Experimental Studies for Application of the Fixed Lung as an Oxygenator

为研制一种耐久性好、抗原性低的动物肺人工肺，进行了以下几方面的研究：1.机械去氧肺灌注系统对固定肺气体交换能力的评价：研制了一种去氧血持续灌注肺保存装置。用4%多聚甲醛和0.325%戊二醛混合液固定兔肺，用该系统测定其气体交换能力。5个肺中有2个能够在5小时评估期间进行评价。D-PO_2（流入和流出的血液之差）在5 h时分别为28和40 μ mol/L（FiO_2 = 0.21）。2.用在体灌注模型评价固定肺的气体交换能力：将犬左全肺用相同的固定剂原位固定。分别在双肺通气（I组）和左单肺通气（II组）下评价气体交换能力。Ⅰ组（n=3）分别于2、3、4 h处死。第一次评估时（FiO 2 =1.0）D-PO 2（动、静脉血差值）分别为190、212和321 mmHg。Ⅱ组（n=3）3只犬中有2只在右肺结扎后即刻死亡，1只存活2小时。D-PO_2首次测定值为158 ℃。这些结果表明，如果在适当的条件下固定，切除的肺保持与新鲜肺相当的气体交换能力，但很难将固定剂从肺中完全冲洗出来。期望改进用于固定肺的方法，并且为此目的，需要完全地改进。期望改进用于固定肺的方法，并且为此目的，需要开发不会留下甚至痕量的固定剂的技术或用于物理固定的技术。

The following studies were carried out for the purpose of developing an artificial lung from animal lung which has more durability and less antigenicity.1.Evaluation of gas exchange ability of fixed lung using a perfusion system with mechanical deoxygenator : An apparatus to preserve the resected lung by continuous perfusion with deoxygenated blood was developed. Free rabbit lungs which were fixed by the mixture of paraformaldehyde and glutaraldehyde (4% paraform-aldehyde+0.325% glutaraldehyde) were evaluated its gas exchange ability using this system. Two of 5 lungs were able to evaluate during 5 hour assessment period. D-PO2 (the difference of in-and out-flowing blood) were 28 and 40 torr at 5 hour of assessment (FiO2=O.21).2.Evaluation of gas exchange ability of fixed lung using an in vivo perfusion model : The left whole lung of canine was fixed by the same fixative in site. Gas exchange ability was evaluated under bilateral ventilation (Group I) and left single lungventilation (Group II). In Group I (n=3), all dogs were died at 2,3 and 4 hours of assessmsnt respectively. D-PO2 (the difference of arterial and venous blood) were 190,212 and 321 torr at the first assessment (FiO2=1.0). While, in Group II (n=3), 2 of 3 dogs were died just after ligation of right lung, and only one dog could be alive for 2 hour. D-PO2 at the first assessment was 158 torr.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, but it is very difficult to flush out fixative from lung completely. Improvements in the method for fixation of the lung are desired, and, for this purpose, the completely. 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.