Predictive and Prognostic Performance of the Phoenix Sepsis Criteria and Phoenix Sepsis Score in PICU Patients With Suspected Infection: A Multicenter Prospective Study

Objectives: Evaluate the predictive and prognostic performance of the Phoenix Sepsis Criteria (PSC) and Phoenix Sepsis Score (PSS) compared with International Pediatric Sepsis Consensus Conference (IPSCC) criteria and other organ dysfunction scores in children admitted to the PICU with suspected infection. Design: Multicenter, prospective cohort study. Setting: Eight PICUs within the Italian Network of PICU Study Group (TIPNet). Patients: Patients younger than 18 years admitted with suspected infection (from February 2022 to April 2024). Interventions: None. Measurements and Main Results: Vital signs, organ dysfunction markers, and organ support requirements were collected during day 1 and day 2 of PICU admission. Sepsis was assessed using IPSCC criteria and PSC. IPSCC Severe Sepsis, PSS, Phoenix-8, Pediatric Logistic Organ Dysfunction-2 (PELOD-2), pediatric Sequential Organ Failure Assessment, and Pediatric Multiple Organ Dysfunction Score were calculated as organ dysfunction scores. Sepsis criteria predictive performance was assessed using sensitivity and positive predictive value (PPV). Organ dysfunction scores prognostic performance was assessed using the area under the precision-recall curve (AUPRC). Primary outcome was PICU mortality. Among 687 patients, PSC showed higher predictive performance than IPSCC sepsis criteria, with improved sensitivity and PPV for mortality on day 1 (PSC: sensitivity, 96.4%; 95% CI, 95.0–97.8%; PPV, 7.6%; 95% CI, 5.6–9.6% and IPSCC: sensitivity, 82.1%; 95% CI, 79.3–85.0%; PPV, 6.2%; 95% CI, 4.4–8.0%) and day 2 (PSC: sensitivity, 100.0%; 95% CI, 100.0–100.0%; PPV, 10.0%; 95% CI, 7.6–12.5% and IPSCC: sensitivity, 75.0%; 95% CI, 71.5–78.5%; PPV, 9.0%; 95% CI, 6.7–11.3%). PELOD-2 exhibited the highest AUPRC for mortality (day 1, 0.45; 95% CI, 0.26–0.63 and day 2, 0.59; 95% CI, 0.38–0.77). IPSCC Severe Sepsis score was outperformed by all other organ dysfunction scores, including PSS and Phoenix-8. All prognostic performances improved from day 1 to day 2. Conclusions: PSC and PSS performed superior to IPSCC criteria in diagnosing and prognosticating pediatric sepsis, with improved performance at day 2 of PICU admission. This study first validated PSC and PSS in a European cohort.