Anaesthesia - Death or Brain Damage - Brain damage

How can brain damage happen?

The risk of developing brain damage as a result of an anaesthetic is extremely small.

Brain damage is caused by the death or damage of brain cells. This can occur as a result of a wide range of causes, including major head injury or severe infections like meningitis. However, in the context of an anaesthetic, it usually occurs because the brain cells are deprived of oxygen in some way.

Symptoms of moderate or severe brain damage
These include:

  • Fitting (convulsions).
  • Abnormal dilation of the eyes.
  • Inability to awake from sleep.
  • Weakness in extremities.
  • Loss of coordination.
  • Confusion.
  • Aggressive, abnormal behaviour.
  • Slurred speech.
  • Coma.

There are two main reasons why a patient may develop brain damage during an anaesthetic.

1. Having a stroke during the anaesthetic

Commonly during a stroke, a blood clot blocks the blood supply to part of the brain. If the blood supply has been stopped, no oxygen will be able to reach that part and if the blood supply is not restored quickly, the cells in that area will die or be damaged.

The risk of having a stroke during surgery is higher:

  1. In older people.
  2. In people with 'furred' or 'hardened' arteries (atherosclerosis).
  3. In anyone who's had a stroke before.
  4. In people having surgery on the head, neck or heart.

It is usually the combined effects of the surgery and the anaesthetic that cause the stroke. A stroke can happen up to 10 days after surgery.

2. Not enough oxygen getting to the brain

Very, very rarely, brain damage can be caused by not getting enough oxygen to the brain. This might be caused by problems putting in the breathing tube. The breathing tube allows oxygen to be delivered to the lungs, and therefore the brain, during an anaesthetic.

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  • Dr S White; Risks associated with your anaesthetic - Section 15: Death or brain damage Royal College of Anaesthetists, 2017
Dr Jennifer Hares
Peer Reviewer:
Dr Hayley Willacy
Document ID:
29008 (v2)
Last Checked:
03 May 2017
Next Review:
01 June 2020

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.