The Annals of thoracic surgery
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During less invasive coronary bypass operations on the beating heart, as well as conventional operations using continuous warm cardioplegia, a precise anastomosis is facilitated by a bloodless field. To maintain a clear field, many surgeons use high-flow gas insufflation. However, the potentially damaging effects of gas insufflation on coronary endothelium have not been elucidated. ⋯ These data demonstrate that high-flow carbon dioxide gas insufflation denudes the coronary artery of its endothelium. This exposes blood elements to the subendothelium and promotes clotting, and endothelial loss may promote smooth muscle cell migration and proliferation. These events set the stage for early and late graft failure.
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Profound hypothermia is used for circulatory arrest during cardiovascular operations. Cold retrograde cerebral perfusion enhances cerebral protection during circulatory arrest. This study examines the results of circulatory arrest under moderate systemic hypothermia and cold retrograde cerebral perfusion. ⋯ Systemic hypothermia of 23 degrees C (nasopharyngeal) and cold retrograde cerebral perfusion (10 degrees C) appear to be safe for circulatory arrest times of less than 30 minutes. This strategy of cerebral protection may also be adequate for longer circulatory arrest times.
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Cardioplegia infusion pressure is usually not directly monitored during neonatal heart operations. We hypothesize that the immature newborn heart may be damaged by even moderate elevation of cardioplegic infusion pressure, which in the absence of direct aortic monitoring may occur without the surgeon's knowledge. ⋯ Hypoxic neonatal hearts are very sensitive to cardioplegic infusion pressures, such that even moderate elevations cause significant damage resulting in myocardial depression and vascular dysfunction. This damage is avoided by using low infusion pressures. Because small differences in infusion pressure may be difficult to determine without a direct aortic measurement, we believe it is imperative that surgeons directly monitor cardioplegia infusion pressure, especially in cyanotic patients.