What is Hypoxic Ischemic Encephalopathy and what causes it?
A significant number of long-term disabilities that occur in newborns today is due to Hypoxic Ischemic Encephalopathy (HIE), sometimes called birth asphyxia. HIE occurs when babies are deprived of oxygen during the labor and delivery process. It is common where there are delivery room errors. Oxygen is necessary to sustain critical cells within the body, most notably brain cells. If the brain does not receive proper oxygenation, cell death occurs. This lack of oxygen (also known as anoxia or hypoxia) and subsequent cell death, can result in mental and physical damage. The extent and seriousness of the damage depends on the length of time that the baby was deprived of oxygen. Generally speaking, the longer an infant goes without oxygen, or with decreased oxygen, the more severe and permanent the injury will be.
Statistics reveal that the mortality rate in severe HIE cases is about 25-50%. Up to 80% of infants that survive severe HIE develop serious complications; 10-20% develop moderately serious problems; and up to 10% are healthy. For babies with moderately-severe HIE, about 30-50% may have serious long-term problems while about 10-20% develop minor neurological issues.
There are a number of causes of HIE, including those falling into the following categories:
- umbilical cord injuries such as a nuchal cord (the cord gets wrapped around the baby’s neck); a prolapsed cord (the umbilical cord precedes the fetus' exit from the uterus, the cord becomes compressed and unable to deliver oxygen to the baby); umbilical compression due to hyperstimulation (excessive uterine activity)
- problems with the placenta or uterus such as a ruptured uterus; placenta previa (placenta is attached to the uterine wall close to or covering the cervix); or placental insufficiency
- tachysistole (excessively frequent uterine contractions)
- elevated fetal heart resting tone in between contractions
- trauma to the baby’s brain during delivery
- delayed delivery of the baby
Brain imaging studies such as CT scans, PET scans and MRIs, blood tests electroencephalogram (EEG), ultrasounds and other medical studies help diagnose HIE and it’s underlying causes.
Treatment of HIE
Traditional treatment of HIE has been supportive care. This entailed a hospital using conventional measures such as ventilation, physician support, NICU care and care from specialty physicians in an attempt to allow the baby’s body and brain to repair itself. Recently, however, a new therapy called hypothermia or brain cooling has been introduced specifically for HIE and has shown to improve the outcome of babies with birth-associated HIE by reducing the severity of neurological injury.
In brain cooling therapy, a cooling cap is applied to the baby’s head. A machine circulates water through the cap at specific temperatures to ensure moderate cooling of the baby to around 91 degrees F. This is done for 72 hours and then the infant is warmed back to normal temperature. By lowering the baby’s temperature, the metabolic rate slows allowing cell recovery over a longer period of time, avoiding further damage that can occur if normal oxygenation or blood flow is restored too quickly to injured cells.
In addition to watching the baby’s temperature, neonatal staff also closely monitors respiration, heart rate, oxygenation and brain wave activity. Physicians use all of this data to determine how the baby is responding to the cooling treatment.
Timing is very important when using this hypothermia treatment. The most favorable outcomes are seen when brain cooling is started as soon as possible after the birth injury occurs, preferably within 6 hours of birth. The treatment also requires that the newborn is at least 36 weeks gestation.
Brain cooling is now widely used in neonatal units throughout the United States. If you have comments about this new therapy or personal experiences, please share them below.
If you have been told that your baby suffered from birth asphyxia or Hypoxic Ischemia Encephalopathy, the birth injury attorneys at Reiter & Walsh ABC Law Centers can help. We are available to answer any questions you may have and to offer advice on whether the injury was preventable. Call us at 888-419-BABY (2229).