Neonatal Hypoxic-Ischemic Encephalopathy Staging (Sarnat) — free guideline decision tool

Sarnat staging grades neonatal hypoxic-ischemic encephalopathy (HIE) as mild, moderate or severe from the overall pattern of consciousness, tone, reflexes, autonomic function and seizures.

A stage-3 pattern in any domain = severe (stage 3); any moderate feature or seizures = moderate (stage 2); otherwise mild (stage 1). Hypothermia eligibility = stage 2–3 + asphyxia evidence + GA ≥ 35 wk + < 6 h of age.

Use in term/near-term newborns with suspected perinatal asphyxia to grade encephalopathy severity and decide on therapeutic hypothermia.

Moderate-to-severe HIE (stage 2–3) within 6 hours of birth, with evidence of perinatal asphyxia, is the trigger for therapeutic hypothermia at 33–34 °C for 72 hours. Staging is based on the evolving overall pattern, not a single sign; seizures or any moderate-domain feature already place the infant at stage 2. Supportive care (normothermia, glucose, perfusion, seizure control) and multimodal prognostication (neuro exam, aEEG/EEG, MRI) accompany staging regardless of cooling.

For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.

Inputs: Level of consciousness Hyperalert / irritable (1), Muscle tone Normal or mildly increased (1), Primitive reflexes (suck / Moro) Active / normal (1), Autonomic function Sympathetic predominant (mydriasis / tachycardia) (1), Seizures None, Evidence of perinatal asphyxia (cord pH ≤ 7.0 or BE ≤ −12 / 10-min Apgar ≤ 5 / required resuscitation) AND GA ≥ 35 wk AND < 6 h of age Not met → Result: Sarnat stage Stage 1 (mild)（Stage: Stage 1 mild: hyperalert, normal or mildly increased tone, active reflexes, sympathetic overactivity, no seizures, usually < 24 h, Hypothermia eligibility: Stage 1 (mild) generally does not warrant hypothermia; monitor closely and reassess if it progresses to moderate-to-severe and criteria are met, Management direction: Supportive care: maintain normothermia (avoid hyperthermia), glucose, electrolytes, perfusion and oxygenation; control seizures; multimodal prognostication (evolving neuro exam + aEEG/EEG + MRI)） Inputs: Level of consciousness Stupor / coma (3), Muscle tone Flaccid (3), Primitive reflexes (suck / Moro) Absent (3), Autonomic function Depressed (fixed pupils / unstable) (3), Seizures Present, Evidence of perinatal asphyxia (cord pH ≤ 7.0 or BE ≤ −12 / 10-min Apgar ≤ 5 / required resuscitation) AND GA ≥ 35 wk AND < 6 h of age Met → Result: Sarnat stage Stage 3 (severe)（Stage: Stage 3 severe: stupor/coma, flaccid, absent reflexes, brainstem and autonomic depression, suppressed EEG, Hypothermia eligibility: Eligible: moderate-to-severe HIE (stage 2–3) + evidence of perinatal asphyxia + GA ≥ 35 wk + < 6 h of age → start therapeutic hypothermia (target 33–34 °C × 72 h, whole-body or selective head cooling) with continuous monitoring and aEEG/EEG, Management direction: Supportive care: maintain normothermia (avoid hyperthermia), glucose, electrolytes, perfusion and oxygenation; control seizures; multimodal prognostication (evolving neuro exam + aEEG/EEG + MRI)）