embodiment, the measurement system is configured to continuously determine the pressure loss in the fluid flow along a predetermined length of the conduit and determine the fluid flow rate based on the pressure loss to allow the determination of the fluid flow rate without the need for a dedicated flow restrictor.

[0163] In an embodiment, the measurement system is configured to continuously determine the fluid flow rate of the fluid passing through the conduit and integrate the flow rate over time to obtain a measurement of the total volume of urine discharged from the bladder. For users of intermittent catheters, knowing the total volume of urine discharged is particularly useful, and this provides an indication of whether further urination is required. The total volume of urine discharged can also be an indication of the user's health.

[0164] In an embodiment, the at least one fluid parameter includes pressure, wherein at least the catheter of the intermittent catheter has a predefined characteristic pressure drop, the measuring device includes at least one pressure gauge in fluid communication with the flow path, and wherein the signal processing device is configured to determine the fluid flow rate based at least on the predefined characteristic pressure drop and the pressure determined by the at least one pressure gauge. The predefined characteristic pressure drop is used to determine the characteristic pressure drop / fluid flow rate correlation and allows the determination of the fluid flow rate. The predefined characteristic pressure drop can be predetermined based on reference measurements on the implemented intermittent catheter, or the implemented intermittent catheter can be a standardized intermittent catheter, wherein the predefined characteristic pressure drop is based on reference measurements on another standardized intermittent catheter.

[0165] In an embodiment, the measuring device includes a valve configured to allow obtaining a variable fluid flow cross-sectional area in fluid communication with the flow path. This allows the user to change the fluid flow rate in the flow path by adjusting the valve. In one embodiment, the valve can vary between a set of different predefined cross-sectional areas. In this embodiment, the valve can be used as a combination of a flow restrictor and a pressure gauge. In this case, the fluid flow rate can be determined based at least on the predefined cross-sectional area of the valve and the pressure measured by the pressure gauge. Accordingly, if a higher measurement accuracy is desired, the user can reduce the predefined cross-sectional area, and if a larger fluid flow rate is desired, the user can increase the predefined cross-sectional area.

[0166] In an embodiment, the valve is configured to automatically change the fluid flow cross-sectional area based on the determined fluid flow rate or the pressure in the flow path. In this case, the valve can be used as a flow restrictor, and the valve can automatically increase the cross-sectional area to increase the fluid flow rate in response to a measured fluid flow rate or pressure below a first threshold and automatically reduce the cross-sectional area to improve the measurement accuracy in response to a measured fluid flow rate or pressure above a second threshold. This allows for the automatic optimization of the relationship between measurement accuracy and urination time.

[0167] Figure 1 A schematic cross-sectional view of an implemented intermittent catheter assembly 1 is shown, which has an intermittent catheter 3 and a measurement system 4. The intermittent catheter 3 includes an intubation tube 5. The intubation tube 5 includes an insertable portion 7 intended to be inserted into the user's urethra, a non-insertable portion 9 not intended to be inserted into the user's urethra, and a connecting portion 10 integral with the non-insertable portion 9. The intermittent catheter 3 further includes a catheter 11 extending longitudinally within the intubation tube 5. The catheter 11 defines a flow path 12 from the distal insertion end 13 of the catheter 3 to its proximal outlet end 15. Only the non-insertable portion 9 of the intubation tube 5, the connecting portion 10, and the proximal outlet end 15 of the intermittent catheter 3 are shown, while the insertable portion 7 and the distal insertion end 13 of the intubation tube 5 extend into Figure 1 the area not shown.

[0168] Figure 1 The intermittent catheter assembly 1 further includes a measurement system 4 for determining at least one fluid parameter in the flow path 12. In the illustrated embodiment, the measurement system 4 includes two sensor elements 17 configured to determine at least one fluid parameter in the catheter 11 and / or in a space in communication with the catheter 11. The measurement system 4 further includes signal processing means 19 having a housing 21. The housing 21 has an engagement mechanism 23 that can removably secure the signal processing means 19 relative to the connection portion 10 of the intermittent catheter 3. The signal processing means 19 further includes an interface 24 for connecting the signal processing means 19 to the sensor elements 17. In Figure 1 the embodiment, the two sensor elements 17 are contained within the housing 21, in which case the interface 24 connects the sensor elements 17 within the housing 21 to the signal processing means 19. In Figure 1 the embodiment, the engagement mechanism 23 is removably secured to the connection portion 10 by firmly inserting the protruding engagement mechanism 23 into the receiving cavity of the connection portion 10.

[0169] In one embodiment, the intermittent catheter 3 is configured to remain in the user's urethra for a period of no more than 15 minutes, and at least the outer surface of the insertable portion 7 of the cannula 5 includes a hydrophilic surface coating. The illustrated cannula 5 is a single lumen tube, and the catheter constitutes the only passage between the distal insertion end 13 and the proximal outlet end 15.

[0170] In Figure 1 the embodiment, the intermittent catheter assembly 1 includes a flow restrictor 25 in the signal processing means 19. When the signal processing means 19 is removably secured relative to the cannula 5, the flow restrictor 25 is in fluid communication with the flow path 12. The catheter 11 includes a lumen having a first maximum cross-sectional area, and the flow restrictor 25 forms a through passage 27 having a second minimum cross-sectional area. Figure 1 The flow restrictor 25 of

[0171] In Figure 1In it, the first sensor element 17a is a first pressure gauge 17a adapted to be in fluid communication with the flow path 12 upstream of the flow restrictor 25, and the second sensor element 17b is a second pressure gauge 17b adapted to be in fluid communication with the flow path 12 downstream of the flow restrictor 25. When in use, the signal processing device 19 determines the flow rate based on the difference between the first pressure determined by the first pressure gauge 17a and the second pressure determined by the second pressure gauge 17b.

[0172] Generally, when determining the fluid flow rate, the signal processing device 19 uses the flow characteristics of the orifice tube to determine the flow rate, which can be derived using Bernoulli's principle to obtain:

[0173] Q = K1√(ΔP)

[0174] where K1 is a specific constant measured for urine, that is, the dimensions of the flow path and its extensions (including the first maximum cross-sectional area of the inner cavity and the second minimum cross-sectional area of the through-passage 27). ΔP is the difference between the first pressure and the second pressure, and Q is the fluid flow rate. The signal processing device 19 may have a set of predetermined values of K1, and each predetermined value of K1 corresponds to a specific type and size of the intermittent catheter 3. In some embodiments, the signal processing device 19 is configured to identify the type and size of the intermittent catheter 3 and automatically select the correct predetermined value of K1, and in some embodiments, the signal processing device 19 includes means for receiving user input related to the type and size of the intermittent catheter 3.

[0175] In Figure 1 embodiments, the measurement system 4 includes a first part 29 and a second part 31. The first part has the sensor element 17 in the housing 21, and the second part is for contacting the catheter 11. The barrier element 33 prevents the liquid in the catheter 11 from contacting the sensor element 17. In Figure 1 embodiments, the barrier element 33 includes a flexible membrane and a certain amount of sealed atmosphere.

[0176] In embodiments, the signal processing device 19 includes a data processing unit 35 and a power source (such as a battery or a photovoltaic system).

[0177] Figure 2 Shows a schematic cross-sectional view of the implemented intermittent catheter assembly 1, which is a Figure 1 variant. In Figure 2 embodiments, the flow restrictor 25 is arranged differently relative to the sensor element 17. In Figure 2In an embodiment, the first pressure gauge 17a is adapted to be in fluid communication with the flow path 12 upstream of the flow restrictor 25, while the third pressure gauge 17c is disposed in the through-passage 27 of the flow restrictor 25. The relatively small second minimum cross-sectional area of the through-passage 27 acts to increase the fluid velocity therethrough, which in turn results in a pressure drop from the first pressure gauge 17a to the third pressure gauge 17c. In practice, the pressure from the first pressure gauge 17a to the third pressure gauge 17c is also attributed to the sudden change in cross-sectional area and possibly surface roughness. Accordingly, in Figure 2 an embodiment, an increase in the pressure difference can be achieved with each change in flow rate, thereby obtaining higher measurement accuracy. Figure 2 The relative arrangement of the sensor element 17 and the flow restrictor 25 shown is not limited to a specific embodiment, but can generally be applied to different embodiments and aspects.

[0178] Figure 3 A schematic cross-sectional view of the implemented intermittent catheter assembly 1 is shown, which is Figure 1 and Figure 2 a variant in which the flow restrictor 25 is arranged differently relative to the sensor element 17. In Figure 3 an embodiment, the third pressure gauge 17c and the fourth pressure gauge 17d are disposed in the through-passage 27 of the flow restrictor 25 having the second minimum cross-sectional area. Additionally, the inner surface of the through-passage 27 has a third liquid friction coefficient that is greater than the fourth liquid friction coefficient upstream of the flow restrictor 25. The flow restrictor 25 produces a pressure drop due to the relatively large third friction coefficient. In this case, the signal processing device 25 can use the following formula to determine the flow rate Q:

[0179] Q = K2ΔP

[0180] where K2 is another specific constant that depends on the third and fourth friction coefficients and other types of flow losses in the flow path and its extensions. Similarly, the signal processing device 19 can have a set of predetermined values of K2, each predetermined value of K2 corresponding to a specific type and size of the intermittent catheter 3. In some embodiments, the signal processing device 19 is configured to identify the type and size of the intermittent catheter 3 and automatically select the correct predetermined value of K2, and in some embodiments, the signal processing device 19 includes means for receiving user input related to the type and size of the intermittent catheter 3.

[0181] Figure 4 A schematic cross-sectional view of the implemented intermittent catheter assembly 1 is shown. In Figure 4In an embodiment, this at least one sensor element 17 of the measurement system 4 is a first pressure gauge 17a adapted to be in fluid communication with the flow path 12 and the conduit 11 upstream of the flow restrictor 25. The flow restrictor 25 defines a through-passage 27 having a second minimum cross-sectional area and is arranged near the signal processing device outlet 36. In the embodiment, the distance between the flow restrictor 25 and the signal processing device outlet 36 is less than the diameter of the flow path between the flow restrictor 25 and the outlet 36. In this case, the pressure downstream of the flow restrictor 25 is equal to or very close to the ambient pressure, and the pressure drop across the flow restrictor 25 is determined based on the difference between the first pressure measured by the first pressure gauge 17a and the ambient pressure. The ambient pressure can be measured or set to a predefined value. In one embodiment, the first pressure gauge 17a measures the first pressure relative to the ambient pressure, and in this case, the fluid flow rate is determined based on the first pressure.

[0182] In Figure 4 In the example shown, the engagement mechanism 23 is detachably fixed to the connecting portion 10 by firmly inserting the protruding connecting portion 10 of the intermittent catheter 3 into the receiving portion of the engagement mechanism 23.

[0183] Figure 5 A schematic cross-sectional view of the implemented intermittent catheter assembly 1 is shown. In Figure 5 In an embodiment, the measurement system 4 includes a valve 37 in fluid communication with the flow path 12. By gradually rotating the valve 37 in a plane perpendicular to the plane of the drawing, the valve 37 allows obtaining a variable fluid flow cross-sectional area in fluid communication with the flow path 12. When the connecting portion 10 is detachably fixed to the engagement mechanism 23 and the valve 37 is set to completely cut off the flow in the flow path 12 and the conduit 11, the pressure gauge 17 measures the pressure, and the static pressure in the flow path 12 is determined based on the measured pressure. In one embodiment, the static pressure in the space in fluid communication with the flow path 12 and the conduit 11 is determined based on the measured pressure. In all embodiments, when the intermittent catheter 3 is inserted into the user's urethra, the space in fluid communication with the flow path 12 and the conduit 11 can be the user's bladder. In one embodiment, the signal processing device 19 includes an air outlet that does not allow liquid to pass through due to the pore size, and the air outlet is arranged to allow the liquid to reach the pressure gauge 17 when the valve 37 is closed.

[0184] In one embodiment, by turning valve 37 through a set of predetermined degrees of rotation, valve 37 can vary between a set of different predetermined cross-sectional areas, and these degrees of rotation can be marked, for example, by a visual indicator or a click sound on valve 37. In this embodiment, valve 37 also serves as a combination of a flow restrictor 37 and a pressure gauge 17. Then, the fluid flow rate is determined based at least on the predetermined cross-sectional area of valve 37 and the pressure measured by pressure gauge 17. In one embodiment, signal processing device 19 has a user interface (not shown) that allows a user to input, for example, the degrees of rotation of valve 37 to determine the fluid flow rate.

[0185] Figures 6 to 9 Embodiments with different types of valve 37 are shown. In Figure 6 the embodiment, valve 37 is of the electronic type. In one embodiment, coil 39 is wound around a part of signal processing device 19 to interact with a ferromagnetic valve element 41 (e.g., a sphere) disposed between a first stationary element 43a and a second stationary element 43b. By controlling the current in the coil, the ferromagnetic valve element 41 can be pushed towards the first stationary element 43a, in which case valve 37 cuts off the liquid flow, or it can be moved towards (or allowed to be pushed towards) the second stationary element 43b to allow liquid to flow through valve 37. In Figure 7 the Figure 6 embodiment, coil 39 has been replaced by a manually slidable ferromagnetic element 45, thus allowing the user to selectively push the ferromagnetic valve element 41 towards the first stationary element 43a or the second stationary element 43b. In Figure 8 and Figure 9 the embodiment, valve 37 is in the form of a push rod 47 that incorporates a flexible valve membrane 49, thus allowing valve 37 to be opened without the flexible valve membrane 49 restricting the flow, as Figure 8 shown; and allowing valve 37 to be closed by pushing the push rod 47 downwards to force the flexible valve membrane 49 to cut off the liquid flow through valve 37, as Figure 9 shown.

[0186] Figure 10 and Figure 11 show embodiments of an intermittent catheter assembly 1, where measurement system 4 includes a pressure gauge 17 in fluid communication with flow path 12 and catheter 11. When connection portion 10 is detachably fixed to engagement mechanism 23, using Figure 10 the user's finger in Figure 11The plug 51 in cuts off the liquid flow at the outlet 36 of the signal processing device. In this case, the pressure gauge 17 measures the pressure, and based on the measured pressure, the static pressure in the flow path 12 is determined. In one embodiment, based on the measured pressure, the static pressure in the space communicating with the flow path 12 and the conduit 11 is determined. When the intermittent catheter 3 is inserted into the user's urethra, the space communicating with the path 12 and the conduit 11 can be the user's bladder.

[0187] Figure 12 An embodiment of the intermittent catheter assembly 1 is shown, in which the measurement system 4 is configured to prevent flow through the signal processing device 19, which includes the at least one sensor element 17 (in the form of a pressure gauge 17). In this case, when the intermittent catheter 3 is removably fixed to the signal processing device 19, the liquid flow in the flow path 12 and the conduit 11 is blocked. Accordingly, the pressure gauge 17 measures the pressure, and based on the measured pressure, the static pressure in the flow path 12 is determined.

[0188] has been shown and described with respect to the first aspect Figures 1 to 12 . In an embodiment of the fourth aspect, variants of the shown embodiments are also contemplated, in which the measurement system 4 is fixedly connected to or integrated with the non-insertable portion 9 of the cannula 5. In these variants, the connecting portion 10 and the engaging mechanism 23 are replaced with a permanent fixed connection, where the connecting portion 10 and the engaging mechanism 23 are removably connected, or the cannula 5 and the signal processing device 19 are integrally formed, and where the connecting portion 10 and the engaging mechanism 23 are removably connected.

[0189] Figure 13 A schematic cross-sectional view of a flow limiter 25 (in the form of a Venturi tube 53) is shown. The Venturi tube 53 defines a through passage 27 having a second minimum cross-sectional area. The Venturi tube 53 includes a barrier element 33 (in the form of a flexible membrane and the atmosphere). The barrier element is arranged to allow a first pressure to be measured by a first pressure gauge 17a that is in fluid communication with the flow path 12 at a first barrier element 33a upstream of the flow limiter 25 and provides a first pressure communication path, and to allow a third pressure to be measured by a third pressure gauge 17c at the second minimum cross-sectional area and at a third barrier element 33c that provides a third pressure communication path. The shown Venturi tube 53 can be implemented as the flow limiter 25 in the signal processing device 19, or as a measurement sub-structure embedded in or integral with the cannula 5. In some embodiments, the first pressure gauge 17a and the third pressure gauge 17c are contained in the housing 21 of the signal processing device 19 and are configured to interact with the measurement sub-structure through the barrier element 33, as Figure 14As shown. The relatively small second minimum cross-sectional area of the through-passage 27 of the Venturi tube acts to increase the fluid velocity passing through it, which in turn results in a pressure drop from the first pressure gauge 17a to the third pressure gauge 17c. In practice, the pressure from the first pressure gauge to the third pressure gauge is also attributed to the non-zero surface roughness of the Venturi tube 53, and the pressure of the Venturi tube 53 is less than Figure 2 the pressure of the flow restrictor 25 shown.

[0190] Figure 14 The following embodiments are shown: wherein the first pressure gauge 17a to the third pressure gauge 17c are contained in the housing 21 of the signal processing device 19, and wherein the Venturi tube 53 is implemented as a measurement sub-structure integrally formed with the non-insertable portion 9 of the cannula 5. The connecting portion 10 of the intermittent catheter 3 and the engaging mechanism 23 are implemented as magnets that attract each other. The non-insertable portion 9 includes a barrier element 33 (in the form of a flexible membrane and the atmosphere). The barrier element is arranged to allow the first pressure gauge 17a, which is in fluid communication with the flow path 12 upstream of the flow restrictor 25 at the first barrier element 33a, to measure the first pressure, and to allow the third pressure gauge 17c at the third barrier element 33c at the second minimum cross-sectional area to measure the third pressure.

[0191] Figure 15 The following embodiments are shown: wherein the Venturi tube 53 is implemented as a measurement sub-structure integrally formed with the connecting portion 10 of the intermittent catheter 3. In Figure 15 the embodiment, the first pressure gauge 17a and the second pressure gauge 17c are embedded in the non-insertable portion 9 of the intermittent catheter 3. The interface 24 of the signal processing device 19 for connecting the signal processing device 19 to the sensor element 17 includes electrical contacts arranged to contact the first pressure gauge 17a and the third pressure gauge 17c. In one embodiment, the first pressure gauge 17a and the second pressure gauge 17c are powered by the battery of the interface 24 and the signal processing device 19.

[0192] Figure 16Shows a schematic cross-sectional view of the implemented intermittent catheter 3. The intermittent catheter 3 includes an insertion tube 5. The insertion tube 5 includes an insertable portion 7 designed to be inserted into the urethra of a user, a non-insertable portion 9 not designed to be inserted into the urethra of the user, and a connection portion 10 integral with the non-insertable portion 9. The intermittent catheter 3 further includes a catheter 11 extending longitudinally within the insertion tube 5. The catheter 11 defines a flow path 12 from the distal insertion end 13 of the catheter 3 to its proximal outlet end 15. The insertion tube includes an eyelet 56 at the distal insertion end 13. The eyelet 56 allows liquid to enter the catheter 11. The intermittent catheter 3 further includes a measurement sub-structure in the form of a restrictor 25, embedded in the connection portion 10. The non-insertable portion 9 includes a barrier 33 in the form of a flexible barrier to allow the pressure sensor 17 and the measurement sub-structure in the form of the restrictor 25 to measure pressure.

[0193] Figure 17 Is a graph of the measured voiding time of 155 ml of liquid water on the y-axis 57 versus the diameter at the second minimum cross-sectional area of the through-passage 27 of the orifice plate for the implemented intermittent catheter assembly 1 on the x-axis 59. For all the plotted measurements, the inner lumen diameter of the catheter 11 with the first maximum cross-sectional area is 2.6 mm. The time on the y-axis is plotted in seconds, while the diameter on the x-axis is plotted in mm.

Claims

1. An intermittent catheterization assembly for self-catheterization, comprising: - An intermittent catheter, the intermittent catheter comprising: ○ An insertion tube, the insertion tube comprising an insertable portion adapted to be inserted into the urethra of a user, a non-insertable portion not adapted to be inserted into the urethra of the user, and a connection portion integral with or mounted to the non-insertable portion; and ○ A catheter, the catheter extending longitudinally within the insertion tube and defining at least a portion of a flow path from a distal insertion end to a proximal outlet end of the intermittent catheter; wherein the insertion tube is a single lumen tube and the catheter constitutes the sole passageway between the distal insertion end and the proximal outlet end of the intermittent catheter; - A measurement system for determining at least one fluid parameter in the flow path, the at least one fluid parameter including pressure and fluid flow rate, the measurement system comprising: ○ At least one sensor element configured to determine the at least one fluid parameter in the catheter and / or in a space in fluid communication with the catheter; ○ Signal processing means, the signal processing means comprising: ■ A housing having engagement means for detachably securing the signal processing means relative to the connection portion of the intermittent catheter; and ■ An interface for connecting the signal processing means to the at least one sensor element, wherein: - The intermittent catheterization assembly includes a flow restrictor, the flow restrictor in the form of an orifice plate, orifice tube or venturi tube being a measurement sub-structure embedded in or integral with the insertion tube, the flow restrictor being in or adapted to be in fluid communication with the flow path and forming a through-passage, the flow restrictor being configured to restrict the flow therethrough, wherein the catheter defines a lumen having a first maximum cross-sectional area and the through-passage of the flow restrictor has a second minimum cross-sectional area, the size of the second minimum cross-sectional area of the through-passage of the flow restrictor being in the range of 17 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter; - The at least one sensor element includes at least one pressure gauge in fluid communication with the flow path, - At least the catheter of the intermittent catheter has a predefined characteristic pressure drop, and wherein the signal processing means is configured to determine the fluid flow rate based at least on the predefined characteristic pressure drop and the pressure determined by the at least one pressure gauge.

2. The intermittent catheterization assembly according to claim 1, wherein, The intermittent catheter is configured to remain in the urethra of the user for a period not exceeding 15 minutes.

3. The intermittent catheterization assembly according to claim 1 or 2, wherein, At least the outer surface of the insertable portion of the insertion tube includes a hydrophilic surface coating.

4. The intermittent catheterization assembly according to claim 1 or 2, wherein, At least one of the at least one sensor elements is included in the signal processing means.

5. The intermittent catheterization assembly according to claim 1 or 2, wherein, The measurement system includes a measurement sub-structure embedded in or integral with the insertion tube and configured to allow measurement of the at least one fluid parameter in combination with the at least one sensor element.

6. The intermittent catheterization assembly according to claim 1, wherein, The measurement system includes: - The first part, which includes the at least one sensor element in the housing of the signal processing device, the at least one sensor element being configured to determine at least one fluid parameter in the catheter and / or in the space in communication with the catheter when the signal processing device is fixed relative to the intermittent catheter; - The second part, which is adapted to contact the intermittent catheter; - A barrier element between the first part and the second part for preventing liquid in the catheter from contacting the at least one sensor element.

7. The intermittent catheterization assembly according to claim 6, wherein, The barrier element is embedded in the cannula.

8. The intermittent catheterization assembly according to claim 6 or 7, wherein, The barrier element includes a liquid-impermeable flexible barrier.

9. The intermittent catheterization assembly according to claim 6 or 7, wherein, The barrier element includes a gas conduit configured to establish a gaseous buffer between the flow path and the signal processing device.

10. The intermittent catheterization assembly according to claim 1 or 2, wherein, At least one of the at least one sensor elements is embedded in the cannula or integrally formed therewith.

11. The intermittent catheterization assembly according to claim 1, wherein: - The through-passage defines an inner surface having at least a third liquid friction coefficient; - At least a portion of the outer periphery of the flow path upstream of the flow restrictor has a fourth liquid friction coefficient; And wherein, - The third liquid friction coefficient is at least greater than the fourth liquid friction coefficient.

12. The intermittent catheterization assembly according to claim 1 or 2, wherein, The flow restrictor is an orifice plate or an orifice tube.

13. The intermittent catheterization assembly according to claim 12, wherein, The size of the second minimum cross-sectional area of the through-passage of the orifice plate or orifice tube is in the range of 30 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

14. The intermittent catheterization assembly according to claim 12, wherein, The size of the second minimum cross-sectional area of the through-passage of the orifice plate or orifice tube is in the range of 60 - 90% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

15. The intermittent catheterization assembly according to claim 1 or 2, wherein, The flow restrictor is a Venturi tube.

16. The intermittent catheterization assembly according to claim 15, wherein, The size of the second minimum cross-sectional area of the through-passage of the Venturi tube is in the range of 17 - 80% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

17. The intermittent catheterization assembly according to claim 15, wherein, The size of the second minimum cross-sectional area of the through-passage of the Venturi tube is in the range of 30 - 60% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

18. The intermittent catheterization assembly according to claim 15, wherein, The Venturi tube has at least a second liquid friction coefficient at the circumference of the second minimum cross-sectional area of the through-passage of the Venturi tube, and wherein at least a portion of the lumen of the intermittent catheter has a first liquid friction coefficient, and wherein the second liquid friction coefficient is less than the first liquid friction coefficient.

19. The intermittent catheterization assembly according to claim 1 or 2, wherein, The at least one pressure gauge includes: - A first pressure gauge arranged in the flow path of the catheter or adapted to be in fluid communication with the flow path upstream of the flow restrictor; and - A third pressure gauge arranged in the through-passage, And wherein the signal processing device is configured to determine the fluid flow rate based on the difference between the first pressure determined by the first pressure gauge and the third pressure determined by the third pressure gauge.

20. The intermittent catheterization assembly according to claim 1 or 2, wherein, The at least one pressure gauge includes: - A first pressure gauge, the first pressure gauge being arranged in the flow path of the catheter or being adapted to be in fluid communication with the flow path upstream of the restrictor; and - A second pressure gauge, the second pressure gauge being arranged in the flow path downstream of the restrictor or being adapted to be in fluid communication with the flow path downstream of the restrictor, and wherein the signal processing device is configured to determine the fluid flow rate based on the difference between the first pressure determined by the first pressure gauge and the second pressure determined by the second pressure gauge.

21. The intermittent catheterization assembly according to claim 1 or 2, wherein, The measurement system is configured to continuously determine the pressure loss in the fluid flow along a predetermined length of the catheter and to determine the fluid flow rate based on the pressure loss.

22. The intermittent catheterization assembly according to claim 1 or 2, wherein, The measurement system is configured to continuously determine the fluid flow rate of the fluid passing through the catheter and to integrate the fluid flow rate over time to obtain a measurement of the total volume of urine discharged from the bladder.

23. The intermittent catheterization assembly according to claim 1 or 2, wherein, The measurement system includes a valve, the valve being configured to allow obtaining a variable cross-sectional area of the fluid flow in fluid communication with the flow path.

24. The intermittent catheterization assembly according to claim 23, wherein, The valve is configured to automatically change the cross-sectional area of the fluid flow based on the determined fluid flow rate or the pressure in the flow path.

25. The intermittent catheterization assembly according to claim 6, wherein the second portion is for contacting the catheter of the intermittent catheter.

26. An intermittent catheterization assembly, comprising: - An intermittent catheter, the intermittent catheter comprising: ○ An insertion tube, the insertion tube including an insertable portion intended to be inserted into the urethra of a user and a non-insertable portion not intended to be inserted into the urethra of the user; ○ A catheter, the catheter extending longitudinally within the insertion tube and defining at least a portion of the flow path from the distal insertion end to the proximal outlet end of the intermittent catheter; wherein the insertion tube is a single lumen tube and the catheter constitutes the only passage between the distal insertion end and the proximal outlet end of the intermittent catheter; - A measurement system, the measurement system being fixedly connected to or integral with the non-insertable portion of the insertion tube to determine at least one fluid parameter in the flow path, the at least one fluid parameter including pressure and fluid flow rate, the measurement system including: ○ At least one sensor element, the at least one sensor element being configured to determine the at least one fluid parameter in the catheter and / or in a space in fluid communication with the catheter; ○ A signal processing device, the signal processing device including a data communication interface, wherein: - The intermittent catheterization assembly includes a flow restrictor, and the flow restrictor in the form of an orifice plate, orifice tube or Venturi tube is a measurement sub-structure embedded in or integral with the catheter. The flow restrictor is in or adapted to be in fluid communication with the flow path and forms a through-passage. The flow restrictor is configured to restrict the flow therethrough, wherein the catheter defines a lumen having a first maximum cross-sectional area; and the through-passage has a second minimum cross-sectional area, and the size of the second minimum cross-sectional area of the through-passage of the flow restrictor is in the range of 17 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter; - The at least one sensor element includes at least one pressure gauge in fluid communication with the flow path, - At least the catheter of the intermittent catheter has a predefined characteristic pressure drop, and wherein the signal processing device is configured to determine the fluid flow rate based at least on the predefined characteristic pressure drop and the pressure determined by the at least one pressure gauge.

27. The intermittent catheterization assembly according to claim 26, further comprising a bag assembly for accommodating the intermittent catheter and the signal processing device, wherein, When the bag assembly is in the closed state, in the bag assembly, the signal processing device is operatively connected to or operatively integrated with the intermittent catheter.

28. The intermittent catheterization assembly according to claim 26 or 27, wherein The intermittent catheter is configured to remain in the user's urethra for a period not exceeding 15 minutes.

29. The intermittent catheterization assembly according to claim 26 or 27, wherein, At least the outer surface of the insertable portion of the catheter includes a hydrophilic surface coating.

30. The intermittent catheterization assembly according to claim 26 or 27, wherein, The measurement system includes a measurement sub-structure embedded in or integral with the catheter and configured to allow measurement of the at least one fluid parameter in combination with the at least one sensor element.

31. The intermittent catheterization assembly according to claim 26 or 27, wherein, At least one of the at least one sensor elements is embedded in or integrally formed with the catheter.

32. The intermittent catheterization assembly according to claim 26, wherein: - The through-passage defines an inner surface having at least a third liquid friction coefficient; - At least a portion of the outer periphery of the flow path upstream of the flow restrictor has a fourth liquid friction coefficient; And wherein, - The third liquid friction coefficient is at least greater than the fourth liquid friction coefficient.

33. The intermittent catheterization assembly according to claim 26 or 27, wherein, The flow restrictor is an orifice plate or an orifice tube.

34. The intermittent catheterization assembly according to claim 33, wherein, The size of the second minimum cross-sectional area of the through-passage of the orifice plate or orifice tube is in the range of 30 - 95% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

35. The intermittent catheterization assembly according to claim 33, wherein, The size of the second minimum cross-sectional area of the through-passage of the orifice plate or orifice tube is in the range of 60 - 90% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

36. The intermittent catheterization assembly according to claim 26 or 27, wherein, The flow restrictor is a Venturi tube.

37. The intermittent catheterization assembly according to claim 36, wherein, The size of the second minimum cross-sectional area of the through-passage of the Venturi tube is in the range of 17 - 80% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

38. The intermittent catheterization assembly according to claim 36, wherein, The size of the second minimum cross-sectional area of the through-passage of the Venturi tube is in the range of 30 - 60% of the size of the first maximum cross-sectional area of the lumen of the intermittent catheter.

39. The intermittent catheterization assembly according to claim 36, wherein, The Venturi tube has a second liquid friction coefficient at least at the circumference of the second minimum cross-sectional area of the through-passage of the Venturi tube, and wherein at least a part of the inner lumen of the intermittent catheter has a first liquid friction coefficient, and wherein the second liquid friction coefficient is less than the first liquid friction coefficient.

40. The intermittent catheterization assembly according to claim 26 or 27, wherein, The at least one pressure gauge comprises: - a first pressure gauge arranged in the flow path of the catheter or adapted to be in fluid communication with the flow path upstream of the restrictor; and - a third pressure gauge arranged in the through-passage, and wherein the signal processing device is configured to determine the fluid flow rate based on the difference between the first pressure determined by the first pressure gauge and the third pressure determined by the third pressure gauge.

41. The intermittent catheterization assembly according to claim 26 or 27, wherein, The at least one pressure gauge comprises: - a first pressure gauge arranged in the flow path of the catheter or adapted to be in fluid communication with the flow path upstream of the restrictor; and - a second pressure gauge arranged in the flow path downstream of the restrictor or adapted to be in fluid communication with the flow path downstream of the restrictor, and wherein the signal processing device is configured to determine the fluid flow rate based on the difference between the first pressure determined by the first pressure gauge and the second pressure determined by the second pressure gauge.

42. The intermittent catheterization assembly according to claim 26 or 27, wherein, The measurement system is configured to continuously determine the pressure loss in the fluid flow along a predetermined length of the catheter and to determine the fluid flow rate based on the pressure loss.

43. The intermittent catheterization assembly according to claim 26 or 27, wherein, The measurement system is configured to continuously determine the fluid flow rate of the fluid passing through the catheter and to integrate the fluid flow rate over time to obtain a measurement of the total volume of urine discharged from the bladder.

44. The intermittent catheterization assembly according to claim 26 or 27, wherein, The measurement system includes a valve configured to allow obtaining a variable fluid flow cross-sectional area in fluid communication with the flow path.

45. The intermittent catheterization assembly according to claim 44, wherein, The valve is configured to automatically change the fluid flow cross-sectional area based on the determined fluid flow rate or the pressure in the flow path.

46. The intermittent catheterization assembly according to claim 26 or 27, wherein, At least the outer surface of the insertable portion of the cannula comprises a hydrophilic surface coating, and wherein the intermittent catheterization assembly includes an outer bag and an inner bag, the inner bag being impermeable to gas and / or liquid, wherein the outer bag encloses the intermittent catheterization assembly when in the closed state, and wherein the inner bag encloses at least the insertable portion of the cannula when in the closed state and includes a certain amount of liquid swelling medium.

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