Levels of protein c activity and clinical factors in early phase of pediatric septic shock may be associated with the risk of death

Severe sepsis and septic shock are major causes of morbidity and mortality among children in pediatric intensive care units (PICUs) worldwide. Activated protein C (PC) is a critical endogenous regulator of coagulation and inflammation in patients with sepsis. However, the role of PC in pediatric sepsis is still obscure. We prospectively recruited infants and children aged between 1 month and 15 years old who were admitted to PICU with a clinical diagnosis of systemic inflammatory response syndrome, sepsis, or septic shock. Clinical data were recorded and blood samples kept for further analysis. We then measured the levels of PC activity. Of the approximately 1, 100 pediatric patients admitted to PICU from January 1, 2004 to December 31, 2005, 75 were diagnosed with septic shock (6.8%), and 67 samples were available for analysis. Out of these, 41 (61%) were survivors, and 26 (39%) were nonsurvivors. The average plasma PC activity (%) was at 37.8 +/- 4.4. Plasma PC activity (%) was significantly lower in the nonsurvivors compared with the survivors at 23.6 +/- 4.3 and 46.8 +/- 6.3 (P = 0.002), respectively. D-Dimer levels were not significantly different between the survivors (1,461 +/- 266 ng/mL) and the nonsurvivors (1,989 +/- 489 ng/mL (P = 0.68). Also, there was no correlation between plasma PC activity and D-dimer levels (r = -0.07; P = 0.6). Importantly, the odds of dying were significantly higher in patients whose level of PC activity was less than 25% (odds ratio = 5.6; P = 0.02). Pediatric patients with septic shock demonstrate very low levels of PC activity, and this may be associated with an increased risk of death.