PORCINE PERITONEAL SEPSIS - MODELING FOR CLINICAL RELEVANCE

The characteristics of two types of intraperitoneal (i.p.) soilage sep sis models, autologous fecal inoculum (FEC) and a pure culture of Esch erichia coli (EC), were studied in 26 male Yucatan minipigs (20-30 kg) . Early (1-4 h) and late (24-72 h) changes were different between the two groups. The EC group was characterized early by hypotension, low c ardiac output, and increased systemic and pulmonary vascular resistanc es, along with leukopenia, hypoglycemia, lactacidemia, and elevated bl ood urea nitrogen. Of the pigs in the EC group that survived the early effects, there were few significant differences in physiological para meters, compared to control pigs, that would indicate ongoing patholog ical processes. In contrast, the FEC group pigs demonstrated early hyp otension, but with increased cardiac output and reduced systemic vascu lar resistance. Other parameter changes were similar to those seen in the EC pigs, but to a lesser degree, with the exception of elevations in serum lactate dehydrogenase. Also in contrast to the EC group, most of the changes in the FEC group persisted in later days, and FEC pigs demonstrated leukocytosis. There were also greater elevations in circ ulating lipopolysaccharide (LPS) concentrations in the EC group that r eturned later to baseline levels. In the FEC group, there were persist ently elevated LPS concentrations over 72 h. These observations sugges t that pigs challenged with intraperitoneal E. coli demonstrated an in itial acute peritonitis and damaging physiologic effects of high level s of circulating LPS. Survivors in this group improved and were physio logically stable after 24 h. Pigs that received i.p. autologous feces developed an early acute peritonitis phase with lower levels of circul ating LPS, and later developed pronounced peritoneal reaction as demon strated by multiple abdominal abscesses, pyogenic granuloma formation, and adhesions with physiological evidence of developing sepsis over 7 2 h. These observations indicate that i.p. EC models evoke a systemic response not unlike intravenous administration of LPS or EC, however, the FEC model produced a systemic response akin to a slower developing septic process.