Splanchnic Vasoregulation After Major Abdominal Surgery in Pigs

Background: Unrecognized reduction of blood supply to intestinal organs is associated with significant postoperative morbidity in abdominal surgery. The aim of this study was to determine whether—in the absence of hypovolemia—intestinal hypoperfusion as a result of blood flow redistribution occurs after abdominal surgery. Methods: Standardized operative trauma was induced in 14 healthy pigs. Systemic, regional, and local blood flow, intestinal and gastric intraluminal-to-end-tidal pCO2 gradients representing mucosal perfusion, and oxygen transport variables were measured for 10 postoperative hours. Normovolemia was maintained using continuous infusion of Ringer's lactate and additional boluses of colloids in response to blood pressure, pulmonary wedge pressure, and urinary output. Results: Postoperative blood flow was significantly increased in the celiac trunk (76% increase [percentage of baseline flow], p=0.003) and the hepatic (136% increase, p=0.002) and splenic (36% increase, p=0.025) arteries. Blood flow was significantly decreased in the mesenteric artery (25% decrease, p=0.007) and portal vein (13% decrease, p=0.028). Carotid and renal artery blood flow remained unchanged. Conclusions: Maintenance of normovolemia is insufficient to protect from intestinal hypoperfusion after abdominal surgery. Postoperative redistribution of cardiac output results in decreased intestinal and increased hepatic and splenic arterial blood flo