Comparison of saccharides as osmotic impermeants during hypothermic lung graft preservation

We have previously shown that the trisaccharide raffinose is largely responsible for the superior lung graft performance seen after storage in University of Wisconsin solution. To investigate the use of osmotic agents in perfusates for hypothermic lung graft storage, we compared saccharides of various molecular weights in an isolated rat lung model. Grafts were flushed with 1 of 6 preservation solutions (n=5 each group) containing either a monosaccharide (glucose [G] or fructose [F]), disaccharide (trehalose [T] or sucrose [S]), or trisaccharide (raffinose [R] or melezitose [M]. Grafts were stored for 6 hours at 4 degrees C, reperfused by a veno-venous circuit from an anesthetized support animal for 60 min, and ventilated with room air. The best graft function was seen when trisaccharides were used (PO2; R 126 +/- 3 mm Hg, M 129 +/- 3 mm Hg, blood flows: R 10.2 +/- 0.42 ml/min, M 10.3 +/- 0.22 ml/min). Disaccharides produced similar oxygenation (T 133 +/- 3 mm Hg, S 129 +/- 3 mm Hg) and flows (T 10.3 +/- 0.29 ml/min, S 9.7 +/- 0.4 ml/min) at 60 min, but initial flows were reduced. Monosaccharides produced the least satisfactory graft function, with impaired oxygenation (F 110 +/- 14 mm Hg, P<0.05; G 69 +/- 10 mm Hg, P<0.01) and blood flows (G 6.5 +/- 0.6 ml/min, F 9.1 +/- 0.6 ml/min, P<0.01 each). Only glucose-stored lungs demonstrated a significant decrease in compliance (P<0.01) and weight gain (P<0.01). The worst results were seen with glucose, which is the osmotic agent most commonly used for clinical lung storage. A solution containing a trisaccharide or disaccharide may be more appropriate for this purpose.