Therapeutic Hypothermia for Babies with Hypoxic-Ischemic Encephalopathy (HIE)

Hypoxic-ischemic encephalopathy (HIE) is a type of neonatal brain injury caused by oxygen deprivation and/or limited blood flow to the brain at or near the time of birth. It can result in permanent brain damage, lifelong disabilities such as cerebral palsy (CP), and even infant death. However, a cutting-edge treatment called therapeutic hypothermia can minimize the risks associated with HIE.


What is hypoxic-ischemic encephalopathy (HIE)?

Hypoxic-ischemic encephalopathy (HIE) occurs when the flow of oxygenated blood to a baby’s brain is impeded around the time of birth. HIE occurs in roughly 2 per 1,000 live births (1). It may be caused by placental abruption, umbilical cord prolapse, or a variety of other complications and medical mistakes.

The initial oxygen-depriving insult is not the only injury; rather, it sets off a chain reaction: rippling outward from the initial injury site, cells become injured, die, and release certain substances that are toxic to other cells.

Infants who experience moderate HIE have a 10% risk of fatality, and those who live have a 30% risk of disabilities (2). Infants with severe HIE have a 60% risk of fatality, and nearly all of the survivors experience disabilities.

Therapeutic hypothermia is the standard treatment for HIE. It can slow down the injury process, allowing the baby’s brain to heal and minimizing the spread of damage. Clinical evidence has shown that therapeutic hypothermia has benefited full-term infants with moderate to severe HIE (1).

What is therapeutic hypothermia?

Therapeutic hypothermia (also known as hypothermia therapy, brain cooling, cooling therapy, and cooling treatment) is a procedure used to help slow down the injury process associated with HIE (1). While it is now being used in numerous different fields (including for treating heart attacks, strokes, and traumatic injuries in adults), in the context of birth injury, the process focuses specifically on slowing down a baby’s brain damage.

Neonatal therapeutic hypothermia is used to treat HIE by cooling the baby to about 33.5 – 34.5 degrees Celsius for 72 hours, ideally within six hours of birth/the oxygen-depriving event (3).

To administer therapeutic hypothermia, doctors may use either a cooling cap (selective brain cooling) or a cooling blanket (whole body cooling). Either of these methods can be effective, the choice of one or the other depends on the clinical picture as well as the equipment that is available in that particular NICU (5).

During the treatment, neonatal staff closely monitor vital signs like respiration, oxygenation, heart rate, and brain wave activity. Physicians use this data to determine how the baby is responding overall to the cooling treatment.

Following therapeutic hypothermia, the body is re-warmed slowly (over at least four hours), at a rate of 0.5 degrees Celsius per hour until they are at 36.5 – 37 degrees Celsius (3).

How does therapeutic hypothermia work?

Lowering the body’s temperature slows the metabolic rate and allows cells more time to recover from neurological damage.

Cooling has been shown to positively affect the following in infants with HIE (2):

  • Nitric oxide production
  • Apoptosis
  • Cerebral metabolism and blood flow
  • Excitatory amino acids
  • Cerebral energy

Therapeutic Hypothermia - Brain Cooling - Body Cooling | Treatment for Hypoxic-Ischemic Encephalopathy (HIE)

When should doctors perform therapeutic hypothermia?

Guidelines for therapeutic hypothermia continue to evolve as research progresses, and exact criteria vary from hospital to hospital. However, the Academic Medical Center Patient Safety Organization (AMC PSO) provided the following general recommendations from a task force on neonatal encephalopathy in 2016 (5).

Therapeutic hypothermia should be given when all three of the following criteria are met:

  1. The baby is less than six hours of age* and was born after at least 36 weeks of pregnancy.
  2. At least one of the following:
    • A complication before delivery, such as cord prolapse, uterine rupture, or profound fetal bradycardia
    • An Apgar score of five or lower at 10 minutes of life
    • Prolonged resuscitation at birth
    • Severe acidosis
    • Abnormal base excess within 60 minutes of birth, as shown in umbilical cord gas or neonate blood gas
  3. At least one of the following:

Additionally, physicians are advised to consider administering therapeutic hypothermia when all three of these criteria are met:

  1. The baby is no more than 12 hours of age* and was born after at least 34 weeks of pregnancy.
  2. At least one of the following:
    • A complication before delivery, such as cord prolapse, uterine rupture, or profound fetal bradycardia
    • An Apgar score of five or lower at 10 minutes of life
    • Prolonged resuscitation at birth
    • Acidosis
    • Abnormal base excess within 60 minutes of birth, as shown in umbilical cord gas or neonate blood gas
    • A collapse after birth that results in hypoxic-ischemic injury.
  3. At least one of the following:
    • Signs of neonatal seizures
    • Evidence of neonatal encephalopathy in a clinical exam

*Recent research indicates that therapeutic hypothermia may still be beneficial when started up to 24 hours after birth. Learn more about that here.

When should a baby not receive therapeutic hypothermia?

The AMC PSO guidelines state that babies should not receive therapeutic hypothermia if they were born very preterm (under 34 weeks into pregnancy), and that physicians should exercise extreme caution if they weigh less than 1,750 grams, have severe congenital abnormalities, suffered major intracranial hemorrhage, have overwhelming septicemia, or show evidence for a blood clotting disorder that could make the treatment dangerous (5).

Current evidence does not support the cooling of babies born before 35 weeks or who have mild hypoxic-ischemic encephalopathy (3).


About ABC Law CentersReiter & Walsh, PC | Birth Trauma Attorneys

ABC Law Centers is a medical malpractice law firm focused exclusively on cases involving HIE and other birth injuries. In a birth injury case, settlement money can be used to pay for a child’s lifelong treatment, therapy, and a secure future. If you believe that your child’s HIE may have been caused by a negligent medical professional or hospital, or that your child was not given therapeutic hypothermia when they should have been, you may have a case. Please contact us to learn more. We are happy to talk to you free of any charge. In fact, you would pay nothing throughout the entire legal process unless we win your case.

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Video: Michigan HIE lawyers discuss therapeutic hypothermia and hypoxic-ischemic encephalopathy (HIE)

In this video, Michigan HIE lawyers Jesse Reiter and Rebecca Walsh discuss the causes of and treatments for HIE.  Negligence by the medical team is often the cause of HIE and birth asphyxia.

How do you pronounce hypoxic-ischemic encephalopathy?


Related reading

Hypoxic-Ischemic Encephalopathy (HIE)

Hypothermia Therapy May Be Effective 6-24 Hours After Birth

Research Update: Combining EPO and Hypothermia Therapy to Treat HIE

Sources

  1. Davidson, J. O., Wassink, G., van den Heuij, L. G., Bennet, L., & Gunn, A. J. (2015). Therapeutic Hypothermia for Neonatal Hypoxic-Ischemic Encephalopathy – Where to from Here?. Frontiers in neurology, 6, 198. doi:10.3389/fneur.2015.00198
  2. Shankaran, Seetha, et al. Whole-Body Hypothermia for Neonates with Hypoxic–Ischemic Encephalopathy. N Engl J Med 2005; 353:1574-1584. October 13, 2005. DOI: 10.1056/NEJMcps050929.
  3. Mosalli R. (2012). Whole body cooling for infants with hypoxic-ischemic encephalopathy. Journal of clinical neonatology, 1(2), 101-6.
  4. Guillet, R. Seven- to eight-year follow-up of the CoolCap trial of head cooling for neonatal encephalopathy. Pediatr Research 2012 Feb; 71(2):205-9. doi: 10.1038/pr.2011.30. Epub 2011 Dec 21.
  5. The Academica Medical Center Patient Safety Organization (AMC PSO) Neonatal Encephalopathy Task Force. (2016). Therapeutic Hypothermia in Neonates: Recommendations of the Neonatal Encephalopathy Task Force[Pamphlet].