Oxygen free radical scavengers decrease reperfusion injury in lung transplantation

An in vivo canine model was used to assess the ability of an oxygen free radical scavenger to decrease reperfusion injury in lung transplantation. In 12 dogs, the left lungs were transplanted after they had been preserved for 24 hours at 4 degrees C after pulmonary artery flushing with modified Eurocollins solution. In 6 dogs, dimethylthiourea, a potent oxygen free radical scavenger, was added to the flush solution and was also given to the recipients just before reperfusion. In all animals, the contralateral pulmonary artery and bronchus were ligated and lung function was assessed for 12 hours or until death. Three dogs died prematurely in the control group, whereas only 1 dog died prematurely in the dimethylthiourea group. This resulted in a statistically significant difference in the average length of survival (p less than 0.05). Pulmonary artery and right atrial pressures were significantly lower in the dimethylthiourea group during the first 6 hours (p less than 0.05). Treatment with dimethylthiourea resulted in a significantly higher arterial oxygen tension at 4 hours, and intrapulmonary shunt tended to be lower. Thus, it would appear that dimethylthiourea has a protective effect on lungs preserved for 24 hours before transplantation in dogs.