A radionuclide model for studying changes in the regional blood volumes during early endotoxic shock: an experimental...

Septic shock constitutes a great threat to patients undergoing major abdominal surgery and also to trauma patients. The current state of knowledge on pathophysiological mechanisms in septic shock is not fully known. The aim of this study was to develop an experimental model that resembled the clinical situation and allowed the exploration of central and peripheral vascular mechanisms in endotoxic shock. Seven anesthetized sheep (weighing 30-45 kg) were provoked to lethal endotoxic shock by intravenous injection of 3 mg/kg bodyweight Escherichia coli endotoxin. The arterial pressure was monitored. Serial radionuclide images of the chest and abdomen were recorded after injecting technetium-99m-labeled RBC's. The volumetric (blood) alterations of liver, spleen, kidney, heart, and lungs, as well as peripheral muscle were measured. Prior to injection of endotoxin base-line data were obtained. Two to 4 minutes after injection, spleen volume decreased by -36% (mean) followed by a slow restoration; the left ventricular volume and kidneys increased by a maximum of 10-15%, while the liver volume increased by 38% of initial volume.