Pediatric Sepsis: The Phoenix Criteria and Organ Dysfunction Scoring

Summary

• Sepsis in children with suspected infection is defined by a Phoenix Sepsis Score ≥2, indicating potentially life-threatening dysfunction of the respiratory, cardiovascular, coagulation, and/or neurological systems [1].
• Septic shock is sepsis plus at least 1 cardiovascular point: severe hypotension for age, blood lactate >5 mmol/L, or vasoactive medication requirement [1].
• Phoenix Sepsis Score ≥2 carries in-hospital mortality of 7.1% (higher-resource settings) and 28.5% (lower-resource settings), more than 8 times the mortality of children with suspected infection who do not meet criteria [1].
• Septic shock mortality is 10.8% and 33.5% in higher- and lower-resource settings, respectively [1].
• Lactate >5 mmol/L contributes a cardiovascular point to the Phoenix score; lactate >2 mmol/L and >4 mmol/L carry independent prognostic weight [1,3].
• 2025 AHA/AAP PALS guidance favors reassessment after every fluid bolus over fixed aggressive volume loading [11].

Score organ dysfunction in Phoenix Sepsis Score →

Phoenix Sepsis Score

The 2024 SCCM Pediatric Sepsis Definition Task Force Phoenix criteria replaced the 2005 IPSCC SIRS-based definitions [1,2]. SIRS criteria captured many febrile children with benign viral illness while missing children with poorly perfused, "quiet" sepsis who did not meet inflammatory thresholds. Phoenix criteria substitute objective organ dysfunction for inflammation-based screening [1].

Components (maximum 13 points):

Renal and hepatic dysfunction are not part of the core Phoenix criteria. An expanded Phoenix-8 Score adding these systems exists for research use only [1].

Caution. Phoenix criteria are intended for diagnosis, benchmarking, quality improvement, and research. They are not screening tools and are not designed to guide treatment decisions. Separate early-recognition screening tools are under development [1].

Performance versus IPSCC:

• Positive predictive value: 5.3-7.1% (baseline mortality 0.6-0.7%) vs. IPSCC severe sepsis PPV of 3.6-4.8% [1]
• Sensitivity: 69.2-84.4% vs. IPSCC 58.7-70.7% [1]
• Derivation cohort: >3 million encounters across 10 sites in the US, Colombia, Bangladesh, China, and Kenya [1]
• 2026 multicenter European validation: sensitivity 96.4%, PPV 7.6% on PICU admission day 1 [4]

Pediatric SOFA (pSOFA)

pSOFA adapts the adult SOFA score for children, scoring six organ systems 0-4 each (total 0-24):

The Phoenix Sepsis Score was derived in part from pSOFA subscores, collapsing levels where performance was unaffected (for example, pSOFA respiratory subscores of 1 and 2 were combined into one level). Phoenix prioritizes simplicity and lower dependence on laboratory measures while preserving predictive performance [1].

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Vasoactive-Inotropic Score (VIS)

VIS = dopamine (mcg/kg/min) + dobutamine (mcg/kg/min) + [100 × epinephrine (mcg/kg/min)] + [100 × norepinephrine (mcg/kg/min)] + [10 × milrinone (mcg/kg/min)] + [10,000 × vasopressin (U/kg/min)] [5,6]

Higher VIS reflects greater medication burden and more severe circulatory instability. VIS at 48 hours correlates with ICU length of stay (r=0.53) and ventilator days (r=0.52) [5]. Each unit increase in VIS at 48 hours is associated with a 13% increase in ICU length of stay and an 8% increase in ventilator days [5].

Track vasopressor burden in VIS Score →

Trajectory groups (2022, critically ill children with shock) [7]:

The mild-fast-resolving and severe-prolonged groups are identifiable within the first 24 hours. The two moderate groups are indistinguishable early but diverge in outcome over time [7].

Clinical pearl. Rising VIS indicates deterioration despite treatment. Falling VIS suggests therapeutic response. If vasopressor requirements escalate and VIS stays elevated after 4-6 hours of aggressive management, reconsider occult infection source, inadequate source control, or a resistant organism.

Pediatric Early Warning Scores (PEWS)

PEWS systems identify deteriorating hospitalized children before sepsis or ICU transfer develops. BedsidePEWS is a validated 7-item score, range 0-26 [8].

• EPOCH multicenter RCT across 21 hospitals: PEWS rises over the 24 hours preceding urgent PICU admission [9].
• At a score of 8: sensitivity 82%, specificity 93% for identifying children requiring urgent ICU admission [9].
• 2026 comparative study: the Parshuram (BedsidePEWS) model had the highest diagnostic accuracy among four PEWS models, AUC 0.816 for ICU admission at threshold ≥8 [10].

Score deterioration risk at bedside in PEWS Calculator →

Indications for Urgent Evaluation

Fever alone does not establish sepsis. The following combinations warrant urgent evaluation:

• Fever with disproportionate tachycardia
• Petechial rash (concerning for meningococcemia)
• Altered mental status
• Elevated lactate (>2 mmol/L)
• Prolonged capillary refill (>3 seconds) with weak pulses

Management

Fluid resuscitation (2025 AHA/AAP PALS) [11]:

• Reassess after every fluid bolus for responsiveness and volume overload (Class 1)
• 10 mL/kg or 20 mL/kg aliquots are both reasonable initial bolus volumes with frequent reassessment (Class 2a)
• Isotonic crystalloids or colloids can both be effective initial choices (Class 2a)
• Balanced or unbalanced solutions can both be effective; balanced crystalloids are generally preferred (Class 2a)
• Epinephrine or norepinephrine as initial vasoactive infusion for fluid-refractory septic shock (Class 2a)

Two RCTs found that higher fluid volumes or faster fluid del

References

1. Sanchez-Pinto LN, Bennett TD, DeWitt PE, et al. Development and Validation of the Phoenix Criteria for Pediatric Sepsis and Septic Shock. JAMA. 2024;331(8):675-686.
2. Schlapbach LJ, Watson RS, Sorce LR, et al. International Consensus Criteria for Pediatric Sepsis and Septic Shock. JAMA. 2024;331(8):665-674.
3. Weiss SL, Peters MJ, Alhazzani W, et al. Surviving Sepsis Campaign International Guidelines for the Management of Septic Shock and Sepsis-Associated Organ Dysfunction in Children. Pediatr Crit Care Med. 2020;21(2):e52-e106.
4. Marchetto L, Daverio M, Comoretto R, et al. Predictive and Prognostic Performance of the Phoenix Sepsis Criteria and Phoenix Sepsis Score in PICU Patients With Suspected Infection: A Multicenter Prospective Study. Crit Care Med. 2026.
5. McIntosh AM, Tong S, Deakyne SJ, Davidson JA, Scott HF. Validation of the Vasoactive-Inotropic Score in Pediatric Sepsis. Pediatr Crit Care Med. 2017;18(8):750-757.
6. Belletti A, Lerose CC, Zangrillo A, Landoni G. Vasoactive-Inotropic Score: Evolution, Clinical Utility, and Pitfalls. J Cardiothorac Vasc Anesth. 2021;35(10):3067-3077.
7. Perizes EN, Chong G, Sanchez-Pinto LN. Derivation and Validation of Vasoactive Inotrope Score Trajectory Groups in Critically Ill Children With Shock. Pediatr Crit Care Med. 2022;23(12):1017-1026.
8. Parshuram CS, Hutchison J, Middaugh K. Development and Initial Validation of the Bedside Paediatric Early Warning System Score. Crit Care. 2009;13(4):R135.
9. Parshuram CS, Dryden-Palmer K, Farrell C, et al. Effect of a Pediatric Early Warning System on All-Cause Mortality in Hospitalized Pediatric Patients: The EPOCH Randomized Clinical Trial. JAMA. 2018;319(10):1002-1012.
10. Tazegul M, Turkmen Karaagac A, Guven S. Comparative Evaluation of Different Pediatric Early Warning Scores in Predicting Clinical Outcomes in Pediatric Emergency Observation Units. Pediatr Emerg Care. 2026;42(3):e52-e59.
11. Lasa JJ, Dhillon GS, Duff JP, et al. Part 8: Pediatric Advanced Life Support: 2025 American Heart Association and American Academy of Pediatrics Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Pediatrics. 2026;157(1):e2025074351.