Introduction: Neonatal sepsis causes significant morbidity and mortality, yet there are no accepted criteria for identifying sepsis in this vulnerable population. The Phoenix Sepsis Criteria (2024) utilizes organ dysfunction criteria to identify pediatric sepsis and accurately predicts mortality risk, but these criteria excluded premature neonates and birth admissions. Thus, it is important to assess if these criteria can be applied to neonates. Methods: Neonates at four NICUs who underwent sepsis evaluation within the first 3 months of life were included in this retrospective cohort study. A sepsis evaluation was defined as having a blood culture (time 0) and antibiotics ordered within 6hrs and sepsis treatment as antibiotic duration >48hrs. The time 0 Phoenix 8-point sepsis score was calculated. Performance of the Phoenix sepsis score in predicting mortality and antibiotic duration >48hrs was evaluated by creating area under the receiver operating curves (AUROC) for the full score and its subcomponents. Results: There were 3,045 neonates included (57% male, mean gestational age 35 weeks); 791 (26%) received treatment for sepsis. Phoenix-8 score was a strong predictor of mortality (AUC 0.81). It was inversely associated with time to mortality (p< 0.0001, HR: 1.50, 95% CI: 1.39 to 1.62) indicating a 50% increase in the risk of death for each 1-point increase in the score. The best 4 performing subscores in predicting mortality were cardiovascular (AUC 0.79, p< 0.0001), respiratory (AUC 0.74, p< 0.0001), coagulation (AUC 0.67, p< 0.0001) and endocrine (AUC 0.62, p=0.006). The Phoenix 8-point score performed poorly in predicting clinician-diagnosed sepsis (AUC 0.61). Four organ subscores were associated with clinician-diagnosed sepsis including respiratory (p< 0.0001), cardiovascular (p=0.02), coagulation (p=0.03) and immunologic (p< 0.0001). Conclusions: The Phoenix 8-point score performs poorly in predicting neonatal clinician-diagnosed sepsis. Despite significant differences in physiology and immune maturity between neonates and children, the Phoenix Sepsis Criteria performs well in predicting neonatal mortality. The best performing organ subscores included respiratory, cardiovascular, coagulation, immunologic and endocrine which could be used to modify the criteria to best identify sepsis in neonates.
Katchen et al. (Sun,) studied this question.