CN105194749B - A kind of double pulsating flow pouring methods of the batch (-type) for reducing deposition of foreign material vascular wall - Google Patents

Abstract

An intermittent double-pulse flow perfusion method for reducing foreign matter deposition on the blood vessel wall, combining pulsation and constant flow, entering the blood vessel in a periodic flow state for perfusion, comprising the following steps: (1), measuring the weight of the foreign matter in the blood vessel; (2) Determine the surface pressure required to impact the foreign body according to the obtained weight of the foreign body, and then obtain the perfusion speed; (3) Introduce intermittent double pulsation flow into the blood vessel, and observe the vascular dynamics generated during the attention process through medical means Medical phenomena, and determine the angiodynamic parameters for evaluating the quality of vascular perfusion based on medical data. Finally, according to the comparison of two kinds of angiodynamic parameters, the perfusion quality of vascular perfusion with intermittent pulsating flow is analyzed to ensure the stability of perfused vessels, and at the same time, the situation of foreign matter deposition on the vascular wall is well improved, effectively improving the cleanliness of the vascular wall.

Description

An intermittent double-pulse flow perfusion method for reducing foreign matter deposition on the vessel wall

technical field

The invention relates to an intermittent dual-pulse flow perfusion method for reducing foreign matter deposition on the blood vessel wall, specifically a method for combining pulse flow and constant flow and performing blood vessel perfusion in a periodic blood flow state.

Background technique

The mortality rate induced by liver disease is very high in both developed and underdeveloped areas at home and abroad. Liver transplantation is currently the only effective means of treating end-stage liver disease. The quality of the liver donor is one of the key links affecting the success rate of liver transplantation. Cleaning (perfusion) of the liver donor before operation is a necessary medical procedure. Therefore, the quality of vascular perfusion directly affects the success of the operation. Many scholars at home and abroad have studied the process of vascular perfusion, analyzed the different phenomena and final effects of different vascular perfusion methods, in order to find a better vascular perfusion method to achieve the purpose of cleaning the blood. So far, there are not many research results on vascular perfusion before liver transplantation at home and abroad. These studies mainly revolve around modeling blood vessels, deriving their mathematical models, and performing corresponding mechanical analysis on this basis. With the aid of medical imaging, it is expected that blood cleaning can be more thorough, reducing the influence of subjective factors in the process of liver donor perfusion on the cleaning quality, and used to guide medical research and prepare for medical operations (such as intestinal tract before anorectal surgery). cleaning, organ cleaning before organ transplantation, etc.) to provide theoretical support. For vascular perfusion, constant flow perfusion is mainly used, and some swirl perfusion is also used. Constant flow perfusion is easy to operate, but due to the stability of constant flow, its scouring force on the tube wall is very small, resulting in a poor cleaning effect on the liver donor; the subsequent swirl perfusion, on the one hand, stabilizes the blood flow , to reduce turbulence; on the other hand, it can make the blood vessel wall smooth and wash away, and reduce the deposition of harmful substances in the blood (such as lipids, etc.) on the blood vessel wall. And in recent years, someone has begun to apply this swirling flow principle to clinical medicine. This method is good, but it is very difficult to operate, and the cost consumption is relatively high.

Contents of the invention

In order to solve the above problems, the present invention proposes an intermittent double-pulse flow perfusion method to reduce foreign matter deposition on the blood vessel wall. On the one hand, the pulsating flow state can give an external force to the foreign matter adhering to the blood vessel wall; on the other hand, the constant flow state can scour the blood vessel wall well under the action of inertial force, so as to ensure the slight deformation of the blood vessel and achieve the reduction of foreign matter For the purpose of deposition in the vessel wall.

The technical solution adopted by the present invention to solve its technical problems comprises the steps:

An intermittent double-pulse flow perfusion method to reduce foreign matter deposition on the vessel wall is to combine pulsation and constant flow, and enter the blood vessel in a periodic flow state for perfusion, including the following steps:

1. Measure the weight of the foreign body in the blood vessel;

2. Determine the surface pressure required to impact the foreign matter according to the weight of the obtained foreign matter, and then obtain the perfusion speed;

3. Introduce intermittent double-pulse flow into the blood vessel, observe the angiodynamic phenomenon generated during the attention process through medical means, and determine the angiodynamic parameters for evaluating the quality of vascular perfusion according to medical data.

Further, the perfusion velocity obtained above is the flow velocity required for constant-flow perfusion, and the inlet velocity is constant v=0.273 [m/s] during constant-flow vessel perfusion.

Further, when the above-mentioned intermittent double-pulse flow vessel perfusion is used, the inlet velocity needs to be equivalent to a sinusoidal function according to the constant flow perfusion velocity:

v=if(t>=2[s],0.28[m/s]sin(2×pi×t/1[s])+0.28[m/s],0.28[m/s])

This formula shows that the initial flow velocity at the inlet is 0.28 [m/s].

Further, the above-mentioned angiodynamic parameters include perfusion flow rate, shear force, and vascular deformation.

The technical effect of the present invention is: it can improve the quality of vascular perfusion in the liver transplantation process, and at the same time provide more scientific theoretical guidance for clinical medicine. The method combines the pulsating flow state and the constant flow state, not only can reduce blood turbulence, but also can It is very good at scouring the blood vessel wall, easy to operate, and has an ideal effect on cleaning foreign matter deposits in the blood vessel wall.

Description of drawings

Figure 1 is a schematic diagram of a first-level blood vessel model, and the raised part in the middle is a foreign body adhered to the blood vessel wall;

Figure 2 is a schematic diagram of the inlet velocity during intermittent double-pulse flow perfusion;

Fig. 3 is a schematic diagram of blood flow velocity in blood vessels during constant flow perfusion;

Fig. 4 is a schematic diagram of intravascular blood flow velocity during intermittent double-pulse flow perfusion;

Figure 5 is a schematic diagram of the shear force on the vessel wall during constant flow perfusion;

Figure 6 is a schematic diagram of the shear force on the vessel wall during intermittent double-pulse flow perfusion

7 is a schematic diagram of the overall deformation of blood vessels during constant flow perfusion;

Figure 8 is a schematic diagram of the overall deformation of blood vessels during intermittent double-pulse flow perfusion

detailed description

In order to make the content of the present invention more easily understood, the present invention will be described in further detail below in conjunction with the accompanying drawings according to specific embodiments of the present invention. Formally, that is, through the finite element analysis software to carry out the first-level vascular perfusion simulation.

The overall idea of the invention to solve its technology is:

(1) Before liver transplantation, during the cleaning (perfusion) process of the liver donor, the weight of the foreign body in the blood vessel is first measured; secondly, the surface pressure required to impact the foreign body is determined according to the obtained foreign body weight, and then the perfusion rate is obtained ;Finally, intermittent double-pulse flow is introduced into the blood vessel, and the angiodynamic phenomenon generated during the attention process is observed by medical means, and the angiodynamic parameters for evaluating the quality of vascular perfusion are determined according to medical data, indicating that the intermittent double-pulse flow can achieve vascular Infusion purpose. (2) The perfusion physical parameters such as the foreign body weight can be measured and calculated by medical means. (3) The perfusion velocity is the impact velocity required for constant flow perfusion calculated according to the calculation, which needs to be further equivalent to the perfusion velocity of intermittent double pulsation flow, and the specific perfusion cycle needs to be determined according to the weight of the foreign matter.

The specific embodiment of the intermittent double-pulse flow blood vessel perfusion method of the present invention is provided below, including the following steps:

(1) Firstly, three-dimensional software is used for first-level vessel modeling, as shown in Figure 1. The middle protrusion is a foreign body adhered to the vessel wall. Then import the vascular geometric model into the finite element analysis software for simulation. Two methods are used in the simulation process. The first step is to perfuse blood vessels with constant flow. Through the simulation, the angiodynamic parameters of constant flow perfusion will be obtained, and the perfusion quality will be evaluated to form a comparison item. The second step applies intermittent double pulsatile flow for vascular perfusion. Likewise, the same angiodynamic parameters as constant flow perfusion, such as blood flow rate, shear force, etc., will be obtained through simulation. Finally, according to the comparison of angiodynamic parameters between the two groups, as shown in Figure 3-Figure 8, the perfusion quality of the intermittent double-pulse flow for blood vessel perfusion was analyzed and evaluated.

(2) The geometric model of the blood vessel is provided by medical imaging (CT, or MRI) data, and the fluid is set as an incompressible non-Newtonian fluid. Existing medical images cannot distinguish between blood flow and blood vessels, and the thickness of the blood vessel wall is uniformly set to 2mm in the reverse engineering software.

(3) The flow direction of the perfusate in the schematic diagram is from left to right, and the weight of the foreign body in the primary blood vessel is 0.03 g.

(4) When the constant flow is used for blood vessel perfusion, the inlet velocity is 0.273 [m/s].

(5) The expression of the inlet velocity when using the intermittent double-pulse flow vessel perfusion is: v=if(t>=2[s],0.28[m/s]sin(2×pi×t/1[s] )+0.28[m/s],0.28[m/s])

This formula shows that the initial flow velocity at the inlet is 0.28 [m/s], the time period t = 4 [s], and the schematic diagram of the inlet velocity is shown in Figure 2. This expression is determined according to the relationship between the effective value of speed and the maximum value of speed, where the effective value of speed is 0.273[m/s] and the maximum value is 0.28[m/s]. And the velocity expression is given in the form of sine function, so that the inlet velocity curve of the intermittent double-pulsating flow is a pulsating flow.

Figure 3 and Figure 4 show the distribution of blood flow velocity in blood vessels in the process of adopting constant current perfusion and intermittent double-pulse flow vascular perfusion respectively. By comparing the results in the two figures, it can be clearly seen that using the intermittent double-pulse flow proposed by the present invention After the flow perfusion method, the flow rate of the blood in the blood vessel is significantly increased, which is more conducive to taking away the foreign matter adhering to the blood vessel wall and achieving the purpose of depositing foreign matter on the blood vessel wall.

Adopt the wall shear force distribution of constant flow perfusion and pulsation-constant flow perfusion, as shown in Figure 5 and Figure 6, compare the shear force distribution of these two kinds of methods, it can be known that adopting the intermittent double pulsating flow perfusion method proposed by the present invention can obviously Increase the shear stress of the wall surface, give the foreign matter a greater impact force, and achieve the purpose of reducing the deposition of foreign matter and scouring the pipe wall.

During the perfusion process, blood vessels will be deformed, as shown in Figure 7 and Figure 8, respectively showing the deformation of blood vessels caused by constant flow perfusion and intermittent double pulse flow perfusion. Through comparison, it can be seen that the intermittent double-pulse flow perfusion method proposed by the present invention has the same deformation of blood vessels as that produced by constant flow perfusion, which ensures the stability of perfused blood vessels.

It should be noted that this invention is a perfusion method aimed at the deposition of foreign matter in the liver blood vessel wall. Its purpose is to improve the quality of blood vessel perfusion during liver transplantation, and at the same time provide more scientific theoretical guidance for clinical medicine, but it is not a treatment for diseases. Target and treat. The content of liver transplantation and treatment described in the background art is only for understanding the background of the present invention. In addition, the present invention is simple to operate, low in cost, and has an ideal foreign matter removal effect. Therefore, the present invention is not limited to the embodiments herein. Those skilled in the art should make obvious improvements and modifications to the present invention based on the disclosure of the present invention. within the protection scope of the present invention.

Claims (4)

1. An intermittent double-pulse flow perfusion method for reducing foreign matter deposition on the vessel wall, characterized in that: it is carried out in the form of computer simulation, that is, a first-level blood vessel perfusion simulation is performed through finite element analysis software, and pulsation and constant flow are combined , entering the blood vessel in a periodic flow state for perfusion, including the following steps: (1) Measure the weight of the foreign body in the blood vessel; (2) Determine the surface pressure required to impact the foreign matter according to the weight of the obtained foreign matter, and then obtain the perfusion speed; (3) Introduce intermittent double-pulse flow into the blood vessel, observe the angiodynamic phenomenon during the attention process through medical means, and determine the angiodynamic parameters for evaluating the quality of vascular perfusion according to medical data. 2. The intermittent dual-pulse flow perfusion method for reducing foreign matter deposition on the vessel wall according to claim 1, characterized in that: the obtained perfusion velocity is the required flow rate for constant-flow perfusion, and the inlet velocity during constant-flow vessel perfusion is The constant v=0.273m/s. 3. The intermittent double-pulse flow perfusion method for reducing foreign matter deposition on the vessel wall according to claim 1, characterized in that: when the intermittent double-pulse flow blood vessel perfusion is used, the inlet velocity needs to be equivalent to a sinusoidal function according to the constant flow perfusion velocity : v=if(t>=2s, 0.28m/s×sin(2×pi×t/[1s])+0.28m/s, 0.28m/s), This formula shows that the initial flow velocity at the inlet is v=0.28m/s. 4. The intermittent dual-pulse flow perfusion method for reducing foreign matter deposition on the vessel wall according to claim 1, characterized in that: said angiodynamic parameters include perfusion flow rate, shear force, and vascular deformation.