Importance: The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) uses the Sequential Organ Failure Assessment (SOFA) score to grade organ dysfunction in adult patients with suspected infection. However, the SOFA score is not adjusted for age and therefore not suitable for children.

Objectives: To adapt and validate a pediatric version of the SOFA score (pSOFA) in critically ill children and to evaluate the Sepsis-3 definitions in patients with confirmed or suspected infection.

Design, setting, and participants: This retrospective observational cohort study included all critically ill children 21 years or younger admitted to a 20-bed, multidisciplinary, tertiary pediatric intensive care unit between January 1, 2009 and August 1, 2016. Data on these children were obtained from an electronic health record database. The pSOFA score was developed by adapting the original SOFA score with age-adjusted cutoffs for the cardiovascular and renal systems and by expanding the respiratory criteria to include noninvasive surrogates of lung injury. Daily pSOFA scores were calculated from admission until day 28 of hospitalization, discharge, or death (whichever came first). Three additional pediatric organ dysfunction scores were calculated for comparison.

Exposures: Organ dysfunction measured by the pSOFA score, and sepsis and septic shock according to the Sepsis-3 definitions.

Main outcomes and measures: The primary outcome was in-hospital mortality. The daily pSOFA scores and additional pediatric organ dysfunction scores were compared. Performance was evaluated using the area under the curve. The pSOFA score was then used to assess the Sepsis-3 definitions in the subgroup of children with confirmed or suspected infection.

Results: In all, 6303 patients with 8711 encounters met inclusion criteria. Each encounter was treated independently. Of the 8482 survivors of hospital encounters, 4644 (54.7%) were male and the median (interquartile range [IQR]) age was 69 (17-156) months. Among the 229 nonsurvivors, 127 (55.4%) were male with a median (IQR) age of 43 (8-144) months. In-hospital mortality was 2.6%. The maximum pSOFA score had excellent discrimination for in-hospital mortality, with an area under the curve of 0.94 (95% CI, 0.92-0.95). The pSOFA score had a similar or better performance than other pediatric organ dysfunction scores. According to the Sepsis-3 definitions, 1231 patients (14.1%) were classified as having sepsis and had a mortality rate of 12.1%, and 347 (4.0%) had septic shock and a mortality rate of 32.3%. Patients with sepsis were more likely to die than patients with confirmed or suspected infection but no sepsis (odds ratio, 18; 95% CI, 11-28). Of the 229 patients who died during their hospitalization, 149 (65.0%) had sepsis or septic shock during their course.

Conclusions and relevance: The pSOFA score was adapted and validated with age-adjusted variables in critically ill children. Using the pSOFA score, the Sepsis-3 definitions were assessed in children with confirmed or suspected infection. This study is the first assessment, to date, of the Sepsis-3 definitions in critically ill children. Use of these definitions in children is feasible and shows promising results.