What is Brain Cooling?
For a very long period of time it was thought that there was no real effective treatment for children born with hypoxic ischemic encephalopathy meaning neurological dysfunction in the setting of decreased oxygen and blood flow. Beginning in the late 2000s, around 2009, 2010 studies were performed that looked at the effectiveness of cooling children who are born with hypoxic ischemic encephalopathy or HIE.
Brain Cooling to treat HIE
The studies showed that if a baby is born with HIE and they are passively cooled meaning they are made hypothermic or their temperature is dropped for a period of approximately 60 to 72 hours that it helps decrease the chance of profound neurological problems from what is known as reperfusion injury, and reperfusion injury is a phenomenon whereby once the brain starts functioning again normally and the baby starts physiologically acting normally after a severe lack of oxygen the brain suffers an injury, a secondary injury, and what has been found since 2009 and 2010 is that this type of reperfusion injury can be avoided with brain cooling. Brain cooling is identified as a treatment by using protocols. Many hospitals have very specific protocols in determining who should be cooled and who should not be cooled. Among the items that are examined are things such as evidence of birth asphyxia, which would include an Apgar score meaning a score of how well the baby is doing the first 10 minutes of life.
Another factor is the need for mechanical ventilation or resuscitation at 10 minutes of age, and health care providers also look at what’s called cord blood gasses, which tell you how much acid is in the baby’s blood, and if the acid in the baby’s blood is below certain values then that means that there has likely been HIE or birth asphyxia and a baby who is greater than 36 weeks gestation will then be considered for cooling. The other pathway to be a candidate or to be qualified for cooling is if a newborn has evidence of moderate or severe encephalopathy and that would include evidence of decreased neurological function in the immediate newborn period.
Symptoms of HIE
Those items can include lethargy, decreased level of consciousness, decreased activity, decreased tone, decreased primitive reflexes, such as decreased suck and decreased moro, and healthcare providers can look at the pupils and the gaze of the baby and heart rate and the respirations, and there is a grading system provided by a doctor whose last name is Sarnat. It’s the Sarnat staging system and generally it’s believed that if a baby’s born and there’s evidence of asphyxia and the baby is Sarnat Stage 2 or Sarnat Stage 3 then the baby will be a candidate for cooling.
Where is Brain Cooling done?
Many hospitals do not have the equipment or the capabilities of performing either brain cooling or total body cooling, and so what will happen is many of babies who qualify for cooling will be sent to tertiary facilities for the benefit of cooling, and what those facilities will do is they will passively cool the child even during the transport to the tertiary facility, and they will continue to passively cool for again 60 to 72 hours, and in those time periods they’ll monitor the temperature and they will take scans of the baby’s brain, and what the healthcare providers are looking for is that any injury to the brain that was identified in the first hours of life is not getting worse, and that’s really the goal of cooling to make sure that any injury to the brain from hypoxic ischemic encephalopathy or HIE or decreased lack of blood flow and oxygen is not progressing.
Listen to an audio recording of this information below:
Books & Resources
For more information on brain cooling and HIE, the following resources are available: