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Table 1 Modified Sarnat scale for clinical encephalopathy staging

From: Hypothermia for encephalopathy in low and middle-income countries (HELIX): study protocol for a randomised controlled trial

Categories (total 6)

Signs of neonatal encephalopathy (NE) in each category

Normal

Mild NE

Moderate NE

Severe NE

1. Level of consciousness

 

Alert, responsive to external stimuli (state dependent, e.g. post feeds)

Hyper-alert, has a stare, jitteriness, high-pitched cry, exaggerated responds to minimal stimuli, inconsolable

Lethargic

Stupor/coma

2. Spontaneous activity

 

Changes position when awake

Normal or decreased

Decreased activity

No activity

3. Posture

 

Predominantly flexed when quiet

Mild flexion of distal joints (fingers, wrist usually)

Moderate flexion of distal joint, complete extension

Decerebrate

4. Tone

 

Strong flexor tone in all extremities + strong flexor hip tone

Normal or slightly increased peripheral tone

Hypotonia (focal or general) or hypertonia

Flaccid

Rigid

5. Primitive reflexes (circle only the highest level in each sign; the maximum score is only 1 in any one category)

 Suck

Strong, easily illicit

Weak, poor

Weak but has a bite

Absent

 Moro

Complete

Partial response, low threshold to illicit

Incomplete

Absent

6. Autonomic system (circle only the highest level in each sign; the maximum score is only 1 in any one category)

Pupils

In dark: 2.5–4.5 mm; in light: 1.5–2.5 mm

Mydriasis

Constricted

Deviation/dilated/non-reactive to light

Heart rate

100–160 bpm

Tachycardia (HR > 160)

Bradycardia (HR < 100)

Variable HR

Respiration

Regular respirations

Hyperventilation (RR > 60/min)

Periodic breathing

Apnoea or requires ventilator

Total score

  1. The level of encephalopathy will be assigned based on which level of signs (moderate or severe) predominates among the six categories. If moderate and severe signs are equally distributed, the designation is then based on the highest level in Category #1: The level of consciousness. If the level of consciousness is equal, then designation of the NE stage is based on the tone (Category #4). An infant who has seizures will be moderate or severe NE, depending on the neurologic exam. Seizure with normal or mild NE or moderate NE on neurologic exam will be ‘Moderate NE’. Seizure with severe NE will be ‘Severe NE’