What Does Hypothermia Treatment for HIE Entail & What Babies Are Eligible?

What Does Hypothermia Treatment for HIE Entail & What Babies Are Eligible?

Babies with hypoxic ischemic encephalopathy must receive hypothermia therapy within 6 hours* of the time they experienced the insult that caused oxygen deprivation in the brain. This usually means that treatment must be given within 6 hours of birth. The more severe the insult, the sooner the treatment should be initiated. When a baby receives hypothermia treatment, her core body temperature is cooled to 33.5 degrees for 72 hours. A cooling blanket is usually used for the therapy, and this is what was used in the recent JAMA study. In some cases, a cooling cap is used to lower the baby’s temperature.

Since therapeutic hypothermia is so beneficial for babies with hypoxic ischemic encephalopathy, it is crucial for the medical team to closely monitorbabies suspected of experiencing an oxygen-depriving insult during or near the time of birth so they can promptly determine if a baby is eligible for the treatment. In determining whether a baby is eligible, many hospitals use the eligibility criteria that previous research trials used when studying HIE and brain cooling. The eligibility requirements for hypothermia treatment in many hospitals are listed below.

Neonatal Requirements for Therapeutic Hypothermia

1.  Gestational age greater than 36 weeks

2.  pH is less than 7 or base deficit is 16 or greater in an umbilical cord arterial blood gas sample (baby’s blood at birth is acidic, which is a sign of severe oxygen deprivation)

If pH is 7.01 – 7.15, base deficit is 10 – 15.9, or a blood gas sample is not available, the additional criteria are required:

1.  A sudden event during labor occurred, such as nonreassuring fetal heart tones (late or variable decelerations) umbilical cord prolapse or rupture, uterine rupture, maternal trauma, hemorrhage or cardio-respiratory arrest AND either a 10 minute Apgar score of 5 or less or assisted ventilation (baby is on a breathing machine or is being bagged) at birth that lasts 10 minutes or more. (Non-reassuring heart tones mean a baby is being deprived of oxygen)

2.  Evidence of seizures or neonatal encephalopathy (global brain injury) by a standard neurological exam

Hypoxic Ischemic Encephalopathy & Hypothermia Treatment

Hypoxic ischemic encephalopathy (HIE) is a brain injury caused by oxygen deprivation and decreased blood flow in the baby’s brain. Birth asphyxia is the term used to describe a lack of oxygen in a baby’s brain during or near the time of birth and it is the most common cause of birth injuries in babies. HIE often results in the newborn having seizures, permanent brain damage and cerebral palsy.

Hypoxic ischemic encephalopathy begins with an oxygen-depriving insult to the brain. When oxygen deprivation (hypoxia) is prolonged, the baby’s blood pressure drops and there is a decreased flow of oxygen-rich blood in the brain. At this point, the baby already has abnormally low levels of oxygen in her blood. Reduced blood flow in the brain (ischemia) coupled with the low oxygen level in the blood, along with other factors, lead to brain injury. Brain injury is an evolving process. First, there is primary energy failure, which is when brain cells die, mainly because they aren’t getting enough oxygen and glucose. This leads to toxins within the cell being released / created, which causes cell death. If the baby survives, blood flow is restored in the brain and the healthy chemical reactions for energy start to occur again in the brain cells. But then there is a secondary phase of brain injury that occurs when the blood flow (perfusion) is restored. On the one hand, adequate blood flow must occur for the baby to survive. On the other hand, reperfusion causes further brain injury due to inflammation and oxidative damage. During this time, there is additional cell injury and programmed cell death. Indeed, the restored blood flow helps sustain tissue-damaging reactions, leading to scarring of the brain tissue.

This secondary phase of hypoxic-ischemic injury typically begins between 6 and 72 hours after the brain insult. This is why it is crucial for hypothermia treatment to begin before the 6 hour mark. The treatment not only halts the injurious processes that occur during the phase of primary energy failure, but it helps stop the damaging events that occur at the secondary phase, when perfusion is restored. During this phase, cooling the brain has many benefits, such as reducing pressure within the brain, decreasing damaging inflammatory processes and minimizing free-radical damage.

*Research Update: Hypothermia Therapy May Be Effective 6-24 Hours After Birth

A recently-published study in the Journal of the American Medical Association (JAMA) suggests that hypothermia therapy may be effective 6-24 hours after birth. Laptook et al. (2017) conducted a randomized clinical trial of infants with moderate or severe HIE. 83 infants were given hypothermia therapy, while 85 were maintained at a normal body temperature (control group). The authors then followed up with these cohorts between 18 and 22 months of age. Their results were non-significant under traditional frequentist analysis, but they suggested that hypothermia therapy may still be helpful more than six hours after birth. Laptook et al. stress that further research is warranted, because an improved prognosis in even a small percentage of patients could be of clinical importance due to the severity of HIE-related brain damage. Moreover, they found “no evidence of commensurate harm” – in other words, the potential benefits of administering hypothermia therapy between 6-24 hours may outweigh the costs.

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What Causes Hypoxic Ischemic Encephalopathy?

Birth asphyxia, the primary cause of HIE, is usually caused by problems with the placenta, uterus (womb) or umbilical cord. When the baby is in the womb, she is completely dependent on her mother for oxygen. Oxygen-rich blood travels from the mother’s circulatory system through vessels that run through the uterus and placenta (called the uteroplacental circulation). The blood then enters the umbilical cord vein where it travels to the baby and becomes part of the baby’s circulatory system. Once the blood is finished carrying oxygen to the baby’s cells, it contains waste products and it then travels back to the mother through the umbilical arteries.

An unborn baby receives oxygen-rich blood through the following pathway: maternal circulation –> uteroplacental circulation –> umbilical vein –> fetal circulation. The fetoplacental circulation includes the umbilical cord and blood vessels within the placenta that carry fetal blood.

The following is a list of conditions that can cause birth asphyxia if not properly managed. These conditions usually occur during or near the time of delivery.

• Umbilical cord problems, such as a nuchal cord (cord wrapped around baby’s neck), umbilical cord prolapse, short umbilical cord and cord in a true knot
• Ruptured uterus
• Preeclampsia / eclampsia
• Placental abruption
• Placenta previa
• Anesthesia mistakes, which can cause blood pressure problems in the mother, including a hypotensive crisis. This can greatly decreases the supply of oxygen-rich blood going to the baby.
• Oligohydramnios (low amniotic fluid)
• Premature rupture of the membranes (PROM) / premature birth
• Prolonged and arrested labor
• Intracranial hemorrhages (brain bleeds), which can be caused by a traumatic delivery. Forceps and vacuum extractors can cause brain bleeds. Sometimes intense contractions (hyperstimulation) caused by labor induction drugs (Pitocin and Cytotec) can cause head trauma. Mismanagement of cephalopelvic disproportion (CPD), abnormal presentations (face or breech presentation), and shoulder dystocia also put a child at risk of having a brain bleed.
• Hyperstimulation caused by Pitocin and Cytotec can also cause oxygen deprivation that gets progressively worse.
• Fetal stroke
• Postmaturity syndrome
• Failure to quickly deliver a baby when fetal distress is evident on the fetal heart rate monitor (delayed emergency C-section)

Award Winning HIE Lawyers Helping Children for Almost 3 Decades

If you are seeking the help of a lawyer, it is very important to choose a lawyer and firm that focus solely on birth injury cases. Reiter & Walsh ABC Law Centers is a national birth injury law firm that has been helping children with birth injuries for almost 3 decades.

Birth Injury lawyer Jesse Reiter, president of ABC Law Centers, has been focusing solely on birth injury cases for over 28 years, and most of his cases involve hypoxic ischemic encephalopathy (HIE) and cerebral palsy. Partners Jesse Reiter and Rebecca Walsh are currently recognized as being two of the best medical malpractice lawyers in America by U.S. News and World Report 2015, which also recognized ABC Law Centers as being one of the best medical malpractice law firms in the nation. The lawyers at ABC Law Centers have won numerous awards for their advocacy of children and are members of the Birth Trauma Litigation Group (BTLG) and the Michigan Association for Justice (MAJ).

If your child was diagnosed with a birth injury, such as cerebral palsy, a seizure disorder or hypoxic ischemic encephalopathy (HIE), the award winning birth injury lawyers at ABC Law Centers can help. We have helped children throughout the country obtain compensation for lifelong treatment, therapy and a secure future, and we give personal attention to each child and family we represent. Our nationally recognized birth injury firm has numerous multi-million dollar verdicts and settlements that attest to our success and no fees are ever paid to our firm until we win your case. Email or call Reiter & Walsh ABC Law Centers at 866-822-7484 for a free case evaluation. Our firm’s award winning lawyers are available 24 / 7 to speak with you.