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

我们先前的研究得出结论：供肺局部降温保存的最佳温度为8ﾟ℃左右(ATS1992；53：101108)。低温保存低于最适温度会导致NO=复流现象(NRP)，而冷应激超过最适温度则会引起通透性水肿。为了进一步研究移植物损伤，我们对这种NRP进行了讨论。采用兔心-肺传导阻滞模型进行移植物功能评价。比较了4ﾟC和8ﾟC两种不同的温度。局部降温18小时后，从肺循环的角度评估移植物的功能。移植物用EP4保存液灌洗肺内血液。在评估过程中，移植物被注入同种异体血液。4ﾟC组灌流压高于8ﾟC组，氧分压低于8ﾟC组。4ﾟC组移植物灌流后湿/干重比(W/D)较低，与血液湿重/干重比值相近，而8ﾟC组湿重/干重比较高。这些结果提示，4ﾟC组发生了非应激反应。NRP的部位在中央区，而不是肺毛细血管。肺血残留不是NRP的原因。NRP通过复温是不可逆的。高渗物质对NRP无效，对NRP的进一步研究有助于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.