A CLUE for Better Assessment of Donor Lungs: Novel Technique in Clinical Ex-vivo Lung Perfusion.

Background
Direct lung ultrasound evaluation (CLUE) technique was proven to be an accurate method for monitoring extravascular lung water in donor lungs during ex-vivo lung perfusion (EVLP) in an experimental model. The aim of this study was to examine the application of CLUE in clinical setting.
Methods
Lungs were evaluated using acellular EVLP protocol. Ultrasound images were obtained directly from the lung surface. Images were graded according to the percentage of B-lines seen on ultrasound. CLUE scores were calculated at the beginning and end of EVLP for the whole lung, each side, and lobe based on the number of images in each grade and the total number of images taken.
Results
Out of the 45 lungs, 22 were deemed suitable resulting in 13 lung transplants (LTx) with no hospital mortality. Primary graft dysfunction occurred in only one recipient (PGD3 no PGD2). Significant differences were found between suitable and non-suitable lungs in CLUE scores (1.03 vs 1.85, p<0.001) unlike PaO2/FiO2 ratio. CLUE had the highest area under the receiver-operating characteristic curve (0.98) when compared to other evaluation parameters. The initial CLUE score of standard donor lungs was significantly better than marginal lungs. Final CLUE score in proned lungs showed improvement when compared to initial CLUE score, especially in the upper lobes.
Conclusion
CLUE technique shows the highest accuracy in evaluating donor lungs for LTx suitability compared to other parameters used in EVLP. CLUE can optimize the outcomes of LTx by guiding the decision making through the whole process of clinical EVLP.

背景
已有实验模型证实，直接肺部超声评估（CLUE）技术可在离体肺灌注（EVLP）过程中精准监测供体肺的血管外肺水水平。本研究旨在探究CLUE技术在临床场景中的应用价值。

方法
本研究采用无细胞EVLP方案对供肺进行评估，直接从肺脏表面采集超声图像。依据超声图像中B线（B-lines）所占比例对图像进行分级，基于各分级图像的数量与总采集图像数，分别在EVLP开始与结束阶段，计算全肺、每侧肺及各肺叶的CLUE评分。

结果
45例供肺中，22例符合筛选标准，最终完成13例肺移植（LTx），无住院死亡病例。仅1例受者发生原发性移植物功能障碍（PGD3，无PGD2）。与动脉血氧分压/吸入氧分数（PaO2/FiO2）比值不同，符合与不符合筛选标准的供肺间CLUE评分存在显著差异（1.03 vs 1.85，p<0.001）。相较于其他评估参数，CLUE的受试者工作特征曲线（receiver-operating characteristic curve）下面积最高，达0.98。标准供肺的初始CLUE评分显著优于边缘供肺。俯卧位供肺的术后CLUE评分较初始评分有所改善，尤以肺上叶为著。

结论
相较于EVLP中应用的其他评估参数，CLUE技术在评估供肺是否适合肺移植方面具有最高的准确性。通过指导临床EVLP全流程的决策制定，CLUE技术可优化肺移植的手术结局。