Tissue viability assessment via laser-based fluorescence monitor

A preliminary study of the degree to which recently introduced inhalation anesthetics influence the intracellular energetic metabolism of isolated perfused rat livers is undertaken via NADH fluorometry. During liver transplantation, anesthesiologists desire to maintain a high level of metabolic energy status in newly transplanted liver tissue. Ischemic storage of donor liver tissue prior to transplantation is known to inhibit mitochondrial electron transfer, which results in decreased levels of ATP and increased levels of NADH in the stored tissue. The ability of transplanted liver tissue to regenerate ATP at normal levels is desirable for early post- operative recovery of liver function. Previous studies have examined the differential effects inhalation anesthetics have on the energetic metabolism of tissue at the cellular level; the trend of such agents is to induce a dose-dependent increase in NADH fluorescence in accordance with their strengths as general anesthetics. The present study evaluates the differential effects exhibited by new inhalation anesthetics on the return of function of energetic metabolism in liver tissue. The third-harmonic (355 nm) output of a Nd:YAG laser is spatially filtered and used as the excitation source for surface fluorometric measurements of isolated buffer-perfused rat livers. Lastly, maximum fluorescence emission versus spot-size are measured.