Inferior Vena Caval Obstruction From Increased Intra-abdominal Pressure

Abstract

IT HAS recently been demonstrated that partial obstruction of the suprahepatic segment of the abdominal inferior vena cava may accompany abdominal ascites in patients with cirrhosis or severe congestive heart failure.¹Doppman and others reproduced this unusual form of vena caval obstruction in experimental animals and demonstrated that the narrowing resulted from increased intra-abdominal pressure and was the result of physical forces acting on the collapsible venous segment at its site of exit from the abdomen.²The precise hemodynamic consequences of this functional form of vena caval obstruction have not, however, been previously determined. In the present experiments, the effects of graded increases in intra-abdominal pressure on pressure and flow in the inferior vena cava were studied in the dog. <h3>Methods</h3> Twelve mongrel dogs, ranging in weight from 14 to 20 kg, were anesthetized with sodium pentobarbital administered intravenously (35 mg/kg) and ventilated with a volume-controlled respirator supplying