Phoenix Sepsis Score

Total (0–13) = respiratory (0–3) + cardiovascular (0–6) + coagulation (0–2) + neurologic (0–2), each per JAMA 2024 Table 2. RESPIRATORY is support-gated and cumulative. The PaO₂:FiO₂ (P/F) and SpO₂:FiO₂ (S/F) ratios are evaluated together, S/F only when SpO₂ ≤ 97%, and either can trigger a tier: 1 point for any support with P/F < 400 or S/F < 292, 1 more for invasive ventilation with P/F < 200 or S/F < 220, and 1 more for invasive ventilation with P/F < 100 or S/F < 148. No support scores 0 regardless of the ratio, and non-invasive support cannot exceed 1. High-flow nasal cannula counts as support here, because Phoenix includes it explicitly. CARDIOVASCULAR sums three independent 0–2 sub-scores with no cap: vasoactive agents (0 → 0, 1 → 1, ≥ 2 → 2, counting dobutamine, dopamine, epinephrine, milrinone, norepinephrine and vasopressin), lactate (< 5 → 0, 5 to < 11 → 1, ≥ 11 → 2 mmol/L), and age-banded MAP (0, 1 or 2). COAGULATION adds 1 point each for platelets < 100 ×10³/µL, INR > 1.3, D-dimer > 2 mg/L FEU and fibrinogen < 100 mg/dL, capped at 2. For D-dimer, mg/L and µg/mL are the same number while ng/mL is a thousand times larger, so select the unit the report uses. NEUROLOGIC is hierarchical, not additive: bilaterally fixed pupils score 2 outright, whatever the GCS; otherwise GCS ≤ 10 scores 1; otherwise 0. An uncapped sum, which would return 3 for fixed pupils at GCS 8, is wrong. MISSING INPUTS are imputed at their normal end, each independently of the others: an uncomputable ratio as 500, GCS as 15, pupils as not fixed, respiratory support as absent, lactate and vasoactive agents as 0, the coagulation labs as normal. A fixed-pupils entry therefore scores its 2 points even with no GCS recorded. BOUNDARIES are compared continuously, matching the task force’s reference software rather than the integer bedside tables, at the four values where the two disagree: MAP 30.5 in a child under 1 month scores 1, lactate 10.95 scores 1, and a P/F of exactly 200 or an S/F of exactly 220 on invasive ventilation scores 1. Sepsis is reported when infection is suspected or confirmed and the total is ≥ 2; septic shock when sepsis is met and the cardiovascular component is ≥ 1, not merely when the total is ≥ 2.

A diagnostic criterion, not a graded severity ladder. A HALF-ENTERED PHOENIX READS FALSELY LOW, because every unentered value is imputed at its normal end, and a total below 2 on an incomplete entry is not evidence against sepsis. The same convention produces one discontinuity worth stating outright: with no arterial gas, a child on invasive ventilation at FiO₂ 1.0 scores respiratory 3 at SpO₂ 97 but 0 at SpO₂ 98, because the ratio is simply not computable above 97. Read that as “not measurable”, never as “not hypoxaemic”, and obtain a gas. HIGH-FLOW NASAL CANNULA counts as respiratory support here, while PICANet and ANZPIC exclude it from the ventilation field they collect, so the same child reads differently against registry data. SCOPE. The criteria were derived in children under 18 years (216 months, an exclusive ceiling) and exclude newborns during the birth hospitalization and infants under 37 weeks post-conceptional age; age is not adjusted for prematurity. A sedated child’s neurologic point may be measuring the sedation, which is the authors’ own caveat. The 8-organ Phoenix-8 extension is research-only and out of scope.