One of the most serious disorders that can happen following a birth complicated by medical or obstetrical negligence is called hypoxic-ischemic encephalopathy, which is often abbreviated as HIE. The term may sound confusing, but it actually refers to three readily understandable concepts.
Before breaking down the meaning of each part of hypoxic-ischemic encephalopathy, it is useful to understand that, in birth injury cases, it tends to denote a hypoxic-ischemic injury, which just means that a newborn baby has suffered a particular type of brain injury caused by a lack of oxygen or blood flow. In other words, a baby will suffer a hypoxic-ischemic brain injury if, for instance, there were signs of fetal distress during labour and your doctors or nurses did not act quickly enough to deliver your baby and remove them from a dangerous situation.
What does Hypoxia Mean?
The first part of hypoxic-ischemic encephalopathy refers to hypoxemia, which, in technical terms, is a deficiency in oxygen within circulation and at a cellular level. Simply put, hypoxia means not enough oxygen. In the womb, the baby needs oxygen, which is delivered to the fetus via the placenta. In fact, the placenta serves as the interface between the mother and her baby; it provides the exchange of gases, nutrients, hormones, waste products and immunoglobulins.
The human placenta is actually understood as a temporary fetal organ, which connects to the mother’s uterus and to the fetus through the umbilical cord.
We will now discuss how a baby receives oxygen while in the womb in detail, including about how the placenta mediates circulation of oxygenated blood, but for the purposes of this discussion, the important point to understand is that the mother supplies her developing baby with oxygen throughout gestation and until birth. This process can disrupted or impaired with complications such as excessive uterine activity during labour, umbilical cord prolapse, cord compression, a placental abruption, or placental insufficiency.
When the baby is not getting enough oxygen, there will be abnormalities in the fetal heart rate. Doctors and nurses monitor the fetal heart rate during labour and delivery (and at other times, too) to make sure the baby is getting enough oxygen and is tolerating the stresses of labour and delivery. There are criteria for atypical and abnormal fetal heart rates that tell us that the baby is not receiving enough oxygen, which may mean that delivery needs to be expedited via Cesarean-section (or through operative vaginal delivery such as with a kiwi vacuum in certain circumstances where the concern is evident in the very late stages of labour).
The bottom line is that the baby needs oxygen and the flow of oxygen can sometimes be impaired during labour and delivery or during pregnancy before labour begins. This may be a medical emergency requiring the baby to be delivered urgently. If the baby is not getting enough oxygen, it may be said that he or she is in a hypoxic intrauterine environment – again, hypoxia is a lack of oxygen – and this is why they must be rescued by delivery to the outside world.
What Does Ischemia Mean?
Ischemia means inadequate perfusion of blood. In the context of hypoxic-ischemic encephalopathy, it refers to insufficient cerebral blood flow, or blood flow to the fetal brain. When we talk about a baby suffering a brain injury consistent with hypoxia-ischemia, what we mean is that ischemia (not enough blood flow) is associated with hypoxia (not enough oxygen) at a cellular level. The two concepts are intertwined in this context.
There are two main processes which may individually or collectively cause this type of injury. Hypoxemia is a diminished amount of oxygen in the blood supply, and ischemia (in this context) is a diminished amount of blood perfusing the brain. The unifying theme is disturbance to neural tissue through a deficit in oxygen supply resulting in an energy deficit.
Ischemia is the more important source of brain injury because it appears something more than just deprivation of oxygen is required to create a hypoxic-ischemic injury in the fetal or newborn brain. It is instead both glucose and oxygen which are thought to be depleted where permanent injury of this kind occurs.
What Does Encephalopathy Mean?
Encephalopathy means a disease or disorder of the brain. In the context of hypoxic-ischemic encephalopathy, it refers to neonatal encephalopathy, which is the appearance of abnormal neurological function, in the first few days of life (e.g., seizures).
What is the Cause of Hypoxic-Ischemic Encephalopathy?
When medical malpractice lawyers sue on behalf of a baby who has suffered a brain injury consistent with HIE, you will often hear the phrase “birth trauma.” Typically, in these types of cases, the baby was asphyxiated in the womb and this resulted in a permanent brain injury.
Lawyers who practice in obstetrical negligence or birth trauma litigation often advocate for babies who should have been delivered earlier. There are guidelines in place that tell doctors when to expedite delivery in response to signs of fetal distress. One example is from the Society of Obstetricians and Gynecologists of Canada entitled “Fetal Health Surveillance.” The bottom line is that there are ways to tell when a baby is not receiving enough oxygen, and we expect our doctors to take decisive action in time to prevent a permanent brain injury, including those consistent with hypoxic-ischemic encephalopathy.
Sadly, doctors do not always act quickly enough to respond to signs of fetal asphyxia, and the result can be devastating. The fetus can actually withstand a deprivation of oxygen for an impressive amount of time (more than an adult!) but that capacity is not absolute. It may be, then, that parents of a child diagnosed with hypoxic-ischemic encephalopathy have to bring a legal claim to compensate their child for their extraordinary care needs, lost ability to earn a wage, and other aspects of the loss they have suffered.
How is a Hypoxic-Ischemic Brain Injury Diagnosed?
In cases of birth asphyxia, there are three main criteria for diagnosing HIE:
- (1) signs of fetal distress (e.g., concerning fetal heart rate);
- (2) the presence of metabolic acidosis (which is discussed elsewhere on this blog);
- (3) neonatal encephalopathy in the first days of life.
If you believe your child suffered a brain injury during birth, you should contact the lawyers at Wagners who have extensive experience representing clients with hypoxic-ischemic encephalopathy and who take the time to understand the complex issues involved in litigation birth injury cases.