Correlation between PaO2/FiO2 and airway and vascular parameters in the assessment of cellular ex vivo lung perfusion system

Ex vivo lung perfusion (EVLP) may be an essential process for the pre-transplant evaluation of the donor lungs. Currently, the partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2, or PF) ratio is the standard in the assessment of lung function in cellular EVLP, whereas other parameters, including airway and vascular parameters, have only been partially utilized. The primary purpose of this study is to assess the potential utility of other parameters as a surrogate of lung function in EVLP.Yorkshire swine lungs (n = 12) and rejected human donor lungs (n = 12) were perfused in cellular-based EVLP for 2 hours. PF ratio, airway parameters (peak airway pressure, plateau pressure, dynamic compliance and static compliance) and vascular parameters (pulmonary vascular resistance and pulmonary artery pressure) were measured. The correlations between PF ratio and one of these parameters were analyzed.Correlations were identified in the following combinations: PF ratio and airway parameters (p < 0.05, each); PF ratio and vascular parameters (p < 0.05, each); static compliance and pulmonary vascular resistance in swine lungs (p = 0.0001); and PF ratio and airway parameters in rejected human lungs (p < 0.05, each). There were significant differences in all parameters between suitable cases and non-suitable cases in swine lungs (p < 0.02, each).Our results show that airway parameters are complementary quantitative indicators of lung function in cellular EVLP, based on the correlations with PF ratio in both swine lungs and human lungs.