Hemodynamic and hormonal responses to the sudden interruption of caval flow:: Insights from a prospective study of hepatic vascular exclusion during major liver resections

Hepatic vascular exclusion (HVE) combines portal triad clamping and occlusion of the inferior vena cava. Although HVE has been performed for major liver resections during the last 2 decades, little is known about the mechanisms that explain its satisfactory hemodynamic tolerance. Consequently, we performed a comprehensive study of both hemodynamic and hormone responses to HVE. Twenty-two patients who underwent liver resection for secondary tumors developed in noncirrhotic livers were prospectively studied. Heart rate, arterial blood pressure, pulmonary artery pressure, mixed venous saturation, cardiac output, and left ventricular dimensions determined by transesophageal echocardiography were monitored in HVE patients. Blood concentrations of arginine vasopressin (AVP), epinephrine, norepinephrine, dopamine, and atrial natriuretic peptide and plasma renin activity (PRA) were measured before clamping; 5, 15, and 30 min after clamping; and 15 min after unclamping.