OVERVIEW

What is brain death?

Brain death is a crucial criterion for determining a person's death, referring to the permanent loss of all brain functions, including the brainstem (even if spinal cord and heart functions persist).

In cases of brain death, other organs in the body may still function normally, but over time, these organs will inevitably fail, and death becomes irreversible.

Once diagnosed, it is legally recognized as death, and an increasing number of people now accept that brain death equates to death.

Are brain death and vegetative state the same?

No.

Brain death is irreversible, meaning the person has died. Even with medications and the most advanced equipment to sustain other organs (e.g., heart, lungs), revival or survival is impossible.

In contrast, a vegetative state involves unconsciousness but allows for potential recovery, and survival may not require medication or equipment. Click "vegetative state" to learn more.

Is brain death legally recognized?

In some countries, such as the U.S. and Spain, brain death is legally acknowledged. However, in China, there is currently no law defining brain death as death, and the primary criterion remains the cessation of breathing and heartbeat.

SYMPTOMS

What are the manifestations of brain death?

• Coma.
• No response to any stimuli.
• Absence of pupillary light reflex.
• Inability to maintain breathing and heartbeat without life support.

Before confirming brain death, doctors conduct a series of strict examinations to make the diagnosis.

CAUSES

What are the common causes of brain death?

The primary causes of brain death are trauma and subarachnoid hemorrhage (a clinical syndrome caused by the rupture of blood vessels at the base or surface of the brain, leading to direct blood flow into the subarachnoid space). Other causes include intracerebral hemorrhage, hypoxic-ischemic encephalopathy, and ischemic stroke.

Any condition that causes permanent and widespread brain damage can lead to brain death.

Which areas are typically affected in brain death?

Brain death refers to the irreversible cessation of function in both the brain and the brainstem.

How does brain death develop?

Traditionally, the cessation of heartbeat was considered the definition of death. However, the brain often dies before the heart stops. The brain is the organ most sensitive to oxygen deprivation, and even 2–5 minutes of hypoxia can lead to brain death.

With advances in medicine, vital signs such as heartbeat and respiration can be maintained through medications and advanced equipment. However, if the brain and brainstem die, no medical intervention can ultimately prevent cardiac death.

Therefore, using brain death as the criterion for determining death is more scientifically sound and allows more time for organ transplantation, though this is not the driving factor behind brain death legislation.

DIAGNOSIS

How is brain death diagnosed?

The diagnosis of brain death must be extremely rigorous and cautious.

Hospitals, departments, and doctors qualified to determine brain death, as well as the procedures for determining and implementing brain death criteria, must adhere to strict standards. Generally, brain death should meet the following criteria:

• Inability to breathe autonomously; cessation of respiration.
• Disappearance of brainstem reflexes (cranial reflexes).
• Pupil dilation or fixation, with no response to light.
• Disappearance of brain waves (recorded via specialized electrodes to reflect the functional state of the brain), showing a flatline.
• Complete cessation of cerebral blood circulation.

What conditions are easily confused with brain death?

• Brain death is easily confused with locked-in syndrome. Patients with locked-in syndrome are awake and conscious, but due to diffuse damage to the base of the pons, bilateral corticobulbar and corticospinal tracts are blocked, resulting in the inability to move limbs, trunk, or facial muscles. Thus, patients cannot communicate verbally or through limb movements but can do so via eye movements.

• Brain death is easily confused with neuromuscular paralysis. Neuromuscular paralysis is often seen in severe acute polyneuropathy (some patients may lose pupillary reflexes) or due to neuromuscular blocking agents, but it does not meet other criteria for brain death diagnosis.

What are the benefits of establishing brain death criteria for patients?

• Helps preserve the dignity of the deceased: The loss of function after brain death is irreversible, and resuscitating a brain-dead individual is meaningless. Excessive resuscitation disregards the dignity of the deceased. The thought of a patient in the ICU covered with tubes is chilling.

• Helps families move on from grief sooner: A brain-dead patient may still have a beating heart and normal body temperature, with life signs maintained for some time using advanced equipment like ventilators. However, this requires significant financial and emotional resources from the family, who may believe death only occurs when heartbeat and breathing stop, leading to reluctance to cease resuscitation. Establishing brain death criteria allows families to accept the patient's death more readily.

What are the societal benefits of establishing brain death criteria?

• Promotes scientific progress: Brain death criteria are more scientifically sound than cardiac death criteria. While modern medicine can often revive patients after cardiac death, brain death is irreversible, and no brain-dead patient has ever recovered despite full resuscitation efforts.

• Facilitates rational use of healthcare resources: Brain-dead patients cannot be revived, yet maintaining their heartbeat and respiration wastes limited healthcare resources. This not only strains medical supplies but also affects fair resource allocation and adds emotional and financial burdens to families.

• Supports organ transplantation: Brain death occurs earlier than cardiac death, and earlier organ retrieval improves organ quality, survival rates, and transplant outcomes.

• Clarifies ethical and legal responsibilities: Scientifically determining the time of death helps doctors define the endpoint of their life-saving obligations, improves medical quality, and provides evidence for liability. Legally, it offers proof for resolving related disputes.

TREATMENT

Can brain death be reversed?

Patients meeting brain death criteria cannot recover. Once brain death is confirmed, all life support measures can be discontinued.

If assisted ventilation and medication support are stopped, heartbeat and breathing will cease shortly afterward.

In adults, the interval between brain death and subsequent somatic death rarely exceeds a few days. After brain death, cardiac function deteriorates, and even with medication, cardiac arrest will eventually occur.

DIET & LIFESTYLE

If the immediate family members of a brain-dead patient wish to donate organs, which organizations can they seek assistance from?

Immediate family members include the patient's spouse, adult children, and parents. If the deceased's immediate family members wish to donate organs, they can express their intention through the Organ Procurement Organization (OPO) affiliated with the hospital or the Human Organ Donation Office.

What is the organ donation process for brain-deceased Chinese citizens?

The posthumous organ donation process for Chinese citizens mainly includes eight steps: registration, donation evaluation, donation confirmation, organ procurement, organ allocation, body handling, humanitarian assistance, and donation documentation archiving:

• Registration: Includes registration during the donor's lifetime or posthumous donation applications.
• Donation evaluation: A brain death assessment expert panel evaluates whether the organs can be donated.
• Organ procurement: Human organ donation coordinators or Red Cross staff witness the entire organ procurement process.
• Organ allocation: According to national regulations, donated organs must be allocated and shared by OPOs through the China Organ Transplant Response System (COTRS).
• Body handling: After organ removal, surgical incisions are carefully sutured, and prosthetic replacements are placed to restore the donor's appearance. The body can be donated for medical research, or the OPO or provincial Human Organ Donation Office can assist with funeral arrangements.
• Humanitarian assistance: This includes financial aid, employment support, educational assistance for children, legal aid, and other forms of help.
• Donation documentation archiving: The OPO organizes and archives all relevant organ donation records.

PREVENTION

None