Experimental Sutdies for Application of the Heterogeneous Lung as Oxygenator

下面的研究是为了开发一种天然呼吸机，它保留了活体肺的优点，更耐用，没有抗原性。1.切除游离肺功能评价仪的研制：研制了一种氧合血灌注间歇静脉血灌注保存切除肺的仪器，并在不同时间点同时评价气道阻力、肺动脉压和气体交换能力。2.保存肺功能评价：用上述仪器连续监测保存的切除肺的气体交换能力，并评价最佳保存条件。单纯浸泡保存的兔肺功能在48小时内保持良好，但在72小时后功能明显下降。3.固定肺的气体交换能力：评价最大限度保存肺功能的固定方法。在10%福尔马林、0.625%戊二醛、4%多聚甲醛+ 0.25%戊二醛的混合物中，多聚甲醛和戊二醛的混合物效果最好，其气体交换能力与新鲜肺相当。4.具有异质血液和气体交换能力的灌注：考察天然肺是否可以作为跨物种的充氧器。切除的狗肺对兔血有足够的气体交换能力。5.肺的影像学研究：作为异质肺移植物发展的基础步骤，肺功能的MRI研究。根据磁共振图像评估肺中水的动力学，这决定了肺的气体交换能力。在保存的兔肺中计算的各项参数值随湿/干重比的变化而变化，湿/干重比是肺含水量的指标。这些结果表明，切除的肺在适当条件下固定后仍保持与新鲜肺相当的气体交换能力，异质肺显示出气体交换能力，肺的气体交换能力因水肿变化引起的气血屏障增厚而降低，MRI对这些变化的无创检测是有用的。需要改进肺部固定方法，为此，需要开发不留下任何固定物的技术或物理固定技术。少

The following studies were carried out for the purpose of developing a natural ventilator which retains the merits of the in vivo lung,is more durable,and has no antigenicity. 1.The development of an apparatus for functional evaluation of the resected free lung: An apparatus to preserve the resected lung by perfusion with oxygenated blood with intermittent perfusion with venous blood was developed,and airway resistance,pulmonary artery pressure,and gas exchange ability were evaluated simultaneously at various time points. 2.functional evaluation of the preserved lung: The gas exchange ability of the preserved resected lung was serially monitored with the above apparatus,and optimal conditions of preservation were evaluated. The function of the rabbit lung preserved by simple immersion was well maintained for 48 hours but was significantly reduced after 72 hours. 3.Gas exchange ability of the fixed lung: The fixation method for maximum preservation of the lung function was evaluated. Am … More ong 10% formalin,0.625% glutaraldehyde,4% paraformaldehyde + 0.325% glutaraldehyde,the mixture of paraformaldehyde and glutaraldehyde was the best and showed a gas exchange ability comparable to the fresh lung. 4.Perfusion with heterogeneous blood and gas exchange ability: Whether the natural lung can be used as an oxygenator across the species was examined. The resected dog lung showed sufficient gas exchange ability for rabbit blood. 5.Imaging studies of the lung by ^1H-MRI: As a basic step for the development of a heterogeneous lung graft,the lung function was studied by MRI. The dynamics of the water in the lung,which determines its gas exchange ability,was evaluated according to MR images. The values of various parameters calculated in the preserved rabbit lung changed with the wet/dry weight ratio,which is an index of the water content of the lung.These findings suggest that the resected lung retains gas exchange ability comparable to that of the fresh lung if it has been fixed under appropriate conditions,that heterogeneous lungs show a gas exchange ability,that the gas exchange ability of the lung is reduced by thickening of the air-blood barrier due to edematous changes,and that MRI is useful for noninvasive detection of these changes. Improvements in the method for fixation of the lung are desired,and,for this purpose,the development of techniques that do not leave even a trace amount of the fixative or techniques for physical fixation is needed. Less