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Divergent PICU lengths of stay despite identical phoenix sepsis scores: heterogeneity in pediatric sepsis outcomes according to system involvement profiles

Year: 2026

Type: article

Abstract: Objective This study examined how different subsystem involvement patterns in the Phoenix Sepsis Score relate to PICU length of stay among children with sepsis, focusing on patients with identical total scores, and explored clinical factors associated with these differences. Methods We retrospectively included 107 children with sepsis admitted to a single PICU (2024–2025). Patients were grouped by the number of affected Phoenix subsystems (respiratory, coagulation, circulatory, neurological): single-system ( n = 37), dual-system ( n = 62), and multi-system ( n = 8). We further compared the largest subgroups with identical total scores of 2—isolated respiratory involvement ( n = 29) versus respiratory-coagulation involvement ( n = 59). Multivariable logistic regression identified predictors of prolonged PICU stay (≥10 days), and the association between IMV and PICU length of stay was further explored. Results Respiratory and/or coagulation involvement accounted for 89.7% (96/107) of cases, with the respiratory–coagulation combination being most frequent (55.1%). The multi-system group had the highest total scores, lactate levels, and mortality (37.5%, all P < 0.05). Despite identical total scores [2 (2, 2), P = 0.457], the isolated respiratory group had significantly prolonged PICU stay [10 (9, 12) vs. 6 (4, 8) days, P < 0.001], higher ventilation rates (100% vs. 25.4%, P < 0.001), and longer ventilation duration [6 (4, 7) vs. 0 (0, 0) days, P < 0.001]. Invasive ventilation was the strongest risk factor for prolonged stay (OR=18.80, 95% CI: 3.78–123.24, P < 0.001). Adjusting for ventilation attenuated the group effect from OR=6.92 ( P < 0.001) to OR=1.27 ( P = 0.739), suggesting that the subgroup difference in PICU length of stay was largely explained by the higher IMV use in the single-respiratory group. Since IMV is part of the Phoenix respiratory subscore, this attenuation likely reflects shared information rather than formal mediation. Conclusions In septic children with the same Phoenix total score, different system involvement patterns yield substantially different outcomes and resource use. A respiratory subsystem score ≥2 signals high risk of prolonged PICU stay, largely explained by the greater need for invasive ventilation. The total Phoenix score alone is insufficient for resource planning; the respiratory component may provide additional information beyond the total score.

Source: Frontiers in Pediatrics

DOI: 10.3389/fped.2026.1986840