RU2826522C1 - Method of cardiopulmonary bypass in cardiac transplant recipient during its transplantation and system for its implementation - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions refers to medicine and medical equipment, namely to a cardiopulmonary bypass system in a cardiac transplant recipient and a cardiopulmonary bypass method in a cardiac transplant recipient during its transplantation. Cardiopulmonary bypass system comprises a first venous cannula for connection to a femoral vein, first, second venous lines, centrifugal and roller pumps, first, second oxygenators, first, second and third branching tees; first and second arterial lines, an arterial cannula with a luer port for connection to a femoral artery, first and second straight connectors, a cardiotomy reservoir (CTR), a wound suction line, a left ventricular drain cannula, a left ventricular drain line, a second venous cannula for connection to a superior vena cava (SVC), a haemoconcentrator, a straight connector with a luer port and a line for connecting a pressure sensor, a gas-air mixture line of the first oxygenator, a gas-air mixture line of the second oxygenator. First venous line connected by one end to the first venous cannula, by the second end is connected to the centrifugal pump, output of the centrifugal pump is connected through a first oxygenator having a gas-air mixture line and a first branching tee to a first arterial line, output of the first arterial line through the second branching tee is connected to an arterial cannula with a luer port for connection to a femoral artery. Second branching tee is connected through a first straight connector to a second arterial line, output of the second arterial line through a straight connector with a luer port and a line for connecting a pressure sensor is connected through a third branching tee to a haemoconcentrator and a second oxygenator having a gas-air mixture line; output of the second oxygenator is connected through a roller pump to the input of the CTR connected to the second straight connector connected to the first branching tee. Second venous line with a second venous cannula for connection to the SVC, a wound suction line, a left ventricular drainage cannula and a left ventricular drainage line are connected to the CTR inputs. Method involves using a centrifugal and roller pump to control blood flow. In the method, in case of bleeding, the wound suction line is used to evacuate blood from the sternotomy wound and return the blood to the patient’s arterial system.

EFFECT: reduction of traumatism of procedures, prevention of development of complications, simplification of technique of surgical intervention, provision of possibility of adjustment of gas composition of blood only by oxygenator of cardiopulmonary bypass, reduction of frequency of multiple organ failure in recipients of heart.

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Description

The group of inventions relates to medicine, namely to cardiovascular surgery, transplantology, medical technology, and can be used in performing heart operations, including repeated ones, in patients with high surgical risk and critical heart failure who are on extracorporeal membrane oxygenation as a bridge for heart transplantation.

The use of temporary mechanical circulatory support in potential heart recipients with acute and rapidly progressing heart failure refractory to drug therapy remains the only way to restore systemic hemodynamics, which ensures the preservation of the body's viability and leaves prospects for subsequent heart transplantation (HT).

There has been increased interest in the use of venoarterial extracorporeal membrane oxygenation (ECMO) as a method of extracorporeal life support and one of the options for temporary assisted circulation (AC) in potential heart recipients (Fumagalli R., Bombino M., Borelli M. Percutaneous bridge to heart transplantation by venoarterial ECMO and transaortic left ventricular venting // Int. J. Artif. Organs. 2004; 27 (5): 410-413).

One of the actively developed areas of clinical application of veno-arterial ECMO in the implementation of the HT program is its use in potential recipients as mechanical support of blood circulation before HT. Veno-arterial ECMO allows for rapid restoration of systemic hemodynamics, maintenance of adequate perfusion of the main organ systems, and helps prevent the development or rapid regression of multiple organ disorders, which makes it possible to perform HT in this most severe category of potential heart recipients.

When choosing the method of ECMO, preference is given to its peripheral technique, which is associated with less trauma of the procedure, lower risk of hemorrhagic, infectious complications, the possibility of faster activation of patients and preservation of an intact chest, which is important for subsequent implementation of HT and prevention of infectious complications from the surgical wound in patients undergoing immunosuppressive therapy after transplantation. Prevention of lower limb ischemia remains fundamental when performing peripheral veno-arterial ECMO, especially with anatomically small sizes of the femoral artery and expected long periods of extracorporeal support.

Since the use of veno-arterial ECMO as a method of pre-transplant VC requires timely implementation of HT, which leads to the need for more frequent use of hearts from donors with extended criteria, the risk of developing hemodynamically significant transient early dysfunction of the cardiac graft increases. In this regard, veno-arterial ECMO initiated before HT and continued after its implementation already acts as a means of post-transplant circulatory support.

In most recipients, the use of veno-arterial ECMO was continued in the early post-transplant period, including as a means of hemodynamic support in the case of severe manifestations of cardiac graft dysfunction, which ensured the adequacy of systemic circulation at the stage of restoration of the pumping function of the cardiac graft.

The essence of the classical veno-arterial ECMO method is the placement of a transfemoral venous reinforced cannula, positioning it in the right atrium, then the venous cannula and the first port of the ECMO device centrifuge pump are connected using a venous line, for example, 3/8 inch. The second port of the centrifuge pump is connected to the ECMO oxygenator, from which an arterial line extends, which is connected to the femoral arterial reinforced cannula, from which a line extends, connected to a catheter installed below the site of the arterial cannula placement to prevent lower limb ischemia.

Thus, the patient's venous blood from the right atrium is pumped into the ECMO oxygenator by active drainage, i.e. using a centrifugal pump. Then, the oxygenated, i.e. arterial, blood enters the patient's arterial system through the femoral arterial cannula with the possibility of perfusing the lower limb (Le Gall, Arthur; Follin, Arnaud; Cholley, Bernard; Mantz, Jean; Aissaoui, Nadia; Pirracchio, Romain Veno-Arterial-ECMO in the Intensive Care Unit: From Technical Aspects to Clinical Practice. Anaesthesia Critical Care & Pain Medicine, S2352556817300590-. doi:10.1016/j.accpm.2017.08.007).

However, this method of VC does not provide for the possibility of performing operations on the heart with the opening of its cavities for the following reasons: there is no technical possibility to compress both vena cava when access to the heart is achieved; opening the cavities of the heart will lead to massive air embolism of the extracorporeal circuit; there is no possibility of returning the blood volume to the patient's bloodstream.

Thus, this method can be used for long-term support of blood circulation and cannot be used as a method of artificial circulation (AC) for operations requiring opening of the heart cavities.

A method of peripheral CBF is known, applied in heart surgeries (L.S. Lokshin, E.R. Charchyan, Yu.V. Belov et al. Artificial circulation in aortic surgery. // Medical almanac No. 4 (28) September 2013. P. 14-16). The essence of the method is active drainage of the right atrium with a cannula through the femoral vein and return of oxygenated blood to the femoral artery. The advantage of this method is short-term CBF with the possibility of stopping cardiac activity without opening the right chambers of the heart.

However, this method has the following disadvantages:

1. Active drainage of the right atrium categorically does not involve opening the right chambers of the heart, since this will cause air embolism and the atrial venous catheter will stop, and therefore cannot be used in heart surgeries that involve opening them, including HT.

2. The system can only be installed immediately before the operation, since the operating time of the type of oxygenator used is no more than 6 hours, which subsequently manifests itself as its dysfunction and requires either replacement of the oxygenator or removal of the entire implanted VC system.

3. Long-term obstruction of the femoral artery by an arterial cannula creates conditions for the development of ischemia of the lower limb distal to the cannulation site.

4. The method does not provide for the possibility of preventing ischemia of the lower limb on the side of which the peripheral CPB system is being implanted.

There is also a method of VC using veno-arterial ECMO and drainage of the left atrium by installing an additional drainage cannula into the left atrium from a transfemoral approach in potential heart recipients (RU 2526880, C1). This method ensures adequate hemodynamic unloading of the left ventricle in order to reduce its linear and volumetric characteristics, decrease left ventricular end-diastolic pressure, left atrial pressure and eliminate blood congestion in the pulmonary circulation, manifested by regression of clinical and instrumental signs of pulmonary edema. The essence of the method is similar to classical veno-arterial ECMO, and differs only in the presence of an additional drainage cannula installed into the left atrium via a transfemoral approach on the opposite side from the cannulation of the femoral vein and artery.

However, this method is used for long-term mechanical support of blood circulation and is a method of VC with the aim of reducing pressure in the pulmonary circulation and, like the classical method of veno-arterial ECMO, cannot be used in HT surgery in isolation without traditional CPB.

The prototype of the proposed method is a method in which peripheral ECMO is installed at the preoperative stage, operates during the HT operation itself in isolation from the CPB and can perform its function after the completion of HT. In this case, the CPB is connected separately during HT in a traditional way (Peripheral veno-arterial membrane oxygenation as a method of mechanical support of blood circulation before heart transplantation // Poptsov V.N., Spirina E.A., Shumakov D.V. et al. // Bulletin of Transplantology and Artificial Organs Vol. 15 No. 2, 2013, pp. 23-35).

The method of CPB is as follows: venous blood from the superior vena cava (SVC) and inferior vena cava (IVC) through previously installed venous cannulas, united by a common venous line, is directed into the cardiotomy reservoir (CTR), into which blood also flows from the sternotomy wound using wound aspirators and the left atrium by installing a drainage cannula into it. Then, venous blood from the CTR is pumped into the first port of the CPB oxygenator using a roller pump, with a gas-air mixture line connected to it. Arterial blood coming out of the second port of the CPB oxygenator is directed through the arterial line of the CPB into the ascending aorta, in which the arterial cannula is installed.

Thus, during TS using the prototype method, there is simultaneous use of the IR and ECMO systems, but they work in isolation.

Since the connection of IR involves additional aggressive interventions, the prototype method has the following disadvantages.

1. When accessing the heart, trauma to the heart chambers with bleeding is possible, without the possibility of immediately returning it to the patient’s bloodstream, thus reducing the preload and reducing the speed of the ECMO pump until it stops.

2. There is a risk of air embolism of the ECMO venous line when cannulating the SVC and IVC to connect traditional CPB, in which case the ECMO centrifugal pump will fail and stop due to a malfunction, leading to circulatory arrest in the patient.

3. During the main stage of the operation, ECMO works to prevent thrombosis of the ECMO oxygenator, the performance of which is 0.7-1.2 l / min (the arterial blood flow is directed from the femoral artery to the aorta), and traditional CPB works with a higher performance, determined taking into account the surface area of the patient's body; in this case, arterial blood moves from the aorta to the femoral artery, thus creating a turbulence zone when two mutually opposite flows meet, this process can contribute to hyperperfusion in the body, which disrupts the utilization of carbon dioxide and oxygen delivery, increasing anaerobic metabolism and contributes to inadequate tissue perfusion.

4. The flow of air mixture supplied to the ECMO oxygenator (1-1.5 l/min) with the ECMO centrifuge pump running at 0.7-1.2 l/min during the operation of the CPB apparatus creates a low partial pressure of carbon dioxide and a high partial pressure of oxygen in the blood, which increases the toxic effect of oxygen on the brain.

5. Additional consumables are used for cannulation of the IVC and ascending aorta, given that at the time of surgery the patient has a cannula in the femoral artery and femoral vein, i.e. it is already possible to collect venous blood from the IVC system and return oxygenated blood to the arterial bed, which accordingly increases the cost of the operation.

6. Increased surgical trauma due to the need to apply additional purse-string sutures to the IVC and ascending aorta with their subsequent cannulation, which is associated with the possibility of complications in the form of bleeding. This is especially dangerous in patients who have previously had heart surgery, since the existing adhesion process significantly complicates access to the heart and main vessels for their cannulation and bypass. Accordingly, much more time is spent on connecting the CPB before the main stage of the operation begins, namely, cutting off the recipient's heart and sewing on the donor heart, which ultimately increases the duration of the operation.

Thus, this method is labor-intensive and is associated with a high risk of uncontrolled bleeding from the beginning of the operation until the end of the connection of the CPB device, especially in patients undergoing repeated surgery, since it involves taking venous blood from both vena cava and returning arterial blood to the ascending aorta (with an existing cannula in the femoral vein and femoral artery to ensure ECMO operation).

The following CPB system can be selected as a prototype of the CPB system for a heart transplant recipient, including a sequentially connected IVF cannula, an HI 1 B cannula, a venous line, a KTR with wound suction and left ventricular drainage lines connected to it with a left ventricular drainage cannula, a roller pump, an CPB oxygenator, an arterial line, and an arterial cannula of the ascending aorta. (Gudrun Kunst, Milan Milojevic, Christa Boer, Filip M.J.J. De Somer, Tomas Gudbjartsson, Jenny van den Goor, Timothy J. Jones, Vladimir Lomivorotov, Frank Merkle, Marco Ranucci, Luc Puis, Alexander Wahba, Peter Alston, David Fitzgerald, Aleksandar Nikolic, Francesco Onorati, Bodil Steen Rasmussen, Staffan S venmarker. 2019 EACTS/EACTA/EBCP guidelines on cardiopulmonary bypass in adult cardiac surgery. British Journal of Anaesthesia, Volume 123, Issue 6, 2019, Pages 713-757, ISSN 0007-0912, https://doi.Org/10.1016/j.bja.2019.09.012).

This system is intended only to ensure the implementation of surgical intervention of the TC, namely, it ensures the bypass of the left and right chambers of the heart and drainage of its cavities. However, this system does not imply use in the pre- and post-transplant periods, is associated with an extremely high risk of intraoperative complications, especially with repeated interventions, due to the need to achieve complete cardiolysis, the application of purse-string sutures to the orifice of the IVC and the ascending aorta with their subsequent cannulation.

Our goal is to develop a method and system that can reliably provide blood circulation during HT in heart recipients with systemic hemodynamic disorders, high surgical risk and critical heart failure, including during repeated heart surgeries, as well as in patients on ECMO in the preoperative period.

The medical and technical result achieved by implementing the proposed group of inventions consists in the simultaneous

- reducing the trauma of procedures that ensure stabilization of central hemodynamics by eliminating additional access to the main vessels during the combined use of CPB and ECMO in heart recipients;

- prevention of the development of complications associated with the occurrence of bleeding during HT, due to the possibility of immediate return of blood to the bloodstream of the heart recipient, which allows in these cases to correct the patient's volume status, thereby maintaining the operation of ECMO and reducing the frequency of use of donor blood elements;

- simplification of surgical intervention technique, reduction of surgical trauma due to the absence of the need for manipulations on the NSV and ascending aorta, which are necessary for their cannulation;

- prevention of the development of air embolism of the ECMO venous line due to the absence of the need for purse-string sutures and cannulation of the venous line;

- the possibility of immediate return of blood to the patient’s vascular bed in case of any trauma to the heart sections at the stage of access, thus creating conditions for performing interventions in the most difficult surgical situations;

- prevention of air embolism, prevention of circulatory arrest in the event of undesirable and emergency situations by means of the possibility of deaeration of the venous line and the ECMO system due to the presence of an integrated CTP of the ECMO system and the possibility of continuing the operation in the event of a malfunction of the ECMO centrifugal pump due to the presence of a roller pump;

- prevention of complications caused by the development of oxygenator thrombosis, due to the sufficient speed of blood movement in it, as well as the absence of a turbulence zone of two mutually opposite flows under conditions of continued blood movement in the ECMO oxygenator;

- providing the ability to regulate the gas composition of the blood only with the CI oxygenator, which makes it possible to perfuse the body with optimal parameters;

- reducing the incidence of multiple organ failure in heart recipients due to reliable prolonged stabilization of central hemodynamics during HT.

The possibility of immediate return of blood to the patient's vascular bed in case of any trauma to the heart sections already at the stage of surgical access is especially relevant for patients who have previously undergone heart surgery. In these cases, the existing adhesion process significantly complicates access to the heart, main vessels and creates a high risk of ongoing bleeding.

The absence of the use of additional consumables for cannulation of the IVC and ascending aorta reduces the cost of the operation when performing TS using the proposed method.

The patented group of inventions allows for the integration of the ECMO system into the ECMO system during HT, including during repeated heart surgeries, as well as in recipients requiring ECMO before and after donor heart transplantation.

The essence of the invention is as follows.

A system for artificial blood circulation in a heart recipient during its transplantation is proposed, comprising a first venous cannula for connection to the femoral vein; first, second venous lines; first, second pumps; first, second oxygenators; first, second, third tee-branchers; first, second arterial lines; an arterial cannula with a luer port for connection to the femoral artery; first, second straight connectors; a cardiotomy reservoir (CTR); a wound suction line; a left ventricular drainage cannula; a left ventricular drainage line; a second venous cannula for connection to the superior vena cava; a hemoconcentrator; a third straight connector with a luer port and a line for connecting a pressure sensor; a first line of a gas-air mixture of the first oxygenator; a second line of a gas-air mixture of the second oxygenator.

Moreover, the first venous line, connected at one end to the first venous cannula, is connected at the second end to the first pump, the output of which is connected through the first oxygenator, which has the first gas-air mixture line and the first tee-branch, to the first arterial line, the output of which is connected through the second tee-branch to the arterial cannula.

The second tee-branch is connected through the first straight connector to the second arterial line, the output of which is connected through the third straight connector with a luer port and a line for connecting a pressure sensor through the third tee-branch to the hemoconcentrator and the second oxygenator, which has a second line of gas-air mixture, while the output of the second oxygenator through the second pump is connected to the input of the KTR, which is also connected to the second straight connector, connected to the first tee-branch.

The second venous line with the second venous cannula; the wound suction line; the left ventricular drainage cannula and the left ventricular drainage line are also connected to the KTR inputs.

A method for CB in a heart recipient during its transplantation using the system presented above is also proposed. The femoral venous cannula is connected to the femoral vein and the arterial femoral cannula is connected to the femoral artery. After that, the first pump is turned on at a speed equal to half the volumetric blood flow rate of the patient. The connection of the first arterial line with the KTR and the first arterial line with the second arterial line is clamped by applying clamps between the first tee-branch and the second straight connector, as well as between the second tee-branch and the first straight connector. The SVC is cannulated with the second venous cannula, the second venous line is clamped. The left chambers of the heart are cannulated with the left ventricular drainage cannula, after which the clamps are removed between the first tee-branch and the second straight connector, as well as between the second tee-branch and the first straight connector. The second pump is turned on at a rate equal to the blood flow rate of the first pump with simultaneous clamping of the first arterial line between the first tee-splitter and the second tee-splitter. Then the second venous line is opened and the blood flow rate of the second pump is set in accordance with the calculated perfusion rate. Hemoconcentration is performed by opening the lines before and after the hemoconcentrator in the direction of blood flow by opening a connection between the KTR and the third tee-splitter. Completion of CPB is performed by reducing the blood flow rate of the second pump by 50% of the calculated perfusion rate and simultaneously clamping the junction of the first tee-splitter with the second straight connector and removing the clamp from the first arterial line between the first tee-splitter and the second tee-splitter. Then the second pump is stopped, leaving open the connection between the second tee-splitter and the first straight connector. When bleeding occurs, the wound suction line first evacuates blood from the sternotomy wound to the CTE, and then, using a second pump, returns the blood to the patient's arterial system.

The essence of the inventions is explained by the following figures.

Fig. 1 shows a diagram of the proposed system for performing IR in a heart recipient during its transplantation.

Fig. 2 shows a diagram of the CI with active venous drainage of the IVC system, passive venous drainage of the SVC system and return of arterial blood to the femoral artery.

Fig. 3 shows a diagram of the transition from IR to VC, during which blood is returned to the patient.

The following notations are used in the figures:

1 - venous femoral cannula;

2 - the first venous trunk;

3 - first pump (centrifugal pump);

4 - first oxygenator;

5 - first tee-branch;

6 - first arterial line;

7 - second tee-branch;

8 - arterial femoral cannula with luer port;

9 - first straight connector;

10 - second straight connector;

11 - CTE;

12 - wound suction line;

13 - left ventricular drainage cannula;

14 - left ventricular drainage line;

15 - venous cannula of the SVC;

16 - the second venous trunk (SVC trunk);

17 - second pump (roller pump);

18 - second oxygenator;

19 - third tee-branch;

20 - hemoconcentrator;

21 - straight connector with luer port and line for connecting pressure sensor;

22 - the second arterial line;

23 - gas-air mixture line of the first oxygenator;

24 - gas-air mixture line of the second oxygenator.

The arrows in Fig. 2 and 3 show the direction of blood flow in the system.

The proposed system for artificial blood circulation in a heart recipient during its transplantation (Fig. 1) comprises a venous femoral cannula 1; a first venous line 2; a first pump 3 made in the form of a centrifugal pump; a first oxygenator 4; a first tee-branch 5; a first arterial line 6; a second tee-branch 7; an arterial femoral cannula 8 with a Luer port; a first straight connector 9; a second straight connector 10; a cardiotomy reservoir KTR 11; a wound suction line 12; a left ventricular drainage cannula 13; a left ventricular drainage line 14; a venous cannula SVC 15; a second venous line (SVC line) 16; a second pump 17 made in the form of a roller pump; a second oxygenator 18; third tee-branch 19; hemoconcentrator 20; straight connector with luer port and line for connecting pressure sensor 21; second arterial line 22; line of gas-air mixture of first oxygenator 23; line of gas-air mixture of second oxygenator 24.

Venous line 2 is connected via venous femoral cannula 1 to pump 3, the output of which is connected via oxygenator 4, which has gas-air mixture line 23 and tee-branch 5 to arterial line 6, the output of which is connected via tee-branch 7 to arterial femoral cannula 8 with a Luer port.

The tee-branch 7 is connected via a straight connector 9 to the arterial line 22, the output of which is connected via a straight connector 21 with a luer port and a line for connecting a pressure sensor via a tee-branch 19 to a hemoconcentrator 20 and an oxygenator 18, which has a gas-air mixture line 24.

In this case, the output of the oxygenator 18 is connected via the pump 17 to the input of the KTR 11, which is also connected to the direct connector 10, connected to the tee-branch 5.

Also connected to the KTR 11 inputs are the venous line 16 with the SVC cannula 15; the wound suction line 12; the left ventricular drainage cannula 13 and the left ventricular drainage line 14.

The block containing the ECMO elements is presented as follows. The venous femoral cannula 1 is connected to the venous line 2 and the pump 3; then the pump 3 is connected by a line to the oxygenator 4, to which the line 23 of the gas-air mixture of the first oxygenator is connected. From the oxygenator 4, the arterial line 6 extends, connected to the arterial femoral cannula 8 with a luer port.

Arterial line 6 is connected to the RZ block via tee-branch 5 and tee-branch 7 through straight connector 9 and straight connector 10.

The CI block is represented by a KTR 11, to which a wound suction line 12, a left ventricular drainage line 14 with a left ventricular drainage cannula 13, a venous line 16 with a venous cannula of the SVC 15 are connected. The KTR 11 is connected by a pump segment installed in a pump 17 with an oxygenator 18 with a line 24 of the gas-air mixture of the oxygenator. The output of the oxygenator 18 is connected to a tee-branch 19, which in turn is connected by free ports to a hemoconcentrator 20 and a straight connector 21 with a luer port, to which a pressure sensor line is connected, the free port of the connector 21 is connected to the port of the second arterial line 22. The hemoconcentrator 20 is located between the KTR 11 and the third tee-branch 19.

The connection of the block containing the ECMO elements with the CPB block is performed by connecting the direct connector 10 with the KTR 11 and the direct connector 9 with the arterial line 22 using a line (Fig. 1).

The ECMO unit containing the ECMO elements is prepared as follows. In a sterile room, observing the rules of asepsis and antisepsis, assemble the disposable system, supplied as one set, which includes a set of lines with a pump 3, an oxygenator 4 and a set of lines in a sterile plastic box for the operating table, for example, 3/8-3/8 inches, i.e. two tubes connected by an adapter, which after disconnection create a venous line 2 and an arterial line 6.

The assembly of the ECMO unit containing the ECMO elements is carried out by sequentially connecting the lines of pump 3 with the oxygenator 4, to which the line 23 of the gas-air mixture is connected. Then the lines are connected in a sterile plastic box for the operating table, namely, the venous line 2 is connected to the pump 3, and the arterial line 6 is connected to the port of the oxygenator 4.

Recommendations for assembling an ECMO system are widely known to specialists (e.g., Gajkowski, Evan F.; Herrera, Guillermo; Hatton, Laura; Velia Antonini, Marta; Vercaemst, Leen; Cooley, Elaine. ELSO Guidelines for Adult and Pediatric Extracorporeal Membrane Oxygenation Circuits. ASAIO Journal 68(2): p 133-152, February 2022. DOI: 10.1097/MAT.0000000000001630).

Immediately before the TS operation, the disposable system of the CPB block, which ensures CPB and hemoconcentration, is assembled in a sterile room in compliance with the rules of asepsis and antisepsis. The CPB block system includes a KTR 11 connected by a pump segment installed in a pump 17 with a second oxygenator 18 with a gas-air mixture line of the second oxygenator 24, a third tee-branch 19, a hemoconcentrator 20, a straight connector 21 with a luer port with a pressure sensor line, a second arterial line 22, as well as a wound suction line 12, a left ventricular drainage cannula 13, a left ventricular drainage line 14, a venous cannula of the SVC 15, a second venous line 16.

The assembly of the IR block is carried out as follows: KTR 11 is connected by a pump segment installed in pump 17 to the second oxygenator 18, to which the oxygenator gas-air mixture line 24 is connected. The output of the oxygenator 18 is connected through the tee-branch 19 to the free port of the hemoconcentrator 20 and the straight connector 21 with the luer port with the pressure sensor line, and the free port of the straight connector 21 with the luer port is connected to the port of the second arterial line 22. The hemoconcentrator 20 is located between the KTR 11 and the tee-branch 19. After that, the assembled CPB apparatus is transported to the operating room, where the assembly is completed, namely, the wound suction line 12, the left ventricular drainage line 14 with the left ventricular drainage cannula 13, the venous line 16 with the venous cannula of the SVC 15 are connected to the KTR 11.

Recommendations for assembling an CPB system are widely known in the field (e.g., Clinical Evaluation of the Terumo Capiox ® FX05 Hollow Fiber Oxygenator with Integrated Arterial Line Filter. Joseph Deptula, MS, CCP, Melinda Valleley, MS, CCP, Kimberly Glogowski, MS, CCP, John Detwiler, BS, RRT, James Hammel, MD, and Kim Duncan, MD. J Extra Corpor Technol. 2009 Jul; 41(4): 220-225).

The integration of the ECMO unit with the ECMO elements is performed at the intraoperative stage by implanting a tee-branch 5 into the arterial line 6, the free port of which is connected to the straight connector 10. This ensures the connection of the arterial line 6 with the KTR 11. The arterial line 22 is integrated into the arterial line 6 using a tee-branch 7, the free port of which is connected to the straight connector 9 (Fig. 1).

In the operating room, the ECMO block containing the ECMO elements is filled with a crystalloid solution, such as Ringer's solution, and the EC block is filled with a solution containing 500 ml of gelofusine, 100 ml of mannitol, 100 ml of sodium bicarbonate with 1 ml of heparin, and 300 ml of ionosteril; in this case, the line between the tee-branch 5 and the straight connector 10, as well as between the tee-branch 7 and the straight connector 9 is clamped (Fig. 2).

The method of IR in TS is carried out as follows.

After three times processing of the surgical field in the area of the sternum and groin, the puncture method according to Seldinger is used to install the femoral venous cannula 1 in the femoral vein. In a similar way, the femoral artery is catheterized and then cannulated using the femoral arterial cannula 8 with a luer port, to which a catheter for perfusion of the lower limb is connected and this catheter is punctured below the cannulation site of the femoral cannula 8.

After completion of cannulation, they proceed to connect the implanted cannulas with the corresponding lines, i.e. connect the patient's main vessels with the proposed system, namely, connect the venous femoral cannula 1 with the venous line 2, which is connected to the pump 3. This pump is necessary for pumping venous blood into the oxygenator 4. The function of the oxygenator is to enrich the blood with oxygen and utilize carbon dioxide, respectively, the venous blood pumped into it becomes oxygenated, i.e. arterial. Then, arterial blood is directed through the arterial line 6, connected to the femoral cannula 8 with a luer port, into the femoral artery. After connecting the femoral cannulas to the lines of the same name, pump 3 is turned on at a speed equal to half the initial volumetric blood flow rate of the patient. This ensures blood circulation in the patient's body and blood flow in the lower limb from the side of the cannulation of the femoral artery. Volumetric blood flow rate is the volume of blood flowing through the cross-section of a vessel per unit of time, measured in ml/min or l/min.

Next, access to the heart is performed through a median sternotomy. After this, it is necessary to ensure drainage of the SVC system with subsequent cessation of the inflow to the heart from the SVC system before the main stage of the HT operation. For this, the SVC is cannulated with a venous cannula SVC 15 and connected to the venous line (SVC line) 16, which in turn is connected to the KTR 11 and clamped. The next stage is drainage of the left heart chambers. For this, the left atrium and left ventricle are cannulated through the upper right pulmonary vein with a cannula 13 of the left ventricle drainage, which is connected to the KTR 11 using the line 14 of the left ventricle drainage. The final stage of the formation of the CPB system is the connection of the line 12 of the wound suction to the KTR 11.

Having created conditions for the surgical intervention of heart transplantation (HT), we proceed to CB. To do this, we remove the clamps between the tee-branch 5 and the straight connector 10, as well as between the tee-branch 7 and the straight connector 9, and turn on the pump 17 at a speed equal to the blood flow rate of the pump 3 with the simultaneous application of a clamp to the arterial line 6 between the tee-branch 5 and the tee-branch 7. After this, we open the venous line (the SVC line) 16 and increase the blood flow rate of the pump 17 taking into account the calculated volumetric blood flow rate determined taking into account the Mosteller formula. After this, the blood flow in the pulmonary circulation is stopped, i.e. the flow of venous blood into the right sections of the heart is prevented by clamping the mouths of the IVC and SVC with tourniquets.

Thus, CPB is provided with active venous blood collection from the IVC system, passive drainage of the SVC system, active drainage of the left cavities of the heart and the blood appearing in the wound with active pumping of the collected and oxygenated blood into the patient's arterial system through the femoral artery. If the hematocrit is below 26%, hemoconcentration is performed by opening the hemoconcentrator lines 20, located between the KTR 11 and the tee-splitter 19, while increasing the speed of the pump 17 by 0.4-0.5 l/min. After suturing the donor heart, achieving adequate surgical hemostasis, effective cardiac activity is restored with the possible use of drugs and the patient is warmed up to 37°C. After which CPB is stopped with continued operation of the CPB unit containing ECMO elements in the "maintenance" mode, provided that the pumping function of the heart is satisfactory after surgery.

The “maintenance” mode may be useful, for example, in case of delayed graft dysfunction, left ventricular, right ventricular failure, or in a mode that ensures effective blood circulation and stable hemodynamics, which is also possible in case of primary graft dysfunction.

Completion of CPB with continued operation of the CPB unit containing ECMO elements is performed under control of stable arterial pressure and volumetric load by reducing the speed of pump 17 to 50% of the estimated blood flow rate and clamping the junction between the tee-branch 5 and the straight connector 10, while simultaneously removing the clamp from the arterial line 6 between the first tee-branch 5 and the tee-branch 7. Then pump 17 is stopped, leaving open the connection between the tee-branch 7 and the straight connector 9. If bleeding occurs, blood is evacuated from the sternotomy wound into the CTR 11 using the wound suction line, returning it to the systemic bloodstream. With satisfactory hemostasis and stable hemodynamics, decannulation of the SVC and left atrium is performed. The existing volume of blood in the CPB system is returned to the patient's bloodstream under the control of arterial and central venous pressure, after which the line between the tee-branch 7 and the straight connector 9 is clamped.

In Fig. 2, the arrows show the movement of blood during CPB at the time of TS. The patient's venous blood is actively drained from the IVC system through the venous femoral cannula 1 and the venous line 2 is pumped into the oxygenator 4 using the pump 3. Then the connections are opened between the tee-branch 5 and the straight connector 10, as well as between the tee-branch 7 and the straight connector 9, while the arterial line 6 is clamped between the tees-branchers 5 and 7. Accordingly, the venous blood from the oxygenator 4 is directed to the KTR 11, where the blood from the sternotomy wound, coming from the line 12 of the wound suction, the blood from the heart cavity, coming through the cannula 13 of the left ventricle drainage with the line 14 of the left ventricle drainage connected to it, as well as from the SVC system, coming through the venous cannula of the SVC 15 with the line 14 of the left ventricle drainage connected to it, is concentrated. venous line of the SVC 16. The blood collected in the KTR 11 from the sternotomy wound, the heart cavity and the SVC system is directed by means of a pump 17 through a line with a silicone fragment into the oxygenator 18, to which the line 24 of the gas-air mixture of the oxygenator 18 is connected. Then the arterial blood is directed through the arterial line 22 into the arterial femoral cannula 8 with a luer port, passing through the open connection between the straight connector 9 and the tee-branch 7.

The movement of blood after the attachment of the donor heart and restoration of cardiac activity is carried out as follows (see Fig. 3).

The patient's venous blood actively passes through the venous femoral cannula 1 along the venous line 2, and is pumped into the oxygenator 4 using the pump 3. Then, the arterial blood is pumped into the femoral artery via the arterial line 6 through the cannula 8.

Thus, CPB is provided in a protective (supportive) mode. In this case, the connection point between the tee-branch 5 and the straight connector 10 is pinched, and the space between the tee-branch 7 and the straight connector 9 remains open. This allows the blood coming from the sternotomy wound to be returned to the patient's bloodstream, for example, in case of bleeding, and also to displace the blood volume from the CPB system.

The proposed system and method of CB allow hemoconcentration to be performed during the entire period of CB, for which it is necessary to open the lines before and after the hemoconcentrator 20. In this case, the blood is directed through the tee-branch 19 to the hemoconcentrator 20, and then to the KTR 11 (see Fig. 2, 3).

The patented system and method can be used to provide CPB during open heart surgery in HT. The CPB unit containing ECMO elements can be in a preserved state and immediately used when the need for surgical intervention arises, while ensuring effective blood circulation and gas exchange in the most complex category of patients.

Ensuring active drainage from the IVC system is important to prevent thrombus formation and a decrease in the oxygenating capacity of oxygenator 4. Drainage of the SVC system, left heart chambers and evacuation of wound blood in the CTR 11 create the necessary conditions for working on a stopped heart with redirection of the blood flow of the pulmonary circulation by clamping the mouths of the vena cava.

The absence of the need for aortic and IVC cannulation significantly facilitates surgical intervention, reduces the duration of the operation, reduces the risk of surgical complications and to a greater extent ensures the safety of cardiolysis and the prevention of complications associated with it, such as rupture of the right ventricular wall, due to the ability to collect blood with wound suction and immediately return it to the patient's bloodstream. This ensures effective hemodynamics, gas exchange, control of acid-base balance and electrolyte balance, which creates conditions for the successful implementation of surgical intervention - TS.

The CPB system containing ECMO elements can be used before and after HT: at the stage of preparing the patient for surgery, namely to stabilize the patient's condition due to the presence of critical heart failure, manifested by low cardiac output and, as a consequence, a drop in central hemodynamics, as well as a means of hemodynamic support in the presence of complications after HT, manifested by pronounced signs of dysfunction of the cardiac transplant, which ensures the adequacy of systemic circulation at the stage of restoring the pumping function of the cardiac transplant.

In this case, the blood movement is carried out as follows: the patient's venous blood actively passes through the venous femoral cannula 1 and the venous line 2 with the help of the first pump (centrifugal pump) 3 and is pumped into the first oxygenator 4, to which the gas-air mixture line of the first oxygenator 23 is connected. Venous blood, being oxygenated, becomes arterial. Then, arterial blood, passing through the first arterial line 6, connected to it by the arterial femoral cannula 8 with a luer port, is pumped into the femoral artery.

We provide evidence of the possibility of implementing the stated purpose and achieving the specified medical and technical result.

Clinical example

Patient I., 15 years old, diagnosed with: Dilated cardiomyopathy. Chronic heart failure. Circulatory failure 2A. Functional class III. Implantation of pacemaker. Height 160 cm, weight 45 kg. Body surface area 1.4 m. Implantation of veno-arterial ECMO system. Orthotopic heart transplantation was performed using the bicaval technique. Pacemaker explantation. Longitudinal median sternotomy. The pericardium was opened. The arterial and venous lines of the heart-lung machine are integrated into the lines of the ECMO machine in accordance with the proposed method by implanting the first tee-splitter into the first arterial line, the free port of which is connected to the second straight connector. Thus, the first arterial line is connected to the KTR, and the second tee-splitter is implanted into the first arterial line, the free port of which is connected to the first straight connector. Thus, the second arterial line is integrated into the first arterial line. Cannulation of the SVC. CPB is started with a temperature of 35.7°C. The estimated perfusion rate is 3.5 L/min. The ascending aorta is clamped, the recipient's heart is excised together with the pacemaker electrodes. A left atrial rosette is formed. The heart graft is placed into the pericardial cavity, external cooling of the graft is performed. The left atria are anastomosed with a 3-0 Prolene locking suture. The IVC and SVC are anastomosed with a continuous 4-0 Prolene locking suture, respectively. The diameter of the recipient's aorta and pulmonary artery correspond to similar parameters of the donor. The left ventricle is drained through the orifice of the right superior pulmonary vein. The aorta and pulmonary artery of the graft are anastomosed to the aorta and pulmonary artery of the recipient using a 5-0 prolene locking suture. The aortic clamp is removed with air embolism prevention. Cardiac activity was restored with one defibrillator discharge. The rhythm is imposed by the pacemaker. The drainage from the left ventricular cavity is removed. CPB is completed against the background of inotropic drugs. Decannulation. Protamine. Careful hemostasis. The pericardial cavity and anterior mediastinum are drained. The pacemaker electrode is sutured to the right ventricle. The sternum is sutured with 6 wire sutures. The pacemaker with the remaining electrodes is explanted through a separate incision in the left subclavian region. Layer-by-layer suturing of surgical wounds. Transplant ischemia time is 179 min. Sewing time is 35 min. There were no complications in the postoperative period. The patient was discharged from the hospital 21 days after the operation.

IR according to the proposed method was performed in 17 patients. All patients were in critical condition before HT; 3 patients had signs of multiple organ failure before the operation. 14 patients were discharged in satisfactory condition. 3 patients died in the post-transplant period for reasons not related to surgery and IR.

The result obtained using the proposed systems and method consists in improving the quality and simplifying all stages of IC in TS.

The use of the method leads to an increase in the number of heart transplants; reduces the time for cannulation of the main vessels; reduces trauma to red blood cells; minimizes surgical trauma when accessing the heart during cardiolysis of the recipient's own heart during repeated surgical intervention; ensures the possibility of immediate return of blood to the patient's bloodstream in the event of bleeding, while reducing the frequency of use of donor blood elements; stabilizes central hemodynamics and, as a result, reduces the incidence of multiple organ failure and neurological dysfunction; provides the possibility of prolonged vascular insufficiency, supplemented by membrane oxygenation after completion of HT, eliminating the need for additional access to vessels.

Claims (2)

1. A system for artificial circulation (AC) in a heart transplant recipient, comprising a first venous cannula for connection to the femoral vein; first and second venous lines; a centrifuge pump and a roller pump; first and second oxygenators; first, second and third tee-branchers; first and second arterial lines; an arterial cannula with a Luer port for connection to the femoral artery; first and second straight connectors; cardiotomy reservoir (CTR); a wound suction line; a left ventricular drainage cannula; a left ventricular drainage line; a second venous cannula for connection to the superior vena cava (SVC); a hemoconcentrator; a straight connector with a Luer port and a line for connecting a pressure sensor; a gas-air mixture line of the first oxygenator; a gas-air mixture line of the second oxygenator; a first venous line connected at one end to a first venous cannula, and connected at its second end to a centrifuge pump, the outlet of the centrifuge pump is connected through a first oxygenator having a gas-air mixture line and a first tee-branch to the first arterial line, the outlet of the first arterial line is connected through a second tee-branch to an arterial cannula with a luer port for connection to the femoral artery; the second tee-branch is connected through a first straight connector to the second arterial line, the outlet of the second arterial line is connected through a straight connector with a luer port and a line for connecting a pressure sensor and is connected through a third tee-branch to a hemoconcentrator and a second oxygenator having a gas-air mixture line; the outlet of the second oxygenator is connected through a roller pump to the inlet of the KTR, connected to the second straight connector connected to the first tee-branch; The second venous line with the second venous cannula for connection to the SVC; the wound suction line; the left ventricular drainage cannula and the left ventricular drainage line are connected to the KTR inputs. 2. A method for CB in a heart recipient during its transplantation using the system according to claim 1, in which the femoral venous cannula is connected to the femoral vein and the femoral arterial cannula is connected to the femoral artery, after which the centrifuge pump is turned on at a speed equal to half the volumetric blood flow rate of the patient, the connection of the first arterial line with the KTR and the first arterial line with the second arterial line is clamped by applying clamps between the first tee-branch and the second straight connector and between the second tee-branch and the first straight connector; the SVC is cannulated with the second venous cannula, the second venous line is clamped; the left chambers of the heart are cannulated with the left ventricular drainage cannula; then the clamps between the first tee-splitter and the second straight connector and between the second tee-splitter and the first straight connector are removed, the roller pump is turned on at a speed equal to the blood flow rate of the centrifugal pump with simultaneous application of a clamp to the first arterial line between the first tee-splitter and the second tee-splitter; then the second venous line is opened and the blood flow rate of the roller pump is set in accordance with the calculated perfusion rate; hemoconcentration is performed by opening the lines before and after the hemoconcentrator in the direction of blood flow by opening a connection between the KTR and the third tee-splitter; completion of CPB is performed by reducing the blood flow rate of the roller pump by 50% of the calculated perfusion rate and simultaneously clamping the junction of the first tee-splitter with the second straight connector, and removing the clamp from the first arterial line between the first tee-splitter and the second tee-splitter; then the roller pump is stopped, leaving the connection between the second tee-branch and the first straight connector open; if bleeding occurs, the wound suction line first evacuates blood from the sternotomy wound to the CTE, and then the roller pump returns the blood to the patient's arterial system.

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