Splanchnic and total body oxygen consumption in experimental fecal peritonitis in pigs: effects of dextran and iloprost.

Tissue oxygenation in the gastrointestinal tract and in the liver was studied in a porcine model where septic shock was induced by fecal peritonitis. The effects of different fluid regimes were compared. In one group (n = 8) a moderate amount of crystalloid fluids was given, in another (n = 7) crystalloids and colloids, and in a third group (n = 6) iloprost, a prostacyclin analogue, was administered intra-arterially (10 ng x kg-1 b.w. x min-1) in combination with the crystalline and colloid fluid regime. Septic shock induced by fecal peritonitis reduced cardiac index and oxygen supply to splanchnic organs. Iloprost improved the hepatic arterial blood flow, and tended to attenuate the reduction in liver oxygen delivery. Oxygen consumption (VO2) in the gastrointestinal tract and the liver was significantly increased in the group given crystalloids. These animals developed a hypovolemic/hypodynamic septic shock. Liver VO2 in these animals became flow dependent reflected by increasing hepatic venous lactate values and inversion of lactate turnover by the liver. In the two other groups gastrointestinal and liver VO2 remained constant during the observation period. Oxygen extraction over the liver increased when oxygen delivery decreased. The increased liver VO2 is suggested to be secondary to impaired microcirculation and accumulation of macrophages and leukocytes in the septic liver.