| Background: Recently, the research about the ischemical reperfusion injury ,which has already become a serious complication to surgery,especially to our cardiac surgery, is getting more and more. The ischemical reperfusion injury is refers to on the foundation of ischemia, restoring the tissue perfusion can result in more severe injury than that of continous ischemia, even the irreversible damage. Ischemia can lead to a series of changes in the organization, such as hypoxia, acidosis, lack of energy, so as to cause organ damage. All organs can be tolerated a certain degree of ischemia, such as cerebral ischemic tolerance in general for 30 minutes, the heart for about 1 hour. It is expected to resume their functions if organs can be restored blood perfusion during the ischemic tolerance time. Beyond that Time, it will enter the irreversibility damage time and reperfusion will aggravate tissue damage. Almost all organs of the human body can occur ischemia-reperfusion (I / R), such as heart, liver and kidneys. Reperfusion injury occurred or not and the severity depends on the ischemic time, the degree of ischemia, ischemic organizations oxygen demand, as well as the degree of reperfusion conditions and so on. Its mechanism is that ,in the period of ischemia, ischemia and hypoxia led toâ‘ the reduction of ATP synthesis;â‘¡the augmentation of decomposition product of the metabolism, in particular the purine base and acid metabolite in cell number. On this basis, oxygen free radicals, which is produced due to restoration of perfusion and calcium overload and the inflammatory response will lead to reperfusion injury.The beginning of the 1950s, the femoral artery cannulation was started to be used in cardiopulmonary bypass, and femoral artery was considered the best choice for cannulation during the operation of type A aortic dissection. The incidence of aortic aneurysm and aortic dissection is increasing gradually in recent years, the currently main method to cure aortic aneurysm is operation. In the surgical treatment, because of dissection involving ascending aortic or the left heart bypass that is needed, so the femoral artery cannulation has always been used as a common practice. However, due to blockage of the distal femoral artery by catheterization, it can cause severe lower limb ischemia. There is a big challenge to aneurysm surgery is how to reduce complications and improve the quality of life .The traditional femoral cannulation results in complete occlusion of the femoral artery around the cannula, thus eliminating antegrade flow into the distal femoral artery and possibly resulting in lower extremity ischemia. In order to provide antegrade blood flow and minimize the incidence of ischemia in the cannulated lower limb, various improved methods have been reported to put into use. Now several technologies which was extensively used in the world will be introduced as follows: 1) After cardiopulmonary support is established, a standard 8.5F Arrow-Flex cordis catheter is placed into the superficial femoral artery. The cordis catheter's point of insertion is distal to that of the cardiopulmonary support arterial line. This can be accomplished via the percutaneous Seldinger technique or via direct cannulation if the artery already has been exposed for placement of the cardiopulmonary support catheter. The cordis catheter is directed distally into the superficial femoral artery and connected to the side port of the cardiopulmonary support artery line. 2) The femoral artery catheter is inserted from the superficial femoral artery and the end of catheter is just arriving at the bifurcation of superficial femoral artery and deep femoral artery. This ways can provide the antegrade blood flow to deep femoral artery so as to avoid total ischemia of hind limb. 3) After systemic heparinization, occluded the femoral artery both proximally and distally. Suture to a longitudinal arteriotomy a segment of a 10-mm standard polytetrafluoroethylene(PTEE) graft in an end-to-side fashion with a 5-0 polypropylene suture. Release the femoral arterial occlusion, and place a clamp on the graft. After bleeding has been controlled, cannulate the graft with a 24F femoral cannula. The bulb on the cannula should fit snugly in the graft. Connect the cannula to the standard arterial inflow tuding from the arterial pump head.With the further understanding of ischemia-reperfusion injury, we are very concerned about the lower limb damage of hypoperfusion due to femoral artery cannulation in the aneurysm surgery. But until now there is no research about the effects of lower limb perfusion on using the different improved methods. The purpose of the experiment is to compare the several femoral artery cannulations which is widely used in the world and assess the degree of ischemia-reperfusion injury in lower extremity in order to find out the best way of femoral artery cannulations.Purpose: To simulation femoral artery cannulation in aneurysm surgery, there are divided into four groups according to the different ways of cannulation. After a certain period of nonpulsatile flow reperfusion, we can assess the degree of ischemia-reperfusion damage by comparing biochemical data of blood samples. In addition, we can also observe the cell shape of gastrocnemius muscle by H-E staining. From those results, we can evaluate the effect of different femoral artery cannulations to the cannulated lower limb perfusion.Methods: 16 healthy adult male rabbits were divided into 4 groups, according to the different methods of femoral artery cannulation. Group A: The traditional cannulation group (there are no antegrade arterial perfusion on the distal of cannula, so the cannulated hind limb will continuously be in state of totally ischemia). Group B: Selective deep femoral artery perfusion group (It can provide the continuous perfusion flow for deep femoral artery during the period of cannulation). Group C: Selective superficial femoral artery perfusion group(It can provide the continuous perfusion flow for superficial femoral artery during the period of cannulation). Group D: Graft group (It can provide the continuous perfusion flow for both superficial femoral artery and deep femoral artery during the period of cannulation). Animals were provided by Laboratory Animal Center of Kyushu University, Japan. Sixteen Japanese white rabbits weighting from 3.0 to 3.5 kg were used. The animal were anesthetized initially with ketamine and selactar. A tracheotomy was performed and the trachea was intubated with a 3.5 endotracheal tube. A 3Fr catheter was introduced via the right carotid artery and positioned in the aortic arch for monitoring the aortic pressure and blood sampling. The pressure monitoring catheter was connected to a Analog-to-digital converter (MacLab System, AD Instrument, Ltd, Dunedin North, NZ). A median sternotomy was performed and exposed the left atrium, then a median peritoneotomy was performed and freed the abdominal aorta from the distal of inferior mesenteric artery to the bifurcation of left and right iliac artery where all the branches were ligated. Each animal received heparin sodium(1000U/kg) to maintain the activated clotting time above 400s during this protocol. An inflow cannula (20Fr) was inserted into the left atrium. After the abdominal aorta was blocked under the inferior mesenteric artery, an outflow cannula was inserted into the distal of abdominal arota till the bifurcation of left and right iliac artery. Both the inflow and outflow cannulas were connected to TinyPump (Department of Artificial Organs, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan). The superficial and deep femoral artery of one side were segregated clearly and arteries were ligated for 1hour according to the different groups. Group A: The traditional cannulation group (both superficial and deep femoral arteries were ligated). Group B: Selective deep femoral artery perfusion group (only superficial femoral artery was ligated). Group C: Selective superficial femoral artery perfusion group (only deep femoral artery was ligated). Group D: The graft group (both superficial and deep femoral artery were not ligated). We set the Group D as the control group. The femoral artery ligation time was set on 1 hour and reperfusion time was 3hours. Arterial blood samples from carotid artery were collected for blood gas analysis and blood routine examination, and those from cannulated limb's femoral veins were collected for blood gas analysis and biochemical analysis. The time point of getting blood samples was before the cannulation(0H) and on 1H, 2H, 3H, 4H after the femoral artery was ligated. At the end of the experiment, we gather tissue sample from gastrocnemius of the cannulated leg for H-E staining in order to observe the muscle cell shape of ischemia lower limb. From the results above, we can estimate the degree of ischemia-reperfusion injury and evaluate the effects of different cannulation methods.Results: Until 1 hour after the femoral artery ligation, lower limb of A group appeared a serious situation of acidosis and lactic acid, creatine phosphokinase (CPK), lactate dehydrogenase (LDH) levels in plasma also increased to varying degrees. With the restoration of blood flow reperfusion for 3 hours, there was no obvious improvement of the acidosis in cannulated lower limb and a variety of enzymes levels in plasma remained high degree and even increased than before. But under the same condition, C and D groups have not presented the acidosis in the whole experiment process, whereas B group would present transient metabolic acidosis after 1hour of superficial femoral artery ligation and return to the normal levels quickly after 1hour of reperfusion. Enzyme in plasma of B, C, D group were maintained at normal levels, no significant increasing. H-E staining results of experimental limb's gastrocnemius indicated: In A group, muscle tissue subjected to regional ischemia demonstrates a marked infiltration of cell nuclei, as compared with B,C,D group, in which have not seen any obvious infiltration of cell nuclei.Conclusions: Comparing with the traditional femoral artery cannulation, many improvement ways could provide antegrade perfusion for lower limb in surgical procedures in order to avoid a serious ischemia-reperfusion injury. It would greatly reduce the complications accompanied with femoral artery cannulation.
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