Real-time Lung Weight Measurement during Cellular Ex Vivo Lung Perfusion: An Early Predictor of Transplant Suitability

Background. Increased extravascular lung water during ex vivo lung perfusion (EVLP) is associated with ischemia reperfusion injury and poor pulmonary function. A non-invasive technique for evaluating extravascular lung water during EVLP is desired to assess the transplant suitability of lungs. We investigated real-time lung weight measurements as a reliable method for assessing pulmonary functions in cellular EVLP using a porcine lung model. Methods. Fifteen pigs were randomly divided into 3 groups: control (no warm ischemia) or donation after circulatory death groups with 60 or 90 min of warm ischemia (n = 5, each). Real-time lung weight gain was measured by load cells positioned at the bottom of the organ chamber. Results. Real-time lung weight gain at 2 h was significantly correlated with lung weight gain as measured on a back table (R = 0.979, P < 0.01). Lung weight gain in non-suitable cases (n = 6) was significantly higher than in suitable cases (n = 9) at 40 min (51.6 ± 46.0 versus-8.8 ± 25.7 g; P < 0.01, cutoff = +12 g, area under the curve = 0.907). Lung weight gain at 40 min was significantly correlated with PaO₂/FiO₂, peak inspiratory pressure, shunt ratio, wet/dry ratio, and transplant suitability at 2 h (P < 0.05, each). In non-suitable cases, lung weight gain at 66% and 100% of cardiac output was significantly higher than at 33% (P < 0.05). Conclusions. Real-time lung weight measurement could potentially be an early predictor of pulmonary function in cellular EVLP.