PIRO classification in pediatric severe sepsis and septic shock: a new model for staging and its potential usefulness in prognoses

Sepsis is a dynamic process that involves complex interactions between the pathogenic micro-organisms and the host. The understanding of this heterogeneous disease has led to the development of a new system for stratification of septic patients: the PIRO system: Predisposition (P) -Insult/Infection (I) -Response (R) -Organ disfunction (O), a classification aimed to determine the risk of death in patients with sepsis. Only a few studies have validated this classification system in children. To empirically test the accuracy of the PIRO system in pediatric patients with septic shock and severe sepsis and associate its individual components to predict mortality. A retrospective chart review was performed in a 13 bed PICU during 24 months (January 2006 to December 2007) Demographic, clinical and microbiological data were recorded in all patients with a diagnosis of septic shock and severe sepsis during the study period. For all patients the PIRO classification system was applied by one of four authors using paramethers measured at admission. Atotal of 42 patients were included with a mean age of 11 months (range 3.25-58.3) of which 52% were male. Overall mortality was 19% and variables associated with mortality for each category were: (P) Chronic illness (OR: 7 IC95% 0.95-51) and Immunodeficiency (OR: 6.2; IC95% 1.1-35.2); (R) leucopema (OR 9; IC95%: 1.96-41.72); (O) more thanthree dysfunctional organs (OR: 6.1; IC95%: 1.22-31). None of the (I) variables were associated with mortality. The PIRO classification system identified factors associated with a fatal outcome in our population. The test is relatively simple to apply but cross-sectional studies are required to define variables associated with death that should then be prospectivelly validated.