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Phoenix Sepsis Score

In months. Determines the age-adjusted MAP band. The criteria were derived in children < 18 years and exclude newborns and infants < 37 weeks post-conceptional age.

Clinical judgment. Phoenix sepsis requires suspected/confirmed infection AND a score ≥ 2 — the score alone does not decide whether infection is present.

The 1-point tier needs any support; the 2- and 3-point tiers need invasive mechanical ventilation. A low ratio with no support scores 0.

From an arterial blood gas. Used for the PaO₂:FiO₂ (P/F) ratio when available; otherwise SpO₂:FiO₂ is used. Accepts mmHg or kPa.

Room air is 0.21. Needed for the P/F or S/F ratio. Accepts a fraction or a percentage.

Used for the SpO₂:FiO₂ (S/F) ratio only when SpO₂ ≤ 97% (above that the ratio saturates and is uninformative). Prefer PaO₂:FiO₂ when an arterial gas is available.

Count of distinct systemic vasoactive medications running (dobutamine, dopamine, epinephrine, milrinone, norepinephrine, vasopressin): 0 → 0 pts, 1 → 1 pt, ≥ 2 → 2 pts.

0 pts if < 5, 1 pt if 5 to < 11, 2 pts if ≥ 11 mmol/L. Accepts mmol/L or mg/dL.

Age-adjusted scoring (0–2 pts). May be computed as DBP + (SBP − DBP)/3. Accepts mmHg or kPa.

In ×10³/µL (K/µL). Contributes 1 coagulation point when < 100.

International normalized ratio (unitless). Contributes 1 coagulation point when > 1.3.

In mg/L fibrinogen-equivalent units (FEU). Contributes 1 coagulation point when > 2.

Contributes 1 coagulation point when < 100 mg/dL. Accepts mg/dL or g/L.

Total GCS 3–15. Contributes 1 neurologic point when ≤ 10. Only the numeric total is used.

Contributes 1 neurologic point (additive with the GCS point; neurologic component caps at 2).

Independent clinical validation: pending

Two independent clinical validators will be named here once review is complete.

Validator slot open 1
Validator slot open 2

How it is calculated

Total (0–13) = respiratory (0–3) + cardiovascular (0–6) + coagulation (0–2) + neurologic (0–2), each per JAMA 2024 Table 2. Respiratory is scored only when respiratory support is present, from the PaO₂:FiO₂ (P/F) ratio when an arterial gas is available, otherwise the SpO₂:FiO₂ (S/F) ratio when SpO₂ ≤ 97%: on invasive mechanical ventilation, 3 pts if P/F < 100 (S/F < 148) or 2 pts if P/F < 200 (S/F < 220); on any support, 1 pt if P/F < 400 (S/F < 292); otherwise 0 (PaO₂ and MAP in mmHg, FiO₂ a fraction). Cardiovascular sums vasoactive points (0 agents → 0, 1 → 1, ≥ 2 → 2), lactate points (< 5 → 0, 5 to < 11 → 1, ≥ 11 → 2 mmol/L), and age-banded MAP points (2 if MAP < low, 1 if low ≤ MAP < high, 0 if MAP ≥ high, with half-open [low, high) thresholds by age band). Coagulation adds 1 point each — platelets < 100 ×10³/µL, INR > 1.3, D-dimer > 2 mg/L FEU, fibrinogen < 100 mg/dL — capped at 2; neurologic adds 1 point for GCS ≤ 10 and 1 for bilaterally fixed pupils, capped at 2. A missing input contributes 0 to its component. Sepsis is reported as 1 when infection is suspected/confirmed and total ≥ 2; septic shock as 1 when sepsis is met and the cardiovascular component ≥ 1.

Limitations and notes

Diagnostic criterion, not a graded severity ladder: sepsis = suspected/confirmed infection AND total ≥ 2; septic shock = sepsis AND cardiovascular component ≥ 1 (a cardiovascular point, not merely total ≥ 2). The vasoactive sub-score is a COUNT of distinct agents (0/1/≥2), not the VIS. Missing inputs contribute 0 to their component (reference-package convention), so the score reflects documented dysfunction — a teaching UI should show a missing input as missing, not as normal. The S/F ratio is used only when SpO₂ ≤ 97%; P/F is preferred when an arterial gas is available. Only the numeric total GCS (3–15) is consumed; the GCS response-descriptor wording is a separate instrument (Teasdale & Jennett) and is not reproduced or licensed by the Phoenix papers. The validated cohort was children < 18 years and excluded newborns during the birth hospitalization and infants < 37 weeks post-conceptional age — applying the score to those groups is outside the validated population. The 8-organ research extension Phoenix-8 is out of scope. The MAP age bands are implemented as half-open [low, high) intervals (matching the reference package) so non-integer MAP scores exactly. The per-input plausible min/max are input-validity guardrails, not published Phoenix thresholds (the research labels these ranges as heuristics, not published thresholds); pao2/spo2/map upper bounds were widened beyond the research's 'typical' ranges to avoid false rejections and are annotated in code.

Accepted input ranges

  • Age — 0–215 months
  • Suspected or confirmed infection
  • Respiratory support
  • Arterial PaO₂ — 20–700 mmHg
  • Fraction of inspired oxygen (FiO₂) — 0.21–1 fraction
  • Pulse-oximeter oxygen saturation (SpO₂) — 50–100 %
  • Number of distinct vasoactive agents — 0–6
  • Blood lactate — 0.3–30 mmol/L
  • Mean arterial pressure (MAP) — 10–200 mmHg
  • Platelet count — 5–1000 10^3/uL
  • INR — 0.8–10
  • D-dimer — 0.1–50 mg/L FEU
  • Fibrinogen — 30–800 mg/dL
  • Glasgow Coma Scale (total) — 3–15
  • Bilaterally fixed pupils

References

  1. Sanchez-Pinto LN, Bennett TD, DeWitt PE, et al; SCCM Pediatric Sepsis Definition Task Force. Development and Validation of the Phoenix Criteria for Pediatric Sepsis and Septic Shock. JAMA. 2024;331(8):675–686.PMID 38245897DOI 10.1001/jama.2024.0196
  2. Schlapbach LJ, Watson RS, Sorce LR, et al; SCCM Pediatric Sepsis Definition Task Force. International Consensus Criteria for Pediatric Sepsis and Septic Shock. JAMA. 2024;331(8):665–674.PMID 38245889DOI 10.1001/jama.2024.0179
  3. DeWitt PE, Russell S, Rebull MN, Sanchez-Pinto LN, Bennett TD. phoenix: an R package and Python module for calculating the Phoenix pediatric sepsis score and criteria. JAMIA Open. 2024;7(3):ooae066.DOI 10.1093/jamiaopen/ooae066

Version and changelog

v1.0.0 · Sepsis

  • 2026-07-25 v1.0.0 — Initial release: four-organ Phoenix Sepsis Score with age-banded MAP, sepsis and septic-shock flags.

Important

For use by qualified health professionals as an informational and educational aid. It supports clinical judgment and does not replace it. Verify every result independently before making a clinical decision. This is not a medical device.