Anne Heche is brain-dead due to the injuries she sustained after a fiery car accident last week, a spokesperson for the actress said Friday.
“While Anne is legally dead according to California law, her heart is still beating, and she has not been taken off life support so that One Legacy can see if she is a match for organ donation,” the spokesperson said in a statement to NBC News.
On Thursday, Heche’s spokesperson said in another statement that the actress was “not expected to live” following the August 5 car accident, in which she suffered a “severe anoxic brain injury.” At the time, Heche was in a coma, in critical condition.
Here's what to know about anoxic brain injuries and their suspected outcomes.
What Is an Anoxic Brain Injury?
An anoxic brain injury is caused by a complete lack of oxygen to the brain, Andrea L. Schneider, MD, PhD, a neurologist at Penn Medicine and assistant professor of neurology at the Hospital of the University of Pennsylvania, told Health.
Anoxic brain injuries and hypoxic brain injuries (a partial or restricted flow of oxygen to the brain) are different from traumatic brain injuries, in which injury is sustained from a direct physical trauma like a blow to the head. Sometimes, these are known as hypoxic-anoxic injuries, or HAIs.
"All cells in your body need oxygen to live," explained Dr. Schneider. The brain receives its oxygen supply from a constant supply of blood—but when that blood flow and oxygen is cut off, brain cells suffer. "If there's a lack of oxygen, the brain cells die," added Dr. Schneider.
It doesn't take long for the brain to feel the effects of a lack of oxygen; some brain cells begin to die within five minutes without oxygen, and brain damage can progress rapidly.
What Causes an Anoxic Brain Injury?
Generally speaking, anything that causes a lack of blood flow to the brain can result in an anoxic brain injury, said Dr. Schneider.
“[An anoxic brain injury] is classically associated with someone’s heart stopping, with cardiac arrest being the biggest cause,” she added. This may be referred to as a hypoxic-ischemic injury, in which an internal event—like the heart stopping—prevents oxygen-rich blood from reaching the brain.
According to the Shepherd Center, a patient rehabilitation center, anoxic and hypoxic brain injuries can also result from a lack of blood in the body or the blood’s inability to properly carry oxygen (anemic anoxia); a chemical or poison that hinders brain function (toxic anoxia); or an overall lack of oxygen at high altitudes or through suffocation (anoxic anoxia).
The Brain Injury Association of America (BIAA) shares some more specific causes of anoxic and hypoxic brain injuries, including:
- Electrical shock
- Carbon monoxide poisoning
Can You Survive an Anoxic Brain Injury?
Generally speaking, hypoxic and anoxic brain injuries present as a loss of consciousness or coma. Severe HAIs often leave the person in what’s known as a vegetative state, in which a person may open their eyes, but are unable to speak, think, or move.
The phrase “time is brain”—which is often related to stroke—is relevant with HAIs, as well. The longer the brain is deprived of oxygen, the worse the damage. “[Recovery] really depends on the length of time” oxygen supply is cut off, said Dr. Shneider. “There is a spectrum.”
If a person sustains a milder hypoxic or anoxic brain injury, they may be capable of making a full or partial recovery, with lingering effects that can resemble those of traumatic brain injuries, including memory impairments, difficulty communicating, or motor impairments.
However, a full recovery from a severe hypoxic or anoxic brain injury is rare. "There are also very severe anoxic brain injuries that can be fatal," said Dr. Schneider.
"Anne had a huge heart and touched everyone she met with her generous spirit," her representative said. "More than her extraordinary talent, she saw spreading kindness and joy as her life's work—especially moving the needle for acceptance of who you love. She will be remembered for her courageous honesty and dearly missed for her light."