Microcirculation in the gastrointestinal tract

Sepsis and multiple-organ failure (MOF) are associated with a prolonged stay and high mortality rate in surgical intensive-care units. In recent years the occurrence of MOF has been linked with previous hypoperfusion of the gut during a variety of critical conditions. In the present study, we focused on the blood flow pattern (rather than the quantity of flow) in the mucosal microcirculation of the gastrointestinal tract during surgery and hemorrhagic shock. In anesthetized pigs subjected to laparotomy and hemorrhage, mucosal blood flow was continuously recorded using multichannel laser Doppler flowmetry (LDF). During normovolemic conditions, flowmotion at a rate of 3-5 cycles per minute occurred in the gastric, jejunal and colonic mucosa in all the animals. The flowmotion disappeared during severe blood loss and during administration of catecholamines. These results suggest that flowmotion, as measured by LDF, is a normal phenomenon in the mucosa of the gastrointestinal tract, but is disrupted during shock. The physiological and clinical significance of these findings awaits further studies.