Question: 

Establishment of a method for the use of isolated perfused rabbit lungs in studies on lung transplantation and organ preservation of marginal donor organs.

Methods: 

New Zealand white rabbits (2.35 ± 0.34kg) were anesthetized and underwent a tracheostomy. The animals were mechanically ventilated with room air using a respiratory rate of 40 breaths/min. After opening the thorax by midline sternotomy, pulmonary artery and left atrium were cannulated, the heart-lung-block was excised and transferred to a water-heated artificial thorax chamber. Lungs (n=16) were perfused with recirculating, albumin-containing Tyrode-Solution (total circuit volume 400ml). The perfusion rate was set at 40–150 ml/min. Furthermore, pulmonary oxygen uptake by the isolated lungs was measured. In another series we preserved lungs for 4h in Perfadex Solution on ice, and thereafter continued ventilation and perfusion to simulate a transplantation situation.

Results: 

The data after 60min of perfusion were pulmonal arterial pressure 9.58 ± 0.29 cmH₂O, pulmonary compliance 1.49 ± 0.01 ml/cmH₂O, pulmonary resistance 0.04 ± 0.00 cmH₂O/ml/s and lung weight 22.4 ± 2.25 g. Inflow perfusate pO₂ increased from 53.6 ± 4.77 mmHg to 120 ± 11.3 mmHg after passing the lungs. If transplantation was simulated, lungs recovered after 4h, but without reaching pre-transplant control values. After 120min of reperfusion pulmonal arterial pressure increased by 34% (8.58 ± 0.62 to 11.48 ± 1.06 cmH₂O), pulmonary compliance was reduced by 55% (2.00 ± 0.13 to 0.9 ± 0.29 ml/cmH₂O), pulmonary resistance was 2.7-fold higher (0.03 ± 0.00 to 0.08 ± 0.03 cmH₂O/ml/s) and lung weight increased by 67% (21.2 ± 1.14 to 35.4 ± 4.23 g).

Conclusions: 

Thus, simulated lung transplantation results in a moderate pulmonary dysfunction as can be clinically observed if marginal donor organs are used, so that this setup provides basic requirements for further investigation in assessment of altered pulmonary function after simulated lung transplantation.