Real-Time Lung Weight Measurement to Assess Pulmonary Function During Cellular Ex Vivo Lung Perfusion

Abstract

<h3>Purpose</h3> Increased extravascular lung water (EVLW) during ex vivo lung perfusion (EVLP) is associated with ischemia reperfusion injury and poor pulmonary function. A non-invasive technique for evaluating EVLW is desirable for assessing transplant suitability of lungs. The purpose of this study was to investigate real-time lung weight gain as a predictor of transplant suitability of lungs in cellular EVLP using a porcine lung model. <h3>Methods</h3> Fifteen pigs were randomly divided into three groups: control (no warm ischemia) or donation after circulatory death groups with 60 or 90 min of warm ischemia (n = 5, each). Lung weight gain was measured by loadcells positioned at the bottom of organ chamber during non-touch period when no one touched the organ chamber and the driving condition of EVLP was stable. Following the non-touch period, lung weight gain was assumed to continue at the same rate until the next non-touch period. The measurements were repeatedly performed, throughout the EVLP and estimated lung weight gain was calculated. Lungs were perfused according to the Lund protocol. At 2 h, transplant suitability was decided. <h3>Results</h3> Lung weight gains in suitable cases (n = 9) and non-suitable cases (n = 6) at 2 h were 34.9 ± 57.4 and 334.0 ± 142.7 g, respectively. Estimated lung weight gain was significantly correlated with lung weight gain on the back table (R = 0.979, P < 0.001, Figure A). Lung weight gain in non-suitable cases were significantly higher than in suitable cases at 40 min (48.3 ± 49.9 vs. -8.8 ± 25.7 g, <i>P</i> < 0.05) and after 50 min <i>(P</i> < 0.01) as shown in Figure B. Lung weight gain at 50 min was significantly correlated with PaO₂/FiO₂, peak inspiratory pressure, shunt ratio, W/D, lung weight gain on the back table at 2 h (<i>P</i> < 0.01, each). In non-suitable cases, lung weight gain in evaluation phase was significantly higher than in recondition phase (<i>P</i> < 0.01). <h3>Conclusion</h3> These results indicate that real-time lung weight measurement was feasible and can be a good early predictor of pulmonary function in cellular EVLP.