A study on no-reflow phenomenon of isolated lung after cold strage.

我们之前的研究表明，外敷冷却保存供体肺的最佳温度在8℃左右（ATS 1992; 53: 101-108）。本研究提出了两种不同的移植物功能退化机制。低于最佳温度的低温保存引起无回流现象（NRP），高于最佳温度的低温保存引起渗透性水肿。为了进一步研究移植物损伤，我们重点研究了这种NRP。采用兔心肺传导阻滞模型进行移植物功能评估。比较了4、8两种不同温度下的温度。局部冷却18小时后，从肺循环的角度评估移植物功能。用EP4保存液冲洗移植物，冲洗肺内血。评估时移植物灌注同种异体血液。4 C组灌注压高于8 C组，氧合低于8 C组。4 / C组移植后的干湿重比（W/D）较低，与血液W/D相似，8 / C组移植后的干湿重比较高。结果表明：4 -丙酸组出现NRP。NRP的发生部位不在肺毛细血管内，而是在肺中央。残留的肺血不是NRP的原因。通过再变暖，NRP是不可逆的。高渗物质对NRP无效。解决NRP的研究需要可能导致肺保存技术的进一步改进。

Our former study concluded optimal temperature for donor lung preservation by topical cooling was around 8ﾟC (ATS 1992 ; 53 : 101-108).Two different mechanism of graft functional deterioration were sugested in this study. Hypothermic preservation less than optimal temperature caused no=reflow phenomenon (NRP) while cold strage more than optimal temperature caused permiability edema. We foccussed on this NRP for further investigation of graft injury. We used rabbit heart-lung block model for graft functional assessment. Two different temperature 4ﾟC and 8ﾟC was compared. Graft function was assessed from the point of view of pulmonary circulation after 18 hours topical cooling. Graft was flushed with EP4 preservation solution for washing out intra pulmonary blood. Graft was perfused with homologous blood during assessment. Perfusion pressure in 4ﾟC group was higher and oxygenation in 4ﾟC group was lower than 8ﾟC group. Wet-dry weight ratio (W/D) after graft perfusion was low in 4ﾟC group which resemble the blood W/D while it was high in 8ﾟC group. These results sugested NRP occured in 4ﾟC group. The site of NRP is in central region rather than pulmonary capillary. Residual pulmonary blood is not the cause of NRP.NRP is irreversible by re-warming. Hyperosmotic substance is not effective for NRP.Father investigation need for resolving NRP may lead to farther improvement of lung preservation technique.