Background Ex vivo lung perfusion (EVLP) is a widespread accepted platform for preservation and evaluation of donor lungs prior to lung transplantation (LTx). Standard lungs are ventilated using volume-controlled ventilation (VCV). We investigated the effects of flow-controlled ventilation (FCV) in a large animal EVLP model. Fourteen porcine lungs were mounted on EVLP after a warm ischemic interval of 2 h and randomized in two groups ( n = 7/group). In VCV, 7 grafts were conventionally ventilated and in FCV, 7 grafts were ventilated by flow-controlled ventilation. EVLP physiologic parameters (compliance, pulmonary vascular resistance and oxygenation) were recorded hourly. After 6 h of EVLP, broncho-alveolar lavage (BAL) was performed and biopsies for wet-to-dry weight (W/D) ratio and histology were taken. The left lung was inflated, frozen in liquid nitrogen vapors and scanned with computed tomography (CT) to assess regional distribution of Hounsfield units (HU). Results All lungs endured 6 h of EVLP. Oxygenation was better in FCV compared to VCV ( p = 0.01) and the decrease in lung compliance was less in FCV ( p = 0.03). W/D ratio, pathology and BAL samples did not differ between both groups ( p = 0.16, p = 0.55 and p = 0.62). Overall, CT densities tended to be less pronounced in FCV ( p = 0.05). Distribution of CT densities revealed a higher proportion of well-aerated lung parts in FCV compared to VCV ( p = 0.01). Conclusions FCV in pulmonary grafts mounted on EVLP is feasible and leads to improved oxygenation and alveolar recruitment. This ventilation strategy might prolong EVLP over time, with less risk for volutrauma and atelectrauma.

中文翻译：

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EVLP 期间的流量控制通气可改善氧合并保持肺泡复张

背景 离体肺灌注 (EVLP) 是一种广泛接受的平台，用于在肺移植 (LTx) 之前保存和评估供体肺。标准肺使用容量控制通气 (VCV) 进行通气。我们研究了流量控制通气 (FCV) 在大型动物 EVLP 模型中的影响。在 2 小时的热缺血间隔后，将 14 个猪肺安装在 EVLP 上，并随机分为两组（n = 7/组）。在 VCV 中，7 个移植物进行常规通气，而在 FCV 中，7 个移植物通过流量控制通气进行通气。每小时记录一次 EVLP 生理参数（依从性、肺血管阻力和氧合）。EVLP 6 小时后，进行支气管肺泡灌洗（BAL），并进行湿干重（W/D）比和组织学活检。左肺膨胀了，冷冻在液氮蒸气中并用计算机断层扫描 (CT) 扫描以评估 Hounsfield 单位 (HU) 的区域分布。结果所有肺都经受了 6 小时的 EVLP。与 VCV 相比，FCV 的氧合更好 (p = 0.01)，而 FCV 肺顺应性的降低较少 (p = 0.03)。W/D 比率、病理学和 BAL 样本在两组之间没有差异（p = 0.16、p = 0.55 和 p = 0.62）。总体而言，FCV 中的 CT 密度往往不那么明显（p = 0.05）。CT 密度分布显示，与 VCV 相比，FCV 中通气良好的肺部分比例更高（p = 0.01）。结论 安装在 EVLP 上的肺移植物中的 FCV 是可行的，并导致氧合和肺泡复张的改善。随着时间的推移，这种通气策略可能会延长 EVLP，同时降低容积伤和肺外伤的风险。