Pediatric Sepsis and the Phoenix Criteria

Pediatric sepsis is infection that threatens life by injuring organs. A fixed list of abnormal vital signs does not define it. The 2024 Phoenix criteria replaced the 2005 International Pediatric Sepsis Consensus Conference criteria. Those relied on systemic inflammatory response syndrome (SIRS) findings, and SIRS predicts poorly. Suspected infection plus a Phoenix Sepsis Score of 2 or more means the child has sepsis. Add cardiovascular dysfunction and it is septic shock. The score counts points in four organ systems: respiratory (oxygenation or ventilation), cardiovascular (mean arterial pressure for age, lactate and vasoactive drugs), coagulation (platelets, INR, D-dimer and fibrinogen) and neurologic (Glasgow Coma Scale and pupil reaction). A lactate of 5 mmol/L or higher earns the cardiovascular point. The criteria cover children under 18 years. They do not apply to birth hospitalizations or to children with postconceptional age under 37 weeks. Do not use them for those patients. The published table holds the points and cut-offs.

Why Kids Are Different

• Tachycardia comes first: a child holds blood pressure up with a faster heart and tighter vessels. Hypotension shows up late.
• Fever is unreliable in young infants: some neonates and young infants with sepsis run cold or stay afebrile. Read the trend and the perfusion. Do not trust the temperature alone.
• Little volume reserve: a 10 kg infant's 20 mL/kg bolus is only 200 mL. Count every volume in mL/kg.
• Age-specific cut-offs: blood pressure thresholds in the Phoenix score move with age. One adult number will mislead you in a child.

How deadly is it? In the Phoenix validation, a score of 2 or more carried an in-hospital mortality of 7.1% in higher-resource settings and 28.5% in lower-resource settings. Septic shock ran 10.8% and 33.5%.

Infection plus a change in perfusion, mental status or organ function. That is sepsis. Compare the child with their own baseline first, then with age norms (see vital signs by age).

These are the hypotension thresholds on this site (systolic, mmHg): term neonate under 60; infant 1 to 12 months under 70; 1 to 10 years under 70 + (2 × age); over 10 years under 90. Use them at the bedside for triage. The Phoenix score runs on mean arterial pressure by age, so score from the published table. Dosing moves to adult doses by weight, 40 kg or more, per protocol. Age does not decide it.

Age-Specific Presentation

• Neonate (0–28 days): poor feeding, unstable temperature, apnea, grunting, lethargy and hypoglycemia. Think sepsis and ductal-dependent heart disease at the same time.
• Infant (1–12 months): irritability, poor feeding, a bulging fontanelle and fewer wet diapers.
• Child (1–12 years): lethargy, cool extremities, abdominal pain or vomiting, and reduced urine output. Up to age 10, use the 1–10 year threshold. From age 11, use the under-90 threshold.
• Adolescent (13–18 years): adult signs and the under-90 systolic threshold apply. Hypotension may show up late, and all at once.

0–5 Minutes

1. Recognize and start the clock: write down the time you suspect septic shock. The one-hour antibiotic target counts from that moment (Paramedic/RN/CCT, per local protocol).
2. Access and glucose: place an IV, or an IO if IV access is not rapidly obtainable, per local protocol (see pediatric vascular access). Check glucose.
3. Draw labs without delay: draw the blood culture only if it will not delay antibiotics. Lactate, CBC, electrolytes, coagulation studies and a blood gas. SSC 2026 strongly recommends measuring lactate at the initial evaluation.

Within 1 Hour

1. Give antibiotics: in suspected septic shock, SSC 2026 strongly recommends antimicrobials, ideally within 1 hour of recognition. Don't wait on culture results. Pick the agent by local protocol and suspected source. Add MRSA or meningitis coverage per protocol.
2. Give a balanced bolus: 10–20 mL/kg isotonic crystalloid over 5–20 min, then reassess. When boluses are needed, SSC 2026 suggests a balanced or buffered solution over 0.9% saline (conditional, very low certainty). The exception is hyponatremia or concern for raised intracranial pressure, such as CNS infection. There, SSC 2026 notes 0.9% saline may be preferred.
3. Set the total: with ICU access, you can give up to 40–60 mL/kg in the first hour, as 10–20 mL/kg boluses. Without ICU access, the cap is 40 mL/kg in the first hour, and only in septic shock with hypotension. Stop when shock resolves. Stop too when fluid overload appears: crackles, rising oxygen need or hepatomegaly.

Sepsis Without Hypotension

1. No bolus without hypotension: sepsis without hypotension, and no ICU access, means no bolus. SSC 2026 strongly recommends against fluid boluses here and favors starting maintenance fluids.
2. Reassess: repeat perfusion, mental status and lactate checks. Escalate to a pediatric-ready ED or PICU if perfusion worsens.

1. Start a vasoactive infusion: when shock persists after fluid, start epinephrine or norepinephrine. SSC 2026 found too little evidence to rank one above the other. Let the clinical picture and local protocol choose. Dopamine is second-line per protocol (see dopamine).
2. Start peripherally when needed: you do not have to wait for a central line. SSC 2026 conditionally recommends peripheral or IO vasoactives (very low certainty). Watch the site for extravasation.
3. Escalate: when you need high-dose catecholamines, SSC 2026 conditionally suggests adding vasopressin or titrating the catecholamines further (low certainty). In children, vasopressin is PICU specialist practice.
4. Hydrocortisone: once fluids and vasoactives have stabilized the child, SSC 2026 conditionally suggests against routine IV hydrocortisone (low certainty). Stress-dose hydrocortisone is for suspected or known adrenal insufficiency.
5. Intubation: resuscitate first, and have a vasoactive running or ready. SSC 2026 conditionally suggests against etomidate for intubating children with sepsis (low certainty).

Every dose runs per kg of measured weight. Only when no weight is available do you fall back to a length-based or age-based estimate (see weight-based dosing).

Fluids and Antibiotics

Vasoactives and Steroids

Infusions are written in mcg/kg/min at a dosing weight. Every vasoactive infusion gets two independent checks: drug, concentration, units and rate.

• Labs: lactate, glucose, electrolytes, BUN and creatinine, CBC, coagulation studies (DIC is common in septic shock) and a blood gas with base deficit. Follow the base deficit as a trend, and skip the fixed cut-off.
• Disposition: PICU or a pediatric-ready ED. Transfer early, before the child needs several infusions or intubation, where possible.

Neonates and Young Infants

• Two causes look alike: sepsis and ductal-dependent heart disease. No response to fluid and antibiotics? Think about the second one.
• Empiric antibiotics: follow the neonatal protocol. Ampicillin with gentamicin or cefotaxime is common. Add acyclovir when HSV is possible.
• Ceftriaxone limits: contraindicated in premature neonates up to 41 weeks postmenstrual age, and in neonates 28 days or younger who need IV calcium (label).
• Glucose: neonatal D10W is 2 mL/kg. Check glucose early, then keep checking.

Adolescents

• Switch point: at 40 kg or more, going by weight and not age, or past the length-based tape, adult protocols and adult maximum doses apply. Follow local protocol.

Neutropenia, Asplenia, Sickle Cell Disease or Immunosuppression

• Treat fever as high risk: with febrile neutropenia, asplenia, sickle cell disease or immunosuppression (including chemotherapy and transplant), start broad-spectrum antibiotics early. The oncology, hematology or local protocol picks the agents.
• Escalate early: these children can fall apart fast, with less reserve to spare. Call the PICU or treating team sooner than you would for an otherwise similar child.

Children With Central Lines or Special Health Care Needs

• Consider the line or device as a source: a central venous catheter, a ventriculoperitoneal shunt or a gastrostomy can seed bacteremia. Ask when it was last changed.
• Carry the Emergency Information Form: it lists devices, prior surgery and home medications. Recent steroids belong on it as well.

• Time to antibiotics: call ahead to the receiving team. Give antibiotics where your protocol allows, as long as transport is not held up.
• Destination: the nearest pediatric-ready ED to stabilize, or a PICU when you expect escalation.
• Restrain on the stretcher: use a size-appropriate restraint. Do not hold the child on a caregiver's lap during transport.
• Keep the child warm: infants lose heat fast. Warm the fluids when that is feasible.
• Handoff: run it in a structured format (IMIST-AMBO or MIST). Say the fluid volumes in mL/kg, the time of each bolus and the antibiotic time.