Questions and answers about birth hypoxia
The Neuro-NICU team at Phoenix Children's Hospital cares for babies who have a neurological diagnosis such as a birth hypoxic event. Through a solid collaboration between two of our renowned Centers of Excellence, the Barrow Neurological Institute at Phoenix Children's Hospital and the Newborn Intensive Care Unit (NICU), Phoenix Children's is the only children's hospital in the Valley offering a complete Neuro-NICU program using state-of-the-art cooling therapies and neurological assessment tools.
If you would like more information about our complete program, please contact Kimberlee Allred, Neuro-NICU coordinator at (602) 546-1444.
Frequently Asked Questions About Hypoxic-Ischemic Encephalopathy (HIE) and Cooling Therapy
Below are some answers to most of the frequently asked questions we receive in the Neuro-NICU.
What is Hypoxic-Ischemic Encephalopathy (HIE)?
The condition called Hypoxic-Ischemic Encephalopathy, or HIE, exists when your baby’s brain has been deprived of oxygen; before and/or during delivery. The seriousness of this condition is based on how long a baby's brain was without oxygen, the affected region and the maturational state of the brain cells. In the event of deprivity, like in the case of an abruption during the birthing process, the medical term is best known as a birth hypoxic insult or HIE.
HIE is a progressive injury that can develop over the next few hours to days. There are three categories of HIE: mild, moderate, and severe. Most babies with mild HIE will recover with no disability. Approximately 40 to 70 percent of babies with moderate HIE have some form of lifelong disability such as cerebral palsy, cognitive deficits and/or seizures. The most severe cases almost always result in severe disabilities or death. Severe disabilities may include mental retardation, severe motor dysfunction and/or seizures.
What causes HIE?
There are three terms used to explain the causes of acute brain injury in newborns: antepartum (before labor and delivery), intrapartum (during labor and delivery) and postpartum (after labor and delivery). An acute intrapartum event, such as a placental abruption (or a loss of blood and oxygen when the placenta is removed from the wall), are among the most common brain injuries seen by the Neuro-NICU. When this occurs, the lack of oxygen causes trauma in the brain until oxygen is re-established. This results in Hypoxic Ischemic Encephalopathy. Although there are other incidents that can lead to HIE in newborns, cooling therapy is used most effectively in the treatment of intrapartum events.
These are some of the incidental examples that can cause HIE:
Examples of antepartum incidents: Placental insufficiencies, umbilical cord accidents, viral infections, growth retardation, congenital heart disease, etc.
Examples of intrapartum incidents: Placental abruption, cord prolapse, shoulder dystocia, abnormal cord insertion, maternal cardiovascular collapse, etc.
Examples of postpartum incidents: Infection, aspiration causing asphyxial event, brain blood vessel abnormality, etc.
What can be done to treat HIE?
Traditionally, babies with HIE were treated with supportive care: help breathing with a ventilator, management of blood pressure, and/or management of seizures. There was no other approved treatment for HIE until recently. The current research supports the use of a whole body Gaymar® cooling blanket for the treatment of neonatal HIE.
What is cooling?
Scientific studies have shown that if a baby’s brain can be cooled down below normal body temperature (which is 37° C) at hypothermic temperatures (ranging in between 33.5° to 35° C) within six hours after birth, the cooling effect may interrupt critical neurological damage.
The main cooling therapy used for Hypoxic Ischemic Encephalopathy (HIE) is the use of a whole body Gaymar®cooling blanket. Shown to improve outcomes for newborns with HIE , a whole body cooling blanket provides accurate and safe patient temperature management. Lying underneath the baby, this whole body system offers the ability to reach and maintain goal temperatures as well as provides controlled re-warming for the newborn patient.
Similiar to the effects of a Cool Cap, the body temperature is slightly lower (by 2°C) than if using selective head cooling, to achieve the same midbrain temperature. During this 72-hour cooling process, your baby’s nurse will carefully monitor your child to ensure the core temperature remains at safe and desired level during the treatment. This therapy has consistently shown its effectiveness, is mobile and convenient.
Your baby’s nurse will carefully monitor your baby during the entire treatment to ensure his/her core temperature remains in the target temperature range during the treatment. Currently, the Neuro-NICU has only used these cooling therapies on babies who are a gestational age of 36 weeks or greater.
What are the side effects of cooling therapy?
There are two expected, benign side effects associated with cooling therapy, although not all babies will experience these. The first, a minor cardiac arrhythmia is called sinus bradycardia (a slow heartbeat), is known to be associated with hypothermia. This will resolve after your baby is re-warmed.
The second side effect is edema, or swelling of the tissue. The condition generally goes away by itself, or with massage and re-positioning. During the 72-hour treatment, the nurse will examine the skin and re-position your baby frequently.
Does cooling cause my baby pain?
No. The cooling system is completely non-invasive, but your baby may be uncomfortable so pain and sedation medications will be given as your baby needs them.
What tests and monitoring will be done for my baby during treatment?
The medical team will closely monitor your baby’s heart rate, respiratory rate, temperature, blood pressure and oxygen saturation. Your baby will be on a ventilator to help them with breathing if they need it. The tests your baby will have include a brain MRI, EEG (to evaluate the injury to your baby’s brain) and blood work. While your baby is cooling, she/he cannot be fed by a bottle. They will receive nutrition through intravenous (IV) fluids. Please continue to pump and store your breast milk. After your baby has been re-warmed for 24 hours, we will usually start feeds slowly. After they tolerate 15ml (1/2 ounce) by mouth, we will do a swallow study to make sure they are safe for bottle/breast feeding. The medical team will discuss the test results with you and your family.
What can I do to help my baby during treatment?
It is extremely important that your baby rests during the entire treatment. You may stay with your baby (per NICU guidelines) but try to keep your interruptions to a minimum. You can coordinate your interaction with your nurse to maintain the best environment for your baby.
Where can I find more information on HIE?
You can obtain more information about HIE at The Emily Center at Phoenix Children's Hospital. Ask your nurse or Emily Center representative for assistance.