Real-Time Lung Weight Measurement during Ex Vivo Lung Perfusion: Clinical Importance of Early Weight Gain

Abstract

<h3>Purpose</h3> Lung weight gain during ex vivo lung perfusion (EVLP) can reduce lung transplant suitability. Therefore, real-time weight measurement can enhance donor lung evaluation. We sought to 1) develop/validate a real-time EVLP weight measurement system, and 2) define the time course of lung weight change during EVLP. <h3>Methods</h3> In our clinical acellular EVLP system, from 6/2019-9/2020, real-time lung weight was measured in 36 cases. Weights were recorded with a scale under the organ chamber, and back table static weights measured after EVLP. Lungs were classified as unfavorable (n = 13) if declined after EVLP (n = 8) or PGD grade ≥ 2 at 72 hrs if transplanted (n = 5). Favorable group lungs were transplanted, with PGD ≤ 1 at 72 hrs (n = 23). <h3>Results</h3> Real-time lung weights correlated well with static/back table weights (r = 0.69, p < 0.01, Figure A). Unfavorable group lungs gained significantly more weight (mean 38 g, range -59 to 135 g) during the 1^st hour of EVLP vs. favorable group lungs (mean -51 g, range -155 to +53 g) (p < 0.01, Figure B). In fact, this effect was most pronounced in the first 10 minutes of EVLP (Figure C), and correlated with an increased pulmonary artery (PA) pressures (7.0 ± 2.2 vs 5.4 ± 1.3 mmHg, p = 0.03). In contrast, lung weight gain was similar between groups during EVLP hours 2 and 3. For the 28 lungs suitable for transplant, 30-day recipient survival was 100%. <h3>Conclusion</h3> Real-time lung weight measurement during EVLP is feasible. Our data suggest that donor lung weight gain in the earliest phase of EVLP correlates with decreased lung transplant suitability and PGD. Further studies are needed to define the significance of lung weight gain early during EVLP.