Lung retrieval from cadaver donors with nonbeating hearts: optimal preservation solution.

BACKGROUND

We have previously studied the time course of pulmonary cell viability, ultrastructural damage, and adenine nucleotide metabolites after circulatory arrest in a rat model to investigate the feasibility of lung retrieval for transplantation from cadavers. This study was designed to investigate the effect of hypothermic flush and subsequent 4-hour storage with either modified Euro-Collins or University of Wisconsin solution on lungs retrieved 4 hours after death.

METHODS

Ninety-six Sprague-Dawley rats were sacrificed by intraperitoneal injection of pentobarbital. Control lungs were flushed immediately after sacrifice and stored for 4 hours. Rats in the experimental groups were sacrificed, and then their lungs were either ventilated with 100% oxygen or not ventilated for 4 hours before flushing with either Euro-Collins or University of Wisconsin solution followed by 4-hour hypothermic storage. At the end of the storage period, all right lungs were maintained at -70 degrees C and used to determine wet-to-dry weight ratios and adenine nucleotide levels with high-pressure liquid chromatography. Left lungs were assessed for viability with trypan blue dye exclusion. The effect on viability of flushing with Carolina rinse solution after storage was also assessed.

RESULTS

The percentage of viable cells in the control group after 4-hour hypothermic storage was 74% +/- 2% in Euro-Collins solution-flushed lungs and 78% +/- 2% in University of Wisconsin solution-flushed lungs. This result was virtually identical to that of lungs retrieved after 4 hours of in situ oxygen ventilation followed by 4 hours of hypothermic storage. Nonventilated cadaver lungs had substantially less viability. Adenosine triphosphate levels were significantly higher in the control group than in the oxygen-ventilated group, which were higher still than those in the nonventilated group. Adenosine triphosphate levels were consistently higher in University of Wisconsin solution-flushed lungs compared with Euro-Collins solution-flushed lungs in all groups. Total adenine nucleotide levels had a similar pattern. Wet-to-dry ratios were significantly lower in the control group (Euro-Collins = 6.27 +/- 0.46, University of Wisconsin = 4.63 +/- 0.07) compared with the oxygen-ventilated (Euro-Collins = 9.80 +/- 0.44, University of Wisconsin = 10.96 +/- 0.60) and nonventilated (Euro-Collins = 9.44 +/- 0.26, University of Wisconsin = 11.54 +/- 1.16; p < 0.0001) groups.

CONCLUSIONS

Four hours of circulatory arrest before 4 hours of hypothermic storage had no additional adverse impact on lung viability compared with lungs subjected to 4 hours of hypothermic storage alone, provided nonperfused lungs were ventilated with 100% oxygen. Adenine nucleotide levels were well maintained in oxygen-ventilated cadaver lungs, more so in University of Wisconsin solution-flushed lungs compared with Euro-Collins solution-flushed lungs.