Learn more about whole body cooling treatments for babies
- What is Whole Body Cooling?
- How HIE Effects Brain Cells?
- How Does Cooling Therapy Work?
- Does Cooling Help HIE?
- Why Would a Newborn Need to Be Cooled?
- Cooling as Treatment for HIE
- Criteria for Cooling Therapy as Treatment
- What Happens After an Infant Receives Hypothermic Therapy?
During labour and delivery, an infant may suffer oxygen deprivation (hypoxia) and limited blood flow to the brain. This condition, known as hypoxic-ischemic encephalopathy (HIE), is a type of birth injury that can cause permanent brain damage. Infants with HIE may later develop cerebral palsy, cognitive disabilities, seizures, hearing and vision impairments, developmental delays, and other neurological conditions.
There is one treatment that may be able to minimize permanent brain damage in a newborn due to HIE. Therapeutic hypothermia, or whole-body cooling, involves cooling the baby down to a body temperature of about 32.8° Celsius to help the brain recover from a hypoxic-ischemic injury. When done promptly, within 6 hours after a birth injury, whole-body cooling has the potential to reduce the incidence of death and disability substantially.
What if your child has suffered moderate or severe HIE? In that case, whole-body cooling may be a viable option to minimize the potential disabilities that your baby may suffer due to this birth trauma.
What is Whole Body Cooling?
Within the last number of years, there have been significant advances in the knowledge and use of head and whole-body cooling to reduce the extent of brain injury associated with a hypoxic-ischemic event (an inadequate supply of oxygen to the brain) and birth injuries.
Those healthcare professionals that practice obstetrics, and physicians who care for newborn children, have an obligation to remain current with these medical developments, to be aware of the inclusion criteria and to have appropriate systems in place to ensure the effective referral and transport of newborn babies who might benefit from whole-body cooling to the appropriate neonatal intensive care unit.
How HIE Effects Brain Cells
A hypoxic-ischemic event during labour can result in a brain injury through two mechanisms. The first is often referred to as the primary insult and refers to the death of the brain cells associated with the hypoxic-ischemic event itself. The secondary insult, which can also result in the death of brain cells, occurs with the swelling of the brain in response to the initial insult. This swelling starts approximately 6 hours after the initial insult. It is these 6 hours that give healthcare professionals time to cool the newborn, which in turn reduces the swelling and the extent of the secondary insult.
It is, therefore, essential that healthcare providers know the inclusion criteria and carefully analyze the clinical situation to determine whether the newborn falls within the criteria. The current criteria require that the baby be more than 35 weeks gestation, weigh more than 1,800 grams, have evidence of a hypoxic-ischemic event during labour based upon an analysis of the blood from the umbilical cord and that the cooling process can begin before 6 hours of age.
There have been some exciting new developments in the area of the head and body cooling with some very good results. Healthcare providers practicing obstetrics and those in charge of newborns must ensure that they remain current with the latest developments in this area and have appropriate policies in place to ensure that newborns that meet the inclusion criteria receive the care they deserve.
How Does Cooling Therapy Work?
The goal of hypothermia therapy is to reduce the baby’s body temperature to about 32.8° Celsius. This is done in one of two ways:
- Using a cooling cap for selective head cooling; or
- Cooling the baby’s entire body (whole-body cooling).
The decision on which method is used is based on several factors, including the protocols and equipment available at the Neonatal Intensive Care Unit (NICU). Check with your local hospitals to find out if they have this intervention capability prior to giving birth there.
Shortly after suffering a hypoxic-ischemic event, a newborn’s body temperature will be lowered to 32.8° Celsius using a cooling cap or cooling blanket. Their temperature will be lowered for a period of 72 hours. After 72 hours, the infant is gradually warmed back to normal temperature over a period of 6 to 8 hours.
Does Cooling Help HIE?
This decreased body temperature helps to slow the body’s metabolic rate, allowing cells to recover and preventing the spread and severity of brain damage due to oxygen deprivation. One potential benefit of cooling therapy for newborns is that it reduces the likelihood of reperfusion injury, which occurs when the blood flow is restored too quickly to injured parts of the brain.
Before, during, and after whole-body hypothermia therapy, doctors and other pediatric medical professionals must monitor the baby’s health and intervene as necessary. Throughout the process, doctors may:
- Assess the oxygenation of the baby by analysis blood samples
- Manage acidosis (excessive acid in the blood)
- Test for and treat infections
- Provide respiratory and cardiovascular support if necessary
- Maintain normal glucose and electrolyte levels
- Monitor for seizure activity using an EEG and controlling seizures, particularly during rewarming
- Maintain sedation
- Test for brain function using amplitude-integrated electroencephalography (aEEG)
A failure to appropriately monitor an infant and treat any issues that may arise may constitute medical negligence.
Importantly, not all hospitals are properly equipped to administer therapeutic hypothermia. In this situation, the neonate should be transferred to a children’s hospital with the capacity to provide this type of therapy within 6 hours of birth. The sooner hypothermia therapy begins, the greater the chance for a more favourable long-term outcome for the baby.
Why Would a Newborn Need to Be Cooled?
Whole-body or head cooling is not indicated for every infant who suffers a birth injury or is diagnosed with HIE. Instead, this type of therapy is only indicated for infants who have been diagnosed with moderate to severe HIE. The qualifying criteria for hypothermia therapy include:
- At least 36 weeks of gestational age;
- No more than 6 hours old; and
- Severe acidosis (cord pH less than or equal to 7.0, or a base deficit greater than or equal to -16); OR
- Abnormal blood gasses, AND a complicated delivery (such as cord prolapse, placental abruption or uterine rupture) AND an Apgar score of less than or equal to 5 at 10 minutes, OR at least 10 minutes of positive pressure ventilation; OR
- Evidence of moderate to severe neonatal encephalopathy as demonstrated by one of the following: seizures; decreased or no activity; at least 3 signs of moderate to severe encephalopathy, such as lethargy or stupor/coma; abnormalities in posture; hypotonic or flaccid; weak or incomplete reflexes; or abnormal pupils/heart rate (bradycardia) or breathing.
If your infant meets these criteria, then cooling therapy may be an appropriate choice to reduce brain damage and permanent disabilities related to asphyxia during birth.
Cooling as Treatment for HIE
Clinical studies in the early 2000s started with a consensus on the science of HIE and the effects of cooling. According to a study published in the Journal of Resuscitation in 2008,
“A reduction of body temperature by 2-3 degrees C (which constitutes modest hypothermia) following a hypoxic-ischemic event has the effect of reducing cerebral metabolic and biochemical abnormalities and cerebral injury.”
Neonatal therapeutic hypothermia is a relatively new treatment option in which an infant’s total body temperature is reduced shortly after birth in order to reduce the chances of severe brain damage and slow down disease progression. According to the National Institute of Health, there are quite a few long-term benefits to neonatal therapeutic hypothermia. For instance, children who underwent treatment as infants were more likely to have a higher survival rate at 6-7 years of age.
We created a helpful infographic to better describe the process of HIE Cooling:
Criteria for Cooling Therapy as Treatment
Infants who are at or greater than 36 weeks gestation and who meet the necessary criteria should be “offered” hypothermia. Active cooling can be accomplished by selectively cooling the infant’s head with cooling caps or total body cooling with cold packs or cooling blankets. Careful management of rectal or esophageal body temperature at an optimal range of 34 degrees C, plus or minus 0.5 degrees C, is important.
The optimal duration of treatment was not initially clear, but most practitioners used 72 hours of cooling. At the same time, “re-warming” of the neonate is not without controversy, and care needs to be taken to slowly restore body temperature. Worsening of encephalopathy and seizures have occurred on rewarming and may require re-cooling of the infant. Subsequent studies on the therapeutic effects of controlled hypothermia for infants presenting with symptoms of HIE continue to support the therapy as part of the applicable standard of care.
Click here for the full Neonatal Practice Guidelines- Hypothermia for Newborns With Hypoxic Ischemic Encephalopathy
What Happens After an Infant Receives Hypothermic Therapy?
After being diagnosed with moderate to severe HIE, an infant who receives cooling therapy should receive follow-up care through infancy and into later childhood. A range of medical professionals from fields such as neonatology, physiotherapy, occupational therapy, neurology, psychology, audiology, and ophthalmology, may be involved in the child’s care.
More than 30% of infants diagnosed with HIE will develop cerebral palsy or another severe disability. Common impairments may include:
- Cognitive deficits, particularly difficulties with reading, spelling, and arithmetic
- Blindness or severe visual impairment
- Hearing loss
- Behavioural difficulties, including emotional problems and hyperactivity
- Childhood epilepsy
For these reasons, parents of a child who has suffered HIE should follow up with a multidisciplinary team of healthcare professionals to ensure that their child receives the best possible care.
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