A novel concept for evaluation of pulmonary function utilizing PaO2/FiO2 difference at the distinctive FiO2 in cellular exvivo lung perfusion-an experimental study.

Abstract

For more accurate lung evaluation in exvivo lung perfusion (EVLP), we have devised a new parameter, PaO2 /FiO2 ratio difference (PFD); PFD1-0.4 = P/F ratio at FiO2 1.0 - P/F ratio at FiO2 0.4. The aim of this study is to compare PFD and transplant suitability, and physiological parameters utilized in cellular EVLP. Thirty-nine human donor lungs were perfused. At 2h of EVLP, PFD1-0.4 was compared with transplant suitability and physiological parameters. In a second study, 10 pig lungs were perfused in same fashion. PFD1-0.4 was calculated by blood from upper and lower lobe pulmonary veins and compared with lobe wet/dry ratio and pathological findings. In human model, receiver operating characteristic curve analysis showed PFD1-0.4 had the highest area under curve, 0.90, sensitivity, 0.96, to detect nonsuitable lungs, and significant negative correlation with lung weight ratio (R2 =0.26, P<0.001). In pig model, PFD1-0.4 on lower and upper lobe pulmonary veins were significantly associated with corresponding lobe wet/dry ratios (R2 =0.51, P=0.019; R2 =0.37, P=0.060), respectively. PFD1-0.4 in EVLP demonstrated a significant correlation with lung weight ratio and allowed more precise assessment of individual lobes in detecting lung edema. Moreover, it might support decision-making in evaluation with current EVLP criteria.