CN105379707A - Liver normal temperature perfusion restoration system - Google Patents

Abstract

Liver normal temperature perfusion repair system, including the liver container, the liver container includes the main body and the upper cover, both of which can be sealed and tightly closed, a silicone soft net is fixed on the liver container body, and a blood return channel is opened at the lower end of the liver container body, and the blood return channel passes through the blood storage The tank is connected to the centrifugal pump, the front end of the blood storage tank is provided with a filter membrane, the outlet end of the centrifugal pump is connected to the oxygenator, and the oxygenator is connected to the oxygen control device. The hepatic artery was perfused by a roller pump, and the portal vein was perfused directly by the other. In the present invention, the hepatic artery acts as a pulsating blood flow through the roller pump, which well simulates the perfusion characteristics of the liver hepatic artery under physiology, and is more conducive to the protection of bile duct cells during the perfusion. The invention maintains the aerobic metabolism of the liver cells at normal temperature, can repair the liver in a short time, and expand the sources of liver donors.

Description

Liver normal temperature perfusion repair system

technical field

The invention relates to a liver perfusion repair system at normal temperature.

Background technique

Liver transplantation is the only effective way to save end-stage liver disease. As the demand for liver transplantation increases year by year, the shortage of donor livers is also becoming more and more obvious, seriously restricting its development. Marginal donor livers or extended standard donor livers (ECD) are gradually included in the selection range, including fatty liver, advanced age, and cardiac death donors (DCD). With the standardization of the domestic organ donation system, DCD liver transplantation has increased year by year, but the average age of this type of donors is relatively high, and the proportion of hepatic steatosis has also increased accordingly. According to statistics, the detection rate of fatty liver in liver transplant donors is close to 30%, and nearly 50% of discarded donor livers are fatty liver. Moderate-to-severe steatosis in the liver seriously affects the quality of the donor liver and is the most important reason for postoperative primary graft nonfunction (PNF). More than 60% bullous fatty liver is not suitable for liver transplantation. Most of the ECD donors that lead to PNF have normal liver function before operation, so it is speculated that the cold ischemic preservation of the donor liver is the direct cause of the irreversible damage of ECD.

Normal temperature perfusion of the liver is a set of perfusion preservation method that uses the blood to pass through the extracorporeal perfusion system, fully oxygenates, maintains the same temperature as the body temperature, supplies nutrients and energy substances to maintain the survival of the tissue, and circulates the donor liver at a certain pressure and flow rate. Normal temperature perfusion can maintain the aerobic metabolism of liver cells, has the potential of pretreatment before transplantation, can monitor the function of the donor liver in real time, and safely extend the storage time.

As early as the middle of the 20th century, room temperature perfusion emerged. However, due to the large size and high cost of perfusion machines, and the rapid development of cold storage fluids, room temperature perfusion has stagnated for a long time. Until the past 20 years, with the increase in demand for liver donors and the expanded application of ECDs such as fatty liver and DCD, normal temperature perfusion has once again become a hot spot in the field of transplantation due to its outstanding advantages. A number of studies have confirmed that normal temperature perfusion can improve the quality of DCD donor liver and increase the survival rate after transplantation.

The difficulty in establishing the normal temperature perfusion system of the liver is that the liver has two blood flow pathways into the liver, namely the portal vein and the hepatic artery. The portal vein provides 75% of the total blood flow of the liver and 50% of the total oxygen, the normal portal pressure is 5-10mmHg, and the hepatic artery provides 25% of the total blood flow and 50% of the total oxygen. The normal hepatic artery is pulsating blood flow, and the pressure is 90-139 systolic blood pressure/60-89 mmHg diastolic blood pressure. How to maintain the physiological level of portal vein and hepatic artery pressure and flow rate is the key to normothermic perfusion system.

At present, the relatively mature room temperature perfusion system is developed by OrganOx, a company directly under the University of Oxford. It uses the centrifugal pump to maintain the perfusion cycle. The blood returned from the inferior vena cava is pushed to the oxygenator by the centrifugal pump, and then divided into the hepatic artery and the portal vein to perfuse the liver. The blood flow from the portal vein first enters the blood storage bag and then is perfused by gravity. By adjusting the rotational speed of the centrifugal pump, timely clamping the valve at the inlet of the blood storage bag and relying on the height of the blood level in the blood storage bag to adjust the flow and pressure of the portal vein.

The disadvantage of this method is that the pressure and flow of the portal vein, the main blood supply for nourishing the liver, are regulated by the liquid level in the blood storage bag. During the perfusion process, the resistance of the portal vein is greatly affected by the intrahepatic microcirculation. The flow rate and pressure will change in real time, and it is difficult to maintain a stable perfusion cycle by adjusting the centrifugal pump speed and the valve at the inlet of the blood storage bag.

The applicant used the OrganOx solution to carry out tests on the perfusion system at normal temperature for many times. It takes about 30 minutes on average from the connection of the blood vessels of the liver to the stabilization of the circulation. Changes, the operator needs to monitor from time to time, and frequently adjust the centrifugal pump and valves to maintain the liquid level in the vertical perfusion blood storage bag. Once the liquid level is low, the portal pressure will drop, the flow rate will increase, the liquid level will drop further, air will enter the circulation system and the centrifugal pump will stop working, and finally the test will fail.

Contents of the invention

In order to solve the deficiencies of the existing technology, provide a stable and simple liver normal temperature perfusion repair system, simulate the physiological circulation of the liver to the greatest extent, monitor the function of the donor liver in real time, and safely prolong the storage time of the liver before transplantation. The present invention adopts the following technical solutions:

Liver normal temperature perfusion repair system, including the liver container, the liver container includes the main body and the upper cover, both of which can be sealed and tightly closed, a silicone soft net is fixed on the liver container body, and a blood return channel is opened at the lower end of the liver container body, and the blood return channel passes through the blood storage The tank is connected to the centrifugal pump, the front end of the blood storage tank is provided with a filter membrane, the outlet end of the centrifugal pump is connected to the oxygenator, and the oxygenator is connected to the oxygen control device. The hepatic artery is perfused through the roller pump, and the portal vein is perfused directly by the other. Ultrasonic flowmeters are installed on the hepatic artery and portal vein pipelines to record the flow rate. One of the arteries is provided with a blood sample collection channel before entering the roller pump.

The silicone soft net fixed on the liver container body of the present invention plays the role of softly supporting the liver and avoiding deformation of the liver under pressure; the lower end of the liver container body is provided with a blood return channel, which is convenient for collecting a small amount of bleeding around the hilum; the container is transparent The upper cover and the body are tightly connected to avoid temperature loss during the filling process.

The invention adopts the centrifugal pump to provide the total power, and the roller pump provides the hepatic artery pulsed blood flow, so as to quickly and accurately adjust the hepatic artery and portal vein blood flow and pressure. In the present invention, the portal vein, the hepatic artery, and the inferior vena cava leaving the liver are successfully connected until the perfusion is started, and the rotational speed of the centrifugal pump and the roller pump is adjusted until the circulation is stable. The whole operation is completed within 1 minute. Compared with the OrganOx solution, the operation of establishing a circulatory system is simple and stable, and the time is greatly shortened.

The invention can conveniently adjust the perfusion flow rate according to the perfusion pressure, and can adjust the flow rate of the hepatic artery and the portal vein accurately to ±1ml, so as to achieve the flow rate ratio (3:1) of the portal vein and the hepatic artery under the physiological state of the liver. And in the subsequent continuous perfusion process, the operator only needs to properly adjust the speed of the roller pump and the centrifugal pump according to the perfusion pressure change per hour, that is, to adjust the pressure to a physiological level.

In the present invention, the hepatic artery acts as a pulsating blood flow through the roller pump, which well simulates the perfusion characteristics of the liver hepatic artery under physiology, and is more conducive to the protection of bile duct cells during the perfusion.

In the present invention, the blood returned from the hepatic vein is connected to the blood storage tank, and there is a filter device inside the blood storage tank, which can absorb cell fragments, microthrombosis and impurities generated during the perfusion process, effectively ensuring the purity of circulating blood. The setting of the blood storage tank also completely avoids the circulation of air intake. After testing, in the previous 20 cases of human liver perfusion experiments and 16 cases of pig liver perfusion experiments, no circulation air intake caused the centrifugal pump to stop. Drugs, cells and gene therapy can be directly added to the blood storage tank, and the blood storage tank is fully mixed with the circulating fluid to avoid excessive drug dosage caused by the circulating fluid directly entering the liver circulation system.

The infusion pump is connected to the blood storage tank, and provides nutritional energy for the liver through the infusion pump, such as injecting fat emulsion, amino acids, trace elements, multivitamins, and electrolytes; injecting albumin to increase the colloid osmotic pressure of the liver; injecting insulin to control the blood sugar of the liver ; inject alprostadil to improve the microcirculation of the liver; inject ursodeoxycholic acid to promote bile secretion in the liver; inject heparin for anticoagulation, etc. At the same time, the corresponding drugs are injected through the infusion pump, which can also provide repairing mesenchymal stem cells to the liver and perform gene therapy on the liver.

The normal temperature liver perfusion repair system of the present invention maintains the aerobic metabolism of liver cells at normal temperature and provides a better carrier for drug pretreatment. After a short period of repair treatment, it is expected to reverse the marginal liver donor and expand the source of liver donors.

Description of drawings

Fig. 1 is a schematic structural diagram of the normal temperature perfusion system for the liver of OrganOx.

Fig. 2 is a schematic structural diagram of the normal temperature perfusion system for the liver of the present invention.

Figure 3 is the pressure measurement diagram of the hepatic artery (HA) and portal vein (PV) during the experiment.

Figure 4 is a flow measurement map of the hepatic artery (HA) and portal vein (PV) during the experiment.

Figure 5 is a graph showing the osmotic pressure and partial pressure of oxygen in the circulating fluid during the experiment.

Fig. 6 is a measurement chart of pH value during the experiment.

Fig. 7 is a measurement chart of urea nitrogen, bile and blood sugar during the experiment.

Fig. 8 is a measurement diagram of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) during the experiment.

Marked in the picture: 1 liver, 2 bile, 3 centrifugal pump, 4 liver dynamic and static flow pressure detector, 5 heat exchanger, 6 oxygen control device, 7 oxygenator, 8 blood transfusion bag, 9 infusion pump, 10 portal vein flow pressure Detector, 11 blood storage tank, 12 roller pump, 31 hepatic artery pressure broken line, 32 portal vein pressure broken line, 41 hepatic artery flow broken line, 42 portal vein flow broken line, 51 osmotic pressure broken line, 52 oxygen partial pressure broken line, 61 is PH broken line , 71 urea nitrogen measurement broken line, 72 bile measurement broken line, 73 blood sugar measurement broken line, 81 alanine aminotransferase (ALT) measured broken line, 82 aspartate aminotransferase (AST) measured broken line.

detailed description

Referring to the attached figure, put the donor liver 1 on the silicone soft net, fix the silicone soft net on the edge of the liver container body, ligate the superior and inferior hepatic vena cava, and insert the inferior hepatic vena cava so that blood from the hepatic vein can flow smoothly into the vena cava. directly into the blood storage tank 11, and a small amount of hepatic porta oozing blood flows into the blood storage tank through the blood return channel at the lower end of the liver container. The blood storage tank is equipped with a filter membrane to filter impurities such as cell debris and microthrombi in the blood. The infusion pump 9 is connected with the blood storage tank to provide nutrition and drug cell therapy for the hepatic circulation. The blood storage tank is connected with the centrifugal pump 3, and the centrifugal pump is responsible for the total hemodynamic output. The blood output by the centrifugal pump is transported to the oxygenator 7 by the action of the centrifugal pump, the oxygenator is connected to the oxygen control device 6, and the oxygen control device is connected to the air pump and the pure oxygen cylinder to give the circulation the most suitable air oxygen ratio for physiology. Hemoglobin promptly carries oxygen, and heat exchanger 5 adjusts the blood temperature after oxygenation to 37 degrees of human physiological temperature. Then the blood flow is divided into two, one path perfuses the hepatic artery through the roller pump 12, and the other path directly perfuses the portal vein, in which the roller pump gives the liver pulsating blood flow, and the rotational speed of the roller pump can be adjusted to change the flow rate of the hepatic artery . The flow displayed at the outlet of the centrifugal pump is the total flow. Both the hepatic artery and the portal vein are equipped with ultrasonic flowmeters 4 and 10 for recording the blood flow. At the same time, a pressure sensor is installed to measure the pressure of the hepatic artery and portal vein. The temperature detection probe is connected to the oxygen. The temperature interface of the combiner is used to adjust the temperature of the heat exchanger to regulate the blood temperature. There is a blood sample collection channel before the hepatic artery enters the roller pump.

On September 17, 2015, a liver was donated from a deceased donor. The donor is male, 178cm in height, 82Kg in weight, and has no history of vasopressor use or cardiopulmonary resuscitation during hospitalization. During the process of obtaining the liver, the warm ischemia time of the liver was 17 minutes, and the cold ischemia time was 8 hours and 24 minutes. The weight of the donated liver was 2200g, and the preoperative pathological results of the donated liver indicated that the liver had severe fatty liver with 50% bullous degeneration. Because the quality of the liver was lower than the use standard, no transplant operation was performed. After obtaining the consent of the donor's family members, the liver was subjected to normal temperature perfusion experiment of human liver.

The experimental system is the liver normal temperature perfusion repair system of the present invention, and the perfusion fluid is 600ml+500ml Wanwen+1000ml Ringer's solution of allogeneic O-erythrocytes. See Table 1 for drug support. After the system was debugged and stabilized, the perfusion started at 0:35 on September 18, 2015. After the start, the perfusion fluid was drawn every 1 hour, and the temperature, blood gas, electrolyte, blood sugar, metabolic waste, liver function, and osmotic pressure were detected, and the flow and pressure values of the hepatic artery and portal vein were recorded. The experiment ended at the 6th hour (6:35 on September 18, 2015), and the system operated stably during the experiment.

During the experiment, the liver temperature, blood gas, and vascular flow pressure were within the physiological range; bile secretion continued to exist, blood sugar and pH remained stable, and the transaminase value was consistent with the level after opening the blood flow of the fat donor liver after liver transplantation.

As shown in Figure 3, the measured pressure maps of the hepatic artery (HA) and portal vein (PV) during the experiment showed that the pressure of the blood vessels entering the liver was at a basically stable physiological level during the experiment.

As shown in Figure 4, the measured flow diagrams of the hepatic artery (HA) and portal vein (PV) during the experiment showed that the blood flow into the hepatic vessels fluctuated within the normal physiological range during the experiment.

As shown in Figure 5, the actual measurement chart of the osmotic pressure and oxygen partial pressure of the circulating fluid during the experiment shows that during the experiment, the perfusate was controlled within the upper limit of the physiological level; Biological side effects caused by excessive oxygen partial pressure produced by pure oxygen.

As shown in Figure 6, the actual measurement graph of the pH value during the experiment. After the experiment started, the acidosis of the perfusion fluid was obvious. Sodium bicarbonate was given to correct the acidosis, and oxygen was given to improve the aerobic metabolism of the liver tissue. The pH value gradually approached and remained at the normal physiological level.

As shown in Figure 7, the measured graphs of urea nitrogen, bile and blood sugar during the experiment. During the experiment, the blood sugar level gradually decreased, indicating the existence of liver glycogen conversion function; the amount of bile gradually increased, reflecting the existence of liver synthesis and secretion function; the gradual accumulation of urea nitrogen indicated the existence of liver metabolism function. This figure reflects that during the experiment, the liver retained its important biochemical functions in the human body and maintained them at a more ideal level.

As shown in Figure 8, the measured graphs of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) during the experiment. During the experiment, the levels of ALT and AST remained stable, reflecting that after the ischemia-reperfusion injury of liver cells, there was no obvious secondary necrosis under the condition of artificial perfusion, and the function and shape of liver cells remained normal.

According to the test of this example, during the 6-hour normal temperature perfusion period of the isolated liver, there was no large amount of secondary necrosis of the liver cells, the synthetic and metabolic functions of the liver remained good, the overall in vitro survival status was good, and the function began to recover.

Claims (1)

1. liver normal temperature perfusion repair system, is characterized in that:

Comprise liver container, liver container comprises body and upper cover, both can seal and cover tightly, liver vessel is fixed with the soft net of silica gel, liver vessel lower end offers blood back passage, blood back passage is connected with centrifugal pump through storage blood tank, storage blood tank front end is provided with filter membrane, the port of export of centrifugal pump is connected with oxygenator, oxygenator connects control oxygen device, the transducer potector of oxygenator is divided into two-way through heat exchanger, arteria hepatica is poured into through roller pump in one tunnel, portal vein is directly poured in another road, arteria hepatica, portal vein pipeline is provided with ultrasonic flowmeter in order to record flow, two-way is connected to pressure sensor for measuring arteria hepatica and portal venous pressure before entering liver, enter a hepatic arterial road before entering roller pump, be provided with blood sample collection passage.