Method for determining functional parameters of a catheter and catheter control assembly

Abstract

The present disclosure relates to a method for determining functional parameters of a catheter and a catheter control assembly. The method includes connecting a catheter to a catheter connector interface comprising a first lumen configured to be in fluid communication with an inflation retention element of the catheter and a second lumen configured to be in fluid communication with a main lumen of the catheter. The method further includes injecting fluid into the first lumen during a predetermined period, measuring a pressure parameter related to the pressure in the first lumen, and determining a functional parameter of the catheter based on the measured pressure parameter.

Description

Technical Field

[0001] The present invention relates to a method and a catheter control assembly for determining functional parameters of a connected catheter.

Background Art

[0002] A catheter is a medical device that can be used in a variety of applications and uses, and includes an elongated body through which one or more flow paths extend. By inserting the catheter into a patient's body cavity or through the patient's skin, the flow path of the catheter can be used to perform a wide range of medical procedures, including inserting surgical instruments, draining fluids, or administering fluids through one or more flow paths that extend through the elongated body. The number and type of flow paths available in a catheter depend on the specific type of catheter and its intended use.

[0003] For example, a catheter may be used to perform rectal irrigation such as trans anal irrigation (TAI), which involves introducing the catheter into the patient's anal canal or rectum and injecting a fluid (e.g., water) to wash away feces and stimulate the patient's intestine. Rectal catheters used for this purpose often have a retention element that, when inserted into the user's rectum, can function to hold the catheter in the insertion position and / or form a seal against the anal canal. The retention element may be, for example, in the form of a cone surrounding the elongated body and sealing the anal canal or rectum when the catheter is used to inject fluid. Alternatively, the rectal catheter may be provided with an inflatable element (e.g., a balloon element) that surrounds the elongated body and creates a seal and / or holds the catheter in place by being inflated inside the anal canal or rectum. Thus, the rectal catheter may be characterized by at least two separate flow paths, namely, a first flow path for injecting the irrigation fluid and a second flow path whose first end terminates inside the inflatable element for inflation of the inflatable element. The level of inflation within the flow path of the inflatable element may be controlled by injecting a fluid such as air or water, whereby the inflatable element creates a seal and / or is inflated to enable the catheter to be held in the insertion position. The same flow path may be used for deflation of the inflatable element when the catheter is removed.

[0004] Problems associated with conventional solutions are that medical staff may have difficulty in grasping different types of catheters and in distinguishing used catheters from new ones. Usually, a catheter is primed at a timing shortly before use, and this priming procedure may involve connecting the catheter to a catheter junction and flowing a fluid, for example, through one or more of the flow paths. In view of these problems, WO20142185 proposes a solution involving attaching one or more magnets on the connector base of a catheter and using a Hall effect sensor coupled to a controller at the catheter junction to detect the number and type of magnets on the catheter-connector. By equipping different types of catheters with different numbers of magnets, the controller at the catheter junction may determine the type of catheter based on the measurement results from the Hall effect sensor, and the controller may ensure, for example, that an appropriate procedure is performed using the connected catheter or that correct information is displayed to the medical staff.

[0005] However, problems associated with this solution are that the existing catheters need to be provided with the correct number of magnets in order for the Hall effect sensor at the catheter junction to be able to appropriately detect the type of catheter, and that the system may be unable to determine whether a catheter has been used previously. This known solution is complex, costly, and cumbersome to use. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] In view of the drawbacks of existing solutions, there is a need for an improved method and catheter device capable of determining the type of catheter. The object of the present invention is to provide such an improved method and catheter device that facilitate the determination of the functional parameters of a catheter. MEANS FOR SOLVING THE PROBLEMS

[0007] According to a first aspect of the present invention, there is provided a method for determining functional parameters of a catheter, the method comprising connecting the catheter to a catheter connector interface, the catheter connector interface comprising a first lumen and a second lumen. The first lumen is configured to be in fluid communication with an expansibility retaining element of the catheter, and the second lumen is configured to be in fluid communication with a main lumen of the catheter. The method further comprises injecting a fluid into the first lumen during a predetermined period, measuring a pressure parameter related to the pressure in the first lumen, and determining a functional parameter of the catheter based on the measured pressure parameter.

[0008] Fluid means any flowing liquid, gas, or material (such as a foam) or a combination thereof. In an embodiment, the fluid is a gas such as ambient air, or a liquid such as a cleaning liquid, for example, water or physiological saline.

[0009] A functional parameter is a parameter indicating a property of the catheter. This property may be one or more properties selected from the group including (a) whether the catheter has an expansibility retaining element, (b) whether the expansibility retaining element of the catheter has been used (where used means that the expansibility retaining element has been previously inflated), (c) whether the expansibility retaining element of the catheter is new (where new means that the expansibility retaining element has not been previously inflated), and (d) the size / volume of the expansibility retaining element. Determining the size / volume of the expansibility retaining element may include determining the absolute size / volume of the expansibility retaining element, or determining whether the expansibility retaining element is of a first size or a second size. Determining the size / volume of the expansibility retaining element may include determining which of at least two sizes / volumes corresponds to the expansibility retaining element. The catheter may be any type of catheter, preferably the catheter is an enema catheter, a urinary catheter, or a ureteral balloon catheter.

[0010] The expandability maintaining element may be a balloon element made of an elastic or resilient material.

[0011] The present invention is at least partially based on the understanding that the pressure parameter is determined according to the functional parameter of the catheter. Therefore, by injecting fluid and measuring the pressure parameter, the functional parameter can be obtained by analyzing the measured pressure parameter without the need for a new type of catheter or retrofitting an existing catheter with a magnet that can be detected using, for example, a Hall effect sensor.

[0012] In one embodiment, the catheter control assembly is configured to determine whether a catheter connected to the assembly comprises an expandability maintaining element. In one embodiment, the catheter control assembly is configured to determine whether the expandable element of a catheter connected to the assembly has ever been expanded before. In one embodiment, the catheter control assembly is configured to determine the size or specific type of a catheter connected to the assembly.

[0013] It is advantageous to ensure that a healthcare provider, or a patient performing self-treatment, uses a catheter intended for the treatment to be performed. This can ensure that the catheter control assembly is not used with a catheter for which it is not suitable, or that the catheter control assembly is not controlled in a manner unsuitable for that catheter. Additionally or alternatively, in the case of a disposable catheter, it may be advantageous for a healthcare provider, or a patient performing self-treatment, not to use a catheter that has been used before. A used catheter may have properties impaired during previous use, may be contaminated, or may not be suitable for continued repeated use for other reasons.

[0014] Using the method of the present invention, the functional parameters of the catheter may be automatically determined, for example, when the catheter is connected to the catheter connector interface during priming of the catheter. The functional parameters may then be presented to a healthcare provider or a patient performing self-treatment, for example, such that a previously used catheter issues a warning when connected to the catheter connector interface. Additionally or alternatively, the functional parameters may be used to control a treatment procedure. For example, if the functional parameters indicate that the catheter does not have an inflation retention element, a valve or pressure source may be controlled to ensure that fluid is not injected into the first lumen during the treatment procedure.

[0015] In some implementations, the pressure parameter is based on a fluid pressure, and the step of measuring a pressure parameter related to the pressure within the first lumen further includes performing at least one measurement of the fluid pressure within the first lumen using a pressure sensor.

[0016] When fluid is injected into the first lumen, the pressure within the first lumen changes in response to the functional parameters of the catheter. By measuring the pressure within the first lumen, the functional parameters of the catheter can be determined based on the measured pressure. The pressure parameter may be based on, for example, a direct measurement of the fluid pressure, average fluid pressure, maximum fluid pressure, or rate of change (derivative) of pressure during a predetermined measurement period within the first lumen. For example, the fluid pressure is measured using a pressure sensor. The pressure sensor is, for example, a pressure transducer.

[0017] Additionally or alternatively, the pressure parameter is based on the result of an indirect measurement of the fluid pressure within the first lumen. When an electric pump is used to deliver fluid into the first lumen, since the work done by the electric pump varies over time according to the functional parameters of the connected catheter, the voltage or current (or power) supplied to the electric pump will indirectly indicate the fluid pressure within the first lumen. Accordingly, the pressure parameter may be based on the measurement result of at least one of the current, voltage, and power supplied to the electric pump that indirectly indicates the pressure within the first lumen. Specifically, the pressure parameter may be a specific measurement sample of the pump voltage or current, average pump voltage or current, maximum pump voltage or current, or rate of change (derivative) of the pump voltage or current during a predetermined measurement period, all of which indirectly indicate the pressure within the first lumen.

[0018] In some implementations, determining the functional parameter includes determining whether the pressure parameter exceeds a first predetermined threshold. If the pressure parameter is determined to exceed the first predetermined threshold, a first value is assigned to the functional parameter; otherwise, a second value is assigned to the functional parameter.

[0019] Accordingly, the functional parameter may be determined by analyzing whether the pressure parameter exceeds a predetermined threshold. The predetermined threshold is set by measuring the pressure parameters for reference catheters with different known functional parameters, and it may then be used to determine the functional parameter of the catheter connected to the catheter connector interface.

[0020] Two or more predetermined thresholds may be provided. For example, determining the functional parameter may further include determining whether the pressure parameter exceeds a second predetermined threshold, where the second predetermined threshold is higher than the first predetermined threshold. If the pressure parameter exceeds the second predetermined threshold, a third value is assigned to the functional parameter.

[0021] In some implementations, a first value of a functional parameter indicates that the catheter has a new inflation retention element, and a second value of the functional parameter indicates that the catheter has a used inflation retention element. As will be described in detail below, a catheter having an inflation retention element that has not been used before can be expected to be associated with a higher pressure parameter than a catheter having an inflation retention element that has been used before. Additionally, a third value of the functional parameter may indicate that the catheter is not provided with an inflation retention element. A catheter without an inflation retention element may be characterized by a sealed inflation lumen or no inflation lumen, i.e., the first lumen of the catheter connector interface is not in fluid communication with a volume portion that substantially changes when fluid is injected. This means that the pressure parameter can either continuously increase or stabilize at a higher level compared to a catheter with an inflation retention element. Thus, a second threshold may be selected to distinguish such a catheter from a catheter with any form of inflation retention element.

[0022] In some implementations, measuring a pressure parameter related to the pressure in the first lumen includes measuring a plurality of pressure parameter samples, and the pressure parameter is based on the plurality of pressure parameter samples. For example, the pressure parameter may be based on a maximum pressure parameter sample or a difference between at least two pressure parameter samples among the plurality of pressure parameter samples.

[0023] The pressure parameter samples describe how the pressure parameter varies over time, i.e., define a pressure parameter function. Thus, the pressure parameter function will depend on the functional parameter of the catheter, and the functional parameter of the catheter may be determined by analyzing the pressure parameter function (including at least two pressure parameter samples).

[0024] Determining the pressure parameter may include comparing a sequence of pressure parameter samples (e.g., a pressure parameter function) to a database of sequences of pressure parameter samples obtained with catheters having different functional parameters, and determining the most matching sequence of pressure parameter samples. The associated functional parameter of the most matching sequence may be the determined functional parameter. Note that there are many alternative means for determining the functional parameter of the pressure parameter when measurement results for reference of the pressure parameter for a character having a known functional parameter are given.

[0025] In some implementations, the first lumen is isolated from the pressure source by one or more valves, and the method further includes opening at least one valve for a predetermined period and injecting pressurized fluid from the pressure source into the first lumen during the predetermined period.

[0026] Alternatively, the first lumen may be in fluid communication with a pump, and the method may further include operating the pump for a predetermined period and using the pump to inject pressurized fluid into the first lumen during the predetermined period. Thus, the fluid may be injected into the first lumen for an appropriate predetermined period that can be adjusted by controlling the valve and / or the pump.

[0027] In some implementations, measuring the pressure parameter includes measuring the pressure parameter during a predetermined period. Thus, the pressure parameter may be measured when the fluid is injected into the first lumen.

[0028] Additionally or alternatively, the predetermined period is a first period, and the method further includes stopping the injection of the fluid after the predetermined first period. Measuring the pressure parameter includes measuring the pressure parameter during a second period, and the second period follows the first period. Thus, the pressure parameter may be measured after the fluid has been injected. Optionally, the method includes opening a relief valve to release the fluid from the first lumen. For example, the relief valve is opened during a predetermined second period.

[0029] In some embodiments, the predetermined period is from 1 millisecond to 10 seconds, preferably from 3 milliseconds to 5 seconds. The pressure parameter is affected by the functional parameter from the start of fluid injection. Thus, a short predetermined period of several milliseconds can be sufficient to determine the functional parameter of the catheter. Alternatively, a long predetermined period of at least 0.5 seconds may be used to determine the functional parameter.

[0030] According to a second aspect of the present invention, there is provided a catheter control assembly comprising a catheter connector interface, the catheter connector interface comprising a first lumen configured to be in fluid communication with an inflatable retaining element of the catheter and a second lumen configured to be in fluid communication with a main lumen of the catheter. The catheter control assembly further comprises a catheter control unit configured to operate fluid injection means to inject fluid into the first lumen for a predetermined period, measure a pressure parameter related to the pressure in the first lumen, and determine a functional parameter of the catheter based on the measured pressure parameter.

[0031] For example, the catheter control unit may comprise a controller and a sensor for respectively operating the fluid injection means and measuring the pressure parameter.

[0032] The catheter control assembly may further comprise a pump, preferably an electric pump. The pump may be incorporated and disposed within a single housing of the catheter control assembly. However, alternatively, the pump may be provided as a separate external pump. The catheter control assembly may further comprise a valve for isolating the output of the pump from the catheter connector interface. Also, additional components such as sensors, an energy source such as a battery, additional pumps, etc. may be provided in the catheter control assembly. Also, a reservoir for containing a certain supply of cleaning fluid may be provided, incorporated and disposed, or connected to the assembly.

[0033] The control unit may be implemented in software executed by a processor such as a CPU or a microcontroller. Also, the control unit may be implemented partially or fully in hardware. The control unit is preferably arranged as an integral part of the catheter control assembly and is preferably arranged within its housing. However, alternatively, the control unit may be arranged externally and connected to the rest of the assembly through a wired or wireless communication connection.

[0034] The fluid injection means may comprise a pump and / or a valve, which valve is configured to control the flow from a container containing the pressurized fluid.

[0035] According to a third aspect of the present invention, there is provided a computer program product comprising instructions which, when executed by a computer, perform the method according to the first aspect of the present invention. A computer program product such as computer-executable software may be provided on a data carrier such as data storage.

[0036] The inventions according to the second and third aspects are characterized by the same or equivalent benefits as the invention according to the first aspect. Any function described in relation to the method may have a corresponding feature in the device or apparatus and vice versa.

[0037] The present invention will be described in more detail with reference to the accompanying drawings, which show presently preferred embodiments of the invention.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5a

Figure 5b

Figure 5c

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Figure 7a

Figure 7b

Figure 8a

Figure 8b

DETAILED DESCRIPTION OF THE INVENTION

[0039] In the following detailed description, preferred embodiments of the present invention will be described. However, it should be understood that the features of different embodiments are interchangeable between embodiments and can be combined in various forms, unless specifically indicated otherwise. Also, for clarity, note that the dimensions of certain components shown in the drawings, such as the length of a medical device, may differ from the corresponding dimensions in the actual implementation of the present invention. Furthermore, the embodiments discussed are particularly suitable for use in a rectal irrigation assembly, i.e., in a catheter control assembly connected to a rectal catheter for use in, for example, transanal irrigation therapy, but similar catheter control assemblies may be used in other applications such as an expandable catheter, a venous catheter, a urethral catheter, etc.

[0040] FIG. 1 shows a block diagram of a catheter control assembly 100 having a second (passage) lumen 130 and a first lumen 120, the second lumen 130 being configured to be in fluid communication with a main lumen of a catheter via a catheter connection interface in such a way as to pass through a catheter connection port 131, and the first lumen being configured to be in fluid communication with an expandable retention element of the catheter via a catheter connection interface in such a way as to pass through an inflation port 121. The illustrated catheter control assembly 100 has two lumens, namely a first lumen 120 and a second lumen 130, but may have additional lumens in any suitable arrangement. For example, the catheter control assembly 100 may have at least two second (passage) lumens 130 in addition to the first lumen 120, and the first lumen 120 and the second lumen 130 may be arranged concentrically, unlike the side-by-side arrangement of the embodiment shown in FIG. 1.

[0041] The second lumen 130 extends between the first catheter connection port 131 and the first passage port 132 and enables, for example, a fluid or an instrument to be passed through the second lumen 130 of the catheter control assembly 100. Although the catheter control assembly 100 shown in FIG. 1 is shown as a single unit, the catheter control assembly 100 may comprise separate units. For example, a catheter connector interface comprising the second lumen 130 and the first lumen 120 may be provided as at least one separate unit, in which case the controller 140 and the sensor 150 are provided as another separate unit (catheter control unit), and the pressure source 160 is provided as yet another separate unit.

[0042] The catheter control assembly 100 preferably comprises a pressure source 160 in fluid communication with the first lumen 120. The pressure source 160 may be a pressure vessel that contains fluid under pressure and / or a pump configured to deliver fluid to the first lumen 120. The pump may be any suitable pump such as a mechanical pump, an electric pump or an electromechanical pump. For example, the pump may be a positive displacement pump, a rotary positive displacement pump (e.g., a screw pump or a gear pump), a reciprocating pump (e.g., a plunger / piston pump or a diaphragm pump), a centrifugal pump or a peristaltic pump. Preferably, the pump is an electric pump. Different types of pumps may exhibit different voltage and / or current characteristics when fluid is injected into the first lumen 120, but the differences in voltage and / or current functions can be observed in different catheters equipped with any type of pump provided there is sufficient voltage and / or current measurement accuracy. Thus, the pump voltage and / or current may be used as pressure parameters for any type of electric pump.

[0043] Another pressure source or medical instrument may be connected to or passed through the passage port 132 to inject fluid into or remove fluid from the catheter, for example, during treatment.

[0044] The pressure source 160 may be associated with a valve 170 that isolates the pressure source 160 from the first lumen 120. In some implementations, the pressure source 160 is a pressure vessel and the valve 170 is a valve of the pressure vessel, so that the valve 170 and the pressure vessel together can form a controllable pressure source. In some implementations, there is a buffer volume 122 between the pressure source 160 and the valve 170. The valve 170 may be a three-way valve, and the valve 170 is further configured to vent the first lumen 120. Alternatively, a relief valve 175 configured to vent the first lumen 120 after a predetermined period is provided. The relief valve 175 may be further configured to hold the injected fluid within the first lumen 120 by being closed during the predetermined period. The relief valve 175 may be controlled by the controller 140.

[0045] The catheter control assembly 100 may further include a sensor 150 configured to detect a pressure parameter related to the pressure within the first lumen 120. For example, the sensor 150 may be a pressure sensor configured to measure the pressure within the first lumen 120. Alternatively or additionally, the sensor 150 may be a voltage, current, or power sensor configured to indirectly measure pressure through the voltage, current, or power supplied to the pressure source 170, where the pressure source is, for example, an electric pump.

[0046] Furthermore, the catheter control assembly 100 may include a controller 140 for controlling at least one of the pressure source 160 and the valve 170. The controller 140 may be configured to operate the pump for a predetermined period and optionally stop the pump after the predetermined period has elapsed. The controller 140 may be configured to open the valve 170 for a predetermined period and close the valve 170 after the predetermined period has elapsed. If the pressure source 160 is a pressure vessel, the valve 170 may be a valve of the pressure vessel.

[0047] Specifically, it should be noted that the pump and the valve 170 may be combined, and the controller 140 may be configured to operate the pump before, simultaneously with, or after the valve 170 is opened. Additionally or alternatively, the controller 170 may be configured to stop the pump before, simultaneously with, or after the valve is closed. Thus, the controller 140 may be configured to allow, for example, a rest period during which the valve 170 is in the open state and the pump is in the stopped state.

[0048] The controller 140 may control the sensor 150 to perform measurements at appropriate times. The controller 140 may be further configured to periodically update the functional parameters by periodically injecting fluid into the first lumen 120 and controlling one or more sensors 150 to measure pressure parameters related to the fluid pressure within the first lumen 120. Additionally, the controller may be configured to control one or more valves 170.

[0049] FIG. 2 schematically shows a catheter 200 comprising an elongated body 210 through which at least two lumens 220, 230 extend at least partially. The catheter may comprise a catheter connector connectable to a catheter connector interface of a catheter control assembly. In the illustrated embodiment, the main lumen 230 extends from a first connector port 231 at a first end of the elongated body 210 to a second port 232 at a second end of the elongated body 210. In use, the main lumen 230 of the catheter 200 may be used to introduce an instrument or fluid to or remove an instrument or fluid from a patient via the first connector port 231 and the second port 232. The catheter 200 may comprise two or more main lumens 230 extending substantially from a first end to a second end of the catheter 200, such as two, three, or more main lumens 230. A plurality of main lumens 230 may be provided to enable simultaneous use of instruments, administration of at least one fluid, and / or removal of at least one fluid (e.g., by use of a suction pressure or negative pressure at port 231 at the first end of the catheter 200).

[0050] The catheter 200 in FIG. 2 is fixed to an elongated body 210 and further includes an expandable retaining element 250 that at least partially surrounds the elongated body 210. The expandable retaining element 250 may be of different sizes depending on the intended use of the catheter 200. Similarly, the expandable retaining element 250 may be made of any suitable flexible or elastic material, such as a plastic material. The expandable retaining element 250 forms an expandable volume portion 251 that is in fluid communication with the inflation lumen 220 via a second inflation port 222. The inflation lumen 220 extends to a first inflation port 221 at the first end of the catheter 200. The expandable volume portion 251 may be expanded by injecting fluid into the inflation lumen 220 via the first inflation port 221, and the volume portion 251 of the expandable retaining element 250 may be reduced by suction or deflation of the inflation lumen 220. Thus, by inserting the elongated body 210, for example, into a patient's anal canal or rectum, when the expandable retaining element 250 is in a contracted state, the expandable retaining element 250 may be expanded by injecting a fluid, such as water or air, into the inflation lumen 220. Thereby, the expandable retaining element 250 expands to hold the catheter in the insertion position and, additionally, may form a seal against the patient's body to hold fluid within the patient's body, such as fluid injected through the second port 232 of the main lumen 230 within the patient's body.

[0051] Further, although the main lumen 230 and the inflation lumen 220 are shown as separate lumens arranged side by side within the catheter 200, other flow path layouts are possible. For example, it should be noted that the main lumen 230 may be concentrically placed inside the inflation lumen 220, and vice versa.

[0052] FIG. 3 shows a catheter control assembly 100 connected to a catheter 200. Although the catheter control assembly 100 is shown as being directly connected to the catheter 200, it should be noted that the catheter control assembly 100 may be connected to a corresponding lumen of the catheter 200 via one or more extension tubes (not shown). Here, with further reference to FIG. 4, a method for determining the functional parameters of the catheter 200 is described.

[0053] In step S1, the catheter 200 is connected to a catheter connector interface that includes a second lumen 130 configured to be in fluid communication with the main lumen 230 of the catheter 200 and a first lumen 120 configured to be in fluid communication with the expandable retention element 250 of the catheter 200. If the catheter 200 does not include an expandable retention element 250, the first lumen 120 of the catheter connector interface configured to be in fluid communication with the expandable retention element 250 of the catheter 200 may be fluidly connected to a lumen of the catheter 200 that is closed, i.e., not in fluid communication with the expandable retention element 250 or the surrounding environment of the catheter 200. As a further example, the catheter 200 may lack any inflation lumen 220, whereby the first lumen 120 of the catheter device 100 is closed when the catheter 200 is connected to the catheter connector interface. Alternatively, a second inflation port 222 may be closed, i.e., the second lumen 120 is in fluid communication with a substantially fixed volume portion of the inflation lumen 220.

[0054] Some catheters used for rectal irrigation do not have an expandable retention element in fluid communication with a first lumen 220. Instead, they either have no retention element at all or have another type of retention element, such as a conical element provided around an elongate body 210 and facing towards the second end of the catheter 200 (which has a second port 232). The conical element is used as an alternative way to hold the catheter in place and create a seal against the patient's body. As an alternative to the conical element, the catheter may comprise a closed (or static) fluid-filled volume (e.g., a spherical element made of a non-elastic material), which is at least partially filled with fluid when the user inserts the catheter, uses the catheter for irrigation, and removes the catheter. This closed fluid-filled volume is, in a sense, an expandable retention element, but it is not intended to be inflated after the user inserts the catheter and is not in fluid communication with the first lumen 220. Thus, since the closed (or static) fluid-filled volume is isolated from the first lumen 220, if the closed (or static) fluid-filled volume is attached to the catheter to facilitate a proper seal during use, the pressure parameters will indicate that the first lumen 220 is not in fluid communication with an expandable retention element.

[0055] Note that some catheters may comprise an expandable retention element 250, a conical element, or both.

[0056] In step S2, fluid is injected into the first lumen 120 of the catheter device 100, such that the fluid may also be injected into the inflation lumen 220 (if present within the catheter 200) and thus into the expandable retention element 250. For example, the controller 140 of the catheter device 100 may perform at least one of operating a pump and opening the valve 170, whereby fluid is injected into the first lumen 120.

[0057] This method proceeds to step S3, which includes measuring a pressure parameter. Step S3 may include at least one of measuring the pressure in the first lumen 120 using the sensor 150 and measuring the current, voltage, or power supplied to the pump. The measurement result of the pressure parameter obtained by the sensor 150 may be provided to a processing unit such as the controller 140 configured to determine the functional parameter of the catheter 200 based on the measurement result. Accordingly, this method may proceed to step S4, which includes determining the functional parameter of the catheter 200 based on the measured pressure parameter.

[0058] In some implementations, the sensor 150 makes at least one measurement of the pressure parameter when the valve 170 is in the open state and / or the pressure source 160 is in the operating state. Additionally or alternatively, the controller 140 may be configured to close the valve 170 or stop the pump 160, whereby the sensor 150 makes at least one measurement of the pressure parameter when the valve 170 is in the closed state and / or the pressure source 160 is in the stopped state. Optionally, the bleed valve 175 is opened before, during, or after the valve 170 is in the closed state and / or the pressure source 160 is in the stopped state. In a further example, the controller 140 may stop the pressure source 160 while the bleed valve 175 is in the closed state, and the sensor makes at least one measurement of the pressure parameter when the pressure source 160 is in the stopped state (during a predetermined rest period).

[0059] In some embodiments, at least one measurement is performed when the pressure in the first lumen 220 stabilizes. Alternatively, at least one measurement is performed at a predetermined timing after the valve 170 has begun to open or is fully open while the pressure inside the first lumen 220 is still changing. Regardless of when at least one measurement of the pressure parameter is taken during pressurization of the first lumen 220, the measurement result will indicate a functional parameter of the catheter. For example, after a predetermined time since the valve 170 is opened, the pressure in the first lumen 220 will be a first value if the first lumen 220 is not connected to an inflatable element, a second value if the first lumen 220 is connected to an inflatable element that has not been used before, and a third value if the first lumen 220 is connected to an inflatable element that has been inflated before. The first value can be greater than the second value, and the second value can be greater than the third value.

[0060] FIG. 5a shows the signal c representing a control signal output by a controller over a predetermined period and / or as a function of time. Referring further to FIG. 3, the control signal c may be a control command transmitted from the controller 140 to the valve 170 and / or the pressure source 160 (pump). A high level H of the control signal c indicates, for example, the timing when the pump is activated or the valve is opened to inject fluid under pressure into the first lumen 120. That is, the high level H of the control signal c indicates a range of a predetermined period. Similarly, a low level L of the control signal c indicates that the pump has been stopped or the valve 170 has been closed. The control signal c takes a high value during a predetermined period between the time t ON and the time t OFF during which fluid is injected into the first lumen 120. Also, the high level H of the control signal c may indicate that the relief valve 175 has been closed, and the low level L may indicate that the relief valve 175 has been opened.

[0061] In some implementations, the pressure source 160 includes a pump that can be in an operating state independently of the control signal (e.g., always in an operating state or can be in an operating state for a duration much longer than the duration of the high level H of the control signal). Alternatively, the pump may be operated when the control signal is at a high level. For example, the valve 170 opens simultaneously with the operation of the pump. The advantage of already operating the pump when the valve 170 is opened is that the valve can open very quickly, which means that the first lumen 220 can quickly reach a pressurized state.

[0062] Referring further to FIG. 5b, for three connected catheters 200 having different functional parameters, the fluid pressure inside the first lumen 120 is shown as functions 11, 12, 13 of time. That is, the pressure function 13 for a catheter without an expandable element, the pressure function 11 for a catheter with an expandable element that has not been used, and the pressure function 12 for a catheter that has been used previously. As can be seen, in all catheters, the pressure inside the first lumen 120 has started to rise from t ON (although at different rates). The maximum pressure reached during a predetermined period depends on whether the catheter 200 has an expandable retention element 250, the size of the expandable retention element 250, and whether the expandable retention element 250 has been used previously.

[0063] The pressure functions 11, 12, 13 in FIG. 5b generally show the pressure inside the first lumen 120 as a function of time for different catheters, and the used or new expandable retention elements are of the same size (when present). A comparison of the pressure as a function of time for catheters with different sizes of expandable retention elements 250 is described below in connection with FIGS. 7a and 7b.

[0064] Therefore, in order to distinguish the maximum pressure (pressure function 12) reached with a catheter having a used expandability retaining element 250 from the maximum pressure (pressure function 11) reached with a catheter having a new (previously unexpanded) expandability retaining element 250, a first threshold T 1 may be set. Since the predicted maximum pressure with a catheter having a new expandability retaining element 250 is higher than the predicted maximum pressure obtained with a catheter having a used expandability retaining element 250, the threshold T 1 may be at least higher than the predicted maximum pressure reached with a catheter having a used expandability retaining element.

[0065] Additionally or alternatively, in order to distinguish the maximum pressure (pressure function 11) reached with a catheter having a new (previously unexpanded) expandability retaining element 250 from a catheter 200 without an expandability retaining element (pressure function 13), a second threshold T 2 may be set. As shown above, catheter 200 without an expandability retaining element 250 may provide a fixed volume portion in the first lumen 120 that cannot be expanded. Thus, unlike the pressure in a catheter 200 having an expandability retaining element 250 that may exhibit a characteristic pressure peak preceding a pressure drop, the fluid pressure continues to rise over a predetermined period.

[0066] Similarly, the rate of change (derivative) of the fluid pressure is different among the measured pressure functions 11, 12, 13. This is particularly true for the rate of rise after t ON or the relatively stable pressure reached after the initial peak of pressure functions 11, 12. Therefore, at least one rate of change (derivative) threshold may be set to distinguish the three types of catheters based on the rate of change of pressure during different intervals of a predetermined period. Additionally, since the rate of pressure drop due to contraction or pressure release using the bleed valve 175 after t OFF is also different depending on the type of catheter, at least one rate of change threshold may be set to distinguish the three types of catheters based on the pressure measured after t OFF .

[0067] Additionally, FIG. 5c shows, for three catheters having different functional parameters, the current supplied to the pump as a function of time. Current function 23 is for a catheter without an inflatable element, current function 21 is for a catheter with an unused inflatable element, and current function 22 is for a catheter that has been used previously.

[0068] When measuring current functions 21, 22, and 23, a constant voltage source was connected to pressure source 160 in the form of an electric pump. However, if a constant current source were employed instead of the constant voltage source, the voltage function of the pump could exhibit characteristics similar to current functions 21, 22, and 23.

[0069] As can be seen, the current rises rapidly to the peak value for each catheter, whereby currents 21, 22, and 23 then vary towards a steady value. The steady current is different when the pump delivers fluid to a catheter without an inflatable element (current function 23), to a catheter having an inflatable holding element 250 that is being inflated for the first time (current function 21), or when the inflatable holding element 250 has been inflated previously (current function 22). Similarly, the maximum value of the current is reached for catheters with an inflatable element 250 (new or used), and the maximum value current and the timing of the maximum value with respect to t ON differ depending on whether the inflatable holding element 250 is new or has been inflated previously. Further, the maximum value corresponds approximately in time to the pressure peaks of the corresponding pressure functions 11, 12, and 13 from FIG. 5b.

[0070] Thus, the functional parameters of the catheter may be determined by analyzing the steady current, the timing of the maximum value with respect to t ON or the maximum value current. For example, a threshold T 1 may be set to distinguish between a catheter with a new inflatable holding element and a catheter with a used inflatable holding element. For example, threshold T 1is greater than the steady current (current curve 22) associated with a pump that delivers fluid to a catheter with a used expandability retention element 250, but may be less than the steady current (current curve 21) associated with a pump that delivers fluid to a catheter with a new expandability retention element 250. Additionally or alternatively, a second threshold T 2 may be set to distinguish a catheter 200 without an expandability retention element (current curve 23) from a catheter 200 with a used expandability retention element 250 (current curve 22) or a catheter 200 with a new expandability retention element (current curve 21). For example, the threshold T 2 for determining whether an expandability-intended element is present is greater than the steady current (current curve 21) associated with a pump that delivers fluid to a catheter 200 with a new expandability retention element 250, but may be less than the steady current (current curve 23) associated with a pump that delivers fluid to a catheter 200 without an expandability retention element 250.

[0071] As a further example, if the current is between two thresholds T 1 and T 2 it can be determined that a new expandability retention element 250 is present.

[0072] Figures 6a and 6b show, for connected catheters 200 with expandability retention elements 250 of different sizes, the current supplied to the pump as a function of t ON and t OFFIt shows how it changes over time with respect to [the relevant object]. In Fig. 6a, the current functions 21, 21' show the current supplied to the pump as a function of time when the catheter has a new expandability maintaining element 250 of the first size / volume (current function 21) and a new expandability maintaining element 250 of the second size / volume (current function 21'), and the second size is smaller than the first size. Similarly, Fig. 6b shows the current functions 22, 22' that show the current supplied to the pump as a function of time when the catheter has a used expandability maintaining element 250 of the first size / volume (current function 22) and a used expandability maintaining element 250 of the second size / volume (current function 22'), and the second size is smaller than the first size.

[0073] As can be seen, the steady current, t ON The subsequent local peak current value and the duration of the local peak are different depending on the size of the new or used expandability maintaining element 250. Therefore, at least one predetermined threshold may be determined to identify whether the expandability maintaining element 250 is of the first size or the second size based on the measurement result of the current supplied to the pump.

[0074] Similarly, the measured pressure as a function of time may be used to determine the size of the catheter. Referring to FIG. 7a, for a catheter with a new expansibility retaining element 250 of a first size / volume (pressure function 11) and a second size / volume (pressure function 11'), the pressure is shown as a function of time, and the second size / volume is smaller than the first size. Thus, for example, the size of the expansibility retaining element 250 may be determined by obtaining the peak value, rate of change, or shape of the pressure functions 11, 11'. Referring to FIG. 7b, for a catheter with a used expansibility retaining element 250 of a first size / volume (pressure function 12) and a used expansibility retaining element 250 of a second size / volume (pressure function 12'), approximate pressure curves 12, 12' of the fluid pressure within the first lumen 120 are shown, and the second size / volume is smaller than the first size. Thus, the difference between the pressure curves 12, 12' may be used to determine the size of the used expansibility retaining element 250.

[0075] t in FIGS. 5, 6, and 7 ON and t OFF The predetermined period between and may be referred to as a long period or a long pulse. A long pulse is a pulse of 0.3 seconds or more, such as a pulse having a length of at least 1 second or 2 seconds that enables the expansibility retaining element to expand sufficiently so that a characteristic peak is reached in the fluid pressure within the first lumen or the voltage and / or current supplied to the pump. About 0.3 seconds was sufficient for the pressure source used in the experiment to ensure that a characteristic peak occurred, but the required time may be shorter or longer depending on the length of the catheter 200, the size and material of the expansibility retaining element 250, the pressure of the pressure source, and the flow rate of the pressure source. For example, if a pressure source with a higher pressure and / or a larger flow rate is used, the characteristic peak may occur earlier, such as after 0.1 seconds or 50 milliseconds.

[0076] Referring to FIG. 8a, a short period or a short pulse is introduced. The short period or short pulse is, for example, short enough that a characteristic peak is not reached. For example, the short predetermined period is from 1 millisecond to 300 milliseconds, such as 2 milliseconds, 5 milliseconds, 10 milliseconds, 100 milliseconds or 200 milliseconds. The short-term control signal c is at its high level state between t ON,S and t OFF,S during which fluid is injected from the pressure source 160 into the first lumen 120.

[0077] FIG. 8b shows, as a function of time, the pressure in the first lumen 120 during a short period for a catheter with a new expandability retaining element of a first size (pressure function 11), a catheter with a new expandability retaining element of a second size (pressure function 11'), a catheter with a used expandability retaining element of the first size (pressure function 12), a catheter with a used expandability retaining element of the second size (pressure function 12'), and a catheter without an expandability retaining element (pressure function 13), where the second size is smaller than the first size. A similar curve distribution is obtained for the current or voltage supplied to the pump during a short period.

[0078] Therefore, if there is sufficient measurement accuracy of the pressure parameter, the functional parameters of the catheter 200 can be determined by measuring the pressure parameter during a predetermined short period. For example, the rate of change or the maximum value reached of the starting pressure curves 11, 11', 12, 12', 13 during a short period may be used to determine the functional parameters of the catheter.

[0079] FIGS. 8a and 8b also show a predetermined rest time between time t OFF,S and time t C . At t OFF,S , the pressure source is stopped but the valve of the relief valve 175 is closed, while at t C , the relief valve 175 is opened to vent the first lumen 120. Therefore, the pressure functions 11, 11', 12, 12', 13 remain substantially constant during the predetermined rest time, but at t CWhen the relief valve 175 is opened later, the pressure begins to drop.

[0080] By closing the valve and stopping the pressure source at a timing slightly before the relief valve 175 is opened, a similar pause time as described in FIG. 5a may also be set for a long predetermined period. The pressure parameter may be measured at any timing during at least one of a predetermined period when the valve is open and / or the pressure source is in an operating state, a pause period when the pressure source is stopped, or a second predetermined period when the first lumen is depressurized.

[0081] Those skilled in the art will recognize that the present invention is in no way limited to the preferred embodiments described above. Rather, many modifications and variations are possible within the scope of the appended claims. For example, the sensor may measure both the fluid pressure within the first lumen and the current or voltage supplied to the pump, in which case the functional parameter is based on at least two pressure parameters, namely the measured pressure within the first lumen and the current or voltage supplied to the pump.

Claims

1. A method for determining functional parameters of a catheter, comprising: connecting the catheter to a catheter connector interface, the catheter connector interface comprising a first lumen configured to be in fluid communication with an inflation retention element of the catheter and a second lumen configured to be in fluid communication with a main lumen of the catheter; injecting fluid into the first lumen for a predetermined period of time; measuring a pressure parameter related to the pressure in the first lumen; determining the functional parameters of the catheter based on the measured pressure parameter. A method as described above.

2. Measuring a pressure parameter related to the pressure in the first lumen further comprises: measuring the fluid pressure in the first lumen using a pressure sensor, and the pressure parameter is based on the fluid pressure. The method according to claim 1.

3. Injecting fluid into the first lumen comprises: operating an electric pump to deliver the fluid into the first lumen, and the pressure parameter is determined based on the voltage or current supplied to the pump. The method according to claim 1 or 2.

4. Determining the functional parameters comprises: determining whether the pressure parameter exceeds a first predetermined threshold, and if the pressure parameter exceeds the first predetermined threshold, assigning a first value to the functional parameter, otherwise assigning a second value to the functional parameter. The method according to any one of claims 1 to 3.

5. Determining the functional parameters further comprises: determining whether the pressure parameter exceeds a second predetermined threshold, where the second predetermined threshold is higher than the first predetermined threshold, and if the pressure parameter exceeds the second predetermined threshold, assigning a third value to the functional parameter. The method according to claim 4.

6. The first value of the functional parameter indicates that the catheter has a new inflation retention element, and the second value of the functional parameter indicates that the catheter has a used inflation retention element. The method according to claim 4 or 5.

7. ​ ​ ​ ​ The method according to claim 5, wherein the third value of the functional parameter indicates that the first lumen is disconnected from fluid communication with the expandability retaining element. **Claim 8** Measuring a pressure parameter related to the pressure in the first lumen includes measuring a plurality of pressure parameter samples, and the pressure parameter is based on the plurality of pressure parameter samples, the method according to any one of claims 1 to 7. **Claim 9** The first lumen is isolated from the pressure source by a valve, The method according to any one of claims 1 to 8, further comprising opening the valve during the predetermined period and injecting pressurized fluid from the pressure source into the first lumen during the predetermined period. **Claim 10** Measuring the pressure parameter includes measuring the pressure parameter during the predetermined period, the method according to any one of claims 1 to 9. **Claim 11** The predetermined period is a first period, The method further includes stopping the injection of the fluid after the predetermined first period, Measuring the pressure parameter includes measuring the pressure parameter during a second period, the second period following the first period, the method according to any one of claims 1 to 10. **Claim 12** The functional parameter indicates at least one of whether the catheter has an expandability retaining element, whether the expandability retaining element is new or used, and the size of the expandability retaining element, the method according to any one of claims 1 to 11. **Claim 13** The predetermined period is from 1 millisecond to 10 seconds, preferably from 3 milliseconds to 5 seconds, the method according to any one of claims 1 to 12. **Claim 14** A first lumen configured to be in fluid communication with an expandability retaining element of the catheter, A second lumen configured to be in fluid communication with a main lumen of the catheter, A catheter connector interface comprising: Operating a fluid injection means to inject fluid into the first lumen for a predetermined period; Measuring a pressure parameter related to the pressure in the first lumen; Determining a functional parameter of the catheter based on the measured pressure parameter; A catheter control unit configured to perform; A catheter control assembly comprising. **Claim 15** A computer program product comprising instructions which, when executed by a computer, perform the method according to any one of claims 1 to 13.

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