Awake porcine model of intraperitoneal sepsis and altered oxygen utilization

We have characterized an awake swine model of septic shock. Hemodynamic, serum chemistry, and oxygen metabolism parameters were compared between eight septic and five sham animals. Eight male Yucatan miniature swine, weighing 20-28 kg, were anesthetized and catheters were placed in the pulmonary artery, external jugular, and the carotid artery. On day 2, 1.1-4.0 x 10(10) cfu Escherichia coli/kg were administered via an intraperitoneal catheter. Hemodynamic parameters were monitored hourly for 6 hours in awake animals. The animals were then placed back into the animal holding facility for clinical observation until the 24 hour post infusion measurements were taken. Septic animals were initially hypodynamic, with a decrease in cardiac index (CI) from a baseline value of 152.8 +/- 24.8 to 87.9 +/- 17.8 ml/kg/min (P less than .05) and an increased systemic vascular resistance index (SVRI) from a control value of 48.1 +/- 9.5 to 65.0 +/- 16.7 dynes*sec*cm-5/kg. At 24 hours post infusion, the animals were hyperdynamic with the CI increased to 211.0 +/- 27.2 ml/kg/min (P less than .05) and a decreased SVRI to 30.64 +/- 3.9 dynes*sec*cm-5/kg (P less than .05). Oxygen utilization (VO2) increased during sepsis from 6.6 +/- 0.8 to 8.1 +/- 0.8 ml/kg/min at 6 hours (P less than .05) and remained elevated at 24 hours at 7.7 +/- 0.4 (P less than .05). Increased oxygen consumption was attained with an increase in oxygen extraction (O2 ext) from 0.34 +/- 0.03 to 0.56 +/- 0.07 (P less than .05) during the first 6 hours of sepsis. At 24 hours, increased oxygen utilization was maintained by high oxygen delivery state. Significant alterations in serum chemistries in conjunction with post mortem evidence of multiple organ system failure were observed. Mortality on or before 4 days post infusion was 50% and positive blood cultures were obtained in 38% of the animals studied. This awake swine model serves as an excellent model to study metabolic pathophysiology and the treatment of septic shock.