The optimal temperature of the pulmonary flush perfusate is still a ma
tter of controversy, At present, a temperature of 10 degrees C is favo
red, This study deals with the structural and functional impact of dif
ferent perfusate temperatures on lung preservation, In an extracorpore
al rat heart-lung model lungs were preserved with Perfadex(R) solution
of 4, 15 and 25 degrees C and submitted to 2 h ischemia. Heart-lung b
locks harvested from male rats were perfused with Krebs-Henseleit solu
tion and ventilated with room air. Lungs were perfused with deoxygenat
ed perfusate via the working right ventricle while the coronary arteri
es were retrogradely perfused with oxygenated perfusate. Oxygenation c
apacity (dPO(2)), peak inspiratory pressure (PIP) and pulmonary vascul
ar resistance were measured. After establishment of baseline functiona
l parameters hearts were arrested with 10 mi St, Thomas cardioplegia a
nd lungs were flushed with 20 mi Perfadex solution, The heart-lung blo
ck was then stored for 2 h at 10 degrees C, Reperfusion was performed
thereafter under the same conditions, At the end of the trial the lung
tissue water was measured by the wet/dry ratio, The perfusion time of
the groups flushed with 15 or 25 degrees C perfusate was significantl
y lower than that of the 4 degrees C group, After 20 min reperfusion d
PO(2) of the groups flushed with 15 or 25 degrees C was superior to th
ose submitted to a 4 degrees C flush perfusion, PIP was significantly
lower in the 15 degrees C group than in the 4 and 25 degrees C groups,
The wet/dry ratio revealed the smallest water content in the 15 degre
es C group, We conclude that the postischemic lung function is depende
nt on the temperature of the flush perfusate, Among the tested tempera
tures, perfusion at 15 degrees C showed the best results, The optimum
may therefore lie in this range.