Doctors, and Lawyers frequently use specific medical terms to discuss the events that may have led to permanent brain injury. Therefore, parents who would like to become more comfortable with the terminology, may refer to the following list of terms and concepts which are defined below.
Fetal distress is a term that is found throughout the medical literature and in many clinical records. This term is used to describe a critical time period during which the fetus' oxygen or blood supply is reduced and the potential for permanent brain damage is present. Fetal distress may be acute or chronic, and it may be precipitated by maternal or fetal conditions that should have been diagnosed and treated by the attending clinicians. The critical point is that physicians and nurses must respond promptly when fetal distress is present, and, if the condition causing the fetal distress cannot be eliminated, delivery may be necessary. Sometimes the clinical setting may even require an emergent or crash cesarean section.
The extent and location of a brain injury will depend upon the timing, duration, and severity of the particular maternal, fetal or neonatal conditions interfering with the normal blood flow to, and oxygenation of, the fetal or neonatal brain tissue. Generally, the term "hypoxia" is used whenever the brain or other tissue is not receiving adequate oxygen. This happens when, despite adequate blood flow, the oxygen content of the blood is reduced below normal levels. For example, cord compression during delivery may interfere with normal oxygenation of the baby and lead to hypoxia, or preeclampsia may interfere with normal blood flow from mother to fetus, leading to ischemia or hypoxia. Some physicians might use the term "hypoxemia" along with, or in place of, hypoxia, since it technically means that there is a diminished amount of oxygen in the blood.
Another potential problem can arise if blood flow to the fetus is disrupted. For example, a placental abruption can totally or partially disrupt normal blood flow to the fetus. The term ischemia would be used to describe this condition, when the amount of blood perfusing the brain or other tissue is diminished. Since blood contains both oxygen and glucose, when ischemia occurs, it can lead to hypoxia, (because the fetus is not receiving adequate oxygen), as well as to hypoglycemia, (low blood glucose levels).
Uteroplacental insufficiency (UPI) is a term used to describe a situation where blood flow to the placenta is impaired, so that there is a risk that inadequate amounts of nutrients or oxygen are delivered to the fetus. If UPI develops, and the fetus does not receive adequate nutrition, intrauterine growth retardation (IUGR) can result. IUGR results in a fetus whose head circumference or body length falls below the tenth percentile. Growth restricted infants can have low birth weight and be small for gestational age. If UPI develops and the fetus does not receive adequate oxygen, hypoxia can result.
How does the fetal brain get damaged when blood flow or oxygenation is diminished? Hypoxia or ischemia, alone, or in combination, can lead to blood gas and pH abnormalities, which may be referred to as acidosis, (either respiratory or metabolic), depending on the chemical components of the abnormality. As acidosis progresses, lactic acid, which is capable of destroying brain cells, accumulates. The term asphyxia is used to describe the sequence of events that begins with hypoxia, or ischemia, or both, and culminates with acidosis. Either the term asphyxia or the phrase "hypoxic-ischemic" brain insult can be used to describe the events that lead to irreversible brain damage and long-term neurological problems, such as cerebral palsy.
Several terms are used to qualify the time period during which asphyxia occurs. For example, phrases such as perinatal asphyxia, intrapartum asphyxia, and birth asphyxia are found throughout the medical literature. Some physicians will use the term perinatal asphyxia to refer to that period of time proximate to delivery. Others will use the terms intrapartum asphyxia or birth asphyxia, which more precisely describe a clinical event that produced irreversible brain damage either during labor or close to the time of delivery. (The American College of Obstetrics and Gynecology is unhappy with the term birth asphyxia and has urged physicians to abandon its use. See Utility of Umbilical Cord Blood Acid-Base Assessment, ACOG Committee Opinion # 91, February, 1991.)
Please Note:
This web site is not intended as legal advice on cerebral palsy, and is not a substitute for obtaining guidance from your own legal counsel about cerebral palsy litigation. It provides general educational information about the standards of care and causation issues that can arise in obstetrical malpractice and cerebral palsy litigation. Readers of the articles contained within this web site should not act upon the cerebral palsy information without first consulting with a lawyer who is experienced in evaluating and litigating cerebral palsy and obstetrical malpractice cases. Mr. Apfel is admitted to practice law in Maryland and the District of Columbia. When Mr. Apfel is asked to participate in cerebral palsy
litigation filed in other states, he will associate with, and act as co-counsel with, an attorney licensed in that state who is familiar with the local laws and procedures.
