The Sarnat Grading Scale of HIE (Hypoxic-Ischemic Encephalopathy) is a scoring system used to grade the severity of an HIE injury.
To the right is Alissa, the founder’s daughter, several days after birth. She suffered severe HIE and is being tapped with a respritary cup to help to clear secretions from her lungs. Also note the NG or Nasal Gastric Tube used for feeding. Her low tone did not allow her body to control saliva from entering and accumlating in her lungs. Also notice the cap on her head, she was kept warm from her birth. Modern treament is to place HIE infants into a cold state to slow down the metabulism and help prevent what is know as the “Cascade of Neurologic Injury” that occurs in the first 48-72 hours after birth.
The clinical characteristics of HIE (Hypoxic-Ischemic Encephalopathy) can be described as mild, moderate, or severe. The most common grading or staging system is by the Sarnat scale developed by Sarnat and Sarnat in 1976.
The Sarnat Score combines clinical and EEG findings (I, II, III = mild, moderate, severe). When using only clinical findings, this grading system is called the Modified Sarnat Score. The different stages are detailed below.
Mild HIE – Sarnat Stage I
- Eyes wide open
- Does not sleep
- No seizures
- Usually lasts < 24 hours
Moderate HIE – Sarnat Stage II
- Lethargy (difficult to rouse)
- Reduced tone of the extremities and/or trunk
- Diminished brainstem reflexes (pupil/gag/suck)
- Possible clinical seizures
Severe HIE – Sarnat Stage III
- Coma (cannot be roused)
- Weak or absent respiratory drive
- No response to stimuli (may have spinal reflex to painful stimuli)
- Flaccid tone of the extremities and trunk (floppy)
- Diminished or absent brain stem reflexes (pupil/gag/suck)
- Diminished tendon reflexes
- EEG severely abnormal (suppressed or flat EEG with or without seizures)
Sarnat Cheat Sheet