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Local anaesthesia and sedation

Published by Bupa's health information team, July 2009.

This factsheet is for people who are planning to have local anaesthesia or sedation, or who would like information about it.

Local anaesthesia stops pain during a medical procedure by blocking pain signals from being carried by nerves to the brain. A person having local anaesthesia will be awake during the procedure.

Your care will be adapted to meet your individual needs and may differ from what is described here. So it's important that you follow your doctor or dentist's advice.

About local anaesthesia
About sedation
What are the alternatives to local anaesthesia or sedation?
Preparing for your local anaesthesia or sedation
What to expect afterwards
Recovering from local anaesthesia or sedation
What are the risks?
Questions and answers
Related topics
Further information
Sources

About local anaesthesia

The word 'anaesthesia' comes from a Greek word meaning absence or loss of sensation. Anaesthesia is one of the most significant developments of modern medicine because it allows once unbearable medical procedures to be performed without discomfort.

Local anaesthetic completely blocks feeling from the treated area and you will stay awake during the procedure.

Local anaesthetic drugs are usually only used for short, simple operations such as stitching a wound or removing a mole. Depending on the drug used, the numbing effect can last from about two to eight hours.

How is it given?

Local anaesthetic drugs can be:

injected into the area
sprayed directly on to the area
rubbed on to the area
injected around a specific nerve supplying the area (nerve block)
injected directly into the fluid (spinal block) or tissue (epidural) around your spine

Nerve blocks, spinal blocks and epidurals are also called regional anaesthesia but they still use local anaesthetic so you will stay awake during the procedure.

You will start to lose feeling very quickly in the treated area.

Your operation won't start until your doctor or dentist is absolutely sure that the area is numb. It's important to realise that local anaesthesia takes away feelings of pain, but you may still feel pressure and movement during your operation.

About sedation

Sedative drugs relieve anxiety and help you to relax without needing to be asleep during the procedure. Sedatives are often used to help people relax during medical procedures. You will remember very little about the treatment done under sedation.

Sedative drugs don't block the pain signals to the brain, so local or regional anaesthesia is often given as well.

How is it given?

Sedation can be:

inhaled - as gas and air
swallowed - in tablet or liquid form
injected - using a fine plastic tube (cannula) into a vein on the back of your hand or in your arm

The type and dose of sedative given depends on the procedure and how anxious you are about it.

Sedation is commonly used during many procedures such as colonoscopy, gastroscopy and cataract operations.

Sedatives can sometimes affect your breathing. While you're sedated, your doctor will constantly monitor the amount of oxygen in your blood through a small device on your finger and you may be given extra oxygen through a mask or a plastic nasal tube.

What are the alternatives to local anaesthesia or sedation?

Instead of a local anaesthetic you may be offered general anaesthesia - this means you will be asleep during the procedure.

Your doctor will advise which type of anaesthesia is most suitable for you.

Preparing for your local anaesthesia or sedation

If you smoke, you will be asked to try and stop as smoking increases your risk of getting a wound infection and slows your recovery.

If you go into hospital, your nurse will explain how you will be cared for during your stay. Your nurse may check your heart rate and blood pressure, and test your urine.

Your doctor will usually ask you to sign a consent form. This confirms that you understand the risks, benefits and possible alternatives to the procedure and have given your permission for it to go ahead.

Preparing for your local anaesthesia

You don't need to make any special preparations to have a local anaesthetic. You should be allowed to eat and drink as usual before you arrive but if you're unsure about this, talk to your doctor.

If you're having regional anaesthesia, you may be asked to follow fasting instructions. Typically you must not eat for six hours before the regional anaesthetic.

Preparing for your sedation

The instructions will vary depending on the type of sedative you're given.

Inhaled sedation doesn't usually require any specific preparation, but it can sometimes make you feel sick, so you may be asked to eat only light meals before your procedure.

If your sedative is being injected or swallowed, you will be asked not to eat for six hours before your procedure and not to drink for two hours before the procedure. Ask your doctor for specific advice about sedation.

What to expect afterwards

After a local anaesthetic it may take several hours before the feeling comes back into the treated area. Take special care not to bump or knock the area.

You may need pain relief to help with any discomfort as the anaesthetic wears off.

After a local anaesthetic or sedation you will usually be able to go home when you feel ready.

After a regional anaesthetic you should rest until the effects of the anaesthetic have passed. Follow the advice of your doctor and nurse about how much activity you do.

You may need to arrange for someone to drive you home.

Recovering from local anaesthesia or sedation

If you need pain relief, you can take over-the-counter painkillers such as paracetamol or ibuprofen. Always read the patient information that comes with your medicine and if you have any questions, ask your pharmacist for advice.

Sedation temporarily affects your coordination and reasoning skills, so you must not drive, drink alcohol, operate machinery or sign legal documents for 24 hours afterwards. If you're in any doubt about driving, please contact your motor insurer so that you're aware of their recommendations and always follow your doctor/surgeon's advice.

What are the risks?

Local anaesthesia and sedation are commonly performed and generally safe. However, in order to make an informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications of these procedures.

Side-effects of local anaesthesia or sedation

These are the unwanted, but mostly mild and temporary effects of successful anaesthesia or sedation, for example a drop in blood pressure or temporary loss of muscle control.

Side-effects of both local anaesthesia and sedation vary depending on which medicine is used. After local anaesthesia you may get a headache, feel sick or vomit and have feelings similar to those of being drunk or hung over.

The side-effects of sedation are similar to local anaesthesia. You may also feel confused, you may not remember the operation and you may be tired or light-headed the following day.

Complications of local anaesthesia or sedation

This is when problems occur during or after the local anaesthetic or sedative. Most people aren't affected.

Complications of local anaesthesia or sedation include:

toxic reactions - signs of a toxic reaction include tingling lips, drowsiness and slurred speech, rarely this can lead to an arrhythmia (a disturbance of the normal heartbeat) and heart attack
low oxygen levels in the blood - this can cause breathlessness and confusion

The exact risks are specific to you and differ for every person, so we haven't included statistics here. Ask your doctor or dentist to explain how these risks apply to you.