The internal cavoatrial derivation for temporary vascular exclusion of the liver in the dog.

Vascular exclusion of the liver by clamping the hepatic pedicle and inserting an internal cavoatrial shunt allows bloodless hepatic surgery to be performed. The internal cavoatrial shunt performed on 30 dogs was studied to define its optimal hemodynamic characteristics. The internal diameter should measure half the caliber of the inferior vena cava and the total surface of the holes allowing blood flow to the shunt must be three times the internal caliber of the shunt. The aortic clamping associated with the clamping of the hepatic pedicle and the insertion of the internal cavoatrial shunt considerably diminishes the arterial blood pressure variations resulting from the splanchnic stasis. Administration of methylprednisolone (30 mg/kg) at the beginning of the experiment also plays a role in preventing alterations in the small intestine.