Introduction: 

Ischemia-reperfusion injury still causes severe problems after lung transplantation. It is supposed that systemic oxygen supply to the transplanted lungs could improve transplantation outcome. By using an ex vivo model of isolated perfused and ventilated rabbit lungs we investigated the influence of systemic oxygenation on pulmonary function during simulated transplantation.

Methods: 

Heart-lung blocks of New Zealand White rabbits were excised and transferred to a 37°C water-heated artificial thorax chamber. Negative pleural pressure ventilation and recirculating perfusion was initiated. The lungs were flush-perfused with Perfadex^® Solution, followed by an ischemic storage for 4h on ice, thereafter ventilation and reperfusion for 2h were continued to simulate a transplantation situation (oxygenated group, pulmonary artery pO₂=120mmHg). In another series the perfusate inflow was additionally gassed with nitrogen to simulate deoxygenation (deoxygenated group, pulmonary artery pO₂=50mmHg).

Results: 

After 2h reperfusion time the oxygenated group showed a significant lower PAP and lung weight compared to the deoxygenated group (p2O, 2h reperfusion 11.5±1.06 cmH₂O; lung weight: initial 22.1±1.32 g, 2h reperfusion 35.4±4.23 g). This development was significantly influenced by the intravascular pO₂ (PAP: initial 9.65±0.43 cmH₂O, 2h reperfusion 8.02±0.63 cmH₂O; lung weight: initial 17.9±1.54 g, 2h reperfusion 21.5±2.29 g, p

Conclusions: 

Oxygenation of the lung perfusate during simulated transplantation attenuates post transplant edema formation and decreases pulmonal arterial hypertension. Transfering this to the surgical situation, revascularisation of bronchial arteries after lung transplantation might initiate positive effects in the early phase after lung transplantation.