Doctors typically treat a brain aneurysm, also known as a cerebral aneurysm, with surgery when one has ruptured or there is a high risk of rupture. Some people may not wake up straight away after surgery. This may happen for several reasons.

A brain aneurysm is a bulge, or ballooning, that arises from a weak area in the wall of a blood vessel in the brain. If a brain aneurysm ruptures, it can cause bleeding in the brain, called a hemorrhagic stroke.

Doctors repair a ruptured brain aneurysm using surgery. They may also suggest preventive surgery if there is a high risk of rupture. Doctors weigh the risks of the aneurysm rupturing against those of surgery. This is because brain surgery has its own associated risks of potentially severe complications, such as stroke or brain damage.

In this article, we examine why someone may not wake up after brain aneurysm surgery. We discuss various states of consciousness and how long it typically takes for people to wake up after brain aneurysm surgery. We also examine recovery after surgery.

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People may not wake up immediately after brain aneurysm surgery for the following reasons:

Postoperative sedation

After brain aneurysm surgery, healthcare professionals move a patient to the intensive care unit (ICU). They observe them for several days before moving them to a regular hospital room.

Many people wake up within a few hours after surgery. However, a neurosurgeon may sometimes decide to keep a person asleep for a few days following surgery with sedation, using strong drugs. Sedating a person can help them recover, particularly if they have any swelling on their brain.

When a person wakes up, they will likely feel sleepy. This is standard and occurs due to anesthesia and pain medications.

Delayed emergence from anesthesia

Some people do not wake up right away from general anesthesia. Doctors call an inability to regain consciousness 30–60 minutes after general anesthesia delayed emergence.

Delayed emergence from general anesthesia is relatively common and may result from the drugs administered during surgery. Rarely, delayed awakening may result from serious causes, such as stroke or brain injury.


A coma is a state of unconsciousness, where an individual cannot wake up and is unresponsive.

A person with a brain aneurysm may enter a coma before or after surgery for several reasons, including:

  • a ruptured aneurysm
  • bleeding into brain tissue
  • swelling and compression of the brain
  • narrowing brain blood vessels that block blood flow, known as a vasospasm
  • brain injury
  • stroke
  • subarachnoid hemorrhage
  • excess fluid in the brain, known as hydrocephalus
  • a lack of oxygen to the brain
  • seizures
  • postoperative infection

According to the National Institute of Neurological Disorders and Stroke (NINDS), a coma rarely continues beyond 2–4 weeks.

Consciousness is a state of being awake. A person has self-awareness and awareness of the surrounding world when conscious.

Wakefulness is the ability to keep the eyes open and have basic reflexes, such as swallowing, sucking, and coughing. Awareness involves more complex thought processes and is challenging for healthcare professionals to assess.

Brain injury by an aneurysm can cause disorders of consciousness. When a person has a consciousness disorder, they have difficulty being aware, awake, or both.

The primary disorders of consciousness may include:

  • coma
  • vegetative state
  • minimally conscious state

Learn more about brain aneurysms here.

A coma is a deep state of unconsciousness. A person in a coma exhibits no signs of being awake or aware and does not respond to their environment, voices, or pain. Some people in a coma can breathe independently, but others require a machine to assist with breathing.

Features of a coma include:

  • an inability to open the eyes
  • no visual tracking
  • no sleep-wake cycles
  • no object recognition
  • the inability to follow instructions
  • no speech or communication
  • no purposeful movement

A coma typically lasts no more than a few weeks. During this time, an individual may wake up or progress to vegetative or minimally conscious states of consciousness.

Learn more about comas here.

A person is in an unaware and unresponsive state, or vegetative state, when they are awake but show no signs of awareness. They are typically able to regulate their breathing and heartbeat without assistance.

Features of a vegetative state include:

  • the ability to open and close the eyes
  • no visual tracking
  • the presence of a sleep-wake cycle
  • possible ability to smile or frown with no apparent cause
  • no awareness of self or environment or no interaction with others
  • no evidence of language comprehension
  • no response to sight, smell, sound, or touch

When a vegetative state continues for more than 1 month, doctors describe it as a persistent vegetative state.

People with a persistent vegetative state have an increased risk of being unable to recover mental function or the ability to meaningfully interact with the environment. However, a few people may improve with their diagnosis changing to a minimally conscious state.

People can be in a minimally conscious state when they show a few signs of awareness and response to stimulation. Their awareness is minimal or inconsistent. Sometimes, they can communicate or respond to instructions, such as moving their fingers.

Features of a minimally conscious state include:

  • opening and closing the eyes
  • possibly visually tracking people or objects for a sustained period
  • the presence of a sleep-wake cycle
  • partial or fluctuating awareness
  • possibly following simple commands
  • possibly answering “yes” or “no” using gestures or simple words
  • some communication with a few words or phrases
  • making automatic movements, such as head scratching, leg crossing, or moving hair away from the eyes
  • possibly responding to people or their environment by smiling, laughing, crying
  • possibly reaching toward or trying to use objects

Some people are minimally conscious while on the route to recovery. However, it could be a permanent state for others.

At the end of brain aneurysm surgery, an anesthesiologist stops giving the person anesthesia medication, and the person can begin to wake up slowly.

Anesthesia typically allows a person to begin waking up within a few minutes in the postoperative period. However, many factors can affect the time to wake up, such as patient factors, anesthesia factors, and the duration of surgery.

When a healthcare team is satisfied that a person is recovering normally, they will take them to a recovery room.

Although a person starts to regain consciousness during this time, they may not be fully awake right away. Some people feel sleepy while the anesthesia wears off, while others may have side effects, such as nausea or chills.

An anesthesiologist continues to care for a person after surgery, monitoring their breathing and heart function and administering pain medication.

How well a person recovers after aneurysm surgery depends on the severity of the damage before surgery. For people with an unruptured aneurysm, recovery is generally faster and may take weeks. When a brain aneurysm ruptures, recovery could take months or longer.

According to the American Stroke Association, after an aneurysm ruptures and bleeds, the chance of death is around 40%, and the chance of a person having some brain damage is 66%, even with treatment. A ruptured aneurysm needs treatment quickly to prevent further bleeding from the ruptured aneurysm and other complications.

After discharge from the hospital, most people require physical, speech, and occupational therapy.

People with a ruptured brain aneurysm, or a brain aneurysm with a high risk of rupture, require surgery. Sometimes, people do not wake up immediately after surgery.

Individuals may not wake up after brain aneurysm surgery due to postoperative sedation, delayed emergence from anesthesia, and coma. People may enter a coma if they experience complications from the brain aneurysm or brain surgery.

Brain aneurysms require monitoring or treatment to prevent rupturing. Once a brain aneurysm ruptures, a person requires urgent surgery due to the risks of brain damage and death.