Ex vivo lung perfusion outcomes
The median partial pressure of oxygen on 100% inspired oxygen (PaO2:FiO2) at the end of EVLP was 516 (478–523) mmHg for transplanted and 342 (322–392) mmHg for non-transplanted donor lungs (Mann–Whitney U = 4, P = 0.02). The median PaO2:FiO2 improvement after EVLP was 321 (186–362) mmHg in transplanted donor lungs (Wilcoxon Z = −2.37, P = 0.03). No improvement was seen in lungs that failed assessment; the median PaO2:FiO2 change was 20 (−42–94) mmHg, (Wilcoxon Z = −0.18, P = 0.91) (Fig. 1).
Figure 1: Physiological characteristics of transplanted and non-transplanted EVLP donor lungs. Box and whisker plots with boxes showing medians with interquartile range and whiskers at max and min. **P<0.05. EVLP; start time: point when the lung had been successfully rewarmed to 37 °C in the beginning of the EVLP; end time: point before start of cooling at the end of the EVLP.
Of the nine lungs that failed EVLP reconditioning, six displayed worsening pulmonary oedema and two showed signs of persistent hyperinflation and raised PVR, suggesting diffuse injury and a degree of intrinsic emphysema. This suggestion was later verified by a pathologist from pulmonary biopsies. Lastly, one set of lungs was turned down due to heavy microbial contamination with multiple gram-negative organisms identified in the tracheal aspirate.