Biophysical aspects of liver aeration by vascular persufflation with gaseous oxygen.

Abstract

Venous systemic oxygen persufflation of the liver (i.e., gaseous insufflation of oxygen via the venous vascular system) has proven to be an effective tool for preventing anoxic tissue injury during extended time periods of ischemic preservation. It also allows for an improved recovery of the persufflated organ after orthotopic transplantation. Biophysical aspects of the persufflation technique with regard to persufflation pressure (9 mmHg versus 18 mmHg) and oxygen concentration (pure oxygen versus air) in the persufflation gas were investigated in rat livers, using epi-illumination microscopic detection of autofluorescence of NADH, which accumulates in anoxic tissue. We demonstrated that a low-pressure persufflation (9 mmHg) is as sufficient as a higher pressure persufflation (18 mmHg) in oxygenating the ischemic organ. Moreover, oxygenation of the liver was found to be complete and rather homogeneous upon the pure oxygen persufflation, irrespective of the insufflation pressure used. In contrast, insufflation of air instead of pure oxygen resulted in insufficient aeration of the liver, even at the higher persufflation pressure of 18 mmHg. Our results indicate that the oxygen concentration of the persufflation gas rather than the persufflation pressure is a determinant of successful tissue oxygenation during cold storage.