Portable device for detecting an obstruction, monitoring the obstruction and deobstructing a catheter

Abstract

The invention relates to a passive injection device for a catheter, having pistons in an integral assembly, at least two push bodies, and an injection body. In a first step, the removal of the integral piston assembly creates a vacuum in the push bodies, and the suction of the substance to be absorbed into the injection body. In a second step, the atmospheric pressure that is applied to the heads of the push pistons advances the integral assembly and allows the substance to be injected at a velocity proportional to the ambient pressure. The device also makes it possible to detect partial or complete obstructions in catheter lines.

Description

[0001] Portable device for detecting obstruction, tracking obstruction and clearing a catheter

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to the field of devices intended to enable the permeability of a catheter suspected of being obstructed to be assessed, and to carry out the unblocking of a catheter likely to present an obstruction, by injecting a substance into the catheter.

[0004] The device can be seen as an intraluminal patency tester, allowing the detection, monitoring and at the same time eradication of obstruction in the catheter, such as a central venous catheter.

[0005] STATE OF THE ART

[0006] The invention occurs in a context of prime importance in the field of care: perfusion, medicinal or not, enteral or parenteral.

[0007] The use of catheters has increased considerably, allowing the development of various therapies (chemotherapies, antibiotics, parenteral nutrition), and facilitating blood sampling. A catheter may have to remain in place for various durations, ranging from a few hours to several months or years.

[0008] For some therapies requiring short and long-term infusions, a portable diffuser can be used, which allows for outpatient care. The portable diffuser is popular with patients and caregivers. It is lightweight and compact, does not require a battery, but has no alarm. In the case of peripheral and central catheters, the occurrence of an obstruction is the most frequent complication, with harmful repercussions for the patient (human cost), and the organization of hospital care services and ultimately the National Health Insurance Fund (additional cost). This obstruction can result from deposits linked to the injected products or secondary to a poorly rinsed blood sample. A priori, we do not know the length of the obstruction or its position along the line.

[0009] The patency of a catheter can be restored by injecting a solution (for example, NaCl 0.9% with or without heparin, thrombolytic), although this injection can lead to rupture of the catheter in the event of significant overpressure.

[0010] To determine whether a catheter is obstructed, in clinical practice resistance to injection and / or aspiration is considered a sign of obstruction, but this resistance, whether manually felt or mechanical and objectified by an alarm from the injectors (pumps or syringe drivers), does not allow us to conclude that there is a partial physical obstruction.

[0011] Catheters are therefore generally changed when either the operator is unable to inject a solution by hand, or an active injection device such as a syringe pump stops, due to the very strong increase in resistance linked to the obstruction, not allowing a product to be injected to unblock (such a product being called a “unblocker” in the remainder of this description).

[0012] As is known from the state of the art and shown in Figure 5A, when the lumen of a catheter (characterized here by the area of ​​the open section of the catheter) has an internal lumen obstructed for example at 80%, the flow rate is of the order of 2% of the value of the flow rate of the unobstructed catheter. The feeling for the operator is therefore that it is no longer possible to unobstruct the catheter, which is in reality not the case. So the catheter is generally replaced, which involves a medical, surgical procedure, an additional cost and a health risk for the patient.

[0013] Currently, in France, it is not possible for medical personnel to carry out unblocking maneuvers with small syringes, given the risk of the catheter exceeding maximum pressures.

[0014] INVENTION

[0015] The present invention aims to solve these problems of the state of the art.

[0016] For these purposes, according to a first aspect, a portable device is proposed for assessing the permeability of a catheter suspected of being obstructed by an injection of a substance S, and for unblocking a catheter likely to have an obstruction by injecting a biological “unblocker” or a chemical “unblocker” S' into a catheter, the device being a passive injection device and with a thrust force solely proportional to the ambient atmospheric pressure Pa which is the thrust driver during the injection, the passive device having: at least two thrust bodies each comprising a piston called a “thrust piston” with a thrust head, the two thrust bodies each allowing, during a first phase of the movement called loading, under the action of a user,to create a vacuum in a sealed part downstream of the head of the thrust piston by moving the thrust pistons in a first translation direction T1, during the loading movement; each thrust body having an opening with a removable sealed plug, intended when it is opened to expel the air and then when it is closed by the removable sealed plug to recreate the vacuum during the movement of the thrust pistons in the first translation direction T1 from the closed opening during the loading movement, a removable injection body comprising a piston called an “injection piston” with an injection head, the thrust bodies being located on either side of the removable injection body, a coupling means, capable of mechanically connecting the three pistons during a second phase of the movement, so that the two thrust pistons and the injection piston are driven by the mechanical coupling in a second translation direction T2,opposite to the first direction of translation T1, during the unloading movement, allowing the injection of the substance at the outlet of the device into a catheter, solely under the effect of the thrust force exerted on the heads of the thrust pistons and which allows an external pressure proportional to the atmospheric pressure to be exerted on the head of the injection piston, the external pressure P being equal to Atmospheric pressure* Total surface area of ​​the thrust pistons / Surface area of ​​the injection piston Si.,

[0017] In some implementations, the injection body is a test injection body, configured to evaluate the patency of a catheter and has volumes less than 20 mL, advantageously less than 10 mL, advantageously less than 5 mL, advantageously less than 1 mL. Advantageously, the test injection body is configured so that the injection plunger has a displacement greater than or equal to 0.5 mm for an injection of a volume of 0.1 mL, advantageously greater than or equal to 1 mm for an injection of a volume of 0.1 mL, advantageously greater than or equal to 5 mm for an injection of a volume of 0.1 mL.

[0018] In certain implementations, the device has means allowing manual loading of the device in the first translation direction T1, but preventing manual pushing on the injection body in the second translation direction T2, during the unloading movement, the movement in the second translation direction T2, during the so-called unloading movement, being possible only under the pushing force, only proportional to the ambient atmospheric pressure Pa which is the thrust driver during the injection.

[0019] Advantageously, the injection body is a test injection body configured to evaluate the permeability of the catheter and has volumes less than 20 mL, advantageously less than 10 mL, advantageously less than 5 mL, advantageously less than 1 mL, and in that the device has means allowing its manual loading in the first translation direction T1, but preventing during the so-called unloading movement the manual pushing on the injection body in the second translation direction T2.

[0020] According to various embodiments, these means are chosen from the following list: the injection piston is breakable or a protective body of the portable device preventing manual pressure on the coupling means and the pistons, during the unloading movement in the second translation direction T2, and a means connected to the device so as to allow the pistons to move only in the first translation direction T1 during the so-called loading movement.

[0021] Advantageously, the injection body is a disobstructing injection body and has a volume equal to or greater than the intraluminal volume of the catheter.

[0022] Advantageously, the device has mechanical / optical / electronic / colorimetric means for detecting and signaling the movement of one of the pistons, such as a stylus, associated with the movement of a ruler linked to the piston whose zero is positioned at the start of the maneuver. The sign " / " is used here to refer to both an alternative (or) and a combination (and) of means.

[0023] In certain implementations, the device has means for measuring, as a function of time, the displacement of the injection piston between an initial position of the injection piston and a subsequent position, the thrust piston heads having been displaced under the action of the external pressure exerted on the device, in the second translation direction T2, during the so-called unloading movement, this subsequent position being measured after a defined time, for example after a test duration of several minutes.

[0024] Advantageously, the device has means for calculating a catheter obstruction index, connected to the measuring means, the obstruction index being equal to or proportional to the displacement for a given observation duration, for example for a duration equal to or less than 1 hour, advantageously less than or equal to 10 minutes.

[0025] Advantageously, for the unclogging injection body or the test injection body, the ratio between the total surface area of ​​the heads of the pushing pistons and the surface area of ​​the head of the injection piston is between 1 and 4, so as to avoid any overpressure which could be harmful to the catheter.

[0026] In embodiments, the device is connected to a syringe called a filling syringe for the injection body by: a three-way tap, one way of which is intended to be connected to the catheter and another way is connected to said syringe, or an inlet of the injection body, the device having an outlet intended to be connected to a catheter.

[0027] Advantageously, the thrust bodies are identical and placed symmetrically with respect to the injection body.

[0028] In certain implementations, the sealing of the piston head(s) is ensured by rolling membranes, such as membranes having an elastic body radially bearing on the thrust bodies and on the injection body.

[0029] In certain implementations, the sealing of the piston head(s) is ensured by: O-rings; or the piston head resting on a bellows.

[0030] Advantageously, the device has means for detecting the volume of unblocking substance at given times in the injection body, advantageously connected to calculation means, so as to calculate the injection flow rate and its variations in the unblocking injection body to evaluate the unblocking in progress.

[0031] According to various embodiments, the injection body is a syringe, advantageously graduated, and advantageously the syringe of the injection body is closed by a sealed cap, the pushing bodies being syringes, advantageously graduated, and advantageously removable.

[0032] Advantageously, the mechanical coupling means is fixed to the thrust pistons and is removably fixed to the injection piston.

[0033] Advantageously, the so-called filling syringe is connected by a valve to a reservoir, in particular to allow possible resupply of the injection body with unblocker substance.

[0034] According to a second aspect, a kit is proposed having: a passive portable injection device as presented above, a test injection body with a given substance S such as a drug or a physiological liquid, and a disobstructing injection body with a substance S' which is a biological or chemical disobstructer.

[0035] According to a third aspect, there is provided a method for assessing the permeability of a catheter suspected of being obstructed, and for unobstructing it, implementing a catheter and a device intended to allow the assessment of the permeability of a catheter suspected of being obstructed, and to carry out the unobstructing of a catheter likely to have an obstruction, the device being a passive portable injection device as presented above, which is based solely on the atmospheric ambient pressure Pa as a thrust motor during the injection, and which is connected to the catheter, method in which:

[0036] (1) the device is set up, the test injection body being filled with a substance S, (2) after having measured the initial position of the injection piston in the injection body or of a thrust piston in the thrust body,

[0037] • the thrust piston heads are allowed to move in the second direction of translation T2, during the unloading movement, under the action of the external pressure, which is exerted on the injection piston, the external pressure P being equal to Atmospheric pressure* Total surface area of ​​the thrust pistons Sp / Surface area of ​​the injection piston Si,

[0038] • then the displacement of the injection piston in the second translation direction T2 is measured, during the unloading movement, after a defined time, for example after a test duration of several minutes:

[0039] (3a) if the injection plunger is moved, then the line has permeability, and the catheter is considered partially obstructed,

[0040] - then the test injection substance S or respectively the test injection body is replaced by a deblocking substance S' or respectively by a deblocking injection body with a quantity of biological "deblocker" or a quantity of chemical "deblocker" S',

[0041] - and the unblocking substance S' is injected for an injection duration, using the device based solely on the atmospheric ambient pressure Pa as the thrust motor of the injection piston;

[0042] (3b) if the injection piston has not moved, the line is considered to be obstructed and not showing permeability.

[0043] Advantageously, in step 3a, the filling syringe and the three-way valve are used to access it.

[0044] Advantageously, the method comprises a step of calculating an obstruction index, by measuring the displacement of one of the pistons as a function of time, during the displacement in the second direction T2, the obstruction index being a function of the volume injected during a given time, and therefore for example the index is chosen equal to 1 / (displacement of the injection piston * section of the injection piston).

[0045] Advantageously, the method comprises a step of calculating the hydraulic resistance generated by the obstruction, with the speed of movement of the injection piston and the injection pressure, making it possible to determine the duration of injection of the unblocker so that it travels through the entire catheter.

[0046] Advantageously, the method comprises a step of calculating the longitudinal location of the obstruction in the catheter, from the compliance of the catheter, the volume injected (at initial t) and the injection pressure.

[0047] The portable device according to the invention is portable, preferably manually portable and hand-held, therefore reduced in volume and weight, and is intended to enable the patency of a catheter to be assessed, regardless of its type and location and the anatomical site of the clearing.

[0048] The invention finds further application in long-term catheterization (several days to several years), for example intravenous catheterization, technical support for a large number of therapeutic interventions.

[0049] DESCRIPTION OF FIGURES

[0050] Other objectives, characteristics and advantages of the invention will emerge from the detailed description of embodiments which follows with reference to the drawings, given for illustrative and non-limiting purposes, among which:

[0051] - Figure 1 A represents a perspective view of a passive injection device, according to one embodiment;

[0052] - Figures 1 B, 1 C and 1 D are sectional views of a first embodiment of the invention, with the two thrust bodies and one injection body mechanically coupled, using a coupling means fixed to the three rods of the three pistons; in Figure 1 B, the device is in an initial state, the injection and thrust pistons, the heads of which have respective surfaces Si and Sp, being in abutment on the end of the injection and thrust bodies; in Figure 1 C, the device is in a filling state, where the set of pistons is pulled back to load it, during the loading movement, in a first direction T1 thanks to a force Fi associated with a pressure greater than atmospheric pressure Pa applied to the two thrust piston heads, creating a vacuum in the two thrust bodies, and allowing the suction of the substance S to be injected into the injection body;in figure 1 D, the device is in an injection state, where the injection piston is subjected (by the mechanical coupling to the two pistons of the thrust bodies subjected to atmospheric pressure Pa) to a force Fp, applying to the substance S to be injected a pressure Pa + 2Pa.Sp / Si, driving it forward in a second direction T2 opposite to the first direction TI, during the unloading movement; - figure 2 is a sectional view of a device which comprises in the injection body an inlet and an outlet for the substance S, the inlet being connected to a syringe for filling the injection body, and the outlet being connected to a catheter;

[0053] - Figure 3 represents a sectional view of a second embodiment of the invention, the passive injection device comprising a single body where two pistons are located on the same rod, the cylindrical body comprising a valve;

[0054] - Figures 4A, 4B and 4C represent the different states of a passive injection device according to Figure 3, during the stages of its operation: an initial state, represented in Figure 4A, where the thrust piston is almost in abutment against the rigid wall separating the thrust body and the injection body, allowing the air to be expelled from the thrust body before the valve located upstream of the rigid wall closes, and the injection piston is in abutment in the injection body; a filling state, represented in Figure 4B, where the integral assembly of the pistons is pulled back, sucking the substance to be injected into the injection body, the movement of the pistons being permitted by an opening between the rigid wall separating the two injection and thrust bodies, and the injection piston, allowing the air to escape from the body, the valve located at the level of the thrust body is kept closed, maintaining a vacuum in the thrust body;an injection state, shown in Figure 4C, where the integral assembly of the pistons is released, under the effect of the atmospheric pressure applied to the thrust pistons driving this assembly of pistons by applying a constant pressure on the injection piston, thanks to the vacuum created in the thrust body, which leads to the injection of the substance to be injected contained in the injection body;

[0055] - Figure 5A presents a curve which shows on the ordinate the variations in flow rate in a catheter (all other things being equal), as a function on the abscissa of the percentage of light available in the part currently being obstructed; the extent of this obstruction is difficult to evaluate and can depend on numerous factors: drug deposits, poorly rinsed blood withdrawals, etc.;

[0056] - Figure 5B is a graph of the piston displacement (in mm / s) as a function of the flow rate, for example for a 10cc syringe, which confirms the difficulty of assessing a possible obstruction when the flow rate is very low; for example, for a flow rate of 25 mL / h, it takes 20 seconds of the operator pressing on the injection syringe to observe a displacement of 1 mm;

[0057] - Figure 5C shows an experimental device including a passive injection device according to Figure 1A and a flow regulator simulating the obstruction of a catheter line;

[0058] - Figure 5D shows the displacement of the plunger for an injected volume of 0.1 mL. The curve shows the displacement of the plunger for different syringe sizes and for an injected volume of 0.1 mL; advantageously to identify whether there is or is not an obstruction, a low-volume syringe is used so that the displacement of the plunger is as visible as possible, a low-volume syringe facilitating the identification of an obstruction in progress by observing the movement of the plunger; the process is all the more relevant since a syringe, for example 5 mL, is sufficient to ensure the filling of the line and at least one start of clearing of the catheter and therefore allow its clearing;it can also be noted that monitoring variations in the piston speed contains information on the degree of progress of the obstruction degradation reaction when the device injects a thrombolytic (but in this case if the de-obstruction has started, 5 mL is no longer sufficient to continue injecting the "de-obstructant"); this figure illustrates the principles of a protocol for detecting and eradicating an obstruction in progress in an implanted catheter;

[0059] - Figures 6A and 6B represent an embodiment where the sealing of the pistons is ensured by rolling membranes, according to several positions: a first state of the thrust and injection bodies, represented in Figure 6A, the two thrust bodies being closed at their end, empty of air, and the injection body containing the substance to be injected, the pistons of the two bodies being mechanically linked and pulled during a filling step by a force Fr, a second state of the thrust and injection bodies, represented in Figure 6B, after their forward movement during the step of injecting the substance to be injected; - Figure 7A is a view of a device according to the invention, in another embodiment;

[0060] - figure 7B is a detailed view of an example of the locking means of a device according to figure 7A;

[0061] - Figure 7C is a view of a device according to the invention, in another embodiment

[0062] DETAILED DESC RI PTION OF THE I NVENTION

[0063] The invention relates to a passive portable device intended to enable the assessment of the permeability of a catheter suspected of being obstructed, and to carry out the unblocking of a catheter likely to present an obstruction, by the injection of a substance into the catheter.

[0064] The device can be seen as an intraluminal permeability tester, its monitoring and at the same time a device that allows the eradication of obstruction in the catheter, such as a central venous catheter.

[0065] Advantageously, the device is small (a few tens of cm at most) and easy to use, and can be used in particular on an outpatient basis, particularly by the patient himself, which makes it very useful.

[0066] First embodiment

[0067] Figures 1A to 1D represent a passive injection device 1 (hereinafter injection device), in a first embodiment. In the embodiment of Figures 1A to 1D, the device 1 allowing the injection of a substance S comprises two thrust bodies B, B' and an injection body A, placed side by side, and respectively having an injection chamber 2a and a thrust chamber 2b, 2b'.

[0068] The injection body A and the thrust bodies B, B' respectively comprise a piston 3a, 3b, 3b' with a head 4a, 4b, 4b', the three pistons 3a, 3b, 3b' being connected by means of a mechanical coupling means 5, thus forming a solid assembly.

[0069] In certain implementations, the thrust bodies B, B' are syringes which have at their end a closing cap 6, or a luer lock, so as to allow an air vacuum to be created after closing the end of the syringes, in a compartment between the head 4b, 4b' of the thrust piston 3b, 3b' and the end of the syringes.

[0070] In some implementations, the injection body A is a syringe.

[0071] By syringe is meant here an instrument comprising a body, generally cylindrical, in which a piston moves and to which a cannula or a hollow needle can be adapted, for the injection or aspiration of a liquid into the tissues, vessels or natural cavities of a human or animal body.

[0072] Syringes may have a body made of polymer material (particularly polypropylene, polyethylene) or a body made of glass. A syringe here refers to a two-part assembly (body and plunger), or a three-part assembly (body, plunger and plunger seal). Syringes have a male tip (for example, a 6% Luer that can be centered or offset). A luer lock here refers to a lock carried by the external part of the tip of a syringe, this lock comprising a screw thread.

[0073] In some implementations, the mechanical coupling means 5 is fixed to the thrust pistons 3b, 3b' and is removably fixed to the injection piston 3a.

[0074] Alternatively, the mechanical coupling means 5 is removably attached to the thrust pistons 3b, 3b', for example by screwing, snap-fastening, magnet or other attachment means, and is attached to the injection piston 3a.

[0075] In some embodiments, the mechanical coupling means 5 is permanently fixed to the ends of the injection piston 3a and the thrust pistons 3b, 3b'.

[0076] During a first step, called filling, the integral assembly moved by a user or any other means (in particular by action on the heads of the thrust pistons 3b, 3b' or on the head of the injection piston 3a) causes an integral movement of the pistons 3a, 3b, 3b' in a first direction of translation T1, creating a vacuum in the thrust chambers 2b, 2b', and the suction of the substance S into the injection chamber 2a.

[0077] The integral assembly can be locked in this position, to prepare the device 1 in advance, for injection.

[0078] During a second step, called injection, once the device 1 is connected to a catheter, the integral assembly is released and, under the action of the ambient atmospheric pressure which is applied to the thrust piston heads 3b, 3b', is driven in a second direction of translation T2, opposite to the first direction of translation T1, allowing the injection of the substance S into the catheter, at an external injection pressure Pi.

[0079] This external injection pressure Pi depends on the atmospheric pressure, the number N of thrust pistons 3b, 3b', the surface Sp of the thrust pistons 3b, 3b' and the surface Si of the injection piston 3a, according to the following formula: Pi = N*Pa*Sp / Si when the thrust pistons are identical.

[0080] When the thrust pistons are not identical, the external injection pressure is calculated according to the following formula, Pi = Pa*Spt / Si, Spt being the total surface area of ​​the thrust pistons.

[0081] This external injection pressure Pi results only from the vacuum in the thrust bodies and is not linked to the action of a pump, a motor or other.

[0082] This external injection pressure Pi is that which is applied in addition to the atmospheric pressure already exerted on the injection piston, and is qualified as overpressure in relation to this atmospheric pressure.

[0083] The thrust bodies B, B' being, in the embodiment of figures 1 A to 1 D, located on either side of the injection body A, the forces are applied to the integral assembly in a symmetrical manner, advantageously at an equal distance from the two thrust bodies B, B', advantageously of identical shape, which makes it possible to symmetrize the forces on the head of the injection piston 3a and to make the device 1 operational, avoiding the twisting of the injection piston 3a in the injection body A, which would increase the friction during movement. Figure 2 represents a first embodiment of an injection device 1 fluidly connected to a supply device 10.

[0084] The supply device 10 comprises a filling syringe 11, fluidically connected to the injection device 1, by a valve 13.

[0085] In certain implementations, the injection device 1 is connected to a so-called filling syringe 11 by one channel of a three-way tap, another channel of which is intended to be connected to a catheter.

[0086] In other implementations, the injection device 1 comprises in the injection body A an inlet 14 and an outlet 15 for the substance S, the inlet 14 being connected to the filling syringe 11, and the outlet 15 being connected to a catheter.

[0087] Advantageously, the filling syringe 11 is connected to a reservoir 12, for example an infusion bag containing the substance S, a valve 13 being placed on the conduit connecting the filling syringe 11 to the reservoir 12.

[0088] Advantageously, the filling syringe 11 is chosen to have a small capacity, for example comprising a volume of less than 10 mL, requiring little effort to fill it, and then to empty it, so that the injection body A fills.

[0089] In other words, the filling syringe 11 can be seen as a pump that can be used by medical personnel to fill the injection device 1 with the substance S (or the unblocker substance S'), and also charge the vacuum in the push bodies B, B'. After filling the injection body A with the substance S, the supply device 10 is advantageously disconnected from the injection device 1, thanks to the valves 13, which is represented by dotted lines in Figure 2.

[0090] The sealing of the piston head(s) 4a, 4b, 4b' can be ensured by rolling membranes 19 such as longitudinally reinforced "glove finger" type membranes, so that they allow good application to the piston liner and skirt, while offering almost no static type friction, as shown in FIGS. 6A to 6B.

[0091] Alternatively, the sealing of the piston head(s) can be ensured by O-rings or the piston head resting on a bellows.

[0092] The device thus meets the following technical constraints: reduced volume to allow outpatient use; ease of implementation; economical operation.

[0093] The device has several advantages.

[0094] The use of a small diameter syringe allows easy filling of the injection reservoir by pumping from the substance bag S or S'. This part being removable, the size of the device in operating mode remains reduced.

[0095] No external energy is required to ensure the operation of the whole.

[0096] The device is advantageously operational thanks to: the symmetrical arrangement of the two thrust bodies B, B' on either side of the injection body A, a vacuum being renewed by opening the caps 6, and a judicious choice of sealing means at the level of the piston heads (this sealing must be sufficient to create the vacuum without generating excessive friction which would limit the movement of the pistons).

[0097] These arrangements allow both the displacement of the pistons in the two translation directions T1 and T2, in particular when loading in the first direction T1 and the maintenance of a sufficient vacuum at the origin of the displacement in the second direction T2.

[0098] Second embodiment

[0099] Figure 3 represents a passive injection device 1' (hereinafter injection device 1'), according to a second embodiment.

[0100] In this second embodiment, the device 1' allowing the injection of a substance S comprises a single body C performing the functions of the injection body and the thrust body, by different sections of the body C delimited by a piston 3c having a head 4c, called injection, and a head called thrust 4'c, and a rigid wall 7 crossed by the piston 3c.

[0101] In some implementations, the body C is a syringe.

[0102] The device 1' comprises a drain valve 8, located at the level of the thrust body C, between the thrust head 4'c and the rigid wall 7, as well as a flow opening 9, located between the rigid wall 7 and the injection head 4c. During a first step, called draining, represented by FIG. 4A, the user opens the drain valve 8 then actuates a pull rod 16, bringing the thrust head 4'c into abutment against the rigid wall 7 (or nearby), thus allowing the expulsion of air from the thrust body C by the drain valve 8, which is then closed.

[0103] During a second step, called filling, represented by figure 4B, the user actuates the pull rod 16 in a first direction of translation T1, creating a vacuum in the thrust chamber 2'c, and the suction of the substance S into the injection chamber 2c, the free movement of the piston heads being possible thanks to the opening of the flow valve 9 allowing the air present between the rigid wall 7 and the head of the injection piston 3c to be evacuated.

[0104] The pull tab 16 can be locked in this position, to prepare the device 1' in advance, for injection.

[0105] During a third step, called injection, represented by figure 4C, once the device 1' is connected to a catheter, the pull tab 16 is released and, under the action of the ambient atmospheric pressure Pa which is applied to the head of the thrust piston 4'c, is driven in a second direction of translation T2, opposite to the first direction of translation T1, allowing the injection of the substance S into the catheter by the injection head 4c.

[0106] The thrust head 4c', of given surface, thus undergoes a force proportional to the ambient atmospheric pressure Pa, and therefore quasi-constant.

[0107] Alternative embodiment The device advantageously has a traction system ensuring the filling of the injection syringe, and the depression of the push syringes can only act in the direction of traction, thus avoiding any false maneuver which would cause excess pressure in the injection syringe by pressing on this traction system in the direction opposite to traction.

[0108] In Figure 7A, PO designates the push syringes, I designates an injection syringe, EM designates the movable assembly for coupling the heads, guided in its movement by guide rods T, ST designates the traction system comprising a traction ring A, B designates a housing containing the system and now immobilizing the syringes in housings. The assembly consists of two half-housings articulated on a hinge C. The push syringes PO are provided with a removable cap Ba. These designations in Figure 7A are also used in Figure 7C.

[0109] When the traction is carried out by the traction ring A, the three heads and the piston bodies move simultaneously in the loading direction T1, ensuring the depression of the pushing syringes PO and the filling of the injection syringe I.

[0110] Advantageously, the system can be kept immobilized by a locking system V, V', an example of which is shown diagrammatically in Figures 7A and 7B.

[0111] When unlocking, the injection syringe I is pressurized (2Pa).

[0112] The movement of the traction system ST is then free and has no effect on the injection syringe I or on the mobile assembly EM in the second direction of translation T2 of unloading, because it has no hold on this mobile assembly EM in this second direction.

[0113] For the best sensitivity of the detection device, it is advantageous to use three 1 cc syringes, which increases the sensitivity by 7 times compared to 5 cc syringes and by 10 times for 10 cc syringes.

[0114] The imposed pressure is advantageously 2Pa maximum, and the traction system ST does not allow any pushing. When filling is carried out, a locking means such as a locking slide V (figure 7B) blocks the system in the filled position, which becomes operational again by simply pulling on the unlocking button BV.

[0115] Advantageously, the case is made up of two half-shells (possibly with a hinge) and an observation window.

[0116] At the outlet of the injection syringe I, a three-way tap allows the injection syringe I to be refilled by switching the tap to the reserve syringe and performing the filling pull. Despite the small volume of the injection syringe I, the unblocking product can therefore be injected into the catheter by successive maneuvers.

[0117] Advantageously, if the friction forces on 1 cc syringes limit performance, 5 cc syringes can be used on the same principle. The traction force required for cocking and filling is then advantageously around 25N.

[0118] Advantageously, the housing is designed to be able to use syringes normally used in medical practice. Figure 7C illustrates a device according to the invention for commercial syringes, with a capacity of 5cc.

[0119] Application to the detection of catheter obstruction

[0120] The obstruction may be endoluminal, of thrombotic origin (clot, poor rinsing after blood sampling), or chemical (drug precipitates, chemical or lipid deposits).

[0121] The obstruction can be extraluminal, caused by any mechanical cause: kinking of the catheter, extrinsic compression, pinching off the catheter, valve, fibroplastic sleeve, adhesion to the wall, or excessive suction causing suction of the vascular wall for example. In this case of extraluminal obstruction, the device according to the invention will make it possible to know whether the obstruction is partial or not, but in the event of partial obstruction being observed, the injection of the deobstructor will not modify this extraluminal obstruction. The medical staff will then be able to assume that the obstruction is extraluminal and take the necessary actions to remedy it.

[0122] Obstruction is mentioned when the caregiver or practitioner experiences difficulty or even impossibility of injection and / or aspiration.

[0123] The reduction of the lumen of a catheter line is accompanied by a sharp increase in hydraulic resistance and therefore in perfusion times: a reduction of the endoluminal radius of the catheter to one tenth of the initial radius would multiply the transit time by 10 4 , it is therefore important to be able to detect such obstructions in order to be able to act accordingly. The device 1, 1' in any of its embodiments described above, can be used to detect an obstruction in a catheter to which it is connected.

[0124] In the implementation shown in Figure 5C, a device 1 of the type described with reference to Figure 1A is connected to a catheter 18, after the so-called suction step during which the user actuates the integral assembly to create the vacuum in the thrust bodies B, B'.

[0125] A flow regulator 17 is placed between the catheter 18 and the injection body A, the flow regulator 17 simulating an obstruction of the injection line of the catheter 18.

[0126] The user then releases the integral assembly during the so-called injection step, applying external pressure to the injection line, and the speed of movement of the pistons in bodies A, B and B' is measured, for different settings of the flow regulator 17.

[0127] The results thus obtained are presented in figure 5B, where the plot of the piston movement speed (in mm / s) as a function of the flow rate Q (in mL / h) highlights a proportional link between these two quantities.

[0128] Process

[0129] The invention also relates to a method for evaluating the permeability of a catheter suspected of being obstructed, and for unobstructing it, using a catheter and a device 1, 1', defined above, and which is connected to the catheter.

[0130] The process includes the following steps:

[0131] (1) pressing on the injection piston 3a or the coupling means 5, and finding resistance to the movement of the injection piston 3a or the coupling means 5;

[0132] (2) movement of the thrust pistons 3b, 3b', creating a vacuum in the thrust body(ies) B, B', in the first direction of translation T1, during the so-called loading movement;

[0133] (3) leaving the piston heads to the action of ambient atmospheric pressure Pa after recording the initial position of the injection piston 3a, and measuring the displacement of the injection piston 3a in the second translation direction T2 after a defined time, during the so-called unloading movement, for example after a test duration of several minutes (for example 10 minutes);

[0134] (a) if the injection piston 3a is moved, then, as the line has a permeability, injection using the device 1, 1', of a quantity of biological "unblocker" such as a thrombolytic unblocker, (for example urokinase, alteplase) or chemical unblocker (for example NaOH, HCl, sodium bicarbonate), for an injection duration;

[0135] (b) if the injection piston 3a has not moved, the line is considered to be obstructed. Advantageously, a calculation is made of the hydraulic resistance generated by the obstruction, with the speed of movement of the injection piston 3a and the injection pressure, making it possible to determine the duration of injection of the unobstructer so that it travels through the entire catheter 18.

[0136] Advantageously, an evaluation is carried out of the longitudinal location of the obstruction in the catheter 18, from the compliance of the catheter, the injected volume and the injection pressure in the event of immediate variation in the position of the injection piston 3a during step a).

[0137] Unlike an automatic syringe pump, or any other flow modulator imposing a flow rate and not a pressure, the device 1, 1' according to the invention makes it possible, in a first step, to evaluate whether or not there is permeability of the catheter line, even very low permeability, and then to inject at low external pressures, without risk of parietal rupture of the catheter, a de-obstructer which will make it possible to destroy or detach the obstruction, even very significant and / or even very rigid, from the walls of the catheter, to then allow it to be evacuated from the catheter with the substance set in motion by the passive device (at low pressure).

[0138] According to the ratio of the Sp and Si sections, the external pressure imposed on the line is proportional to one or more atmospheric pressures Pa (14.69psi, or 101.28 KPa), and can therefore be limited to pressures much lower than the admissible intraluminal pressures in a standard catheter (1.50psi, or 1034.21 KPa) or high pressure catheter (300-360psi, or 2068 to 2482 KPa). The device allows the choice of an appropriate protocol for the complete restoration of the catheter lumen, without the need for additional equipment, which does not exist today in the state of the art.

[0139] Thus, the passive device according to the invention allows the injection of substance S to evaluate the permeability of the catheter, and then if necessary the unblocking of the catheter 18 which would have a partial obstruction noted, by the injection and the action of a unblocker S' (for example via the supply device 10).

[0140] The speed of movement is not imposed by the device, due to the driving force being only proportional to the atmospheric pressure Pa, avoiding any risk to the catheter of high intraluminal pressure, which could lead to catheter rupture and a risk to the patient's health.

[0141] The device according to the invention makes it possible to avoid replacing the catheter when the catheter is only partially obstructed.

[0142] In addition, the device can optionally also be used as a pressure limiter.

[0143] When mounted with possible communication via a three-way valve, the device allows, during an injection, to limit the injection pressure to a value which depends on the area ratio of the syringe surfaces.

Claims

AMENDED CLAIMS received by the International Bureau on July 18, 2024 (18.07.2024) 1 . Portable device intended to enable the permeability of a catheter suspected of being obstructed by an injection of a substance (S) to be assessed, and to unblock a catheter (18) likely to have an obstruction by the injection of a biological “unblocker” (S') or a chemical “unblocker” into a catheter (18), characterized in that the device is a passive injection device and has a thrust force solely proportional to the ambient atmospheric pressure which is the thrust driver during the injection, the passive device having: at least two thrust bodies (B, B') each comprising a piston called a “thrust piston” (3b, 3b') with a thrust head (4b, 4b'), the two thrust bodies (B, B') each allowing, during a first phase of the movement called loading, under the action of a user, to create a vacuum in a sealed part (2b, 2b') downstream of the head of the thrust piston (4b,4b') by moving the thrust pistons (3b, 3b') in a first translation direction (T1); each thrust body (B, B') having an opening with a removable sealed plug (6), intended when it is opened to expel the air and then when it is closed by the removable sealed plug (6) to recreate the vacuum when the thrust pistons (3b, 3b') move in the first translation direction (T1) from the closed opening, a removable injection body (A), comprising a piston called "injection piston" (3a) with an injection head (4a), the thrust bodies (B, B') being located on either side of the removable injection body (A), a coupling means (5) capable of mechanically connecting the three pistons (3a, 3b, 3b') during a second phase of the movement, called unloading, so that the two thrust pistons (3b, 3b') and the piston, AMENDED SHEET (ARTICLE 19) injection body (3a) are driven by the mechanical coupling in a second direction of translation (T2) opposite to the first direction of translation (T1), allowing the injection of the substance (S) at the outlet of the device (1) into a catheter (18), solely under the effect of the thrust force exerted on the heads (4b, 4b') of the thrust pistons (3b, 3b') and which makes it possible to exert an external pressure proportional to the atmospheric pressure on the head (4a) of the injection piston (3a), the external pressure P being equal to Atmospheric pressure* Total surface area of ​​the thrust pistons / Surface area of ​​the injection piston Si, in which the injection body is configured to evaluate the permeability of the catheter and has a volume of less than 20 mL, advantageously less than 10 mL, advantageously less than 5 mL, advantageously less than 1 mL, in which the device has means allowing manual loading of the device in the first direction of translation (T1),but preventing manual pushing on the injection body in the second translation direction (T2), the movement in the second translation direction (T2), during the so-called unloading movement, being possible only under the pushing force, only proportional to the ambient atmospheric pressure which is the thrust engine during the injection, in which the device has means for measuring, as a function of time, the movement of the injection piston between an initial position of the injection piston and a subsequent position, the heads of the pushing pistons having been moved under the action of the external pressure exerted on the device, in the second translation direction (T2), during the so-called unloading movement, this subsequent position is measured after a defined time, for example after a test duration of several minutes., AMENDED SHEET (ARTICLE 19) 2. Portable device (1) according to claim 1, wherein the injection body is configured so that the injection piston has a displacement greater than or equal to 0.5 mm for an injection of a volume of 0.1 mL, advantageously greater than or equal to 1 mm for an injection of a volume of 0.1 mL, advantageously greater than or equal to 5 mm for an injection of a volume of 0.1 mL.

3. Portable device (1) according to one of claims 1 or 2, in which the means preventing manual pushing on the injection body in the second direction of translation (T2) are chosen from the following list: the injection piston is breakable or a protective body of the portable device preventing manual pressing on the coupling means (5) and the pistons during the unloading movement in the second direction of translation (T2), and a means connected to the device so as to allow the pistons to move only in the first direction of translation (T1), during the loading movement.

4. Portable device (1) according to any one of claims 1 to 5. 3, wherein the injection body is a disobstructing injection body and has a volume equal to or greater than the intraluminal volume of the catheter.

5. Portable device (1) according to any one of claims 1 to 5. 4, in which the device has mechanical / optical / electronic / colorimetric means for detecting and signaling the movement of one of the pistons, such as a stylus, associated with the movement of a ruler linked to the piston, the zero of which is positioned at the start of the maneuver. AMENDED SHEET (ARTICLE 19) 6. Portable device (1) according to any one of claims 1 to 6. 5, in which the device has means for calculating a catheter obstruction index, connected to the measuring means, the obstruction index being a function of the volume injected during a given time, for example for a duration equal to or less than 1 hour, advantageously less than or equal to 10 minutes, and for example equal to 1 / (displacement of the injection piston * section of the injection piston).

7. Portable device (1) according to any one of claims 1 to 5. 6, in which the ratio between the total surface area of ​​the heads (4b, 4b') of the thrust pistons (3b, 3b') and the surface area of ​​the head (4a) of the injection piston (3a) is between 1 and 4, so as to avoid any overpressure which could be harmful to the catheter.

8. Portable device (1) according to any one of claims 1 to 12. 7, in which the device (1) is connected to a so-called filling syringe (11) of the injection body (A) by: a three-way tap, one way of which is intended to be connected to the catheter (18) and another way is connected to said syringe (11), or an inlet (14) of the injection body (A), the device (1) having an outlet (15) intended to be connected to a catheter (18).

9. Portable device (1) according to any one of claims 1 to 12. 8, in which the thrust bodies (B, B') are identical and placed symmetrically with respect to the injection body (A).

10. Portable device (1) according to any one of claims 1 to 10. 9, in which the sealing of the piston head(s) (4a, 4b, 4b') is ensured by rolling membranes (19) such as membranes having an elastic body radially bearing on the thrust bodies (B, B') and on the injection body (A). AMENDED SHEET (ARTICLE 19) 11. Portable device (1) according to any one of claims 1 to 9, in which the sealing of the piston head(s) (4a, 4b, 4b') is ensured by: O-rings; or the piston head resting on a bellows.

12. Portable device (1) according to any one of claims 4 to 11, in which the device (1) has means for detecting the volume of unblocking substance (S') at given times in the injection body (A), advantageously connected to calculation means, so as to calculate the injection flow rate and its variations in the unblocking injection body to evaluate the unblocking in progress.

13. Portable device according to any one of claims 1 to 12, in which the injection body (A) is a syringe, advantageously graduated, and advantageously the syringe of the injection body (A) is closed by a sealed cap, and in that the pushing bodies (B, B') are syringes, advantageously graduated, and advantageously removable.

14. Portable device according to any one of claims 1 to 13, wherein the mechanical coupling means (5) is fixed to the thrust pistons (3b, 3b') and is removably fixed to the injection piston (3a).

15. Portable device according to any one of claims 8 to 14, in which the so-called filling syringe (11) is connected by a valve (13) to a reservoir (12), in particular to allow possible resupply of the injection body with unblocker substance (S'). AMENDED SHEET (ARTICLE 19) 16. Kit having: a passive portable injection device (1) according to any one of claims 1 to 15, an injection body with a given substance (S) such as a drug or a physiological liquid, and a disobstructing injection body with a substance (S') which is a biological or chemical disobstructer.

17. Method for assessing the permeability of a catheter suspected of being obstructed, and for unobstructing it, using a catheter (18) and a device intended to enable the assessment of the permeability of a catheter suspected of being obstructed, and to carry out the unobstructing of a catheter (18) likely to have an obstruction, the device being a passive portable injection device according to one of claims 1 to 15, which is based solely on atmospheric ambient pressure as a thrust motor during the injection, and which is connected to the catheter (18), method in which: (1) the device is put in place, the injection body being filled with a substance (S), (2) after measuring the initial position of the injection piston in the injection body or of a thrust piston in the thrust body, • the thrust piston heads are allowed to move under the action of the external pressure in the second direction of translation T2, which is exerted on the injection piston, during the unloading movement, the external pressure P being equal to Atmospheric pressure* Total surface area of ​​the thrust pistons Sp / Surface area of ​​the injection piston Si, • then we measure the displacement of the injection piston in the second direction of translation T2 during the unloading movement, at AMENDED SHEET (ARTICLE 19) after a defined time, for example after a test duration of several minutes: (3a) if the injection plunger is moved, then the line has permeability, and the catheter is considered partially obstructed, - then the test injection substance (S) or respectively the injection body is replaced by a de-obstructing substance (S') or respectively by a de-obstructing injection body, with a quantity of biological "de-obstructing" or a quantity of chemical "de-obstructing" (S'), - and the unblocking substance (S') is injected for an injection duration, using the device based solely on atmospheric ambient pressure as the thrust motor of the injection piston; (3b) if the injection piston has not moved, the line is considered to be obstructed and not showing permeability.

18. A method according to claim 17, wherein in step 3a, the filling syringe (10) and the three-way valve are used to access it.

19. Method according to one of claims 17 or 18, in which an obstruction index is calculated by measuring the displacement of one of the pistons as a function of time, during the displacement in the second direction T2, the obstruction index being a function of the volume injected during a given time, and therefore for example the index is chosen equal to 1 / (displacement of the injection piston * section of the injection piston).

20. Method according to any one of claims 1 7 to 1 9, in which the method comprises a step of calculating the hydraulic resistance generated by the obstruction, with the speed of movement of the injection piston and the injection pressure, making it possible to determine the AMENDED SHEET (ARTICLE 19) of the injection of the unblocker so that it runs through the entire catheter (1 8).

21. Method according to any one of claims 1 7 to 20, in which the method comprises a step of calculating the longitudinal location of the obstruction in the catheter (1 8), from the compliance of the catheter (1 8), the injected volume and the injection pressure. AMENDED SHEET (ARTICLE 19)

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