RU2453342C2 - Disposable extracorporeal circulation and extracorporeal blood treatment apparatus - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions refers to medicine. A cartridge unit comprises a rigid body, a first flexible tube with its first and second ends attached to the rigid body forming a loop part wherein there is a hose pump rotor of a medical device with the first end of the first flexible tube connected to an outlet of a first chamber, a second flexible tube with its first end connected to an inlet of a first chamber, a third flexible tube with its first end attached to the rigid body and being in a liquid connection with a second end of the first tube. A rigid tubular part comprises first and second terminal connector and an intermediate portion passing between the connectors contacting with a fluid medium flowing through the intermediate portion for the purpose of measuring a fluid medium parameter. The first terminal connector is attached to one element chosen from a group consisting of: the second end of the second flexible tube, and the second end of the third flexible tube. The connectors have an external prismatic surface having radially projecting element coupled with a connective socket on a holder of the apparatus. There are disclosed versions of the cartridge unit, the rigid tubular part and a medical apparatus applying them.

EFFECT: reliable and reproducible measurement of blood parameters.

30 cl, 20 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to a single-use extracorporeal circulation circuit, as well as a device for extracorporeal blood processing, adapted for use with the indicated extracorporeal circulation circuit.

BACKGROUND

Extracorporeal circulatory circuits are used to transport blood from the body: blood is usually pumped through tubes, as well as arterial and venous traps for bubbles, a set of disposable tubes connecting the patient to a blood processing device, such as a dialyzer, which is installed on a dialysis device or for processing another type (hemofilter, ultrafilter, hemodiafilter, plasma filter and so on) associated with the corresponding blood processing unit.

Integrated solutions were used to simplify equipment setup before processing.

US Pat. No. 4,263,808 discloses an integral circuit that includes arterial and venous trap chambers for air bubbles into which blood enters through inlets located above the lower parts of the chambers and exits near the lower parts of the chambers. The pressure in the chambers can be determined using pressure sensors placed on impermeable latex membranes covering the openings in communication with the upper parts of the chambers.

US Pat. Nos. 4,798,090 and 4,666,598 describe an integral cassette of fluid flow chambers that can be mounted on an auxiliary apparatus. The cartridge is equipped with a flexible tube that extends from the side wall and forms a loop symmetrical with respect to the axis of the loop, which is directed perpendicular to the side wall so that the pump roller on the apparatus acts on the loop when the front wall is placed on the apparatus. One end of the flexible tube is connected to the outlet of the camera on the bottom of the camera, and the other end is connected to the inlet of the channel in the cassette located at the same distance from the loop axis as the outlet of the camera; the cassette includes two chambers (arterial and venous chambers) and additional flexible tubes for connecting the dialyzer between the channel and the venous chamber; the outlet of the venous chamber is located in the lower part of the venous chamber; and inlets in the arterial and venous chambers are located above the outlet openings of the chambers. During use with the dialyzer, blood from the patient passes through the arterial chamber, the loop of the pump and the channel into the dialyzer, and from it through the venous chamber and back to the patient.

It is also known to measure the concentration of hemoglobin in the blood circulation of a dialysis unit: a known method for determining the concentration of hemoglobin in red blood cells during hemodialysis, using highly accurate invasive type measurements that require laboratory examination of blood samples.

Other dialysis units provide a non-invasive measurement of hemoglobin concentration within the unit. Non-invasive measurements performed in the installation are less accurate compared to laboratory measurements, however, they have the advantage of being able to perform them in real time, due to which the operating parameters of the hemodialysis unit can be instantly adjusted.

Italian Patent IT 1240489 discloses a method for measuring hemoglobin concentration in an apparatus and in a non-invasive manner by measuring the absorption of electromagnetic waves in the blood flowing in the arterial compartment of the primary circuit.

In order to implement this method, the blood circulation circuit, including the arterial line, the venous line and the bubble trap in the arterial line, also including the calibrated and rigid part of the transparent tube, is fixedly connected to the outlet of the bubble trap before connecting to the dialyzer. The specified calibrated part of the transparent tube is designed to be installed in an appropriate holder, in which a radiation source and a sensor function, which emit and then detect the absorption of electromagnetic waves.

US6794194 discloses another method for measuring the concentration of hemoglobin in the extracorporeal circulation circuit of a hemodialysis unit, including measuring the absorption values of electromagnetic waves transmitted through a section of the circuit in the blood, followed by calculating the concentration of hemoglobin based on the absorption values and the measured values of blood pressure, blood temperature and flow rate blood in the above section. According to this method, the rigid part of the calibrated and transparent tube also includes a pressure sensor located between the blood pump and the dialyzer in accordance with the arterial line, in a position in which both the electromagnetic wave sensor and the pressure sensor, which contains the installation.

It is also known to use the measurement of hemoglobin concentration as a parameter that allows you to control the removal of fluid from the blood. For example, you can adjust the speed of ultrafiltration by measuring the concentration of hemoglobin in the blood in front of the apparatus for processing and maintaining a specified concentration of hemoglobin or a parameter that depends on the concentration of hemoglobin (such as filter coefficient) within the acceptable range during processing.

Finally, EP0467805 shows a blood processing device with an optical / electronic system including a light emitting diode (LED) and a photosensitive sensor capable of receiving light emitted by an LED and supplying an appropriate electrical signal. The circuit for processing this electrical signal can be distinguished when, during use, the tube through which blood is supplied is located between the LED diode and the sensor. The equipment is equipped with a test control circuit, which serves to verify the proper operation of the equipment elements.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a disposable cartridge block comprising a blood pump segment and a connected tube portion for reliable and reproducible measurement of a parameter, such as hemoglobin concentration.

Another object of the invention is a disposable cartridge unit, which is designed to isolate the portion of the tube to be measured from interference from drives acting on the blood pump segment.

An additional object of the invention is a disposable cartridge unit in which a portion of a tube designed to be measured is provided with appropriate devices that ensure that the portion of the tube is correctly positioned and identified in order to prevent the use of tubes that are not suitable for measurement.

According to one embodiment, the disposable cartridge block is capable of causing a consistent signal to be generated in the case of measuring hemoglobin concentration or an associated parameter.

According to the present invention, a disposable cartridge block for a medical device for extracorporeal fluid treatment, equipped with at least a peristaltic pump, includes:

a rigid body defining at least a first fluid flow chamber, which also has an inlet in said first chamber and an outlet from said first chamber,

- the first flexible tube, the first and second end of which is attached to the rigid body, forming a part of the loop in which the rotor of the peristaltic pump of the medical device for processing is placed, while the first end of the first flexible tube is connected to the specified outlet of the first chamber,

- a second flexible tube, the first end of which is connected to the inlet of the specified first chamber,

- a third flexible tube, the first end of which is connected to a rigid body and is in fluid communication with the second end of the specified first tube, where the cassette unit further includes:

a rigid tubular part containing:

first end connector

a second end connector opposite the specified first end connector, and

an intermediate portion extending between said first and second end connectors, exposed to a fluid flowing through said intermediate portion to measure at least a fluid parameter,

the first end connector of the rigid tubular part is attached to one selected from the group including the second end of the second flexible tube and the second end of the third flexible tube.

A cassette unit may include one or more of the following features:

- the specified intermediate part may have a constant cross section.

- the specified intermediate part may have a toroidal cross section.

- the specified intermediate part may be at least partially permeable to electromagnetic and / or acoustic waves.

- when the first end connector of the rigid tubular part is attached to the second end of the second flexible tube, the second flexible tube may have an axial extension L, inner diameter Di, outer diameter De and hardness H, which satisfy at least one of the following conditions:

L / Di> 10

2L / (De-Di)> 50

H <85 Shore A

thus defining the deformable part between the rigid body and the rigid tubular part.

- when the first end connector of the rigid tubular part is attached to the second end of the third flexible tube, the third flexible tube may have an axial extension L, inner diameter Di, outer diameter De and hardness H, which satisfy at least one of the following conditions:

L / Di> 10

2L / (De-Di)> 50

H <85 Shore A

thus defining the deformable part between the rigid body and the rigid tubular part.

- said first and second end connectors may have an outer prismatic surface and an inner cylindrical surface, and on the outer prismatic surface of at least one of said end connectors there is a radially protruding element, which is designed so that when used it is connected to a connecting slot located on the holder of the medical device; the radially protruding element can be integral with the rigid tubular part and includes side walls extending from the outer surface of the end connector and an end wall extending transversely to the specified side walls; the side walls of the protruding element may converge slightly when moving from the outer surface of the end connector, while the specified end wall can be essentially flat and parallel to the longitudinal axis of the scan of the rigid tubular part.

- said first and second connectors may have an outer prismatic surface and an inner prismatic surface, wherein the outer prismatic surface of at least one of said connectors has a radial recess, which is designed so as to be connected to the connecting protrusion on the holder of the medical device when used. The outer prismatic surface may have a pair of extensions, including two longitudinal and parallel ridges defining a radial depression.

- the rigid plastic housing may have front and rear walls that are separated from each other, and side walls between said front and rear walls defining said first fluid flow chamber.

- the rigid body may be a one-piece body of transparent plastic, while the rigid tubular part is a one-piece body of transparent plastic.

- the first end connector of the rigid tubular part can be attached to the second end of the second flexible tube, and the specified second end connector of the rigid tubular part is attached to the first end of the fourth flexible tube; in this case, the second end of the fourth flexible tube is equipped with a connector for connection with a vascular access device, and the second end of the third tube is equipped with a connector for connection with a blood processing unit.

- the first end connector of the rigid tubular part can be attached to the second end of the third flexible tube, and the specified second end connector of the rigid tubular part is attached to the first end of the fourth flexible tube. In this case, the second end of the second flexible tube is equipped with a connector for connection with a vascular access device, and the second end of the fourth tube is equipped with a connector for connection with a blood processing unit.

- the rigid body may also include an intermediate wall located between the side walls defining a second fluid flow chamber.

- the rigid body may also include a rigid channel extending above the fluid flow chamber and connecting the first end of the third flexible tube to the second end of said first tube.

- the second fluid flow chamber may have a second inlet and a second outlet, wherein said second inlet is connected to an end of a fifth flexible tube, at the other end of which is a connector for connection to a blood processing unit, and said second outlet is connected to an end of a sixth a flexible tube, at the other end of which there is a connector for connecting to an access device.

A further object of the invention is to provide a medical device into which a cassette unit according to the invention is installed.

Another objective of the invention is the creation of a medical device having the ability to interact with the rigid tubular part of the cassette unit to make accurate and reproducible determinations of the measured parameter, for example, hemoglobin concentration.

The next objective of the invention is the creation of a medical device having the ability to improve the accuracy of measurements, ensuring the correct position of the right rigid tubular part when measuring, in accordance with the correct position.

According to one embodiment, the medical device is capable of generating a consistent signal for measuring hemoglobin concentration, performed only when the correct tubular portion is detected in the correct position.

One or more of the above problems are solved by the cassette unit according to one or more relevant aspects of the invention set forth in the appended claims relating to the cassette unit.

One or more of the above objectives are also accomplished by a medical device in accordance with one or more relevant aspects of the invention set forth in the appended claims relating to the medical device.

According to the invention, a medical device for extracorporeal fluid treatment contains:

a main supporting structure having at least a receiving part and a holder,

a cassette unit according to any one of the preceding paragraphs, mounted on a receiving part supported by the main supporting structure,

at least a peristaltic pump supported by the main support structure and having a rotor, wherein the rotor of the peristaltic pump is placed in the loop portion of the cassette unit,

a holder holding the rigid tubular part of the cassette unit.

A device may also include one or more of the following features:

- the holder may include a base supported by the support structure and determining the mounting location of at least the rigid tubular part, and the first sensor, and also includes at least a signal source and a sensor that can detect a return signal.

- the source may include a wave source that emits electromagnetic or acoustic waves with an intensity and frequency of emission, and the sensor may include a sensor of electromagnetic or acoustic waves, which can detect the received intensity and / or frequency.

- a control unit associated with the first sensor and including a device for calculating the parameter of the fluid circulating through the rigid tubular part, based on one characteristic selected from the group including:

indicated emitted and received intensities

indicated emitted and received frequencies

phase shift between the indicated emitted and received waves.

- a device for calculating a parameter of a fluid circulating in a rigid tubular part may include:

a device for calculating the difference or relationship between the radiation intensity and the received intensity,

a device for determining energy absorption by a fluid circulating in a rigid tubular part based on a specified difference or a specified ratio,

a device for determining a parameter of a fluid circulating in a rigid tubular part based on said absorption.

- when the fluid is blood, the parameter of the fluid circulating through the rigid tubular part includes at least one parameter selected from the group consisting of: blood density, blood hematocrit, hemoglobin concentration in the blood, average blood cell volume.

- the source and the sensor can be placed in accordance with the specified intermediate part of the rigid tubular part.

- the holder may also include a lockable element that is attached to the base and which can be moved between a closed position in which it closes the fastening place and fixes the rigid tubular part in position, and an open position in which the closed element leaves the fastening place open, allowing such thus installing or removing the tubular part, to or from the attachment point. The signal source and the sensor can be placed according to one of the configurations selected from the group including: a solution in which the element to be closed rigidly holds one of the specified source and sensor, and the base rigidly holds the other of the specified source and sensor; a solution in which the element to be locked rigidly holds both the specified source and the sensor; a solution in which the base rigidly holds both the specified source and the sensor.

- the sensor may have a reflector, which is a reflective surface that completely surrounds the intermediate part, a signal source and a sensor placed in accordance with the specified reflector.

- the closable element may include a flap movable around an axis on one side of the base, and the flap rotates around the specified axis, moving between the specified open and closed positions, and includes at least one locking element that interacts with the counter-locking element based on while the locking and counter-locking elements are connected in accordance in the specified closed position. The shutter may have two locking elements, one on each side, each of which interacts with one corresponding counter-locking element on the basis of which the locking and counter-locking elements are connected in accordance with the specified closed position. Each locking element may include an elastically deformable flat foot, one end of which is attached to the sash, and a protrusion is located at the other end, which, in accordance with the specified closed position, engages in a correspondingly shaped slot defined on the basis.

- the holder may also include a second sensor, which is at least capable of detecting when the element to be closed is in the closed position and supplying a signal corresponding to the closing signal.

- the control unit may be connected to the second sensor and may include a device for determining whether the element to be closed is actually in the closed position based on the specified closing signal supplied by the second sensor.

- the mounting location may include a first part repeating the shape of the first end connector, and a second part repeating the shape of the second end connector.

- the first and second parts of the attachment point can be a prismatic surface, the prismatic surface of at least one of the first and second parts having a radial recess that interacts with a connecting protrusion located on one of the end connectors.

- the first and second parts of the attachment point can be a prismatic surface, and the prismatic surface of at least one of the first and second parts has a radial protrusion that interacts with the connecting recess on one of the end connectors.

- the third sensor can be connected to one of the indicated first and second parts of the attachment point in order to detect the presence, as well as the proper position of the rigid tubular part at the attachment point in the holder and give a corresponding signal of coincidence.

- depending on the housing, the third sensor may be designed to detect the presence of the correct connection between the protrusion on the end connector and the radial recess at the attachment point, and provide a matching signal or detect the presence of the corresponding coupling between the protrusion at the attachment point and the radial depression on the end connector, and give the appropriate match signal.

- the control unit may be connected to the third sensor and may include a device that determines whether the proper rigid tubular part is in the correct position within the mounting location, based on the specified signal of conformity supplied by the third sensor.

- the processing unit may be associated with the main supporting structure, the processing unit having a semi-permeable membrane that divides the processing unit into at least a first chamber for blood flow, which is in fluid communication with the cassette unit, and a second chamber, which has, at least an outlet port that is in fluid communication with the outlet line, while there may be a device for regulating the clean flow of plasma water passing through the semipermeable membrane from the first to the second chamber, and vice versa. A device may be present to control the adjusting devices based on values obtained from said calculated parameter.

- the control unit may include a device for determining whether the proper rigid tubular part is in the correct position within the mounting location, based on the specified signal of conformity supplied by the third sensor. The control unit includes a device for controlling the device for activating the first sensor only when the device for determining has given a positive conclusion that the proper rigid tubular part is in the correct position within the mounting location.

- the control unit may also include a device for signaling that the fluid parameter cannot be calculated until the device for determining gives a positive conclusion that the proper rigid tubular part is in the correct position within the mounting location.

- the control unit may also include a device for activating said device for controlling adjusting devices only when the device for determining has given a positive conclusion that the proper rigid tubular part is in the correct position within the attachment point.

- when the device includes a supply line for the processed fluid connected to the inlet of the second chamber of the blood processing unit, then a device for controlling the chemical composition of the processed fluid may be present on the supply line, and the control unit may also include a device controlling the device for controlling the chemical composition based on values obtained from the specified calculated parameter.

Finally, the invention relates to a rigid tubular part for an extracorporeal circulation circuit, which includes:

first end connector

a second end connector opposite the specified first end connector, and

an intermediate portion extending between said first and second end connectors, which is in contact with a fluid flowing through said intermediate portion to measure at least a fluid parameter, i.e., a tube.

The following describes the possible features of the rigid tubular part and the cassette unit in which the rigid tubular part is rigidly fixed.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages will be best understood from the detailed description of some non-limiting embodiments of the present invention. This description will be given below with reference to the accompanying drawings, also given by way of non-limiting example, in which:

FIG. 1 is a front view of a first embodiment of a cartridge unit for use with a medical fluid processing device.

FIG. 1A is a side view of part of the embodiment of FIG. 1.

FIG. 2 is a front view of a second embodiment of a cartridge unit for use with a medical fluid processing device.

FIG. 2A is a side view of part of the embodiment of FIG. 2.

FIG. 3 is an enlarged perspective view of a rigid tubular part for use in the cassette unit of FIG. 1 or FIG. 2.

FIG. 4 is a front view of the rigid tubular portion of FIG. 3.

FIG. 5 is a side view of the rigid tubular portion of FIG. 3.

FIG. 6 is a sectional view along the plane of section VI-VI of FIG. 5.

FIG. 7 is a plan view of the rigid tubular portion of FIG.

FIG. 8 is a sectional view along the plane of section VIII-VIII of FIG. 4.

FIG. 9 is a sectional view along the section plane IX-IX of FIG. 5.

FIG. 10 is an enlarged view of a sectional view of FIG. 6.

FIG. 11 is a partial perspective view of a medical device into which the cassette unit of FIG. 1 can be inserted.

FIG. 12 is a perspective view relative to the holder of the device of FIG. 11, in the closed position.

FIG. 13 is a perspective view relative to the holder of the device of FIG. 11, in an open position.

In FIG. 14 is an enlarged top view of an alternative embodiment of a rigid tubular portion connected to the cassette unit of FIGS. 1 and 2.

In FIG. 15 is an enlarged and partial side view of the rigid tubular portion of FIG.

In FIG. 16 and 17 show a cross-section and a longitudinal section of the attachment point at which the rigid tubular portion of FIG. 14 can operate.

In FIG. 18 and 19, in partial cross section, shows an alternative form of attachment point and a rigid tubular portion.

FIG. 20 is a schematic diagram of a blood processing unit.

DETAILED DESCRIPTION

Regarding the accompanying drawings, reference numeral 1 denotes a medical device for extracorporeal fluid processing. In particular, the device may be a blood processing device, such as, as a non-limiting example, an apparatus for treating kidney or liver failure. In the example shown in the accompanying figures, the medical device 1 is an apparatus for one or more of the following extracorporeal blood treatments: hemodialysis, hemofiltration, ultrafiltration, hemodiafiltration and plasmapheresis.

The device 1 includes a main supporting structure 2 and a working panel 3, which can be located in front of the device, including a user interface 4 (shown only schematically), one or more pumps 5 (volumetric pumps, acting due to the deformation of deformable parts of the tube, such as peristaltic pumps) and at least a holder 6 having a structure that allows the insertion of a rigid tubular portion subjected to non-invasive measurement, as described in detail below.

The device is also equipped with an auxiliary holder 7 for installing at least a blood processing unit 8 (for example, a dialyzer, or an ultrafilter, or a hemofilter, or a hemodiafilter, or a plasma filter). The blood processing unit may include, as is essentially known, and therefore not further shown in detail, the first and second compartments separated by a semipermeable membrane. The first compartment is for the passage of blood, and the second compartment is for the passage of removed substances and / or treated fluid.

The medical device also has a receiving part 9 for holding the cassette unit 10. In the accompanying drawings, the receiving part is located on the front panel 3 in the immediate vicinity of the peristaltic pump 5 and interacts with a rotating leaf, which serves to fix the cassette unit and part of the flexible tube in the working position, interacting with the rotor.

The disposable cartridge unit 10 includes a rigid body 11 defining at least a first fluid flow chamber 12; in fact, in the embodiment shown, the rigid body defines two chambers 12, 13. For example, for determining a two-chamber rigid structure, the rigid body can have front and rear walls and side walls separated from each other between said front and rear walls, as well as an intermediate wall, which interacts with the side walls, defining these two chambers. Pressure sensors 12a and 13a can be connected to each of the walls of the two chambers, as is essentially known, and is not shown in further detail.

If necessary, observe the material that flows in the cassette unit, as, for example, is required in the case of blood processing, the rigid body can be made of transparent plastic. A rigid body, for example, made of a single transparent PVC material, also defines an inlet 14 into the first chamber 12 and an outlet 15 from said first chamber. In the embodiment of FIG. 1, both the inlet 14 and the outlet 15 are respectively located in the lower part of the rigid body 11.

The cassette unit includes a plurality of flexible tubes that are attached to a rigid body. In more detail, the first and second end 17 and 18 of the first flexible tube 16 are attached to the rigid body, forming the part of the loop 19 into which the rotor of the peristaltic pump 5 is inserted: the first end 17 of the first flexible tube is connected to the specified outlet 15 of the first chamber, while the second the end 18 of the first flexible tube is attached to the housing in a position that is offset vertically relative to the first end, as shown in figures 1 and 2.

The first end 21 of the second flexible tube 20 is connected to the inlet 14 of the specified first chamber 12. The first end 23 of the third flexible tube 22 is attached to the rigid body 11 and is in fluid communication with the second end 18 of the specified first tube 16.

The cassette unit 10 further includes a rigid tubular part 24, which is provided with a first end connector 25, a second end connector 26 opposite to the specified first end connector 25, and has an intermediate part 27 that extends between the first and second end connectors 25, 26. The intermediate part 27 is designed and calibrated so that during application, when blood or other fluid flows through it, it allows the fluid flowing through the specified intermediate part 27 to be non-invasive th dimension of some of the fluid parameters. The intermediate portion 27 may have a constant cross section and may be made of at least partially transparent material.

Of course, the cross section may also vary, but this may entail a complication of the measurement procedure. Regarding the shape, referring again to the illustrated embodiment, the intermediate portion 27 may have a toroidal cross section.

In the shown embodiment, the rigid tubular portion 24 is made integrally from a transparent plastic, for example polyvinyl chloride (of course, other hard plastics can alternatively be used).

In the embodiment of FIG. 2, the first end connector 25 of the rigid tubular portion 24 is attached to the second end 28 of the second flexible tube 20. In this case, the second flexible tube 20 has a predetermined axial extension sufficient to absorb, under axial deformation or bending, all relative displacements between the rigid body 11 and the rigid tubular part 24, when in the process of application they are installed on the medical device 1.

For example, the length of the second flexible tube 20 may be equal to or greater than the axial length of the rigid tubular portion 24. According to another aspect, the axial length of the second flexible tube 20 of FIG. 2 may be more than three times its outer diameter.

In accordance with another, alternative or additional aspect, the second flexible tube has an axial elongation L, an inner diameter Di, an outer diameter De, and a hardness H that satisfy at least one of the following conditions:

L / Di> 10

2L / (De-Di)> 50

H <85 Shore A

Thus, determining the deformable part between the rigid body and the rigid tubular part, thus isolating the holder from vibrations that can impair the measurement quality of the specified parameter.

In the example shown:

L / Di> 18

2L / (De-Di)> 55

H <80 Shore A

In the case of figure 2, the second end connector 26 of the rigid tubular portion 24 is attached to the first end 29 of the fourth flexible tube 30, while the second end 31 of the fourth flexible tube 30 is provided with a connector 32 for a vascular access device (such as a cannula, needle, catheter or other access), and the second end 33 of the third tube 22 is equipped with a connector 34 for connection to the corresponding connector on the input port of the first chamber of the blood processing unit (not shown).

In the embodiment of FIG. 1, the first end connector 25 of the rigid tubular portion 24 is attached to the second end 33 of the third flexible tube 22. In this case, the third flexible tube 22 has a predetermined axial extension that is sufficient to absorb, under axial deformation or bending, all relative displacements between the rigid body 11 and the rigid tubular part 24, when in the process of application they are installed on the medical device 1.

For example, the length of the third flexible tube 22 may be equal to or greater than the axial length of the rigid tubular portion 24. According to another aspect, the third flexible tube has an axial elongation L, an inner diameter Di, an outer diameter De, and a hardness H that satisfy at least one of the following conditions:

L / Di> 10

2L / (De-Di)> 50

H <85 Shore A

Thus, determining the deformable part between the rigid body and the rigid tubular part, which is capable of absorbing any relative motion between the rigid body and the holder, thus isolating the holder from vibrations that can impair the measurement quality of this parameter.

In the example shown:

L / Di> 18

2L / (De-Di)> 55

H <80 Shore A

In the case of FIG. 1, the second end connector 26 of the rigid tubular portion 24 is attached to the first end 29 of the fourth flexible tube 30, and the second end 31 of the fourth tube 30 is provided with a connector 34 that connects to a corresponding connector on the inlet port of the first chamber of the blood processing unit (not shown). In the example of FIG. 1, a second flexible tube 20 is provided at its second end with a connector 32 for a vascular access device (such as a cannula, needle, catheter, or other access).

In both embodiments of FIGS. 1 and 2, the cassette unit 10 includes a rigid channel 35 extending above the fluid flow chambers 12, 13 and connecting the first end 23 of the third flexible tube 22 to the second end 18 of said first tube 16. In addition, the second flow chamber the fluid 13 has a second inlet 36 and a second outlet 37 (on which the venous filter 38 can operate): the second inlet 36 is connected to the end of the fifth flexible tube 39, at the other end of which there is a connector 40 connected to the blood processing unit and through an appropriate connector on the outlet port of the first chamber of the blood processing unit (not shown). The second outlet 37 of the second chamber 13 is connected to the end of the sixth flexible tube 41, on the other end of which there is a connector 42 connected to an access device (such as a cannula, needle, catheter, or other access).

In the shown embodiments, the fastening device 43 is connected to a cassette unit for mounting said body to said installation. In this case, the mounting device includes at least one protrusion 44, rigidly attached to the rigid housing. The fastener 43 also includes tubular extensions 45, 46, rigidly attached to one side of the rigid body 11 and connected to the corresponding opposite end of the first flexible tube 16. The specified fastener 43 interacts with the corresponding gripping elements on the front panel of the installation in accordance with the specified receiving part . Of course, other fastening devices may be used, such as extension cords or recesses in positions other than those described above, or the walls of the cassette unit and the corresponding receiving parts may be given a suitable shape and so on.

Turning further to a more detailed description of the rigid tubular portion 24 (see FIGS. 3-9, 14, 15), the first and second end connectors 25, 26 have an external prismatic, for example cylindrical, surface and an internal prismatic surface; the inner prismatic surface of each end connector in the shown embodiments includes a main cylindrical channel 25a, 26a and a front edge 25b, 26b in the form of a truncated cone. The diameter of the cylindrical channels is larger than the diameter of the inner surface 27a of the intermediate part, and thus defines the stop 25c, 26c for connecting the ends of the tube. It should be noted that the inner surface 27a of the intermediate part 27 may be prismatic, and in this case is cylindrical, and extends directly to the stop. In practice, in order to eliminate stagnation areas, the diameter of the cylindrical channels 25a, 26a can be made equal to the diameter of the inner surface 27a of the intermediate part, plus the ends of the tubes attached in accordance with these end connectors can be twice as thick. This ensures that a continuous and smooth channel will pass through the entire rigid tubular part during use. The outer prismatic surface of at least one of these end connectors is provided with a radially protruding element 47, which is designed to interact during use with the corresponding connecting recess 48 located on the holder 6 of the medical device.

The radially protruding element 47 is integral with the rigid tubular part 24 and includes side walls 49 extending from the outer surface of one of the end connectors and an end wall 50 located transversely to the side walls 49. In the shown embodiment, two opposite side walls 49 may protrude on the surface of the end connector and end with the end wall 50. The protrusion can also have two opposite side recesses 51, which in the example of Fig.3-10 pass inside the protrusion, giving the protrusion cross section of a T-shape (see Fig. 8).

Opposite side walls of the protruding element may converge slightly (see FIGS. 6 and 10), at least at their respective end, along the outer surface of the end connector; the end wall is essentially flat and parallel to the longitudinal axis of the scan of the rigid tubular part.

Alternatively or in combination with a protrusion (please see the example of FIGS. 14-17), one of the end connectors 25, 26 may have one or more recesses 52 on its outer surface. In particular, referring to the shown embodiment, the first and second connectors, which have an outer prismatic surface and an inner cylindrical surface, can have a pair of extensions 53 defining a radial recess 52, which serves to interact during use with the corresponding connecting protrusion 54 on the medical holder devices. In the embodiment shown, the extensions include two longitudinal and parallel ridges forming a radial recess having a substantially U-shaped cross section. When the protrusions are connected to the recess 52, the extensions 53 enter the slots 55 of the corresponding shape on the holder 6.

Further, returning to the whole device, the device 1 in the accompanying figures includes, as indicated, a holder 6 for the rigid tubular part 24. The specified holder may include a base 56 supported on a support structure and determining the mounting location 57 for installing at least a rigid tubular parts 24, as well as a first sensor 58 connected to the base and including at least a signal source 59 and a sensor 60 that can detect a return signal. The rigid tubular portion includes at least a portion that is permeable or at least partially permeable to said signals in order to provide a non-invasive measurement taking into account the effect of the liquid on said signals.

In more detail, the signal source includes a wave source that emits electromagnetic or acoustic waves with a specified emission parameter (for example, a specific intensity or frequency), and the sensor includes an electromagnetic or acoustic wave sensor that can detect the received intensity, or frequency, or phase. The control unit 61 associated with the first sensor includes a device for calculating the parameter of the fluid circulating in the rigid tubular part based on the indicated emitted and received intensities, or a phase change between the emitted and received signals, or a frequency change between the emitted and received signal.

In an embodiment described below, a device for calculating a parameter of a fluid circulating in a rigid tubular part may include: a device for calculating a difference or a relationship between an emitted intensity and a received intensity, a device for determining energy absorption of a fluid circulating in a rigid tubular part, based on the specified difference or the specified ratio, a device for determining the parameter of the fluid circulating in the rigid tubular part, on the basis of the specified absorption.

When the fluid is blood, the parameter of the fluid circulating through the rigid tubular part includes at least one characteristic selected from the group including:

- blood density

- blood hematocrit,

- the concentration of hemoglobin in the blood,

- the average volume of blood cells.

The signal source and the sensor 59 and 60 are placed in accordance with the specified intermediate part, which is at least partially permeable to the specified acoustic or electromagnetic waves, the rigid tubular part.

The holder also includes a closable element 62, which is attached to the base and which can be moved between a closed position in which it closes the fastening place and fixes the rigid tubular part in the working position, and an open position in which the closable element leaves the fastening place open, allowing such thus installing or removing the tubular part, on or in place. A lockable element 62 can rigidly hold one of the specified signal source and sensor, while the base rigidly holds the other of the specified signal source and sensor. Alternatively, both the signal source and the sensor may be located on the base, or both may be located on the closable member. When the element to be closed is closed, the signal source and the sensor function in direct contact with the outer surface of the intermediate part. In the embodiment shown, the closable member includes a sash movable about an axis 63 on one side of the base, with the sash being able to rotate about the axis, moving between the open and closed positions.

The leaf includes at least one locking element 64, which cooperates with the counter-locking element 65 on the basis of 56. When the leaf is in the closed position, the locking and counter-locking element are connected to each other, as shown in Fig.12, leaving two holes 66 for the passage of the ends of the tube connected to the rigid tubular part 24.

In the example, two locking elements 64, one on each side, interact with respective counter-locking elements on each side of the base and extend in the holder region 67 opposite to the axis of rotation, and when the flap closes, the rigid part of the tube and its mounting location in the holder located between the axis of rotation and the locking and counter-locking elements of the sash.

Each locking element may include an elastically deformable flat foot, one end 64a of which is attached to the sash, and on the other end 64b there is a protrusion 68, which is included in the corresponding counter-fixing element 65 in the form of a recess (in the embodiment, in the form of a slot), certain based on.

The holder 6 also includes a second sensor 69, which is at least capable of detecting when the element to be closed is in the closed position and to provide a corresponding closing signal. Of course, the sensor 69 can be more complex and can monitor every position of the closure element. In the shown embodiment, the sensor is a Hall sensor 69a, which is located on the base 56 and interacts with the magnet 69b on the leaf. Of course, alternative solutions, such as a switch or relay, or other equivalent solutions that detect the closure of the sash 62 can be used. The control unit is also connected to the second sensor and includes a means for determining whether the element to be closed is in the closed position based on the indicated signal closing supplied by the second sensor.

A third sensor 70 may also be present in the holder, operatively coupled to one of said first and second parts of the attachment point, for detecting the presence and proper position of the rigid tubular part at the attachment point in the holder, and supplying a matching signal. In more detail, the third sensor may be connected to one of said first and second parts in accordance with or in close proximity to said radial recess 48 (or radial protrusion 54, as the case may be) of the attachment point. The third sensor has a design that allows you to detect the presence of an appropriate grip between the protrusion 47 on the end connector and the radial recess at the attachment point and to provide an appropriate match signal.

Alternatively, in the embodiment of FIGS. 14-17, the third sensor is operatively connected to one of said first and second parts in accordance with the radial protrusion of the attachment point and has a structure that allows detecting the presence of a corresponding adhesion between the protrusion 54 at the attachment point and the radial recess 52 on the end connector and give the appropriate match signal. In fact, in the embodiment of FIG. 16, the sensor 70 is placed in the protrusion and detects the presence of ridges 53 in the slots 55. Optical data channels 70a can be provided when the ridges 53 enter the slots 55. As another alternative to FIG. 19 shows an alternative form for a protrusion in place of the holder 6 and the recess 52 on the end connector or connectors.

In any case, the control unit associated with the third sensor includes a device for determining whether the proper rigid tubular portion is in the correct position within the attachment point based on the specified signal of coincidence supplied by the third sensor.

As indicated, the processing unit 8 connected to the main supporting structure has a semi-permeable membrane 8a that divides the processing unit into at least a first blood flow chamber 71 in fluid communication with the cassette unit 9 and a second chamber 72, which has at least an outlet port in fluid communication with the outlet line 73.

The device may include devices for controlling 74 the clean flow of plasma water passing through the semipermeable membrane from the first to the second chamber, and vice versa. Appliances 74 are only shown schematically in FIG. 20 because their design is not relevant to this issue (they may include an ultrafiltration pump or two pumps, one on the inlet line for the process fluid 75 and one on the outlet line 73, which, when operating on different speeds determine ultrafiltration or reverse filtration into the blood circulation circuit 76, or even blood pumps in the blood circulation circuit, which can operate at different speeds).

In addition, the device may include a device 76 for regulating the chemical composition of the processed fluid in the supply line (in this case, details are also not given, since the specific design is not relevant to this issue; as an example, the device 77 may include one or more concentrates in liquid and / or powder state, connected to line 75 and appropriate flow controllers, such as valves or pumps controlled by the control unit, in order to achieve the desired composition the fluid to).

The control unit 61 also includes a device that controls devices 77 for adjusting the chemical composition based on the values provided by the specified calculated parameter. In more detail, the control unit may include one or more of the following devices:

a) a device for determining whether the proper rigid tubular part is in the correct position within the attachment location, based on the specified match signal supplied by the third sensor,

b) an apparatus for activating said first sensor supplying said signal and detecting said return signal,

c) a device for calculating a parameter of a fluid circulating in a rigid tubular part based on said emitted and return signals,

d) a device for controlling the regulating device 74 based on the values provided by the specified calculated parameter,

e) a device for controlling a device for controlling the chemical composition 77 based on the values provided by the specified calculated parameter.

The control unit includes a temporary device for sequential activation of the above devices a) -e).

The control unit may also include the following additional devices.

According to one aspect of the invention, the control unit includes a device for controlling the activating device only when the device for determining has made a positive conclusion that the proper rigid tubular part is in the correct position within the attachment point.

According to another aspect of the invention, the control unit also includes a device for signaling that the fluid parameter cannot be calculated until the device for determining gives a positive conclusion that the proper rigid tubular part is in the correct position within the mounting location.

According to another aspect of the invention, the control unit includes a device for activating said device for controlling the adjusting device only when the device for determining has made a positive conclusion that the proper rigid tubular part is in the correct position within the attachment point.

According to another aspect of the invention, the control unit includes a device for activating said device for controlling the chemical composition of the fluid to be treated in the supply line only when the determination device has made a positive conclusion that the proper rigid tubular part is in the correct position within the attachment point. Depending on the case, the control unit may be a fully digital unit including one or more central processors, or an analog control unit, or a combination of the two types indicated.

When the control unit is of the analog type, each of the above devices of the control unit is determined by a corresponding analog circuit in the control unit, preferably designed to perform a given function.

When, on the other hand, the control unit is partially or fully digital, then each of the above devices of the control unit is determined by the central processor by executing a corresponding program or system software that programs the central processor by determining one or more of the above devices of the control unit.

Claims (30)

1. A disposable cassette unit for a medical device for extracorporeal fluid processing, equipped with at least a peristaltic pump, including:
a rigid housing defining at least a first fluid flow chamber, said housing also having an inlet to said first chamber and an outlet from said first chamber,
the first flexible tube, the first and second end of which is attached to the rigid body, forming a part of the loop in which the rotor of the peristaltic pump of the medical device for processing is placed, while the first end of the first flexible tube is connected to the outlet of the first chamber,
a second flexible tube, the first end of which is connected to the inlet of the specified first chamber,
a third flexible tube, the first end of which is connected to a rigid body and is in fluid communication with the second end of the specified first tube, characterized in that the cassette unit further includes:
a rigid tubular part containing:
first end connector
a second end connector opposite the specified first end connector, and
an intermediate part passing between the first and second end connectors, exposed to a fluid flowing through said intermediate part for measuring at least a fluid parameter, the first end connector of the rigid tubular part being attached to one element selected from the group, comprising: a second end of a second flexible tube and a second end of a third flexible tube; where the specified first and second end connectors have an external prismatic surface, and the external prismatic surface of at least one of these end connectors has a radially protruding element, which is designed to interact with the corresponding connecting recess located on the holder of the medical device, moreover, the radially protruding element includes side walls extending from the outer surface of the end connector, and the end wall, transversely Proposition said sidewalls. 2. The cassette unit according to claim 1, wherein said intermediate part has a constant cross section and is at least partially permeable to electromagnetic and / or acoustic waves, in particular said intermediate part has a toroidal cross section. 3. The cassette unit according to claim 1 or 2, where either the first end connector of the rigid tubular part is attached to the second end of the second flexible tube, the second flexible tube having an axial extension L, inner diameter Di, outer diameter De and hardness H, which satisfy at least one of the following conditions:
L / Di> 10,
2L / (De-Di)> 50,
H <85 Shore A,
defining thus the deformable part between the rigid body and the rigid tubular part; or
the first end connector of the rigid tubular part is attached to the second end of the third flexible tube, the third flexible tube having an axial extension L, inner diameter Di, outer diameter De and hardness H, which satisfy at least one of the following conditions:
L / Di> 10,
2L / (De-Di)> 50,
H <85 Shore A,
thus defining the deformable part between the rigid body and the rigid tubular part. 4. The cassette unit according to claim 1, where the side walls of the protruding element converge slightly when moving from the outer surface of the end connector, and the specified end wall is essentially flat and parallel to the longitudinal axis of the scan of the rigid tubular part. 5. A cassette unit according to any one of claims 1, 2 or 4, wherein the rigid plastic housing has front and rear walls separated from each other, as well as a side wall between said front and rear walls, for determining said first fluid flow chamber, in particular, said rigid housing also includes an intermediate wall located between the side walls, which defines a second fluid flow chamber, in particular, a rigid housing also includes a rigid channel extending above the fluid flow chamber and connecting the first end of the third flexible tube with a second end of the specified first tube. 6. The cassette unit according to claim 1, wherein the first end connector of the rigid tubular part is attached to the second end of the second flexible tube, said second end connector of the rigid tubular part being attached to the first end of the fourth flexible tube, and where the second end of the fourth flexible tube is provided with a connector for connection with a vascular access device, and the second end of the third tube is equipped with a connector for connection with the blood processing unit, or the first end connector of the rigid tubular part is attached to the second end of the tube a flexible tube, wherein said second end connector of the rigid tubular portion is attached to the first end of the fourth flexible tube, and where the second end of the second flexible tube is provided with a connector for connection to a vascular access device, and the second end of the fourth tube is equipped with a connector for connection with a blood processing unit, wherein the second fluid flow chamber optionally has a second inlet and a second outlet, wherein said second inlet is connected to the end of the fifth flexible felling, the other end of which is equipped with a connector for connection with the blood processing unit, and the specified second outlet is connected to the end of the sixth flexible tube, the other end of which is equipped with a connector for connection with the access device. 7. The cassette unit according to any one of claims 1, 2, 4 or 6, including a mounting device for mounting said body on said device, said mounting device comprising at least one protrusion rigidly attached to a rigid body, where the mounting device is optional also includes tubular extensions that are rigidly attached to one side of the rigid body and attached to the corresponding opposite end of said first flexible tube. 8. The cassette unit according to any one of claims 1, 2, 4 or 6, where the rigid body and the rigid tubular part are made of transparent plastic. 9. The cassette unit according to any one of claims 1, 2, 4, or 6, wherein the rigid body is a one-piece transparent plastic case, wherein the rigid tubular part is a one-piece transparent plastic case. 10. A disposable cassette unit for a medical device for extracorporeal fluid processing, equipped with at least a peristaltic pump, including:
a rigid housing defining at least a first fluid flow chamber, said housing also having an inlet to said first chamber and an outlet from said first chamber,
the first flexible tube, the first and second end of which is attached to the rigid body, forming a part of the loop in which the rotor of the peristaltic pump of the medical device for processing is placed, while the first end of the first flexible tube is connected to the specified outlet of the first chamber,
a second flexible tube, the first end of which is connected to the inlet of the specified first chamber,
a third flexible tube, the first end of which is connected to a rigid body and is in fluid communication with the second end of the specified first tube, characterized in that the cassette unit further includes:
a rigid tubular part containing:
first end connector
a second end connector opposite the specified first end connector, and
an intermediate part passing between said first and second end connectors, exposed to a fluid flowing through said intermediate part to measure at least a fluid parameter, said intermediate part having an outer prismatic surface and is at least partially permeable to electromagnetic and / or acoustic waves, in particular said intermediate part has a toroidal cross section, the first end connector of the rigid tubular part rikreplen one element selected from the group consisting of: the second end of the second flexible tube and a second end of the third flexible tube. 11. The cassette unit of claim 10, wherein said first and second connectors have an outer prismatic surface and an inner prismatic surface, wherein the outer prismatic surface of at least one of said connectors has a radial recess that is configured to connect with the corresponding connecting protrusion on the holder of the medical device. 12. The cassette unit according to claim 11, where the outer prismatic surface has a pair of extensions, which include two longitudinal and parallel ridges defining a radial recess. 13. A medical device for extracorporeal fluid treatment, including:
a main supporting structure having at least a receiving part and a holder,
cassette unit, including:
a rigid housing defining at least a first fluid flow chamber, said housing also having an inlet to said first chamber and an outlet from said first chamber,
the first flexible tube, the first and second end of which is attached to the rigid body, forming a part of the loop in which the rotor of the peristaltic pump of the medical device for processing is placed, while the first end of the first flexible tube is connected to the specified outlet of the first chamber,
a second flexible tube, the first end of which is connected to the inlet of the specified first chamber,
a third flexible tube, the first end of which is connected to a rigid body and is in fluid communication with the second end of the specified first tube, characterized in that the cassette unit further includes:
a rigid tubular part containing:
first end connector
a second end connector opposite the specified first end connector, and
an intermediate part extending between said first and second end connectors, exposed to a fluid flowing through said intermediate part for measuring at least a fluid parameter, the first end connector of the rigid tubular part being attached to one element selected from the group including: the second end of the second flexible tube and the second end of the third flexible tube, while the cassette unit is installed on the receiving part located on the main supporting structure,
at least a peristaltic pump mounted on the main supporting structure and having a rotor that is installed in the loop portion of the cassette unit,
a holder supporting the rigid tubular part of the cassette unit, including:
a base located on a supporting structure and defining a mounting location for installing at least a rigid tubular part, and
a first sensor including at least a signal source and a sensor that can detect a return signal. 14. The device according to item 13, where the signal source includes a wave source that emits electromagnetic or acoustic waves with intensity and frequency of emission, and the sensor includes a sensor of electromagnetic or acoustic waves, which can detect the received intensity and / or frequency, the device includes a block control associated with the first sensor and including a device for calculating the characteristics of the fluid circulating through the rigid tubular part, based on one characteristic selected from the group, including One:
indicated emitted and received intensities,
indicated emitted and received frequencies,
phase shift between the indicated emitted and received waves. 15. The device according to 14, where the device for calculating the characteristics of the fluid circulating in the rigid tubular part includes:
a device for calculating the difference or relationship between the emitted intensity and the received intensity,
a device for determining energy absorption by a fluid circulating in a rigid tubular part based on a specified difference or a specified ratio,
a device for determining the characteristics of the fluid circulating in the rigid tubular part, based on the specified absorption, and in particular, where the fluid is blood, and the specified characteristic of the fluid circulating in the rigid tubular part, includes at least one parameter selected from the group including:
blood density
blood hematocrit,
hemoglobin concentration in the blood,
average blood cell volume. 16. The device according to any one of paragraphs.13-15, where the specified source and sensor are placed in accordance with the specified intermediate part of the rigid tubular part, and where the source and sensor are placed according to one of the configurations selected from the group including:
a solution in which the closable element rigidly holds one of the specified source and sensor, and the base rigidly holds the other of the specified source and sensor,
a solution in which the closing element rigidly holds both the specified source and the sensor,
a solution in which the base rigidly holds both the specified source and the sensor, while the sensor optionally includes a reflector, which is a reflective surface that completely surrounds the intermediate part, a signal source and a sensor located in accordance with the specified reflector. 17. The device according to any one of paragraphs.14 and 15, where the holder also includes a closing element that is attached to the base and which can be moved between the closed position, in which it closes the fastening place and fixes the rigid tubular part in position, and the open position, in wherein the closure element leaves the attachment point open, thus allowing installation or removal of the tubular portion to or from the attachment point, wherein the closure element does not necessarily include a flap movable around an axis on one side of the bases s, and the sash rotates around the specified axis when moving between the specified open and closed positions and includes at least one locking element interacting with the counter-locking element on the basis, while the locking and counter-locking elements are connected in accordance with the specified closed position, in particular the sash includes two locking elements, one on each side, each of which interacts with one corresponding counter-fixing element on the base, while the fixing and the trfixing elements are connected in accordance with the specified closed position, each locking element may include an elastically deformable flat foot, one end of which is attached to the sash, and a protrusion is located at the other end, which in accordance with the specified closed position engages in a correspondingly shaped slot defined based. 18. The device according to 17, where the holder also includes a second sensor, which is at least capable of detecting when the element to be closed is in the closed position and supplying a corresponding closing signal, the control unit being connected to the second sensor and including a device for determining whether the element to be closed is in the closed position based on the specified closing signal supplied by the second sensor. 19. The device according to item 13, where the mounting location includes a first part repeating the shape of the first end connector, and a second part repeating the shape of the second end connector, in particular these first and second parts of the mounting location have a prismatic surface, with a prismatic surface of at least at least one of the first and second parts has a radial recess that interacts with a connecting protrusion located on one of the end connectors. 20. The device according to claim 19, wherein said first and second parts of the attachment point are a prismatic surface, wherein the prismatic surface of at least one of said first and second parts has a radial recess that interacts with a corresponding connecting protrusion at one of the end connectors. 21. The device according to claim 19, wherein said first and second parts of the attachment point are a prismatic surface, wherein the prismatic surface of at least one of said first and second parts has a radial protrusion that interacts with a corresponding connecting recess at one of the end connectors. 22. The device according to claim 19, comprising a third sensor operably connected to one of said first and second parts of the attachment point to detect the presence as well as the proper position of the rigid tubular portion at the attachment point in the holder, and provide a matching signal, and including a control unit associated with the third sensor and including a device that determines whether the proper rigid tubular part is in the correct position within the attachment point, based on the specified signal, respectively the third sensor, and the third sensor does not necessarily have a design that allows you to detect the presence of the correct connection between the protrusion on the end connector and the radial recess at the attachment point, and to provide a matching signal, where in detail the control unit includes a device for controlling the activating device only then, when the device for determination gave a positive conclusion that the proper rigid tubular part is in the correct position within the attachment point, in particular, the control unit also includes a device for signaling that the fluid parameter cannot be calculated until the determination tool gives a positive conclusion that the proper rigid tubular part is in the correct position within the attachment point. 23. The device according to item 13, including:
a processing unit associated with the main supporting structure, the processing unit having a semipermeable membrane that divides the processing unit into at least a first chamber for blood flow, which is in fluid communication with the cassette unit, and a second chamber that has at least least an outlet port that is in fluid communication with the outlet line,
a device for controlling the clean flow of plasma water passing through a semipermeable membrane from the first to the second chamber, and vice versa, and where the device optionally includes:
a feed line for the fluid to be treated, the feed line being connected to the inlet of the second chamber of the blood processing unit,
a device for controlling the chemical composition of the processed fluid on the supply line, the control unit also including a device for controlling the device for controlling the chemical composition based on values obtained from said calculated parameter. 24. The device according to item 23, where the signal source includes a wave source that emits electromagnetic or acoustic waves with a specified emission intensity, and the sensor includes an electromagnetic or acoustic wave sensor that can detect the received intensity, the device further includes a control unit associated with the first sensor and with an adjustment device, and the control unit includes:
a device for activating said first sensor for emitting said signal and detecting said reverse signal,
a device for calculating a parameter of a fluid circulating in a rigid tubular part based on said emitted and reverse signals, and
a device for controlling a regulating device based on values obtained from said calculated parameter, in particular a device for calculating a parameter of a fluid circulating in a rigid tubular part, includes:
a device for calculating the difference or relationship between the emitted intensity and the received intensity,
a device for determining energy absorption by a fluid circulating in a rigid tubular part based on a specified difference or a specified ratio,
a device for determining a parameter of a fluid circulating in a rigid tubular part based on said absorption, in particular, a fluid is blood, and a parameter of a fluid circulating in a rigid tubular part includes at least one parameter selected from the group including :
blood density
blood hematocrit,
hemoglobin concentration in the blood,
average blood cell volume. 25. A rigid tubular part for an extracorporeal circulation circuit, which includes:
a first end connector having an external prismatic surface, a second end connector opposite to the specified first end connector and having an external prismatic surface;
an intermediate part extending between said first and second end connectors, which is in contact with a fluid flowing through said intermediate part for measuring at least a fluid parameter, wherein the outer prismatic surface of at least one of said end connectors has a radially protruding element, which is designed to interact during use with the corresponding connecting recess located on the holder device, while the radially protruding element includes side walls extending from the outer surface of the end connector, and an end wall located transversely to the specified side walls. 26. The rigid tubular portion of claim 25, wherein said intermediate portion has a constant cross section and is at least partially permeable to electromagnetic and / or acoustic waves, said intermediate portion optionally having a toroidal cross section. 27. The rigid tubular part according to p, where the side walls of the protruding element converge slightly when moving from the outer surface of the end connector, and the specified end wall is essentially flat and parallel to the longitudinal axis of the scan of the rigid tubular part. 28. A cassette unit for a medical device for extracorporeal processing of a fluid, comprising a rigid tubular part according to any one of the preceding paragraphs 25-27, where the rigid tubular part is integral with a rigid plastic body having front and rear walls separated from each other, as well as side walls between said front and rear walls defining a first fluid flow chamber, and wherein the rigid body and the rigid tubular part are made of transparent plastic, in particular said hard rpus also includes an intermediate wall disposed between the side walls, which defines the second fluid flow chamber. 29. The cassette unit according to claim 28, wherein the rigid body and rigid tubular portion are made of transparent plastic. 30. The cassette unit according to claim 28, wherein said rigid body also includes an intermediate wall located between the side walls, which defines a second fluid flow chamber.

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