The safe interval time of crystalloid cardioplegic solution transfusion during CABG

Background: Cold crystalloid cardioplegic solution is used for cardiac arrest and myocardial protection during CABG intermittently. There is no defined safety interval time for cardioplegia infusion. Measuremen of the metabolite release from myocardial cells in coronary sinus implicateis accurate protective effect and safety interval of cardioplegia. There is no study that surveys the metabolites of coronary sinus during CABG. Materials and Methods: 13 patients that was scaduled for elective CABG cold crystalloid cardioplegia transfused via aortic root. Coronary sinus blood samples were taken in different times, before and after cross clamping of the aorta at the times of 7, 14 and 20 minutes. The samples were analyzed for pH and lactate immediately. Results: The pH and lactae concentration in coronary sinus at the time of 15 minute after transfusion of the first dose (pH=7.18±0.043 lactate=30±3.983 ρ=0.02) and 10 minute after the second dose of antegrade cold crystalloid cardioplegia (pH=7.19±0.045 lactate=28±3.438 ρ=0.03) were out of the range of acceptable level. Conclusion: This study indicates that safe interval time between the first and second dose of cold crystalloid cardioplegia transfusion was 15 minute and the between second and third dose was 10 minutes.