Effect of a free radical scavenger on cadaver lung transplantation

The pulmonary donor pool would increase substantially if lungs could be safely transplanted after cessation of circulation. To determine whether the addition of the free radical scavenger dimethylthiourea to the perfusate of cadaver lungs could improve graft function, canine donors were sacrificed, and lungs retrieved 2 hours after death. In a blinded fashion, dimethylthiourea was added to the modified Euro-Collins solution and infused into recipients (n = 9) perioperatively; a placebo was included in the perfusate of control animals (n = 9). Donor animals were ventilated with 100% oxygen only during flush and harvest. Recipients were rendered dependent upon the single left transplanted lung by occlusion of the right pulmonary artery and bronchus 1 hour after transplantation. Ventilation was maintained at a constant inspiratory oxygen fraction of 0.4. Recipients were followed up for 8 hours or until death. Three of 9 control animals survived the 8-hour observation period, whereas 6 of 9 recipients of cadaver lungs harvested with dimethylthiourea survived the observation period. Two deaths in the dimethylthiourea group occurred after 7 hours, implying that the effects of the ischemia and reperfusion injury were ameliorated by the use of this agent in this model. This study supports the notion that perfusate modification may improve the yield of cadaver lung retrieval and may allow for transplantation of lungs harvested from cadavers after cessation of circulation.