Assessment of Lobar Oxygenation during Ex-Vivo Lung Perfusion May Predict Postoperative Outcomes

Abstract

<h3>Purpose</h3> Assessment of marginal donor lungs during asanguineous ex vivo lung perfusion (EVLP) can be challenging due to limited objective parameters. We hypothesized that determination of PaO2/FiO2 (P/F) ratio from each lobar vein can provide valuable information regarding lobar function. The aim of this study is to determine lobar vein P/F ratio during EVLP and correlate with standard EVLP assessment parameters as well as post-transplant outcomes. <h3>Methods</h3> Data from 139 lungs from 75 donors assessed in asanguineous EVLP from Feb 2016 to April 2020 were analyzed for this study. Transplant suitability of lungs was determined based on standard EVLP parameters. pO2 was assessed from each pulmonary vein at the time of standard evaluation. In transplanted EVLP lungs, primary graft dysfunction (PGD) was assessed at 72 hours. <h3>Results</h3> In the favorable group (defined as PGD grade 0-1), both P/F ratio at left atrium (P/F LA) and P/F ratio at lower lobe pulmonary vein (P/F LPV) were significantly higher than that of the unfavorable group (non-suitable or PGD grade 2-3) (LA, 496±77 vs. 444±74 mmHg, P < 0.001; LPV, 888±82 vs. 307±101 mmHg, p < 0.001). In receiver operating characteristic curve analysis for unfavorable, P/F ratio LPV showed the highest AUC with threshold of 342, sensitivity 0.60 and specificity 0.74 than that of other standard parameters (Table 1). Regarding PGD at 72 hours in transplanted lungs, P/F LA on EVLP assessment was not different between PGD≥2 and PGD≤1 groups (483± 67 vs. 495± 77 mmHg, p = 0.564, Figure], while P/F LPV in PGD≥2 was significantly lower than that in PGD≤1 (332± 88 vs. 388±82 mmHg, p = 0.015]. <h3>Conclusion</h3> These results suggest that determination of lobar P/F ratio during EVLP can provide additional, valuable information for lung assessment. Deterioration of lobar function might be masked assessment of only LA P/F ratio and potentially lead to a greater incidence of high-grade PGD after lung transplantation.