Superior vena cava clamping for brachiocephalic vein cannulation during heart surgery.

A new central venous catheterization during open heart surgery is seldom required. Clamping of superior vena cava (SVC) causes adequate brachiocephalic vein distension which facilitates vein puncture. In our experience, approximately 20 s is enough for adequate brachiocephalic vein distension. I usually prefer subclavian vein puncture by supraclavicular approach. By this approach, average superior vein clamping time is about 45 s.