You and Your Anaesthetic

This guide is written by the Royal College of Anaesthetists. Used here with permission.

Some types of anaesthesia

Anaesthesia stops you feeling pain and other sensations. It can be given in various ways and does not always make you unconscious.

Local anaesthesia involves injections which numb a small part of your body. You stay conscious but free from pain.

Regional anaesthesia involves injections which numb a larger or deeper part of the body. You stay conscious but free from pain.

General anaesthesia gives a state of controlled unconsciousness. It is essential for some operations. You are unconscious and feel nothing.


Anaesthetists are doctors with specialist training who:

  • discuss types of anaesthesia with you and find out what you would like, helping you to make choices
  • discuss the risks of anaesthesia with you
  • agree a plan with you for your anaesthetic and pain control
  • are responsible for giving your anaesthetic and for your well-being and safety throughout your surgery
  • manage any blood transfusions you may need
  • plan your care, if needed, in the Intensive Care Unit.
  • make your experience as calm and pain free as possible.

Before coming to hospital

Here are some things that you can do to prepare yourself for your operation:

  • If you smoke, giving up for several weeks before the operation reduces the risk of breathing problems and makes your anaesthetic safer. The longer you can give up beforehand, the better. If you cannot stop smoking completely, cutting down will help.
  • If you are very overweight, reducing your weight will reduce many of the risks of having an anaesthetic.
  • If you have loose teeth or crowns, treatment from your dentist may reduce the risk of damage to your teeth if the anaesthetist needs to put a tube in your throat to help you breathe.
  • If you have a long-standing medical problem such as diabetes, asthma or bronchitis, thyroid problems, heart problems or high blood pressure (hypertension) you should ask your GP if you need a check up.

Before your anaesthetic

You will be asked some questions to check your health before your operation. This may be at a pre-assessment clinic, by filling in a questionnaire, by talking to doctors on the ward, or when you meet your anaesthetist.

It is important for you to bring a list of:

  • all the pills, medicines, herbal remedies or supplements you are taking, both prescribed and those that you have purchased over the counter
  • any allergies you may have.

On the day of your operation

Nothing to eat or drink – fasting (‘Nil by mouth’) The hospital should give you clear instructions about fasting. It is important to follow these. If there is food or liquid in your stomach during your anaesthetic, it could come up to the back of your throat and damage your lungs.

If you are a smoker you should not smoke on the day of your operation. This will help avoid breathing problems during your anaesthetic.

If you are taking medicines you should continue to take them as usual, unless your anaesthetist or surgeon has asked you not to. For example, if you take drugs to stop you getting blood clots (anticoagulants), aspirin, drugs for diabetes or herbal remedies, you will need specific instructions.

If you feel unwell when you are due to come into hospital, please telephone the ward for advice.

Your anaesthetist will meet you before your operation and will:

  • ask you about your health
  • discuss with you which types of anaesthetic can be used
  • discuss with you the benefits, risks and your preferences
  • decide with you which anaesthetic would be best for you
  • decide for you, if you would prefer that.

Nothing will happen to you until you understand and agree with what has been planned for you. You have the right to refuse if you do not want the treatment suggested or if you want more information or more time to decide.

The choice of anaesthetic depends on

  • your operation
  • your answers to the questions you have been asked
  • your physical condition
  • your preferences and the reasons for them
  • your anaesthetist’s recommendations for you
  • and the reasons for them
  • the equipment, staff and other resources at your hospital.

Premedication (a ‘premed’) is the name for drugs which are given before some anaesthetics. Some premeds prepare your body for the anaesthetic, others help you to relax. They may make you more drowsy after the operation.

If you want to go home on the same day, this may be delayed. If you think a premed would help you, ask your anaesthetist.

A needle may be used to start your anaesthetic. If this worries you, you can ask to have a local anaesthetic cream put on your arm to numb the skin before you leave the ward. The ward nurses should be able to do this.

If you are having a local or regional anaesthetic, you will also need to decide whether you would prefer to:

  • be fully alert
  • be relaxed and sleepy (sedation)
  • have a general anaesthetic as well.

Sedation is the use of small amounts of anaesthetic or similar drugs to produce a ‘sleepy-like’ state.

When you are called for your operation

  • A member of staff will go with you to the theatre.
  • A relative or friend may be able to go with you to the anaesthetic room. A parent will normally go with a child.
  • You can wear your glasses, hearing aids and dentures until you are in the anaesthetic room. If you are having a local or regional anaesthetic, you may keep them on.
  • Jewellery and decorative piercing should ideally be removed. If you cannot remove your jewellery, it can be covered with tape to prevent damage to it or to your skin.
  • If you are having a local or regional anaesthetic, you can take a personal CD or MP3 player with you to listen to music through your headphones.
  • Most people go to theatre on a bed or trolley.
  • You may be able to walk. If you are walking, you will need your dressing gown and slippers.
  • Theatre staff will check your identification bracelet, your name and date of birth, and will ask you about other details in your medical records as a final check that you are having the right operation.

The operating department (‘theatres’)

Your anaesthetic may start in the anaesthetic room or in the operating theatre. The anaesthetist will attach machines which measure your heart rate, blood pressure and oxygen levels.

For many anaesthetics, including some types of local anaesthetic, a needle is used to put a cannula (thin plastic tube) into a vein in the back of your hand or arm.

Local and regional anaesthetics

  • Your anaesthetist will ask you to keep quite still
  • while the injections are given.
  • You may notice a warm tingling feeling as the anaesthetic begins to take effect.
  • Your operation will only go ahead when you and your anaesthetist are sure that the area is numb.
  • If you are not having sedation you will remain alert and aware of your surroundings. A screen shields the operating site, so you will not see the operation unless you want to.
  • Your anaesthetist is always near to you and you can speak to him or her whenever you want to.

General anaesthetics

There are two ways of starting a general anaesthetic:

  • anaesthetic drugs may be injected into a vein through the cannula (this is generally used for adults);
  • you can breathe anaesthetic gases and oxygen through
  • a mask, which you may hold if you prefer.

Once you are unconscious, an anaesthetist stays with you at all times and continues to give you drugs to keep you anaesthetised.

As soon as the operation is finished, the drugs will be stopped or reversed so that you regain consciousness.

After the operation, you may be taken to the recovery room. Recovery staff will be with you at all times. When they are satisfied that you have recovered safely from your anaesthetic you will be taken back to the ward.

Pain relief afterwards

Good pain relief is important and some people need more pain relief than others. It is much easier to relieve pain if it is dealt with before it gets bad. Pain relief can be increased, given more often, or given in different combinations.

Occasionally, pain is a warning sign that all is not well, so you should ask for help when you feel pain.

Here are some ways of giving pain relief:

  • Pills, tablets or liquids to swallow. These are used for all types of pain. They take at least half an hour to work. You need to be able to eat, drink and not feel sick for these drugs to work.
  • Injections. These are often needed, and may be intra-venous (through your cannula into a vein for a quicker effect) or intra-muscular (into your leg or buttock muscle using a needle, taking about 20 minutes to work).
  • Suppositories. These waxy pellets are put in your back passage (rectum). The pellet dissolves and the drug passes into the body. They are useful if you cannot swallow or if you might vomit.
  • Patient-controlled analgesia (PCA). This is a method using a machine that allows you to control your pain relief yourself. If you would like more information ask for a leaflet on PCA.
  • Local anaesthetics and regional blocks. These types of anaesthesia can be very useful for relieving pain after surgery. More details can be found in the leaflet ‘Epidurals for pain relief after surgery’.

What will I feel like afterwards?

How you feel will depend on the type of anaesthetic and operation you have had, how much pain relieving medicine you need and your general health.

Understanding risk

In modern anaesthesia, serious problems are uncommon. Risk cannot be removed completely, but modern equipment, training and drugs have made it a much safer procedure in recent years.

To understand a risk, you must know:

  • how likely it is to happen
  • how serious it could be
  • how it can be treated.

The risk to you as an individual will depend on:

  • whether you have any other illness
  • personal factors, such as smoking or being overweight
  • surgery which is complicated, long or done in an emergency.

More information about risks associated with having an anaesthetic can be found on

Index of side effects and complications

People vary in how they interpret words and numbers. This scale is provided to help:

Very commonCommonUncommonRareVery rare
1 in 101 in 1001 in 1,0001 in 10,0001 in 100,000
  • If something is very common, this means that about one in 10 will experience it.
  • Common means about one in 100.
  • Uncommon means about one in 1000.
  • Rare means about one in 10,000.
  • Very rare means about one in 100,000.

Side effects and complications

See the separate leaflet Anaesthesia Explained'for more information on the side effects and complications.

RA = This may occur with a regional anaesthetic.
GA = This may occur with a general anaesthetic.

Very common and common side effects

Feeling sick and vomiting after surgery
Sore throat
Dizziness, blurred vision
Bladder problems
Damage to lips or tongue (usually minor)
Aches, pains and backache
Pain during injection of drugs
Bruising and soreness
Confusion or memory loss

Uncommon side effects and complications

Chest infection
Muscle pains
Slow breathing (depressed respiration)
Damage to teeth
An existing medical condition getting worse
Awareness (becoming conscious during your operation)

Rare or very rare complications

Damage to the eyes
Heart attack or stroke
Serious allergy to drugs
Nerve damage
Equipment failure

Deaths caused by anaesthesia are very rare. There are probably about five deaths for every million anaesthetics in the UK.

Questions you may like to ask your anaesthetist

  • Who will give my anaesthetic?
  • Do I have to have a general anaesthetic?
  • What type of anaesthetic do you recommend?
  • Have you often used this type of anaesthetic?
  • What are the risks of this type of anaesthetic?
  • Do I have any special risks?
  • How will I feel afterwards?

This guide was written by The Royal College of Anaesthetists, Churchill House, 35 Red Lion Square, London WC1R 4SG. © 2002, RCoA (3rd edition - May 2008). Copyright for this article is with the Royal College of Anaesthetists.