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Diagnosing HIE

In the previous section, we talked about the Symptoms of Hypoxic-Ischemic Encephalopathy, or HIE. In this section, we will continue with a discussion on how HIE is diagnosed focusing on the Sarnat scale.

This information has been compiled from government sources, medical sources, and from consulting with experts on HIE.

Keep reading to learn more about how HIE is diagnosed.

How is HIE Diagnosed?

The main diagnostic tool used to diagnose a newborn with HIE is the Sarnat Scale. This scale looks at multiple aspects of the child’s condition immediately after birth to evaluate the extent of the birth injury.

The Sarnat Scale will include a variety of tests, including:

  • Consciousness levels
  • Gastrointestinal condition
  • General responsiveness
  • Heart rate
  • Muscular control and overall tone
  • Skin color (some HIE babies will have pale or bluish skin)
  • Reflexes
  • Breathing ability
  • Seizure intensity, if any
  • Ability to perform bodily functions on their own (autonomic function)

The Sarnat Scale is usually used in conjunction with the APGAR Score, which we have also covered in this guide. However, the APGAR score is not always reliable, given the somewhat subjective elements of the test.

sarnat scoring tool

Symptoms, Risks, and Causes of HIE

There are many possible symptoms and causes of HIE including high blood pressure, uterine rupture, and premature birth. Such symptoms can be detected before birth, during birth, and in the months following delivery.

The biggest cause of HIE is blood flowing issues that arise during or before birth. Placental abruption and placental insufficiency can create an oxygen-deprived environment for a baby at virtually any stage of pregnancy. Umbilical cord problems during labor can also cut off a child’s oxygen and blood supply, resulting in HIE. Being older than 40 years old and under 17 years old are also potential risk factors.

After birth, HIE can still go undetected in some cases. Within 24 hours but usually right after delivery, doctors will administer a series of common tests for HIE. These tests are often performed for the purpose of evaluating the newborn’s overall health as well as brain injuries.

Common Tests for HIE

The most common test for HIE is the Sarnat Scale, but physicians may also use the APGAR score or APGAR test. This acronym can be summed up as Appearance, Pulse, Grimace, Activity, and Respiratory effort. An APGAR score of under three for a duration longer than a few minutes can be a major warning sign.

This test is performed after birth to ensure the health of the newborn. Babies with HIE or other birth injuries may have pale skin or an abnormal heart rate. Brain damage can also lead to a lack of reflexes post-birth and issues with overall mobility. Respiratory problems and poor breathing are also potential signs of HIE.

Magnetic resonance imaging (MRIs) and computerized tomography (CT scans) are also utilized in the event of a possible brain injury during birth. Specialists can use these tools to take actual photos of the child’s brain to see where the injury occurred and make an assessment for diagnosis. In some cases, ultrasounds can detect signs of brain injuries during pregnancy.

Umbilical cord testing is also a common test for this injury. Doctors will take a small sample of blood from the umbilical cord post-birth. In the blood within the cord has high acidity and low pH, there is a chance that the baby may have HIE.

Common Evaluation Techniques for HIE in Older Children

In some cases of HIE, symptoms won’t be very apparent until the baby starts growing in their first few months of life. Some babies with HIE may begin to exhibit seizures. In this case, a physician may decide to use electroencephalogram (EEG) testing to see what is actually causing the seizures.

Seizures can be the result of many birth injuries or conditions, but they are always considered very serious. Neonatal seizures can further increase brain damage that may already exist and should be treated immediately.

Developmental problems, especially developmental delays, can also be signs of HIE in older babies. A physician may administer some tests to determine in the delays are substantial enough to be the result of a bigger problem.

Is Early HIE Detection Important?

Early HIE detection is extremely important. It’s unfortunate because sometimes it is difficult to determine in a child is suffering from HIE immediately after birth. As a result, a physician should use the Sarnat Scale, perform an APGAR test, and follow up with additional screening and testing as needed. This is especially so if there was a known birth injury that occurred.

Early detection of HIE allows for the chance for physicians to get the child into treatment immediately. Therapeutic hypothermia is the act of lowering a child’s body temperature. This is done to halt or slow the cycle of brain cell death that could continue to accrue in the child’s brain if let untreated.


Allen, K., & Brandon, D. (2011). Hypoxic Ischemic Encephalopathy: Pathophysiology and Experimental Treatments. Newborn And Infant Nursing Reviews, 11(3), 125-133. doi:10.1053/j.nainr.2011.07.004

UpToDate. (2019). Uptodate.com. Retrieved 18 November 2019, from https://www.uptodate.com/contents/clinical-features-diagnosis-and-treatment-of-neonatal-encephalopathy

Help for Children with HIE – Brown Trial Firm. (2019). Brown Trial Firm. Retrieved 18 November 2019, from https://browntrialfirm.com/hypoxic-ischemic-encephalopathy-hie/

(2019). Pdfs.semanticscholar.org. Retrieved 18 November 2019, from https://pdfs.semanticscholar.org/1a14/5e5b73aba362f0490e7c534d1e049b505eea.pdf

(2019). Fn3.sites.medinfo.ufl.edu. Retrieved 18 November 2019, from https://fn3.sites.medinfo.ufl.edu/files/2018/01/Sarnat-Definitions.pdf


About Brown Trial Firm

Getting help for a child with HIE or Cerebral Palsy can make a big difference. Because early intervention is often key to helping improve a child’s wellbeing, it’s important to act swiftly.

At the Brown Trial Firm, our birth injury attorneys can help you investigate your case, find answers to your questions, and determine whether you are entitled to compensation. 

We offer case reviews at no cost or obligation. Many birth injuries that cause cerebral palsy could have been prevented. Don’t wait, get help today. Call us toll free at +1 (866) 223-7465 or email us a [email protected].

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