A new long-term porcine model of fecal peritonitis-induced septic shock hemodynamics, gas exchange, metabolism, and organ function

Introduction: Sepsis is the main cause of death in critically ill patients, in particular when shock and multiple organ dysfunction develop. The aim of this study was to establish a new long-term porcine model of fecal peritonitis-induced septic shock to study the sepsis-related organ dysfunction in a clinically relevant model. 15 anaesthetized and mechanical ventilated pigs (average body weight 42.6 kg) were instrumented to measure: systemic and regional hemodynamics, gas exchange, metabolism, and organ function. Material and methods: After instrumentation, recovery and baseline data collection, in 10 pigs (peritonitis group) fecal peritonitis was induced by 0.5 mg/kg autologous feces instillation, while 5 pigs (control group) served as controls. Mean arterial blood pressure was maintained with Hydroxyethyl Starch (15 ml/kg/hr) and noradrenaline as need. Data were collected before and 12, 18, and 24 hours after peritonitis induction. Results: Compared to controls, animals in the peritonitis group needed significantly more fluid resuscitation and additionally vasopressor support (noradrenaline 0.45 (0.20;0.60) µg/kg/min). Peritonitis-induced sepsis and volume resuscitation resulted in hyperdynamic circulation characterized by significantly increased cardiac output and vasodilation. Sepsis-induced multiple organ dysfunction was also manifested by respiratory failure with a decreased Horowitz-index, liver failure with increased alanine aminotransferase activity and bilirubine concentrations, and renal failure with increased creatinine concentration despite a significantly higher urine production. Conclusion: Our model of fecal peritonitis-induced septic shock with volume resuscitation and vasopressor support, despite a well maintained blood pressure resulted in hyperdynamic circulation and impaired organ function. This model closely mimics the clinical condition and may be a useful research approach for pre-clinical studies of possible therapies