Hypothermic storage alone in lung preservation for transplantation - A metabolic, light microscopic, and functional analysis after 18 hours of preservation

Background. Current lung preservation consists of flushing of the donor organs, with successive hypothermic storage in an inflated state. Recently, hypothermic storage alone was reported to be superior in terms of functional recovery. This study was designed to investigate the metabolic, morphologic, and functional consequences of hypothermic storage alone, in experimental lung preservation. Methods. Orthotopic left-sided lung transplantation was performed in pigs. Donor lungs were flushed with Euro-Collins solution (n=6) or simply explanted (n=6) and stored for 18 hr at 4 degrees C. After this, left-sided single lung transplantation was performed. Sham-operated animals (n=6) served as control. Morphology and metabolism were analyzed in normal lungs, after ischemia and at the end of reperfusion. Gas exchange and pulmonary hemodynamics of the transplanted organs were measured, after exclusion of the native lung from perfusion and ventilation. Results. Metabolic and morphologic evaluation did not show a significant difference between the groups at the end of ischemia. Lungs preserved by hypothermia alone showed a functional recovery close to sham-operated animals and superior to flushed organs. Conclusions. Hypothermia alone is a sufficient means of preservation for explanted lungs for at least 18 hr.