The thromboresistant mechanism of Heparin surface and its application to membrane oxygenator

与瑞典卡罗林斯卡研究所合作开展了肝素表面抗血栓机制及其在膜氧合器上的应用研究。我们得到的结果如下：1。肝素包被本身不占用或发挥Xa因子抑制作用。当抗凝血酶III（AT）吸附在高亲和力和低亲和力的肝素上时，表面具有抑制暴露在表面的Xa因子的能力。结果表明，在高亲和力和低亲和力的肝素上AT的密度决定了Xa因子的抑制能力，而在高亲和力位点上AT的数量限制了反应的速度。通过压缩一段表面肝素化的动静脉分流获得的低壁剪切率段，Xa因子和凝血酶抑制能力相似。在高壁剪切速率段，凝血酶抑制能力下降，表明at介导的丝氨酸蛋白酶抑制依赖于壁剪切速率。研究表明，在狗的体外动静脉旁路循环中，表面肝素化的膜氧合器可以在不进行任何全身肝素化的情况下进行至少24小时。在相同的实验条件下，也可以进行体外静脉-静脉旁路循环。因此，我们认为表面肝素化体外循环膜氧合器是一种有效的呼吸支持系统，也适用于呼吸困难患者的围手术期呼吸支持。在气管切除重建的案例中，我们为呼吸支持准备了该系统，但由于没有必要使用该系统，我们将其保持备用状态。

We have conducted research work on the thromboresistant mechanism of Heparin surface and its application to membrane oxygenator in collaboration with the Karolinska Institute in Sweden. The results we have obtained are as follows;1. The heparin coating did not take up or exert Factor Xa inhibition by itself. With antithrombin III(AT) adsorbed on both high and low affinity heparin the surface had the capacity to inhibit Factor Xa exposed to the surface. It was demonstrated that the density of AT on both high and low affinity heparin determines the Factor Xa inhibition capacity whereas the amount of AT on high affinity sites limits the rate of the reaction.2. The Factor Xa and thrombin inhibitory capacity were similar in low wall shear rate segments which were obtained by compressing a segment of the surface-heparinized arterio-venous shunts. In high wall shear rate segments, the thrombin inhibitory capacity was decreased, thus indicating that the AT-mediated inhibition of the serine protease is dependent upon the wall shear rate.3. It was demonstrated that an extracorporeal arterio-venous bypass circulation with surface-heparinized membrane oxygenator can be performed for at least 24 hours without any systemic heparinization in dogs.4. It was confirmed that an extracorporeal veno-venous bypass circulation call be done as well under the same experimental conditions as above.5. Consequently we have concluded that the surface-heparinized extracorporeal circuit with membrane oxygenator is an effective and useful system for tile respiratory support in the treatment of the patients with respiratory failure and this system is also applicable for the perioperative patients with difficult airways.6. In the case of the tracheal resection and reconstruction we prepared this system for the respiratory support, but as it was unnecessary to use the system we kept it standby.