General anaesthetic: before, during, after

What is a general anaesthetic?

A general anaesthetic puts a person into a state of controlled unconsciousness, so they are asleep and feel nothing during the procedure.

A breathing tube is sometimes used, and it can cause a sore throat afterwards.

How do I prepare?

Hospitals ask people to follow fasting instructions before a general anaesthetic. Trusts give different timings, so the instructions from the hospital's own team apply.

Fasting matters because food or liquid left in the stomach could come back up to the back of the throat and be breathed into the lungs, causing injury. Trusts also give advice about dentures and alcohol beforehand, so the hospital's own instructions apply. Smoking makes a chest infection after an anaesthetic more likely.

One trust leaflet says that an operation will be cancelled on the day if the fasting rules were broken.

What happens afterwards?

After the anaesthetic wears off, common effects include sickness, feeling cold or shivering, and a sore throat. Medication may leave a person drowsy.

The effects of a general anaesthetic can last for around a day, and hospitals give aftercare advice.

What are the risks?

Anyone having a general anaesthetic is at some risk. Possible complications include a chest infection, particularly in people who smoke or have lung problems, and confusion, which is more common in older people and usually temporary.

Allergic reactions can be serious but are rare, and awareness during surgery is also rare. The anaesthetist discusses this before the operation.