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Study of bubbles formation in organic tissue subjected to pressure variation environments and bubble embolism

压力变化环境和气泡栓塞下有机组织中气泡形成的研究

基本信息

批准号：
12650174
负责人：
TSUJINO Tomoji
金额：
$ 2.37万
依托单位：
Kumamoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650174/
关键词：
bubble embolism decompression disease bubble artificial valve cavitation submarine sickness pulsatile flow soft organic tissue 大動脈弁僧帽弁拍動流 HITS 血管閉塞ヘリウム

项目摘要

Bubbles often generate in organic tissue subjected to pressure variation of environments, and consequently the bubbles are responsible for bubble embolism. In this work, the experimental studies are conducted from viewpoint of fluid dynamics in order to clarify decompression disease such as submarine sickness and complication after substitution of an artificial heart valve.(1)During the flow in the pipe with small diameter of 1.15mm, the bubbles of diameter 0.06mm〜0.84mm are generated in oversaturated liquid-gas solutions (oxygen, carbon dioxide, helium). The incorporation phenomena of bubbles and the formation of chain bubbles are also observed. The number of bubbles increase with increasing of gas additional pressure and flow velocity in pipe. In the liquids solved carbon dioxide, the size and the number of occurring bubbles are larger than the case in oxygen and helium. The bubbly flow in the small pipe may be cause of obstruction an of arteriola and venula.(2)In soft organic tissue such as musclar model and fat moder under the conditions of high gas pressure, the bubbles also occur. Carbon dioxide bubbles are easy to make in fat model, and the number of bubble density of helium is large as compare with the cases of oxygen, carbon dioxide.(3)Cavitation phenomena are detected around an artificial valve in pulsatile flow with high velocity. In the conditions of flow rate Q=5L/min and mean flow velocity v=0.57m/s, cavitation bubbles are observed in downstream of aortic valve. The bubbles of the size of 0.2mm〜0.5 mm are detected around aortic valve, and the velocities of movement of the bubbles are 0.46m/s〜1.2m/s. On the upstream side of aortic valve, cavitation phenomena are produced explosively at closing of the valve. The small bubbles produced around artificial valve are responsible for embolism in cardiovascular system and HITS.

受环境压力变化的影响，有机组织中经常产生气泡，因此气泡是气泡栓塞的原因。本文从流体力学的角度进行了实验研究，以阐明潜水病等减压疾病和人工心脏瓣膜置换后的并发症。(1)在直径为1.15mm的小管道中流动时，过饱和的液气溶液（氧气、二氧化碳、氦气）中产生直径为0.06mm ~ 0.84mm的气泡。还观察到气泡的掺入现象和链状气泡的形成。气泡数量随管内气体附加压力和流速的增大而增加。在溶解的二氧化碳液体中，气泡的大小和数量都比氧气和氦气中的气泡大。小管内的气泡流可能是小动脉和小静脉阻塞的原因。(2)在肌肉模型、脂肪模型等软组织在高压条件下，也会出现气泡。在脂肪模型中，二氧化碳很容易产生气泡，并且氦的气泡密度比氧、二氧化碳的气泡密度大。(3)高速脉动流中人工阀周围存在气蚀现象。流速Q=5L/min，平均流速v=0.57m/s时，主动脉瓣下游出现空化气泡。主动脉瓣周围可见0.2mm ~ 0.5 mm大小的气泡，气泡运动速度为0.46m/s ~ 1.2m/s。在主动脉瓣的上游，瓣关闭时发生爆发性空化现象。人工瓣膜周围产生的小气泡是导致心血管系统栓塞和hit的原因。