The Protection Of Pulmonary Artery Single Perfusion With Protective Solution At Earlier Period Of Cardiopulmonary Bypass: A Randomized Controlled Clinical Trial

Objective: To research the protection of pulmonary artery single perfusion with low potassium dextran (LPD) contains L-Arginine at earlier period of cardiopulmonary bypass (CPB).Methods: A prospective randomized single-blind controlled clinical trial. 18 patients who accepted mitral valve replacements were randomly divided into a trial group (n=9) and a control group (n=9). The protective solution was perfused into the main pulmonary artery after the aorta blocked and the left atria dissected in the trial group, and the solution which reflowed through pulmonary vein was drained out of circulation. The routine mitral valve replacements were performed in the control group. In 5 ponits before and after CPB , Oxygen Index (OI), lung static compliance (Cst), endothelin (ET) and nitric oxide (NO) in plasma were measure. Leucocyte count differences (D-WBC) between left atria and right atria were monitored before and after CPB. Lung biopsy specimens were obtained before sternum closed.Results: There was no significant difference of OI between two groups (P=0.192), but the trend of OI descending in the trial group was gentler than in the control group. Cst levels were better in the trial group than in the control group (P=0.033). D-WBCs were lower in the trial group than in the control group (P=0.000). The ET levels in plasma were lower and the NO levels in plasma were higher in the trial group than in the control group. There were linear correlation between ET and NO in all cases before CPB, in the trial group after CPB and in the control group after CPB (P=0.029, 0.048, 0.010. r=0.515, 0.332, 0.422). The linear correlation before CPB seemed to be close with the trial group after CPB, and be far with the control group after CPB. The examination of histopathology demonstrated destroyed lung structure, lung alveolus wall hyperemia and edema, intra-alveolus hemorrhage and edema, leucocyte accumulation, broadened and broken gas-blood barrier in the control group, whereas there were no significant changes in the trial group.Conclusions: Pulmonary artery single perfusion with LPD contains L-Arginine at earlier period of CPB was found to be a protective means. It reduced lung injury after CPB maybe through reducing leucocyte activation and protecting pulmonary vessel endothelial cell.