Effect of treatment delay on disease severity and need for resuscitation in porcine fecal peritonitis

INTRODUCTION: Early treatment in sepsis may improve outcome. OBJECTIVE: The aim of this study was to evaluate the impact of delays in resuscitation on disease severity, need for resuscitation, and the development of sepsis-associated organ and mitochondrial dysfunction. METHODS: Prospective, randomized, controlled experimental study performed at an experimental laboratory in a university hospital. Thirty-two anesthetized and mechanically ventilated pig were randomly assigned (n = 8 per group) to a nonseptic control group or one of three groups in which fecal peritonitis (peritoneal instillation of 2 g/kg autologous feces) was induced, and a 48 hour period of protocolized resuscitation started 6 (ΔT-6 hrs), 12 (ΔT-12 hrs), or 24 (ΔT-24 hrs) hours later. RESULTS: Any delay in starting resuscitation was associated with progressive signs of hypovolemia and increased plasma levels of interleukin-6 and tumor necrosis factor-α prior to resuscitation. Delaying resuscitation increased cumulative net fluid balances (2.1 ± 0.5 mL/kg/hr, 2.8 ± 0.7 mL/kg/ hr, and 3.2 ± 1.5 mL/kg/hr, respectively, for groups ΔT-6 hrs, ΔT-12 hrs, and ΔT-24 hrs; p<0.01) and norepinephrine requirements during the 48-hr resuscitation protocol (0.02 ± 0.04 mcg/kg/min, 0.06 ± 0.09 mcg /kg/min, and 0.13 ± 0.15 mcg/kg/min; p=0.059), decreased maximal brain mitochondrial Complex II respiration (p=0.048), and tended to increase mortality (p=0.08). Muscle tissue adenosine triphosphate decreased in all groups (p<0.01), with lowest values at the end in groups ΔT-12 hrs and ΔT-24 hrs. CONCLUSIONS: Increasing the delay between sepsis initiation and resuscitation increases disease severity, need for resuscitation, and sepsis-associated brain mitochondrial dysfunction. Our results support the concept of a critical window of opportunity in sepsis resuscitation.