Evaluation of cold reperfusion as an indicator of viability in stored organs: a 31P NMR study in rat liver.

Rat livers were studied during hypothermic resuscitation perfusion using 31P nuclear magnetic resonance (NMR) spectroscopy as a viability index. Livers were stored for 48 h after being flushed either with a synthetic solution containing plasma-equivalent concentrations of cations, plus citrate and including gelatin polypeptides as colloid (GC solution), or with a modified lactobionate/raffinose [University of Wisconsin (UWC)] solution. After 48 h in either solution, all NMR-detectable ATP plus ADP had disappeared, inorganic phosphate had increased markedly and pH in the livers had become acidotic. During cold reperfusion, ATP was resynthesized, inorganic phosphate declined, and pH returned toward normal values. ATP recovery and decrease in tissue inorganic phosphate were significantly greater (P < 0.02 and P < 0.005, respectively) after 1 h cold reperfusion with the modified UW compared with reperfusion with the GC. 31P NMR spectroscopy was able to detect differences in the metabolic responses of livers stored in different solutions, and coupled with cold reperfusion may be a useful indicator of viability.