Self-sealing cannula

Abstract

A self-sealing cannula and method of use are disclosed. [Solution] A self-sealing cannula has a self-sealing function at the interface of a blood access site and can be placed minimally invasively in the heart to pump and / or return blood. The cannula can be realized as a single-lumen cannula or a double-lumen cannula and can be used with a ventricular assist device for cardiac assistance, or a heart-lung machine for ECMO and respiratory assistance. The cannula body is attached to a self-sealing device through a self-sealing mechanism attached to the ventricular or atrial wall, and blood is drawn into the lumen using an external pump and returned to the circulatory system through another cannula.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of co-pending and commonly-assigned U.S. Provisional Patent Application No. 62 / 079,876, filed with the United States Patent and Trademark Office on November 14, 2014, entitled "Self-Sealing Cannula", the specification of which is hereby incorporated herein by reference.

[0002] [GOVERNMENT LICENSE RIGHTS] This invention was made with government support under Grant No. HL082631 funded by the National Institutes of Health. The government has certain rights in the invention. TECHNICAL FIELD

[0003] The present invention relates generally to cannula systems, and more specifically to a self-sealing cannula system for draining blood from and / or infusing blood into the circulatory system, and to methods of using such a system. BACKGROUND ART

[0004] The human cardiovascular system functions as the body's substance transport network. The cardiovascular system interacts with the interstitial compartment via diffusion sites throughout the body to exchange fluids, hormones, electrolytes, nutrients, and other substances. This is achieved by the pumping function of the human heart and the circulation of blood through blood vessels. Under appropriate pressure, the heart draws blood from the low-pressure venous system and delivers it to the arterial side of the circulation to maintain the body's circulatory demands. The heart basically consists of four chambers. The four chambers include two atria with thin walls separated from each other by the interatrial septum, and two ventricles with thick walls separated by the interventricular septum. The heart is composed of two separate, series-connected pumping systems. The right atrium and right ventricle function as a single unit that moves venous blood from the vena cava (the superior vena cava (SVC) and the inferior vena cava (IVC)) into the pulmonary circulation. In the pulmonary circulation, venous blood is oxygenated as it passes through the human lungs. The left atrium and left ventricle work together to pump blood from the pulmonary veins into the high-pressure systemic circulation. Blood circulates through the body and returns to the right atrium from the SVC and IVC.

[0005] Heart failure occurs when the heart is unable to pump enough blood to meet the body's needs. Heart failure (HF) affects 5.7 million people in the United States and contributed to approximately 280,000 deaths in 2008 (Roger et al. Circulation. 2012;125(1):e2-220). Heart failure places a significant burden on healthcare providers and is also expensive to treat. The estimated direct and indirect costs of HF in the United States in 2010 were $39.2 billion (Centers for Disease Control and Prevention's "2010 Heart Failure Fact Sheet"). Despite advances in medicine, the prognosis for HF remains poor, especially in its advanced stages. Patients with advanced HF require mechanical circulatory support or a heart transplant to survive. Heart transplants are limited by the supply of donor organs. Mechanical circulatory support is often achieved using a ventricular assist device (VAD). A VAD is a mechanical pump designed to increase or replace the function of one or more chambers of a heart with heart failure. Although the use of VADs is increasing, it has been limited because it requires major surgical intervention.

[0006] Furthermore, lung disease is the third leading cause of death in the United States, accounting for one in six deaths (American Lung Society). Despite $154 billion in spending, 400,000 deaths each year are due to lung factors (Sanovas, "Lung Disease"). Lung failure can occur acutely or chronically. Chronic obstructive pulmonary disease (COPD) is one of the most common lung diseases and is the fourth leading cause of death in the United States. Acute respiratory distress syndrome (ARDS) typically affects 190,000 people annually, with an average survival rate of 30–50% (Rubenfeld et al. N Engl J Med 2005;353:1685-93). When lung failure occurs, either a ventilator or an extracorporeal membrane oxygenation (ECMO) must be used to supply oxygen to the blood and maintain the body's oxygen needs. While ventilators are effective for short-term support, the sustained tidal volume and commonly used airway pressure can damage the lungs. ECMO closely simulates physiological gas exchange, but requires the insertion of a cannula to access blood. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent No. 7473239 [Overview of the project] [Problems that the invention aims to solve]

[0008] In current clinical practice, using VADs and ECMO requires major invasive surgery to implant these devices using a cannula set. Therefore, only a limited number of patients can receive treatment based on these devices. A cannula is a medical tube inserted into the body to drain and inject blood. The main problems with commercially available cannulas for ECMO (U.S. Patent No. 7,473,239, inventors Wang et al.) are: (1) the need for multiple insertions of the cannula and the insertion of large-diameter cannulas cause excessive trauma to the patient; (2) insufficient extracorporeal oxygen supply due to blood recirculation when blood is drawn from the right atrium or central vein and reinjected; (3) insufficient drainage of venous blood due to the placement of the drainage lumen relative to the vein; and (4) bleeding due to the fixation of surgical sutures when the cannula is inserted directly into the heart. Similarly, commercially available cannulas for VADs also have a similar problem of causing unnecessary trauma. Therefore, a minimally invasive, efficient, and simple percutaneous cannula system is needed for ECMO and VAD. [Means for solving the problem]

[0009] This invention discloses a self-sealing cannula. The self-sealing cannula may be configured as a double-lumen cannula or a single-lumen cannula. Figure 1 shows a self-sealing cannula that is a double-lumen cannula (DLC). The self-sealing DLC ​​comprises an drainage cannula, an infusion cannula, a self-sealing double umbrella made of wire mesh, and a self-closing iris made of wire mesh. The self-sealing DLC ​​may be used to directly extract blood from the right ventricle through the drainage lumen and infuse it into the pulmonary artery through the infusion lumen via a minimally invasive pericardial surgery. This configuration may be used for ECMO respiratory support or mechanical circulatory support of the right heart. The infusion lumen is smaller in diameter than the drainage lumen and is partially located inside the drainage lumen. A capable (non-regurgitant) natural semilunar valve between the ventricle and the artery works to minimize "recirculation" flow, i.e., regurgitation of arterial drainage retrograde to ventricular inflow. The cannula can also be used to mechanically assist left heart circulation by drawing blood from the left ventricle and returning it to the aorta. Hemostatic felt is incorporated inside the closure formed by the double umbrella and iris wire mesh for hemostasis.

[0010] A double umbrella (disc) structure is provided around the tip of the discharge cannula to provide hemostasis after the DLC is inserted into the right heart (Figure 1). The double disc structure is made of wire mesh and can be pushed into the sheath introducer together with the dual-lumen cannula. Instead of conventional surgical suturing, which requires a larger insertion site and open chest surgery, the wire mesh, when released from the sheath introducer, expands slightly radially and contracts axially to seal the insertion site on the ventricular wall and conform to the epicardial and endocardial walls. Therefore, the cannula can be easily positioned into the heart through a small hole in the pericardium. This reduces surgical and traumatic complications for the patient. The DLC injection and discharge lumens can be positioned by conventional needle puncture and a Swan-Ganz type guide catheter. After needle puncture, the guide catheter is advanced into the pulmonary artery. The guide catheter, using a dilator, advances the tip of the injection lumen into the pulmonary artery. As the tip of the injection lumen advances, the sheath with DLC acts as an introducer / dilator, further enlarging the insertion site. Once the tip of the drain is properly positioned, the sheath is removed. The double umbrella springs back to its predetermined shape, sealing the insertion site and securing the DLC to the ventricular wall.

[0011] A dual-lumen cannula is placed in the heart and secured to the diaphragm or muscle layer at the incision site. Once it emerges from the skin, a VAD can be connected to provide cardiac support, or an ECMO system can be attached to provide respiratory support. The same procedure may be performed on the left heart to provide left heart support. A self-sealing cannula may also be configured as a single-lumen cannula for draining or injecting blood.

[0012] Cannula placement can be performed using minimally invasive, surgical, intravascular techniques. (a) Ventricular access via a small incision: A subxiphoid approach is used to access the diaphragmatic surface of the right ventricle. A small left thoracotomy or subcostal incision is used to access the left ventricular apex. The cannula is designed to be placed without the use of a temporary cardiopulmonary bypass procedure. This is particularly advantageous for left-sided support, as current extracorporeal ventricular assist devices involving left ventricular cannula insertion generally require a cardiopulmonary bypass facility for placement. (b) Ventricular and arterial access based on the Seldinger technique: The ventricles are accessed using a hollow needle. Guided by fluoroscopy and / or transesophageal echocardiography, a guidewire / guidecatheter is inserted through the hollow needle, through the ventricular lumen, and then into the distal outflow artery. A self-sealing double umbrella is positioned outside the guidewire / guidecatheter within the sheath and is subjected to sequential, stepwise expansion until it is fixed in place, after which the insertion access portion is sealed. The sealing is performed in a manner similar to how an occluder of the interventricular septum seals a wound wider in diameter than a ventricular incision circumferentially, both inside and outside the ventricular lumen. (c) Cannula insertion and positioning: The cannula is pre-inserted and packaged with the sheath, dilator, and guidewire / catheter. Based on markers on the cannula, fluoroscopy / echocardiography guidance positions the cannula so that the distal end of the infusion cannula is within the proximal artery and the distal end of the discharge cannula is within the ventricular lumen. A locking mechanism secures the cannula to the disc of the double umbrella in the desired position. In the case of a single-lumen cannula, the distal tip of the cannula is located within the ventricular lumen. (d) Removal of the cannula: The cannula can be removed by a screw lock mechanism between the outer surface of the cannula body and the central hole of the double umbrella. When the cannula body is removed, the hidden iris springs back and acts as a valve, sealing the hollow hole.

[0013] Many of the advantages of the present invention can be better understood by those skilled in the art by referring to the accompanying drawings. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of a double-lumen cannula (DLC) assembly, including a self-sealing cannula, positioned in the right heart and pulmonary artery according to an embodiment of the present invention. [Figure 2A] Figure 1 is an enlarged cross-sectional view of self-sealing DLC ​​and its components. [Figure 2B] Figure 1 is an enlarged cross-sectional view of the self-sealing DLC, enclosed in a sheath along with two dilators and a guide catheter. [Figure 3] A: Enlarged cross-sectional view of a self-sealing single-lumen cannula in a further embodiment of the present invention. B: Enlarged cross-sectional view of the self-sealing single-lumen cannula of Figure 3A, enclosed in a sheath together with the dilator and guidewire. [Figure 4A] Figure 1 is a schematic diagram of the self-sealing DLC ​​located within the right ventricle and pulmonary artery. [Figure 4B] Figure 1 is a schematic diagram of the self-sealing DLC ​​placed in the left ventricle and aorta. [Figure 4C] Figure 3A is a schematic diagram of a self-sealing single-lumen cannula, which is positioned in the right ventricle as an outlet cannula. [Figure 5A] Figure 1 is a schematic diagram of the DLC (Deep Limb Cortex) when the insertion site is being enlarged with the first dilator in order to position the DLC injection cannula in the right ventricle. [Figure 5B] Figure 1 is a schematic diagram of the DLC (Deep Limb Cannula) when the insertion site is being enlarged with a second dilator to position the DLC's drainage cannula in the right ventricle. [Figure 5C] This is a schematic diagram of the DLC when the DLC shown in Figure 1 is located within the right ventricle and pulmonary artery. [Figure 5D]It is a schematic diagram of the DLC after the DLC of Figure 1 has been placed in the right ventricle and pulmonary artery [Figure 5E] It is a schematic diagram of the self-sealing mechanism of Figure 1 using a double umbrella after the DLC has been removed from the right ventricle.

Mode for Carrying Out the Invention

[0015] The present invention, summarized as above, will be better understood by reference to the following description, the claims, and the accompanying drawings. The following description of embodiments enables the implementation of the present invention, but is not intended to limit the preferred present invention, and is intended to serve as a specific example. Those skilled in the art will understand that, based on the disclosed concepts and specific embodiments, they can readily modify or design alternative methods and alternative systems to achieve the same object of the present invention. Those skilled in the art will also appreciate that such equivalent constructions do not depart from the spirit and scope of the present invention in its broadest form.

[0016] Figure 1 is a schematic diagram of a self-sealing cannula according to an aspect of an embodiment of the present invention, more specifically, a schematic diagram of a self-sealing double lumen cannula (DLC) configured to withdraw blood from the right ventricle through the outer lumen of the DLC and return blood to the pulmonary artery. The double umbrella device functions as a sutureless self-sealing mechanism and a holder for the DLC in proper position over the right ventricle.

[0017] Figure 2 shows a DLC assembly in one embodiment of the present invention. The DLC assembly 1 comprises a circular discharge cannula whose inner surface forms a discharge lumen 2, a side-fused tubular cannula 3 whose inner surface forms an injection lumen 4, and a compressible double umbrella 6. The injection cannula has an injection port 7 with a certain thickness of wall, a thin-walled circular tube 4 fitted into the side wall of the discharge lumen, and a circular extension 5. A portion of the injection cannula passes through the lumen of the discharge cannula. The extension 5 is a thin-walled circular tube, but is further reinforced with a wire frame. Thus, the extension 5 is rigid in the radial direction but flexible and conformable in the axial direction. Furthermore, a portion of the extension 5 of the injection cannula has an exposed zigzag wire frame (shown in the figure). This allows blood returning from the injection lumen to be distributed axially and radially into the target vessel, and prevents obstruction of the return blood flow when the distal tip is positioned against the vessel wall. The double umbrella 6 is attached to the discharge cannula body. The disc-shaped double umbrella 6 has a pair of outwardly opening wire mesh umbrellas 10, a metal ring 9, and an inwardly retracting wire mesh iris 11 (the configuration of the iris 11 is similar to that of a camera iris or shutter). The wire mesh is preferably formed of a shape memory alloy. The shape memory alloy is compressed radially to a diameter smaller than the intended diameter while deployed, and returns to the intended functional shape when heated to the transformation temperature of the shape memory alloy by the patient's own body temperature. In embodiments of the present invention, specifically, the wire mesh of the double umbrella 6 is formed of Nitinol (an alloy commonly made of approximately 55%-56% nickel and 44%-45% titanium by weight). The external configuration of the double umbrella 6 is somewhat similar to an atrial and ventricular septal defect closure device (such as the Amplatzer closure device commercially available from AGA Medical Corp. in Golden Valley, Minnesota).However, as described in more detail herein, the external configuration of the double umbrella 6 has been significantly improved for use with the cannula assembly, allowing for self-sealing after the cannula extending through the double umbrella 6 has been removed.

[0018] Nitinol is an alloy of nickel and titanium. Nitinol possesses superelastic properties. Superelastic properties refer to the ability to deform at low temperatures and then return to its original shape above a certain temperature (transformation temperature). A process called shape setting is used to train nitinol to a desired shape. Typically, this process involves strongly pressurizing the material into the desired shape on a mandrel at 450-550°C for 10-80 minutes, depending on the type of nitinol material. This process is known to those skilled in the art. In at least one embodiment, the best conditions for heat treatment of nitinol wire with a cross-sectional diameter of 0.01 inches (Johnson Matthey Inc., Westchester, Pennsylvania) are 500°C for 70 minutes. This allows the transformation temperature to be 27°C. In another embodiment, the transformation temperature may be between 30°C and 37°C. Below the transformation temperature, the material is unstable and its shape changes easily. A cannula assembly incorporating a nitinol wire mesh structure, and methods for its use and manufacture, are described in PCT International Application No. PCT / US14 / 46978, titled "Self-Expanding Cannula." The specification of PCT International Application No. PCT / US14 / 46978 is incorporated herein by reference in its entirety.

[0019] Alternatively, the wire mesh may be highly flexible, thereby allowing it to be radially compressible (for example, by inserting the wire mesh and cannula into a tearable sheath for the initial insertion of the cannula into the patient's ventricle, as will be further described below) and then return to its unfolded normal shape after the radial compression is removed. Once released from the sheath introducer, the wire mesh becomes radially unfoldable, sealing the insertion site on the ventricular wall and conforming to the epicardial and endocardial walls. Similarly, the iris 11 is preferably formed of a wire mesh of the same shape memory alloy as the double umbrella. A circular metal ring 9 may be attached to the wire mesh and provide a locking mechanism for the discharge cannula body which is attached to the double umbrella 6. Preferably, a male thread is formed on the circular outer surface of the discharge cannula. Preferably, a corresponding female thread is formed on the inner surface of the ring of the double umbrella. The DLC can then be secured in place or removed from the double umbrella 6 by turning the thread inward or outward. The iris 11 of the double umbrella 6 functions as a self-sealing shutter. The self-sealing shutter is similar to the circular shutter of a camera. When the DLC is in use, the iris is forcibly opened by the drainage cannula body. When the drainage cannula is removed, the iris springs back, sealing the central opening of the double umbrella 6. The tip of the drainage cannula is preferably made of a biocompatible metal, such as titanium, and is embedded in the double umbrella 6. Thus, the tip of the drainage cannula protrudes slightly from the ventricular wall, providing excellent blood drainage and preventing abnormal tissue growth into the cannula lumen. The rest of the cannula is made of a biocompatible polymer, such as polyurethane or PVC. The circular body of the drainage cannula is a reinforced wire. The metal tip and the cannula body are molded and fused together. Figure 2B shows the self-sealing DLC ​​1 mounted in the sheath 12 with two dilators 13, 14 and a guide catheter 15. The Double Umbrella 6 and its Iris 11 are compressed within Sheath 12.

[0020] Alternatively, a portion of the artificial blood vessel, including a predetermined purse-string suture, may be sewn onto the double umbrella to perform the function of the iris described above, sealing the central opening of the double umbrella after the cannula body is removed. When the discharge cannula body is withdrawn from the double umbrella by unscrewing, the double purse-string suture is pulled and ligated within the lumen of the artificial blood vessel, sealing the opening.

[0021] In one embodiment of the present invention, a single-lumen cannula assembly is shown in Figure 3A. The self-sealing single-lumen cannula comprises a circular tube 16 having an inner surface 17 forming an excretion lumen or an injection lumen, and a double umbrella 19 with an iris 24. The proximal end is a connector port 18. Figure 3B shows the self-sealing single-lumen cannula 16 assembled within a sheath 20 together with a dilator 21. The dilator 21 is provided with a central hole 22 for passing a guide catheter or guide wire 23. The double umbrella 19 is compressed by the sheath 20, and the iris 24 is opened by the cannula body within the sheath 20. In this configuration, the single-lumen cannula preferably includes a screw connection to the interior of the double umbrella 19 having a configuration similar to the one described above with respect to DLC.

[0022] Figure 4A is a schematic cross-sectional view of a DLC positioned in the right ventricular wall. Blood is drawn from the right ventricle through the drainage lumen of the DLC and returned to the pulmonary artery through the infusion lumen of the DLC. The double umbrella device seals the insertion site on both the endocardial and epicardial sides with a pre-formed, flexible, and adaptable double umbrella wire mesh. The serif sealing iris is open.

[0023] Figure 4B is a schematic cross-sectional view of a DLC placed at the left ventricular apex. Blood is drawn from the left ventricle through the drainage lumen of the DLC and returned to the aorta through the injection lumen of the DLC. Here again, a flexible and adaptable double umbrella is placed at the apex to seal the insertion site. The DLC is placed in the same manner as described above for placement in the right ventricle.

[0024] Figure 4C is a schematic cross-sectional view of a self-sealing cannula configured as a single-lumen cannula. The self-sealing cannula is positioned in the right ventricular wall to draw blood from the right ventricle. An identical self-sealing double umbrella seals the insertion site.

[0025] Figures 5A to 5E illustrate the deployment and removal of a self-sealing DLC ​​into the right ventricle and pulmonary artery according to an embodiment of the present invention. A needle is used to create a hole in the right ventricle for the guidewire to pass through. A Swan-Ganz type balloon catheter can be used, which passes through the central lumen of the dilator inside the injection lumen. Then, a balloon guide catheter with an inflatable balloon is inserted into the right ventricle by the inflated balloon and guidewire and advances into the pulmonary artery. Once the position of the guide catheter (which can be confirmed by X-ray fluorescence fluoroscopy or echocardiography) is determined, the injection lumen cannula with the dilator advances along the guide catheter (Figure 5A) and makes contact with the epicardium of the right ventricle. The advancing conical tip of the dilator gradually enlarges the needle puncture site, pressing the injection cannula against the right ventricle and advancing into the pulmonary artery. At this time, a second dilator for the drainage lumen approaches the insertion site (Figure 5B). The semi-conical dilator further enlarges the insertion site, allowing the tip of the DLC sheath to advance into the right ventricle (Figure 5C). Once the first half of the compressed double umbrella is positioned in the right ventricle, the DLC sheath can be withdrawn. A tear-resistant sheath may be used at this stage. After the sheath is removed, the first umbrella of the double umbrella opens inside the right ventricle and fits against the endocardium. Similarly, after the sheath is completely removed, the second umbrella opens outside the right ventricle and fits against the epicardium (Figure 5D). The DLC is then positioned appropriately for connection to a VAD for mechanical circulatory support or an ECMO system for respiratory support. When support is no longer needed, the DLC can be removed by unscrewing the cannula body and withdrawing the cannula body. As the cannula exits the right ventricle, the iris on the outside of the double umbrella (which was opened by the cannula) springs back to its pre-formed shape, sealing the central opening of the double umbrella (Figure 5E).

[0026] Similarly, the same approach can be used to place a DLC with the above characteristics in the left ventricle (Figure 4B). In the case of a single-lumen cannula, only one dilator is required. The approach described above is easily adaptable to place a single-lumen cannula (Figure 4C). Once the DLC or single-lumen cannula is placed in the circulatory system, its respective ports (exhaust port and infusion port) are connected to a VAD for cardiac support or an ECMO system for respiratory support.

[0027] The advantages of the present invention include any of the following: 1. Minimally invasive insertion and sutureless self-sealing of the cannula for direct insertion into the heart. 2. Avoiding multiple cannula insertion sites in the heart. 3. Drainage that is not obstructed by vein and wall occlusion. 4. Low probability of thrombosis and implantable drainage tip 5. Minimal blood recirculation

[0028] Although preferred embodiments and specific modifications of the basic concepts of the present invention have been fully described, those skilled in the art will readily come up with various other embodiments, along with specific variations and improvements of the embodiments illustrated and described herein, when understanding the basic concepts. Therefore, it should be understood that the present invention may be carried out in ways other than those specifically described herein.

Claims

1. The first cannula is long and slender, A flexible self-sealing closure portion attached to the first cannula, The self-sealing closure portion has a hollow, elongated structure that forms an open interior, and a first connecting portion provided on the inner surface of the open interior of the self-sealing closure portion. The elongated first cannula has a second connecting portion which is detachably attached to the first connecting portion. The first cannula is removably attached inside the self-sealing closure section. The self-sealing closing section includes a self-sealing shutter integrally formed from a shape memory alloy. The self-sealing shutter comprises a double umbrella structure and a self-sealing iris. The aforementioned double umbrella structure comprises a wire mesh umbrella at the end and a wire mesh umbrella at the base. The terminal wire mesh umbrella is configured to fit the endocardial wall of the insertion site formed in the patient's ventricle, and the proximal wire mesh umbrella is configured to fit the epicardial wall of the insertion site and seal the insertion site. The self-sealing closure portion comprises a metal ring provided along the central hole of the self-sealing closure portion, The self-sealing closure portion is configured to expand radially from a compressed state to an uncompressed state when heated to the transformation temperature of the shape memory alloy by the patient's body temperature. In the uncompressed state, the self-sealing closure portion is configured to seal the inner and outer surfaces of the insertion site of the first cannula. In the aforementioned uncompressible state, If the first cannula is inserted into the central hole of the self-sealing closure, the self-sealing iris extends along the first cannula and opens the central hole of the self-sealing closure. A self-sealing cannula system configured such that if the first cannula is removed from the central hole of the self-sealing closure, the self-sealing iris bounces back to close the central hole of the self-sealing closure.

2. The first connecting portion is provided with an internal thread formed on the inner surface of the metal ring. The second connecting portion is equipped with a male thread formed on the outer surface of the first cannula. The self-sealing cannula system according to claim 1, wherein the female thread is fittable onto the male thread.

3. The self-sealing cannula system according to claim 1, further comprising a removable sheath that encloses at least a portion of the self-sealing closure portion and the first cannula.

4. The self-sealing cannula system according to claim 1, further comprising a second cannula positioned within the first cannula and extendable from the first cannula.

5. The self-sealing cannula system according to claim 4, wherein the second cannula has an end formed of a deployable wire frame.

6. The self-sealing cannula system according to claim 5, wherein the deployable wire frame of the second cannula is temperature-responsive and configured to deploy in accordance with the patient's body temperature.

7. moreover, A blood pump attached to the first cannula, and The self-sealing cannula system according to claim 4, further comprising a blood oxygenation device attached to the second cannula.

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