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General anaesthetic

What is a general anaesthetic?

A general anaesthetic is a combination of drugs that causes deep sleep. It is used for operations or procedures as it causes a loss of sensation. You will not be aware of what is happening and afterwards you will not be aware of anything that has happened.

How is a general anaesthetic given?

Most people are sent to sleep by injecting the anaesthetic through a drip (small tube) into a vein. It takes about 30 seconds to work. For some people, it may be more appropriate to go to sleep by breathing an anaesthetic gas through a face mask. This also takes about 30 seconds to work.

Are there any alternatives to a general anaesthetic?

Other forms of anaesthesia include injections near the area of surgery (local anaesthetic) or injections of local anaesthetic near major nerves or your spinal cord (regional, epidural or spinal anaesthetic). Local anaesthetics will numb the area to be operated on but you will be awake or under sedation for the operation.

Is a general anaesthetic safe?

A general anaesthetic is safe for most people.

Your anaesthetist may need to do some tests before the operation to assess how safe a general anaesthetic is for you. These may include an ECG, blood tests or lung-function tests.

What complications can happen?

Minor complications

• Feeling or being sick
• Sore throat
• Headache
• Muscle and back pains
• Dental damage
• Difficulty passing urine

Serious complications

• Loss or change of hearing
• Eye injury
• Nerve injury
• Heart attack
• Stroke
• Chest infection and other breathing problems
• Allergic reaction

How will my anaesthetist know that I am really asleep?

Your anaesthetist continuously monitors the amount of anaesthetic in your body to reduce the risk of you being aware of what is happening.

How soon will I recover?

A general anaesthetic can affect your judgement and reactions for 24 hours.

If you are fit and maintain a healthy weight, you are more likely to do well after having a general anaesthetic


A general anaesthetic  is usually a safe and effective way for you to have an operation or procedure. Most people do not have any problems.

Author: Dr Iain Moppett DM MRCP FRCA

This document is intended for information purposes only and should not replace advice that your relevant health professional would give you.

Copyright © 2017 EIDO Healthcare Limited - The operation and treatment information on this webpage is produced using information from EIDO Healthcare Ltd and is licensed by the Horder Centre.

The intellectual property rights to the information belong exclusively to EIDO Healthcare Limited. You may not copy, print out, download or otherwise reproduce any of the information other than for your personal, non-commercial use. The information should not replace any advice that your relevant health professional would give you.

Issued June 2017 | Expires end of May 2018

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