The word ‘anaesthesia’ means ‘loss of sensation’. If you have ever had a dental injection in your mouth or pain-killing drops put in your eyes, you already know important things about anaesthesia:

• It stops you feeling pain and other sensations
• It can be given in various ways
• Not all anaesthesia makes you unconscious
• It can be directed to different parts of the body

Drugs that cause anaesthesia work by blocking the signals that pass along your nerves to your brain. When the drugs wear off, you start to feel normal sensations again, including pain.

Local anaesthesia
A local anaesthetic numbs a small part of your body. It is used when the nerves can easily be reached by drops, sprays, ointments or injections. You stay conscious but free from pain. In some operations local anaesthesia can be combined with sedation or general anaesthesia, if appropriate.

Regional anaesthesia
Regional anaesthesia can be used for operations on larger or deeper parts of the body. Local anaesthetic drugs are injected near to the bundles of nerves which carry signals from that area of the body to the brain. The most common regional anaesthetics (also known as regional ‘blocks’) are spinal and epidural anaesthetics. These can be used for operations on the lower body such as caesarean sections, bladder operations or replacing a hip joint. You stay conscious but are free from pain. In some operations regional anaesthesia can be combined with sedation or general anaesthesia, if appropriate.

General anaesthesia
General anaesthesia is a state of controlled unconsciousness during which you feel nothing and may be described as ‘anaesthetised’. This is essential for some operations and may be used as an alternative to regional anaesthesia for others. Anaesthetic drugs injected into a vein, or anaesthetic gases breathed into the lungs, are carried to the brain by the blood. They stop the brain recognising messages coming from the nerves in the body. Anaesthetic unconsciousness is different from unconsciousness due to disease or injury and is different from sleep. As the anaesthetic drugs wear off, your consciousness starts to return.