The quality of cold-stored donor livers slowly declines beyond approximately 12 h, although these organs may still be used for clinical transplantation. The aim of the present study was to improve the energetic status and viability of long-term-preserved livers by short-term gaseous oxygen insufflation prior to implantation of the organ using a technique that has already been shown to promote aerobic energy metabolism during hypothermia. Livers from ten male Wistar rats were isolated, rinsed blood-free. Five livers (group 1) were stored for 48 h at 4 degrees C in UW preservation solution, and five livers (group 2) were isolated and stored in the same manner for 47 h, and were then, during the last 60 min of the preservation period, connected to a persufflation device and gaseous oxygen was introduced into the organ via the inferior caval vein, with the liver still immersed in cold UW solution. This technique of endischemic gaseous oxygenation resulted in a significant normalization of vascular resistance upon isolated reperfusion in vitro and a reduction in hepatic efflux of alanine aminotransferase as well as glutamate dehydrogenase, which led to improved recovery of the reperfused grafts of group 2 as evidenced by an elevated energy charge potential at the end of the reperfusion period. In conclusion, the technique described seemed effective in enhancing the preoperative viability of marginal donor grafts.