Single catheter gravity drainage of the right atrium or right ventricle during total cardiac bypass.

The currently employed cannulations preparatory to establishing cardiac bypass with the aid of a pump-oxygenator, include isolation of the superior and inferior vena cavae over tapes and the insertion of catheters into each of these vessels. t At the onset of bypass the caval tapes are tightened around the indwelling catheters and venous drainage is effected by suction applied to the venous line by one of a variety of pumps. During procedures in which the right atrium or right ventricle is opened the venous return to these cavities through the coronary sinus or Thebesian veins is commonly aspirated by low pressure suction and injected into the venous line by pump action. Some workers4’ have advocated gravity drainage of the venous return after insertion of individual caval catheters as described. They have described a smoother operation with absence of venous flutter as advantages of this method. Paneth5 has obtained direct measurements of total venous return through gravity siphon drainage of individual catheters placed in each cava, and in the right atrium and has found that these measurements reflected accurately the arterial pump output over a wide range of perfusion rates. Blood loss during perfusion was accurately reflected in a corresponding reduction in venous return and could be replaced quantitatively from an appropriate reservoir. Our laboratory and clinical experience with the direct approach to the aortic and mitral valves suggested a simplification of this gravity drainage system. It consists of siphonage of total venous return through a single catheter inserted in the right atrium or in the right ventricle. Such drainage is applicable only to bypass employed during operative procedures on the left heart chambers or ascending aorta.