Changes in intestinal transit and absorption during endotoxemia are dose dependent

Background. Septic patients are often intolerant of enteral feedings due to a combination of motility disturbances and impaired absorptive function. O ur laboratory has previously demonstrated that endotoxemia results in rapid intestinal transit and decreased jejunal absorption of water, electrolytes , and glucose. We hypothesized that the changes in jejunal transit and abso rption during endotoxemia may be dependent on the dose of endotoxin. Materials and Methods. Under general anesthesia, rats underwent placement o f an internal jugular line, a femoral arterial line, and a 20-cm jejunal Th iry-Vella loop. The jejunal segment was perfused with an isotonic solution containing polyethylene glycol. For 90 min, baseline measurements of blood pressure, heart rate, jejunal absorption of water, electrolytes, and glucos e, and jejunal transit were made. Following this baseline period I, rats we re given 0.9% NaCl (1 ml/kg) or one of three doses of Escherichia coli lipo polysaccharide (0.5, 1.0, or 5.0 mg/kg). Studies were then repeated for an additional 90 min. Results. Changes in blood pressure and heart rate were similar among the fo ur groups of animals. Endo toxin decreased water and glucose flux, increase d potassium flux, and quickened intestinal transit in a dose-dependent fash ion. Conclusions. We conclude that endotoxemia causes dose-dependent changes in jejunal transit and absorption. The effects of increasing doses of endotoxi n on jejunal absorptive and motor function do not appear to be mediated by changes in blood pressure or heart rate. (C) 1999 Academic Press.