Accidental Awareness During General Anaesthesia — How Rare Is It?

The idea of “waking up” during surgery is something many patients worry about. This phenomenon, called Accidental Awareness During General Anaesthesia (AAGA), is when a patient becomes conscious while under anaesthetic. Thankfully, the most comprehensive research shows that this is extremely rare.

What Do We Know About AAGA?
The UK’s 5th National Audit Project (NAP5) collected data on awareness events during anaesthesia across the country. It found that:

  • AAGA happens in about 1 in 17,000–20,000 anaesthetics overall.
  • The risk is higher (about 1 in 8,000) when muscle relaxants are used.
  • Without muscle relaxants, the risk is much lower (around 1 in 136,000).

What Do Patients Experience?
When AAGA does occur, most patients describe vague or dreamlike experiences. Very few remember actual surgical events or experience pain. Some may feel awareness at the very start (going off to sleep) or at the end (waking up), when anaesthetic levels are naturally changing.

Can It Have Lasting Effects?
Most patients who experience AAGA recover without long-term issues. However, a small number may develop anxiety or post-traumatic stress. Anaesthesia teams are trained to recognise this and offer follow-up support.

How Do Anaesthetists Reduce the Risk?
To keep you safe, anaesthetists:

  • Use muscle relaxants only when necessary.
  • Monitor the depth of anaesthesia throughout surgery.
  • Carefully manage the transition between going to sleep and waking up.
  • Ensure muscle relaxants are fully reversed before you regain consciousness.

Key Takeaway
Accidental awareness during general anaesthesia is very uncommon. Modern monitoring and strict safety protocols make it an even rarer event. If you are worried, your anaesthetist will be happy to discuss the steps taken to keep you safe and comfortable during your procedure.

Reference
Royal College of Anaesthetists. NAP5 Full Report.

 

Armadale Anaesthesia
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