CANNULA FOR DRAINING FLUID FROM A CAVITY

Abstract

One aspect of the invention relates to a cannula (1) for draining fluid from a cavity, comprising a distal end, a proximal end, a main lumen, and a lateral wall comprising: a plurality of lateral openings (113) formed through the lateral wall, in a central portion of the lateral wall; two inflatable balloons (150, 160) arranged in a distal portion of the lateral wall, each balloon assuming an inflated or deflated state, each state leaving the lateral openings free; the first balloon encircling the circumference of the lateral wall; the second balloon encircling the circumference of the main lumen and, in the inflated state, closing the main lumen. Figure 3

Description

Title of the invention: CANNULA FOR DRAINING FLUID FROM A CAVITY TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a cannula for draining fluid from a cavity such as an organ or a venous or arterial vessel. More particularly, the invention relates to a drainage cannula for extracorporeal systems that allow the oxygenation of a blood stream drawn from and reintroduced into an organ or vessel identical or different from the organ or vessel from which the blood was drawn. More particularly still, the invention relates to a drainage cannula for an extracorporeal system of the ECMO (Extracorporeal Membrane Oxygenation) type. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] Today, cannulas are used in conjunction with extracorporeal membrane oxygenation (ECMO) devices. Cannulas are tubes designed to be inserted into a vein, artery, or organ. In ECMO, they allow blood to be drained or injected into or out of the body and are therefore adapted to the blood flow rate to be drawn and injected. A draining—or inlet—cannula is used to draw blood from the body. A return—or injection—cannula is used to inject blood into the body.

[0003] In an ECMO system, the drainage and injection cannulas are connected to a set of extracorporeal components such as a pump, an oxygenator, and a heat exchanger. Together with these components, they form a closed fluid circuit that allows for the extraction of a volume of oxygen-poor blood from an organ or vein, oxygenation, decarboxylation, optional warming, and then reinjection, once artificially oxygenated, into an artery or vein.

[0004] There are two types of ECMO systems: veno-venous ECMO (or ECMO-VV), and veno-arterial ECMO (or ECMO-VA).

[0005] In ECMO-VV systems, the drainage cannula is generally placed in the right atrium of the heart via a femoral vein and then the inferior vena cava. The injection cannula is placed in the right atrium above the drainage cannula, either via the jugular vein and then the superior vena cava, or via the femoral vein contralateral to the drainage cannula and then the inferior vena cava. This type of respiratory support allows for the assistance of failing lungs.

[0006] In VA-ECMO systems, the drainage cannula is also placed in the right atrium of the heart via a femoral vein and then the inferior vena cava. In the less common central configuration, the injection cannula is placed in the ascending aorta. In the more frequent peripheral configuration, the injection cannula is placed in a large-caliber peripheral artery, such as the femoral or axillary artery. This type of circulatory support can supplement, or even replace, the heart, since blood circulation can be entirely achieved by VA-ECMO.

[0007] ECMO-VA is used only in intensive care in severe cases and in an acute setting. For example, it is the standard treatment for refractory cardiogenic shock, refractory cardiac arrest, and decompensated primary or secondary pulmonary hypertension refractory to other treatments. It is the standard treatment for persistent heart failure after heart transplantation and any other cardiac surgery. It is also a preferred technique in cases of poor hemodynamic or respiratory tolerance of lung transplantation and any thoracic or vascular surgery.

[0008] In the case of peripheral ECMO-VA, the retrograde reinjection of oxygenated blood by ECMO-VA causes an increase in left ventricular afterload, which leads to increased pressures in the left ventricle and subsequently to pulmonary edema. The term "retrograde" means in the opposite direction to the physiological flow of blood from the heart to the peripheral tissues. The term "left ventricular afterload" refers to the conditions of blood ejection from the left ventricle.

[0009] Pulmonary edema during VA-ECMO is associated with adverse consequences that most often threaten the patient's life and necessitate limiting the use of VA-ECMO to a median duration of 2 days or, at most, 4 weeks. Indeed, blood that is not drained by the drainage cannula and continues to flow through the heart is no longer oxygenated. Consequently, the first branches of the aorta (coronary arteries, arteries supplying the brain, in particular) are vascularized with a mixture of oxygenated blood from the ECMO and deoxygenated blood from the heart. Furthermore, pulmonary edema can lead to pulmonary superinfection, resulting in pneumonia with a particularly poor prognosis.

[0010] To treat pulmonary edema under ECMO, techniques have been described to unload the left ventricle of the heart: intra-aortic counterpulsation balloon, Impella® intra-ortic pump (Abiomed, Danvers, MA), or percutaneous balloon atrial septotomy.

[0011] Alternatively, the benefit of lowering hydrostatic pressures in the right atrium of the heart has been highlighted, notably in the document "Right Atrial Pressure "Is Associated With Outcomes in Patient With Cardiogenic Shock Receiving Acute Mechanical Circulatory Support" by Davila et al., Front Cardiovasc Med. 2021 Feb 11;8:563853. Lowering pressures in the right sides of the heart does indeed allow for an improvement in right and left ventricular function.

[0012] One way to lower pressures in the right atrium of the heart is to better drain this right atrium.

[0013] Cannulas and cannula systems capable of draining additional blood out of the pulmonary artery are known for this purpose.

[0014] In cannula systems, an additional drainage cannula is generally attached to the ECMO-VA drainage cannula via a Y-shaped connector. The additional drainage cannula is then placed either surgically in the pulmonary artery or percutaneously from the jugular vein to the pulmonary artery.

[0015] However, the use of several drainage cannulas presents several disadvantages.

[0016] First, it requires several insertion sites, which increases the risk of bleeding, infection, and pain or discomfort for the patient.

[0017] Furthermore, there is no medical device specifically designed for draining the additional cannula. Therefore, the blood flow in the additional drainage cannula is not regulated. This leads to damage to the right heart chambers, particularly the tricuspid valve, hemopericardium, and pulmonary artery thrombosis downstream of the additional drainage cannula.

[0018] To overcome these drawbacks, document EP4034187 describes the use of a dual-lumen drainage cannula configured for use with an ECMO-VA system.

[0019] However, the drainage capacity through these cannulas or cannula systems is limited by the suction (negative pressure) applied to them via the ECMO system pump.

[0020] This negative pressure is also applied to the veins and, if increased, causes the flexible walls of the vein to be drawn inward around the drainage cannula. This suction effect can lead to instability, or even a degradation of the drainage flow, and result in damage to or failure of certain organs.

[0021] There is therefore a need to improve the drainage of the right atrium through the drainage cannula of an ECMO system other than by increasing the number of rotation turns of the ECMO system pump or by increasing the intravascular filling of the patient. Summary of the invention

[0022] The invention offers a solution to the problems mentioned above by allowing a depression to be created in the cannula by temporarily blocking the passage of blood in and around the drainage cannula upstream of the right atrium, and by forcing the blood from the right atrium to flow into the drainage cannula.

[0023] To this end, one aspect of the invention relates to a cannula for draining fluid from a cavity, the cannula having a proximal end, a distal end and a lateral wall defining a lumen extending longitudinally through the drainage cannula between the proximal end and the distal end, the lateral wall comprising an internal surface disposed towards the lumen and an external surface, the lateral wall comprising:

[0024] - a central portion comprising a plurality of lateral openings, each side opening passing through the side wall;

[0025] - a distal portion of the lateral wall adjacent to the central portion and comprising the distal end of the drainage cannula, on which are arranged two inflatable balloons, each inflatable balloon taking an inflated or deflated state, each state leaving the lateral openings at least partially clear, the two inflatable balloons comprising an outer balloon enclosing the outer surface of the lateral wall, and an inner balloon disposed on the inner surface of the lateral wall and closing, in the inflated state, the lumen.

[0026] The term cavity refers, for example, to an organ, an artery, or a vein. In particular, the term cavity may refer to the superior vena cava, the right atrium of the heart, or the inferior vena cava.

[0027] By fluid, we mean any fluid normally circulating in a drainage cannula. For example, the fluid may be blood, an perfusion fluid (for example, a macromolecular solution), an organ preservation fluid, a labile blood product, etc.

[0028] The term "light" refers to the interior space enclosed by the side wall. In the context of the invention, the side wall may be a hollow cylindrical tube, and the light designates the interior space of this hollow tube. This hollow tube extends along a longitudinal direction, and the light therefore extends along the same longitudinal direction.

[0029] The "inner surface" of the lateral wall is understood to be the surface delimiting the internal space—that is, the lumen. In other words, the inner surface corresponds to the "inner" surface of the lateral wall, i.e., the one facing the main lumen. The "outer surface" (or "external" surface) refers to the surface of the lateral wall opposite the inner surface, i.e., the surface not facing the lumen. The outer surface corresponds to the surface closest to the cavity walls when the drainage cannula is in place in the subject's body.

[0030] By "through the side wall," it is understood that each opening leads to both sides of the side wall, from the inner surface to the outer surface. This allows fluid exchange between the outside of the side wall (and therefore the drainage cannula) and the inside of the side wall (i.e., the lumen).

[0031] By "each state leaving the lateral openings at least partially unobstructed," it is understood that none of the balloons, whether inflated or deflated, completely obstructs the openings. Thus, fluid exchange can take place regardless of the state of the balloons. In particular, the balloons can be designed such that none of the openings is completely obstructed when the balloons are inflated or deflated.

[0032] By "enclosing the outer surface of the side wall," it is understood that the outer balloon is arranged around the side wall, and that a portion of the balloon closely adheres to a portion of the outer surface of the side wall. For example, the outer balloon may include a portion of its surface pressed against a portion of the outer surface of the side wall. The outer balloon in its inflated state may define, for example, a volume (e.g., the surface of a solid of revolution) through which an opening, such as a central cylinder, passes, having the same diameter as the outer diameter of the side wall (i.e., the diameter of a section of the outer surface in a plane orthogonal to the longitudinal direction). In particular, the outer balloon may be a torus, a sphere through which a central cylinder passes, a hollow cylinder, etc.

[0033] In some embodiments, the inner balloon leaves the lumen open in the deflated state and closes the lumen in the inflated state. Thus, a fluid can flow through the lumen at the level of the inner balloon when the balloon is deflated, but not when the balloon is inflated.

[0034] Thus, according to the invention, the drainage cannula, once placed in the heart of a patient up to the superior vena cava, makes it possible to drain the majority, or even all, of the blood present in the right atrium.

[0035] The inflatable balloons in their inflated states have the effect of blocking (temporarily, for the duration of the inflated state) the passage of blood in and around the drainage cannula upstream of the lateral openings, that is to say at the level of the superior atriocaval junction in the patient's heart.

[0036] The right atrium thus becomes a substantially closed cavity. The stagnant blood in the right atrium is therefore forced to flow into the drainage cannula through the N lateral openings which are left free (i.e. at least partially unobstructed).

[0037] The volume thus drawn into the drainage cannula creates a vacuum that forces blood forward within the cannula: this suction effect allows for greater drainage of the right atrium. This also increases the blood flow through the drainage cannula. The improvement of the Drainage capacity and blood circulation in the drainage cannula allow for lowering of pressures in the right chambers, and subsequently improving right and left ventricular functions.

[0038] When both balloons are deflated, the drainage cannula allows blood to be drained from the superior vena cava, the right atrium, and potentially the inferior vena cava. One of the advantages of performing drainage at different vascular locations is to reduce the blood volume in the right atrium to a greater extent.

[0039] It is noted that the drainage cannula according to the invention is usable as a drainage cannula of an ECMO system.

[0040] In one or more embodiments, the lateral openings are arranged longitudinally, for example along one or more columns. Optionally, from one column to the next, the lateral openings may be arranged on planes orthogonal to the longitudinal direction. Furthermore, the openings may be regularly spaced from one another along the longitudinal axis.

[0041] In one or more embodiments, the inner balloon and the outer balloon are included in a part of the distal portion of the lateral wall, said part not including the distal end.

[0042] In other words, none of the balloons "terminates" the side wall at the distal end.

[0043] In one or more embodiments, the side wall includes a set of inflation channels arranged longitudinally in the side wall, the set of inflation channels being connected to the two inflatable balloons and allowing each of the two balloons to pass into a respective inflated or deflated state.

[0044] By "set of inflation channels", it is understood that one or more inflation channels, each connected to the external balloon and / or the internal balloon.

[0045] For example, each inflation channel can communicate, on the one hand, with one and / or the other of the two inflatable balloons arranged in the distal portion, and, on the other hand, with the outside of the drainage cannula through a proximal opening formed at the level of a proximal portion of the cannula, the proximal portion being adjacent to the central portion and including the proximal end.

[0046] It is noted that there may be one or more inflation channels. In one embodiment, the side wall comprises a single inflation channel communicating on one side with the external balloon and the internal balloon and on the other side with the outside of the drainage cannula at the proximal portion.

[0047] Alternatively, the side wall comprises two separate inflation channels, the first inflation channel communicating with the external balloon and with the outside of the cannula through a first proximal opening, and the second inflation channel communicating with the internal balloon and with the outside of the cannula by a second proximal opening, the proximal openings being formed in the proximal portion of the drainage cannula.

[0048] In one or more embodiments, during a transition from a deflated state to an inflated state, the external balloon extends in a direction orthogonal to a longitudinal direction of the lateral wall.

[0049] For example, the external balloon may include a membrane comprising a first part and a second part, the first part of the membrane being hermetically connected to a distal opening formed in the lateral wall at the distal portion, the distal opening communicating with at least one inflation channel, and wherein: • in the inflated state of said balloon, the first part of the membrane is in direct circumferential and longitudinal contact with the distal portion, and the second part extends laterally and along the distal portion, • in the deflated state of said balloon, the second part of the membrane is flattened around the distal portion.

[0050] Advantageously, the outer or inner balloon may have a toroidal shape. It is understood that both balloons may each have a toroidal shape. This shape advantageously allows the balloon to be inflated via a single inflation port while ensuring that its membrane is, on the one hand, in direct circumferential and longitudinal contact with the cannula, and on the other hand, that it can extend laterally and along the cannula without covering the N lateral openings.

[0051] In one or more embodiments, the side wall further comprises a lateral inflatable balloon fixed to the external surface of the side wall between two lateral openings, the lateral inflatable balloon communicating with a second inflation channel extending longitudinally inside the side wall and being connected to the lateral inflatable balloon, the second inflation channel allowing the lateral inflatable balloon to pass into an inflated or deflated state, the second inflation channel not being connected to the two inflatable balloons arranged in the distal portion of the side wall.

[0052] It is understood that there may be several lateral inflatable balloons.

[0053] For example, each lateral inflatable balloon can communicate with a second inflation channel extending longitudinally inside the lateral wall and communicating with the outside of the cannula at the proximal portion, said second inflation channel being distinct from the inflation channel communicating with the balloons arranged on the distal portion.

[0054] In one or more embodiments, the lateral wall may have a length between 50 cm and 70 cm and the distal portion may have a length between 1 cm and 20 cm.

[0055] Furthermore, the proximal portion can have a length between 2 cm and 10 cm. Thus, the central portion can have a length between 20 cm and 67 cm.

[0056] In some embodiments, the central portion has a length between 10 cm and 15 cm. In these embodiments, the central portion (including the side openings) is relatively small in size compared to the length of the side wall.

[0057] In these embodiments, the side wall includes a second external inflatable balloon arranged in a proximal portion of the side wall, the proximal portion being adjacent to the central portion and including the proximal end of the drainage cannula, the second external inflatable balloon enclosing the external surface of the side wall, and taking a deflated or inflated state, each state leaving the lateral openings at least partially clear.

[0058] In one or more embodiments, the side wall or the external balloon may include at least one radiopaque or echopaque marker. Thus, the cannula provides means of controlling its position in the cavity, either by radiographic control in the case of radiopaque marker(s), or by ultrasound control in the case of echopaque marker(s).

[0059] In one or more embodiments, the side wall and / or the outer balloon and / or the inner balloon may be coated with an anti-thrombotic or anti-proliferative substance.

[0060] In one or more embodiments, the side wall may include at least one flow sensor. Positioned near the distal opening, such a sensor allows the flow rate of the fluid in the cannula to be determined. Alternatively or in addition, the side wall may include at least one pressure sensor. Such flow or pressure sensors can be used to adjust the drainage. Indeed, it is advantageous to be able to finely adjust, or "regulate," the drainage (particularly its flow rate) to adapt to certain parameters such as cardiac recovery. Typically, when the heart recovers, it is beneficial to be able to reduce the drainage.

[0061] Another way to regulate drainage is to vary the size of the opening defined by the side wall. Thus, in one or more embodiments, the opening has a characteristic dimension that can be variable. When the side wall is a hollow cylindrical tube, the characteristic dimension of the opening, which is the internal space of the hollow tube, can be the diameter or the radius of this hollow tube.

[0062] To vary the characteristic dimension of the light, an internal chamber system (i.e., a chamber located inside the side wall) can be used, acting as a sphincter: the internal chamber can be filled (with air or any other fluid) to reduce the internal volume of the wall (and thus the characteristic dimension of the light). For example, the internal chamber could be an inflatable balloon. Of course, other systems can be used. For example, the internal surface of the wall can be covered with a material that deforms under the action of an external stimulus (e.g., under the action of an electric or magnetic field). Mechanical systems such as adjustable springs can also be placed between the external and internal surfaces of the wall, so as to exert a stress on the internal wall and thus change its position, and therefore its diameter.Other implementation methods are possible.

[0063] In one or more embodiments, the side wall may include at least one induction sensor. Such a sensor may be used to detect the formation of a blood clot.

[0064] Another aspect of the invention relates to a fluid drainage system in a cavity comprising: • the drainage cannula defined above, • an inflation system comprising: • at least one inflation pump connected to the two inflatable balloons arranged in the distal portion of the side wall, and • a control unit to control the inflation pump to obtain an inflated or deflated state of each inflatable balloon.

[0065] For example, the control unit can be configured so that the inflated state of the external balloon and the inflated state of the internal balloon are achieved at the same time, and so that the deflated state of the external balloon and the deflated state of the internal balloon are achieved at the same time.

[0066] For example, the control unit can be configured so that the duration of the inflated state of the external balloon and the internal balloon is between 1s and Ih, and that the duration of the deflated state of the external balloon and the internal balloon is between 1s and Ih.

[0067] In one or more embodiments, the control unit is configured to perform an alternation of an inflated state and a deflated state at a regular rate, with a frequency of F2.

[0068] For example, the control unit can further be connected to a frequency sensor to measure a heart rate Fl of a subject, and to determine the frequency F2 of the alternation of the inflated and deflated states as a function of the heart rate Fl.

[0069] Another aspect of the invention relates to an extracorporeal membrane oxygenation system comprising a drainage system as defined above, a fluidic circuit and an injection cannula, the fluidic circuit comprising: • a pump with a fluid inlet and outlet, • an oxygenator with a fluid inlet and outlet, • a heat exchanger with a fluid inlet and outlet, • a tube connecting the proximal end of the drainage cannula of the system drainage at the pump inlet, • a tube connecting the pump outlet and the oxygenator inlet, • a tube connecting the outlet of the oxygenator and the inlet of the heat exchanger, • a tube connecting the outlet of the exchanger and the injection cannula.

[0070] For example, the fluidic circuit pump can be configured to generate a laminar fluid flow.

[0071] Alternatively, the fluidic circuit pump can be configured to generate a pulsed fluid flow.

[0072] Another aspect of the invention relates to a method of using an extracorporeal membrane oxygenation system as defined above, comprising, after the cannula has been introduced and positioned in the cavity with the inflatable balloons in the deflated state and the first interface tube disconnected from the cannula:

[0073] - starting the fluid circulation in the cannula via the starting of the fluidic circuit pump,

[0074] - starting the inflation pump by means of the control unit programmed for:

[0075] receive a signal from the frequency sensor, the signal from the frequency sensor having a frequency Fl,

[0076] in response to the signal from the frequency sensor, determine a frequency F2 as a function of the frequency Fl, the frequency F2 being between 15 and 180 cycles per minute,

[0077] send a command to the inflation pump to perform a sequence comprising an inflated state followed by a deflated state,

[0078] repeat the sequence at frequency F2.

[0079] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0080] The figures are presented for illustrative purposes only and are in no way limiting of the invention. • Figure 1 shows, schematically, an example of an ECMO system according to the invention in position within a patient's body. • Figure [Fig. 2] shows, in schematic form, the ECMO system represented in Figure [Fig. 1], • Figure 3 shows, in schematic form, a cross-sectional view of an inflatable balloon drainage cannula according to the invention. • Figure 4 shows, schematically, a perspective view of the cannula shown in Figure 3 when the balloons are in their inflated state. • Figure 5 shows, schematically, a perspective view of the cannula shown in Figure 3 when the balloons are in their deflated state. • Fig. 6 shows, schematically, an enlarged view of one of the cannula balloons shown in Fig. 3. • Figure 7 shows, schematically, the cannula of Figure 3 in position within a patient's heart. • Fig. 8 shows, schematically, a cross-sectional view of an inflatable balloon drainage cannula as an alternative to the drainage cannula shown in Fig. 3. • Fig. 9 shows, schematically, a cross-sectional view of the cannula shown in Fig. 8. • Fig. 10 shows, schematically, a perspective view of the drainage cannula shown in Fig. 8. • Figure 11 shows, schematically, a cross-sectional view of an inflatable balloon drainage cannula, an alternative to the drainage cannulas shown in Figures 3 and 8. • Figure 12 schematically shows the cannula depicted in Figure 11 in position within a patient's heart. • Fig. 13 shows, in the form of a flowchart, steps of a method of using the cannula system according to an embodiment of the invention. DETAILED DESCRIPTION

[0081] In the following description, it will be assumed that the term "fluid" refers to blood and that the term "cavity" refers to a vein or an organ supplied with blood by a vein.

[0082] The invention relates to systems and methods for assisting a patient's heart using a drainage cannula. In particular, the invention relates to extracorporeal membrane oxygenation (ECMO) systems. More specifically, the invention aims to improve the drainage capacity and flow rate of the drainage cannula of an ECMO system. This allows to improve ECMO treatment and to treat certain complications related to this treatment, including pulmonary edema under ECMO.

[0083] Fig. 1 shows, in schematic form, an example of an ECMO 7 system according to the invention set up on a patient 2.

[0084] In this example, we consider a veno-arterial ECMO system 7, or ECMO-VA. Deoxygenated blood is thus withdrawn from a femoral vein 20, then oxygenated, and possibly warmed. The oxygenated blood is then returned to the patient's body via the femoral artery 205. Naturally, this embodiment is by no means limiting. The ECMO system 7 could, for example, be of the veno-venous type, or ECMO-VV. The blood is then returned to the bloodstream in a vein near the heart.

[0085] As shown in [Fig.1], the ECMO system 7 comprises a drainage cannula system 6 according to the invention, a fluidic circuit 3, and an injection cannula 305.

[0086] The fluidic circuit 3 includes a pump 301, an oxygenator 302 and a set of tubes T2, T3, T4 and T5. The fluidic circuit 3 may also include a heat exchanger 303.

[0087] The pump 301 is configured to a predefined flow rate, which can be further adjusted via a control unit (not shown). The pump 301 allows, on the one hand, the pumping of blood from the cannula system 6 at a flow rate close to the patient's physiological rate, and on the other hand, the injection of this blood, once oxygenated and warmed, into the injection cannula 305. The pump 301 is, for example, a peristaltic pump or a centrifugal pump producing a laminar flow. It can also be a pump generating a pulsed flow.

[0088] The oxygenator 302 comprises a membrane that artificially reproduces the function of the alveo-capillary membrane of the lungs. This membrane allows gas exchange to occur in order to oxygenate the blood and eliminate carbon dioxide.

[0089] The heat exchanger 303 receives oxygenated blood from the oxygenator 302 via the interface tube T4 to warm it. The exchanger 303 is, in effect, a system that transfers thermal energy from a fluid such as water to blood, without mixing the two fluids. The exchanger 303 maintains the blood temperature so that it falls within the temperature range of blood circulating in a patient's body.

[0090] The injection cannula 305 receives oxygenated and warmed blood from the exchanger, via an interface tube T5. This injection cannula 305 is, for example, introduced into the femoral artery and positioned up to the bifurcation of the aorta 206.

[0091] Fig. 2 shows an enlarged view of the cannula system 6 shown in Fig. 2.

[0092] As shown in [Fig. 2], this cannula system 6 comprises a cannula of drainage 1 comprising inflatable balloons (also noted as cannula 1 hereafter) and an inflation system 5 coupled to cannula 1.

[0093] With reference to [Fig. 1], the cannula 1 is introduced into patient 2 through an entry point 20 made in the femoral vein and advanced into the superior vena cava (cf. [Fig. 1], and in particular the enlarged part of this figure).

[0094] The cannula 1, thus positioned, allows deoxygenated blood to be drained from the right atrium 203 and / or the superior vena cava 201 and / or the inferior vena cava 204. The inflation system 5 allows the inflatable balloons of the cannula 1 to be inflated once the cannula 1 has been placed in the patient 2, and / or during the introduction or withdrawal phases of the cannula 1.

[0095] A first embodiment of the cannula 1 is described below in relation to figures 3 to 7.

[0096] In the remainder of the description, and with reference to [Fig.1], the term “distal” applied to cannula 1 refers to the part of cannula 1 closest to heart 200, while the term “proximal” refers to the part of cannula 1 furthest from heart 200.

[0097] As indicated by the arrows shown in [Fig. 1] (particularly in the part of this figure showing an enlarged view of the heart 200), blood enters the right atrium 203 via the superior vena cava 201 and the inferior vena cava 204. It flows through the cannula 1 from its distal end to its proximal end. The terms "upstream" and "downstream," when applied to the cannula 1, refer to this direction of blood flow within the cannula 1.

[0098] Fig. 3 shows, in schematic form, a cross-sectional view of the cannula 1, according to the first embodiment.

[0099] With reference to [Fig. 3], the cannula 1 has a cylindrical shape extending along a longitudinal axis. The cannula 1 has a distal end 104a, a proximal end 105a and a lateral wall 101 extending from the distal end 104a to the proximal end 105a.

[0100] The lateral wall 101 defines an internal passage 112 extending longitudinally through the cannula 1, from the distal end 104a to the proximal end 105a. This passage 112 is conventionally called the lumen 112. The lumen 112 opens to the outside of the cannula by a distal opening 104 located on the distal end 104a, and by a distal opening 105 located on the proximal end 105.

[0101] Fig. 7 shows, schematically, the cannula 1 according to the first embodiment in position in the heart 200 of patient 2.

[0102] As shown in [Fig.7], the distal opening 104 allows blood to enter from the superior vena cava 201 through the cannula 1 (via the lumen 112 shown in [Fig.3]).

[0103] With reference to [Fig. 1], the proximal opening 105 can be connected to the fluidic circuit 3 of the ECMO system 7. The proximal opening 105 is, for example, suitable to cooperate with a connecting mouthpiece from a component of the fluidic circuit 3 of the ECMO system 7. In [Fig.1], the fluidic component is an interface tube T2 coupled to a pump 301, called the ECMO pump 7. The ECMO pump 301 allows suction to be applied to the cannula 1 which facilitates the circulation of blood through the lumen 112.

[0104] The side wall 101 preferably has a circular cross-section. The side wall 101 has an external diameter corresponding to the external diameter of the cannula 1. The side wall 101 has an internal diameter corresponding to the diameter of the lumen 112 or, in other words, to the internal diameter of the cannula 1. The side wall 101 also has a thickness in the lateral direction, denoted 111 in [Fig. 3].

[0105] The cannula 1 preferably has a length between 50 cm and 70 cm. For example, the cannula 1 has a length of 60 cm. In this configuration, a portion of the cannula 1 with a length between 50 cm and 58 cm (for example) is positioned inside the patient 2, and a portion of the cannula 1 with a length between 2 cm and 10 cm (for example) is positioned outside the patient, near the insertion point 20.

[0106] The cannula 1 has an external diameter that can be between 9 French and 30 French, i.e., between 3 mm and 10 mm. For example, the external diameter of the cannula 1 is one of the following diameters: 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0107] The cannula 1 has an internal diameter which depends on the external diameter chosen for the cannula 1. Preferably, this internal diameter is between 2 mm and 9 mm.

[0108] The cannula 1 is made of a biocompatible material. Preferably, this material has a certain degree of suppleness and flexibility to allow its guidance within the patient's body 2. This material is, for example, composed of polyurethane or an elastomer such as PEBAX(TM \

[0109] With reference to Figures 3, 4, 5, and 7, the cannula 1 further has at least two (or N, with N a natural number greater than or equal to 2) lateral openings 113, two inflatable balloons 150, 160, and an inflation line 18 to allow the inflation of these balloons 150, 160.

[0110] Lateral openings 113 are formed through the lateral wall 101. As shown in [Fig.3], each lateral opening 113 opens both outwards from the cannula 1 and into the lumen 112.

[0111] These N lateral openings 113 thus allow additional blood to enter the lumen 112. This blood is added to the blood entering through the distal opening 104. As illustrated in [Fig. 7], the blood entering through the lateral openings 113 comes from the right atrium 203.

[0112] Each lateral opening 113 is, for example, formed substantially perpendicular to the longitudinal axis of the cannula 1. Each lateral opening 113 is preferably circular. The diameter of the lateral opening 113 is then preferably between 0.5 mm and 5 mm.

[0113] With reference to figures 4, 5 and 7, the N lateral openings 113 are spaced from each other both on the circumference (N is here strictly greater than 2) and along the lateral wall 101. The N second lateral openings 113 are for example arranged in a circular pattern extending around circumferences of the lateral wall 101.

[0114] This circumferential arrangement of the lateral openings 113 allows blood to drain all around the cannula 1. This improves the drainage capacity of the cannula 1.

[0115] The lateral opening closest to the distal end 104a is located, for example, at a distance of between 1 cm and 20 cm from the distal end 104a. This distance from the distal end 104a defines a portion 106 of the lateral wall 101, called the distal portion 106 (see [Fig. 3]) on which there are no lateral openings 113.

[0116] Preferably, this distance (and therefore the length of the distal portion 106) is between 5 cm and 10 cm. For example, this distance is equal to 5 cm. Thus, with reference to [Fig. 7], the distal portion 106 is positioned in the superior atriocaval junction 202 and the N lateral openings are positioned downstream of the superior vena cava, in the right atrium and / or the inferior vena cava.

[0117] The lateral opening closest to the proximal end 105a is located, for example, at a distance of between 2 cm and 10 cm from the proximal end 105a. This distance from the proximal end 105 defines another portion of the lateral wall 101, called the proximal portion 109 (see [Fig.3]) on which there are no lateral openings.

[0118] In this configuration, the proximal portion 109 advantageously corresponds to the part of the cannula 1 located outside patient 2, and the N lateral openings extend at least into the right atrium 203 and the inferior vena cava 204. This makes it possible to obtain a cannula 1 suitable for patients of different sizes. This also allows for better drainage of the lower part of patient 2's body (abdomen, hepatic vein).

[0119] With reference to [Fig.3], the lateral opening 113 closest to the distal end 104a and the lateral opening 113 closest to the proximal end 105a define a central portion 107 of the lateral wall 101. In other words, the central portion 107 of the cannula 1 corresponds to the portion comprising the lateral openings 113.

[0120] The inflatable balloons 150, 160 and the associated inflation line 18 are described below.

[0121] As shown in [Fig.3], the associated inflation line 18 preferentially comprises a single inflation channel 180 communicating with a proximal opening 181 and with each inflatable balloon 150, 160 via distal openings 182, 183.

[0122] With reference to figures 2 and 3, the inflation channel 180 is a second lumen 180 arranged longitudinally in the thickness 111 of the lateral wall 101. The inflation channel 180 extends, for example, so as to be substantially parallel to the first lumen 112. Its dimensions and in particular its diameter are compatible with the passage of an inflation fluid, for example pressurized air, physiological saline, a contrast agent or a combination of pressurized air, physiological saline and the contrast agent.

[0123] The inflation channel 180 communicates with the inner balloon 160 through a first distal opening 183 and with the outer balloon 150 through a second distal opening 182.

[0124] The distal openings 182, 183 are provided in the distal portion 106 of the cannula 1. They are configured to connect in a leak-proof manner to the inflatable balloons 150, 160.

[0125] The proximal opening 181 opens onto the inflation channel 180 and onto the outside of the cannula 1. The proximal opening 181 is configured to be connected to the inflation system 5 shown in Figures 1 and 2.

[0126] The inflation line 18 thus arranged inside the side wall 101 allows an inflation fluid to be conveyed into or removed from the inflatable balloons 150, 160 without increasing the external diameter of the cannula 1. An advantage is that the cannula 1 is compatible with an ECMO system 7.

[0127] The proximal opening 181 is preferably formed in the proximal portion 109 of the cannula 1, that is, in the portion of the cannula 1 that is positioned outside the patient 2. This position allows easy connection of the cannula to the inflation system 5, once the cannula 1 has been placed in the patient 2. This position also allows the cannula 1 to be inserted or removed while it is connected to the inflation system 5. An advantage is that the inflatable balloons can be easily placed in inflated states during the insertion and removal phases of the cannula 1, and also once the cannula 1 is in place.

[0128] The inflatable balloons 150, 160 are described below.

[0129] The term "inflatable balloon" here refers to a device that assumes an inflated or deflated state. The inflated state occurs when the internal volume of the inflatable balloon contains a volume of an inflation fluid. The deflated state occurs when the volume of the balloon contains no fluid.

[0130] In the following description, and for the sake of simplicity, the external inflatable balloon 150 will be referred to simply as "external balloon" and the internal inflatable balloon 160 as "internal balloon".

[0131] With reference to Figures 3, 4 and 5, the external balloon 150 and the internal balloon 160 are fixed to a part of the distal portion 106 of the cannula 1. Thus, with reference to [Fig.7], they are positioned in the superior vena cava 201, at the level of the superior atriocaval junction 202.

[0132] The external balloon 150 preferably comprises a membrane on which a first part 151 and a second part 152 are defined. The first part of the membrane 151 is oriented towards the cannula 1 and includes an inflation orifice, while the second part 152 is oriented outwards, i.e. towards the superior vena cava 201.

[0133] The first part 151 of the membrane encloses the circumference of the lateral wall 101, at the level of all or part of the distal portion 106. By "enclosed", it is understood that the first part of the membrane 151, or a part of this membrane, adheres for example by heat sealing or by the use of adhesives to the circumference of the lateral wall 101.

[0134] The external balloon 150 is designed to be inflated and deflated several hundred times, or more. The membrane 151, 152 of the external balloon 150 is therefore made of a material that provides a good seal at low inflation pressures, for example, well below 10 atmospheres, and offers suitable mechanical properties, particularly in terms of puncture resistance and tensile strength. The material also has chemical properties that allow the formation of an adhesive or heat-bonding bond with the cannula 1 and ensure biocompatibility. For example, the external balloon 150 is made of a polyurethane with suitable mechanical and chemical properties. For example, the external balloon 150 is made of the same material as Maquet™ or Teleflex™ type intra-aortic balloon counterpulsation devices.

[0135] Preferably, the outer balloon 150 is torus-shaped, or buoy-shaped, as illustrated in Figures 3 to 6. It has, in the first portion 151 of its membrane, an inflation opening adapted to be connected to the distal opening 182 in a leak-proof manner, for example, by means of a seal or a valve. Leak-proof means that an inflation fluid such as air can be conveyed without leakage through the second opening 180 to the interior of the balloon. The seal can be achieved by heat sealing, bonding, overmolding, or a combination of heat sealing, bonding, and overmolding.

[0136] The inflated state of the external balloon 150 is described below, in relation to figures 3, 4 and 6.

[0137] In this inflated state, the first part of the membrane 151 is in direct circumferential and longitudinal contact with the first portion of the cannula 1, that is to say, it rests on the cannula 1 over a sufficiently large surface and with sufficient force so that the blood coming upstream of the balloon does not circulate between the first part of the membrane 151 and the cannula 1. The first part 151 of the membrane then preferentially presents a smooth appearance on the cannula 1.

[0138] Still in this inflated state, the second part of the membrane 152 is kept stretched in the lateral direction.

[0139] It can also stretch in the longitudinal direction, without however covering the lateral openings arranged there, nor covering the distal opening. The second part of the membrane 152 can, for example, extend longitudinally over a length (denoted 154 in [Fig. 6]) of between 1 cm and 5 cm.

[0140] The second part of the membrane 152 then preferably presents a smooth surface vis-à-vis the cavity, as illustrated for example in [Fig.3].

[0141] With reference to figures 4, 5 and 7, the external balloon 150, in its inflated state, thus has the effect of locally increasing, at the level of at least part of the distal portion 106, the external diameter of the cannula 1. The external balloon 150 in its inflated state does not cover the lateral openings 113 which are therefore left free.

[0142] This extended external diameter 153 is illustrated in [Fig.6]. It can vary depending on a predetermined volume of inflation fluid to be injected and maintained in the external balloon 150.

[0143] Once the cannula 1 is in place in the patient, the extended external diameter 153 is preferably adjusted to match the diameter of the superior vena cava 201 of patient 2.

[0144] The extended external diameter 153 is thus preferably between 15 mm and 30 mm, which corresponds to a lateral dimension of the balloon (taken between the two parts 151, 152 of the membrane) between 5 mm and 10 mm.

[0145] In this inflated state, and with reference to [Fig.7], the external balloon 150 closes the passage of blood from the superior vena cava 201 to the right atrium 203. In other words, the external balloon 150, in its inflated state, creates an occlusion of the superior vena cava.

[0146] When removing cannula 1 from the patient, the extended external diameter 153 can be adapted to allow the removal of blood clots that may have formed on the walls of cannula 1 during the ECMO procedure.

[0147] The deflated state of the external balloon 150 is described below, in relation to [Fig.5].

[0148] In its deflated state, the second part 152 of the membrane is flattened over the cannula 1 on the distal portion 106 of the cannula 1 so as not to cover either the lateral openings 113 or the distal opening 104. The external balloon 150 in its Deflating it does not change, or only minimally changes, the initial external diameter of the cannula 1. Thus, blood can pass normally from the superior vena cava 201 to the right atrium 203.

[0149] With reference to [Fig.3], the inner balloon 160 is fixed on the circumference of the lumen 112, at the level of part or all of the distal portion 106. The inner balloon 160 is, for example, fixed opposite (or at the same level as) the outer balloon 150.

[0150] The internal balloon 160 encloses the second distal opening 183 and is connected to it in a sealed manner.

[0151] Like the outer balloon 150, the inner balloon 160 is suitable for being inflated and deflated several hundred, or more, times. It can be made of the same material, or a similar material, as the outer balloon 150.

[0152] In its deflated state, the internal balloon 160 is flattened around the lumen 112. Thus, it leaves this lumen 112 open and blood from the proximal opening can flow normally through the cannula 1.

[0153] In its inflated state, and as illustrated in [Fig.3], the internal balloon 160 expands towards the longitudinal axis of the cannula 1 until it completely closes the lumen 112. Thus, the internal balloon 160, in its deflated state, makes it possible to block, inside the cannula 1, the circulation of blood coming from the distal opening 104 without blocking that coming from the lateral openings 113.

[0154] With reference to [Fig.3], the inner balloon 160 preferably has a toroidal shape.

[0155] As the internal and external balloons 160, 150 are here both connected to the same Inflation line 18, the inflated state of the inner balloon 160 occurs at the same time as the inflated state of the outer balloon 150. Similarly, the deflated state of the inner balloon 160 occurs at the same time as the deflated state of the outer balloon 150.

[0156] When the cannula 1 is placed in patient 2, the simultaneous inflated state of the internal and external balloons 160, 150 allows for a temporary occlusion of the lumen 112 and the superior vena cava 201 at the level of the atrio-caval junction 202, while leaving the lateral openings 113 free.

[0157] During the temporary occlusion, the right atrium 203 becomes a substantially closed cavity. The N lateral openings 113, which are left free thanks to the position of the internal and external balloons 160, 150, then drain blood out of the right atrium, without the atrium filling. The stagnant blood in the right atrium is thus forced to flow into the cannula 1 through these N free lateral openings 113.

[0158] The volume thus drawn into cannula 1 creates a vacuum that forces blood forward into the drainage cannula: a suction effect allows the right atrium to be drained to a greater extent than with known drainage cannulas. It allows Also, when cannula 1 is assembled in the ECMO system 7 (see [Fig. 1]), the flow rate in the fluid circuit 3 of the ECMO system 7 is improved without increasing the number of rotations of the ECMO pump 301. This allows for a reduction in pressures in the right heart chambers, thereby improving right and left ventricular function.

[0159] When cannula 1 is removed from patient 2, the simultaneous inflated state of the external and internal balloons 150, 160 allows clots formed around and inside cannula 1 to be pulled out.

[0160] Moreover, the simultaneous deflated state allows drainage, with a single cannula 1 and a single lumen 112, of two different vascular locations: the superior vena cava 201 through the distal opening 104, and the right atrium 203 through the N lateral openings 113. This makes it possible to obtain a simpler cannula 1 than known drainage cannulas, which require either several cannulas or a cannula with several lumens.

[0161] The side wall 101 and / or the outer balloon 150 and / or the inner balloon 160 may be coated with an antithrombotic or antiproliferative substance, for example, but not limited to, the anticoagulant heparin, the antithrombogenic aspirin, the antiproliferative sirolimus, or an anti-infective antibiotic. This prevents subsequent complications such as clot formation on the cannula or balloon, or infection.

[0162] Furthermore, with reference to [Fig. 4], the side wall 101 may also include at least one positioning marker 140 to facilitate its insertion and positioning in the heart 200 by external control. The positioning marker 140 may include a discrete element attached to the cannula 1, or a material formed as a single piece with the material of the cannula 1. The positioning marker 140 may be located at any suitable position on the cannula 1. The marker 140 may, for example, be radiopaque. External control is then performed by radiographic imaging. The positioning marker 140 may also be echopaque. External control is then performed by ultrasound imaging. This limits the use of ionizing radiation because the placement of the cannula 1 can be considered solely with ultrasound control, without recourse to fluoroscopic control.

[0163] Finally, the side wall 101 may include at least one sensor as shown in [Fig. 4] to assist the practitioner in adjusting the operation of the cannula with respect to the patient's condition, in particular: • A pressure sensor 141 adapted to measure blood pressure in the cavity. The pressure sensor 141 can be appropriately positioned at any location on the distal portion 106 or the central portion 107 of the cannula 1. The pressure sensor 141 allows for the detection of changes in blood pressure; and / or • A flow sensor 142 adapted to measure the blood flow rate in cannula 1. This sensor is preferably located in the proximal portion 109 of cannula 1; and / or • An induction sensor (or “inductive sensor”) 143 adapted to detect the formation of blood clots on cannula 1. It can be located at any location on cannula 1.

[0164] The cannula 1 may also include, alternatively to the inflation line 18 common to both the external and internal balloons 150, 160, two independent inflation lines (not shown in Figures 3 to 6). Each inflation line is then respectively connected to a single balloon (external or internal 150, 160). The cannula 1 then includes an additional inflation line and an additional proximal opening. The additional inflation line is formed within the thickness of the lateral wall 101 and extends longitudinally through this lateral wall 101. The additional proximal opening is preferably formed at the proximal portion 109 of the cannula and is preferably located less than 10 cm from the proximal end 105a.

[0165] One of the advantages of having two separate inflation lines is that the inflation of the internal and external balloons 160, 150 is better controlled. Another advantage is that the manufacture of the cannula 1 is more convenient.

[0166] Furthermore, thanks to the independent inflation lines, the external and internal balloons do not necessarily have their inflated (or deflated) states at the same time. This allows for a cannula 1 configuration in which only the external balloon 150 is inflated. The external balloon 150 then allows the cannula 1 to be adjusted and maintained in the superior vena cava. This embodiment is advantageous when the cannula 1 is assembled in a veno-venous ECMO system. Indeed, such a system is used to treat respiratory failure and not heart failure and does not require occlusion of the superior vena cava.

[0167] Figures 8 and 9 show respectively, in schematic form, different cross-sectional views of a cannula 1 according to a second embodiment.

[0168] Fig. 10 shows, schematically, a perspective view of the cannula 1 according to this second embodiment.

[0169] This second embodiment is compatible with the first embodiment described above.

[0170] As shown in Figures 8 and 10, the cannula 1 comprises one or more inflatable side balloons 165 (also referred to as side balloons 165 hereafter). These side balloons 165 are attached to the circumference of the side wall 101, between two lateral openings 113 adjacent. The lateral balloons are thus attached at the central portion 109 of the lateral wall 101.

[0171] The lateral balloons 165 are connected to one or more inflation lines 166 similar to the inflation line(s) 18 of the internal and external balloons 160, 150.

[0172] Several inflation lines 166 are illustrated in [Fig.9]. Each balloon or group of balloons can be connected to a dedicated inflation line 166.

[0173] Thanks to the inflation lines thus arranged inside the side wall 101, an inflation fluid can be conveyed from the proximal end of the cannula 1 to the side balloons 165 without increasing the diameter or size of the cannula 1.

[0174] The side balls 165 are for example made of the same material as the outer ball 150.

[0175] They preferentially assume a swollen state once cannula 1 is placed in patient 2.

[0176] As shown in [Fig. 8], each lateral balloon 165 can expand, in its inflated state, primarily in the lateral direction so as to leave the adjacent lateral openings 113 free. It is noted that the lateral balloons can be arranged in a circumferential shape around the cannula 1, but this is not mandatory.

[0177] The lateral balloons 165 in the inflated state allow the diameter of the cannula 1 to be increased locally.

[0178] In use, the lateral balloons help to keep the vein walls away from the cannula 1. This ensures that the lateral openings 113 remain clear for blood flow. This improves vein drainage.

[0179] Lateral balloons 165 are also particularly advantageous when cannula 1 is assembled in a veno-venous ECMO system. Indeed, in this procedure, it is important to be able to move the vein wall away from the lateral openings 113 to improve drainage of the right atrium 203.

[0180] Fig. 11 shows, in schematic form, a cross-sectional view of a cannula 1 according to a third embodiment.

[0181] This third embodiment differs from the first and second embodiments, illustrated in Figures 3 to 7 and then 8 to 10, in that: • the central portion 107 on which the N lateral openings 113 are formed has a shorter length than that of the first and second embodiments, and • The cannula 1 includes a second external inflatable balloon 170 and an inflation line for the second external inflatable balloon 170 communicating with this external inflatable balloon 170 and the outside of the cannula 1. In this mode In realization, the external balloon 150 fixed on the distal portion 106 is then called the first external balloon 150.

[0182] Fig. 12 shows, schematically, the cannula 1 according to the third embodiment in position in the heart 200 of patient 2.

[0183] As shown in [Fig. 12], the length of the central portion 107 is limited to the dimension of the right atrium 203. The central portion 107 can thus have a dimension between 10 cm and 15 cm, for example, equal to 10 cm. Thus, the lateral openings 113 are preferentially located only in the right atrium 203.

[0184] The second external balloon 170 encircles the circumference of the cannula 1 at the distal end of the proximal portion 109. The corresponding portion of the cannula 1 is designated portion 108 in [Fig. 11]. It adjoins, on its proximal side, the most proximal lateral opening 113. With reference to [Fig. 12], this position allows this second external balloon 170 to be positioned at the inferior atriocaval junction.

[0185] This second external balloon 170 is similar, in terms of shape, dimensions, materials and arrangement on the cannula 1, to the external balloon 150 described previously. It can also be coated with an anti-thrombotic or anti-infective substance.

[0186] The inflation line of the second external inflatable balloon 170 can be combined with the inflation line 18 of the first external balloon 150 (in other words, the cannula 1 has an inflation line 18 common to both external balloons 150 and 170). Alternatively, it can be an inflation line dedicated solely to the second external balloon 170. In this case, the inflation line dedicated to the second balloon is arranged longitudinally inside the side wall 101, in a similar arrangement to the other inflation lines 18 and 166.

[0187] In the inflated state, the second external balloon 170 has the same effect as the first external balloon 150: it increases, locally, downstream of the lateral openings 113, the total external diameter of the cannula 1. The N lateral openings 113 are thus left free.

[0188] As illustrated in [Fig.12], when the cannula 1 is placed in patient 2, the second external balloon 170 is sized so that the extended total diameter of the cannula 1 corresponds locally to the diameter of the inferior vena cava 204 of patient 2. Thus, the second external balloon 170 blocks the circulation of blood from the inferior vena cava 204 to the right atrium 203 and the blood present in the right atrium is forced to flow into the cannula 1 through the lateral openings 113.

[0189] In the deflated state (not shown in figures 11 and 12), the second external balloon 170 allows the initial external diameter of the cannula 1 to be maintained and, thus, blood to pass from the inferior vena cava 204 to the right atrium 203.

[0190] Preferably, the second outer balloon 170, the first outer balloon 150 and the inner balloon 160 simultaneously have the same inflated state or the same deflated state.

[0191] Thus, the right atrium 203 is completely closed to the arrival of blood from the superior vena cava 201 and the inferior vena cava 204. This results in an increase in the pressure differential between the cannula 1 and the right atrium 203, and, therefore, an increase in the suction effect in the cannula 1. The drainage of the right atrium 203 is thus improved.

[0192] The central portion 107 can also be equipped, at the level of the central portion 107, with lateral balloons 165.

[0193] Returning to [Fig.2], the inflation system 5 includes a tube Tl, at least one pump 501 and a control unit 503.

[0194] The inflation system 5 allows the inflated and deflated states of the external balloon 150 and internal balloon 160, or of each inflatable balloon 150, 160, 165, 170 present on the cannula 1.

[0195] In the example of [Fig. 2], the inflation system 5 is connected to the cannula 1 via the proximal opening 181 of the cannula 1 by means of the tube T1 having suitable fittings at its ends. Thus, the pump 501 is fluidly connected to the external and internal balloons 150, 160 (recall that the proximal opening 181 and the inflation channel 180 form an inflation line for these balloons).

[0196] The pump 501 is adapted for pumping the inflation fluid. This fluid is a liquid or, preferably, a gas, this gas being, for example, air or helium at low pressures, well below 10 atmospheres. This fluid may alternatively be a liquid.

[0197] The pump 501 includes a device for maintaining the balloons inflated for a certain period of time (i.e., once inflated, the balloons remain inflated) and for maintaining the balloons in a deflated state for another period of time. Such a device may include a valve and a tap (not shown in [Fig. 2]).

[0198] The pump 501 may also include another fluid inlet, this one being connected to a reservoir 502 containing the inflation fluid.

[0199] The pump 501 is controlled by a control unit 503 with which it is in communication.

[0200] The control unit 503 controls the pump 501 so that the balloon is kept inflated for a first time called the occlusion time, then kept deflated for a second time called the opening time.

[0201] The control unit 503 is also preferably configured so that this alternation of the two inflated and deflated states is reproduced regularly, at a frequency F2.

[0202] This alternation of inflated and deflated states allows for circulation through cannula 1 that exhibits regular intervals or pulsations. In other words, the drainage cannula 1 is made pulsatile by the inflation / deflation of the external and internal balloons 150, 160. The advantage is that the blood flow is more homogeneous and closer to the patient's physiology.

[0203] The occlusion time (or duration of the inflated state of the external and internal balloons 150,160) can be between 1 s and 1 h. For example, the occlusion time can be between 1 s and 10 min.

[0204] Similarly, the opening time (or duration of the deflated state of the external and internal balloons 150, 160) can be between 1 s and 1 h. For example, the opening time can be between 1 s and 10 min.

[0205] The duration of occlusion may be greater than or equal to the duration of opening.

[0206] In a first example, the occlusion time is equal to 5 min and the opening time is equal to 30 s. This configuration is advantageous for achieving intermittent occlusion of the superior vena cava.

[0207] In another example, the occlusion time and the opening time are equal to 1 s. The frequency F2 is then preferably adapted to the heart rate of patient 2, and is thus between 15 and 180 cycles per minute.

[0208] The inflation and deflation of the external and internal balloons 150, 160 thus synchronize with the heart rhythm, with the advantage of improving both blood circulation in the ECMO system 7 and the heart's pumping function. The cannula 1 thus allows for the establishment of a pulsatile flow rate, that is, a flow rate close to the patient's physiological state. The advantage is that the blood is more homogeneous and that ECMO 7 is better tolerated, potentially for a longer duration, by the patient 2.

[0209] The frequency F2 is then preferably determined by the control unit 503 from a frequency signal FL. For this purpose, the control unit 503 is also connected to a frequency sensor 504, this sensor 504 preferably being a standalone electrocardiograph measuring, for example via electrodes, an electrical signal of the heart rhythm on the patient. The frequency FL is then the patient's heart rate, that is to say the number of beats per minute.

[0210] Furthermore, the control unit 503 can control the inflation and deflation of the external and internal balloons 150, 160 in response to the two main phases that constitute a heartbeat: systole and diastole. Systole refers to the contracted muscle, and diastole refers to the relaxed muscle. These two phases are determined by the control unit 503 from the electrical signal of the heart rhythm measured by the sensor 504. The control unit 503 controls the pump 501 so that the external and internal balloons 150, 160 are inflated in response to the detection of the systole phase and deflated in response to the detection of the diastole phase. diastolic. The inflation and deflation of the external and internal balloons 150, 160 is then said to be "in phase" with the heart rhythm.

[0211] The advantage of inflating the external and internal balloons 150, 160 during systole is that the external balloon 150 improves the reduction of the volume of the right atrium 203, thus facilitating the expulsion of blood.

[0212] The advantage of rapidly deflating the external and internal balloons 150 and 160 during diastole (within 1 second) is that it increases cardiac filling by generating negative pressure. This negative pressure leads to an increase in the pressure gradient between the right atrium 203 and the right ventricle 207. The right side of the heart is thus better drained, and therefore less voluminous, facilitating contraction and thus the expulsion of blood from the left side of the heart. Overall, the cardiac afterload decreases, and with it, the risk of pulmonary edema.

[0213] Thus, in the system according to the invention, it is possible to inflate and then deflate the balloon, and to reproduce this sequence at a rate close to the physiological rhythm of a patient, i.e., between 15 and 180 cycles per minute. Advantageously, the sequence is reproduced in synchronization with the heart rate measured on the patient by the heart rate sensor. In particular, it is possible to inflate the balloon in response to cardiac systole (the contraction of the heart) and to deflate the balloon in response to diastole (the filling of the heart).

[0214] In this configuration of the control unit 503, the effect of the external and internal balloons 150, 160 arranged on the distal portion (and possibly of the second external balloon 170) is then twofold: they improve blood circulation in the cannula 1 and they improve the "pump" effect of the heart 200. More broadly, this improvement of drainage in the right part of the heart makes it possible to improve the functioning of the left part of the heart, resulting in an overall improvement in the load of the heart.

[0215] The cannula system 6 thus allows for intermittent occlusion of the superior vena cava 203 while remaining usable in an ECMO system. This allows for lowering pressures in the right heart chambers during ECMO, thereby improving right and left ventricular function. The paper "Intermittent Occlusion of the Superior Vena Cava Reduces Cardiac Filling Pressures in Preclinical Models of Heart Failure" by Kapur et al., J Cardiovasc Transi Res. 2020 Apr. 13(2):151-157, highlights the benefit of intermittent superior vena cava occlusion. However, this paper describes an intermittent occlusion technique that is not a drainage cannula but a balloon catheter, which cannot be used concurrently with an ECMO drainage cannula.

[0216] Another aspect of the invention relates to a method of using the ECMO 7 system illustrated in [Fig. 1] and [Fig. 2]. [Fig. 13] illustrates, in the form of a flowchart, steps of this method 8 of use.

[0217] Before the first step SI, the cannula 1 was introduced by the practitioner into the patient's venous system 2 as far as the heart 200, its position was verified, for example by external control using at least one positioning marker 140, and its retention was ensured, for example by suturing the patient's skin around the distal part of the cannula 1. Note that the cannula 1 is introduced using an introducer (not shown) and with the balloon 150 deflated, the inflation system 5 and the fluid circuit 3 not connected. These are connected after the positioning of the cannula 1 has been verified.

[0218] Step SI consists of establishing blood circulation in the cannula 1, and more broadly in the fluid circuit 3. This is achieved by starting the ECMO pump 301. The external and internal balloons 150, 160 are then in their deflated state. The lateral balloons 165 can, if necessary, be inflated at this step SL.

[0219] Step S2 consists of starting the simultaneous inflation and deflation of the external and internal balloons 150, 160. For this, the pump 501 of the inflation system 5 and its control unit 503 are started.

[0220] The control unit 503 receives a frequency signal Fl from the frequency sensor 504 previously positioned on patient 2.

[0221] Step S3 consists, for the control unit 503, in determining the frequency F2 as a function of the received frequency Fl. More precisely, the control unit determines the systolic signal and the diastolic signal from the frequency FL signal

[0222] Step S4 consists of simultaneously inflating the external and internal balloons 150, 160 in response to the systole signal.

[0223] Step S5 consists of deflating the balloons in response to the diastole signal.

[0224] Steps S4 and S5 are repeated at frequency F2.

Claims

Demands

1. Cannula (1) for draining fluid out of a cavity, the cannula having a proximal end (105a), a distal end (104a) and a lateral wall (101) defining a lumen (112) extending longitudinally through the drainage cannula (1) between the proximal end (105a) and the distal end (104a), the lateral wall comprising an internal surface disposed towards the lumen (112) and an external surface, the lateral wall (101) comprising: - a central portion (107) comprising a plurality of lateral openings (113), each lateral opening (113) passing through the lateral wall (101);- a distal portion (106) of the lateral wall adjacent to the central portion (107) and comprising the distal end (104a) of the drainage cannula, on which are arranged two inflatable balloons (150, 160), each inflatable balloon (150, 160) taking an inflated or deflated state, each state leaving the lateral openings (113) at least partially unobstructed, the two inflatable balloons comprising an external balloon (150) encircling the external surface of the lateral wall (101), and an internal balloon (160) disposed on the internal surface of the lateral wall (101) and closing, in the inflated state, the lumen (112).;

2. Drainage cannula (1) according to claim 1, wherein the side wall comprises a set of inflation channels (180) arranged longitudinally in the side wall (101), the set of inflation channels (180) being connected to the two inflatable balloons (150, 160) and allowing each of the two balloons to pass into a respective inflated or deflated state.

3. Drainage cannula (1) according to any one of claims 1 to 2, wherein during a transition from a deflated state to an inflated state, the external balloon (150) extends in a direction orthogonal to a longitudinal direction of the side wall (101).

4. Drainage cannula (1) according to any one of claims 1 to 3, wherein the outer balloon (150) or the inner balloon (160) has a toroidal shape.

5. A drainage cannula (1) according to any one of claims 1 to 4, wherein the side wall (101) further comprises a lateral inflatable balloon (165) fixed to the external surface of the side wall (101) between two lateral openings (113), the lateral inflatable balloon (165) communicating with a second inflation channel extending longitudinally inside the side wall and being connected to the lateral inflatable balloon, the second inflation channel allowing the lateral inflatable balloon (165) to pass into an inflated or deflated state, the second inflation channel not being connected to the two inflatable balloons (150, 160) arranged in the distal portion (106) of the side wall.

6. Drainage cannula (1) according to any one of claims 1 to 5, wherein the lateral wall (101) has a length between 50 cm and 70 cm and the distal portion (106) has a length between 1 cm and 20 cm.

7. Drainage cannula (1) according to claim 6, wherein the central portion (107) has a length between 10 cm and 15 cm.

8. Drainage cannula (1) according to claim 7, wherein the side wall (101) comprises a second external inflatable balloon (170) arranged in a proximal portion (109) of the side wall, the proximal portion (109) being adjacent to the central portion (107) and comprising the proximal end (105a) of the drainage cannula, the second external inflatable balloon (170) enclosing the external surface of the side wall (101), and assuming a deflated or inflated state, each state leaving the lateral openings (113) at least partially clear.

9. A drainage system (6) for draining fluid from a cavity comprising: - the drainage cannula (1) according to any one of claims 1 to 8, - an inflation system (5) comprising: at least one inflation pump (501) connected to the two inflatable balloons (150, 160) arranged in the distal portion (106) of the side wall, and a control unit (503) for controlling the inflation pump (501) to obtain an inflated or deflated state of each inflatable balloon (150, 160).

10. Drainage system (6) according to claim 9, wherein the control unit (503) is configured so that the inflated state of the external balloon (150) and the inflated state of the internal balloon (160) are achieved at the same time, and so that the deflated state of the external balloon (150) and the deflated state of the internal balloon are achieved at the same time.

11. Drainage system (6) according to claim 9 or 10, wherein the control unit (503) is configured to perform an alternation of an inflated state and a deflated state at a regular rate, of frequency F2.

12. Drainage system (6) according to claim 11, wherein the control unit (503) is further connected to a frequency sensor (504) to measure a heart rate Fl of a subject, and to determine the frequency F2 of the alternation of the inflated and deflated states as a function of the heart rate Fl.

13. Extracorporeal membrane oxygenation system (7) comprising a drainage system (6) according to any one of claims 9 to 12, a fluid circuit (3) and an injection cannula (305), the fluid circuit (3) comprising: a pump (301) having a fluid inlet and outlet, an oxygenator (302) having a fluid inlet and outlet, a heat exchanger (303) having a fluid inlet and outlet, a tube (T2) connecting the proximal end (105a) of the drainage cannula of the drainage system (6) to the inlet of the pump (301), a tube (T3) connecting the outlet of the pump (301) and the inlet of the oxygenator (302), a tube (T4) connecting the outlet of the oxygenator (302) and the inlet of the heat exchanger (303), a tube (T5) connecting the exchanger outlet (303) and injection cannula (305).

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