When a general anaesthetic is administered, drugs are injected into a vein, or in some cases gases are fed into the lungs. The drugs are transported by the blood stream to the brain, where they stop the brain recognising the signals that are being sent by the nerves in the body.

Who administers a general anaesthetic?

General anaesthetics are only given by an anaesthetist. These are doctors who have specialist training in anaesthesia, as well as pain management and emergency care.

If you need a general anaesthetic during your operation, your anaesthetist will visit you in the ward, at a pre-assessment clinic or just before your procedure to discuss with you the different types of anaesthesia and the different risks.

The anaesthetist will ensure you are asleep and secure during the procedure (an anaesthetist will stay with you at all times) and that when you come round afterwards you will be comfortable and pain free.

Are there any risks associated with general anaesthesia?

Having general anaesthesia inevitably carries some risks, although these vary from person to person.

You are more at risk in the following situations:

• If you have any other illness
• If you smoke, or are overweight
• If you are having complicated or emergency surgery

Side-effects and complications:

• Cardiac and respiratory problems ⁽¹⁾
• Confusion
• Dizziness or blurred vision
• Headache
• Nausea and vomiting
• Shivering
• Sore throat

Less common side-effects include:

• Bladder problems
• Chest infection
• Damage to teeth, lips or tongue
• Muscle pains
• Pain awareness
• Slow breathing

What do I need to do to reduce risk?

• If you smoke, give up for a few weeks before the procedure. Smoking reduces the levels of oxygen in your blood and can cause breathing problems during and after the procedure
• If you are overweight, try to lose excess weight
• If you have wobbly teeth or loose crowns ⁽²⁾, you should visit your dentist
• If you have a medical problem, such as diabetes, asthma, thyroid problems, epilepsy or high blood pressure, tell your medical team

Is there anything I must do before having a general anaesthetic?

You may be asked to go to a pre-assessment clinic where you will meet your anaesthetist, or you may meet your anaesthetist on the day of your procedure.

You may also need to attend a pre-assessment clinic where you will meet your medical team and have your general health assessed.

Any special instructions about eating and drinking on the day of the procedure will be discussed and you may have blood tests, ECG (heart tracing) or chest X-rays. Pre-assessment clinics may take place a few days before the day of your procedure.

What happens on the day?

You must follow the instructions you were given about eating and drinking. This is because when you are unconscious, if there is any food or liquid in your stomach, it could be regurgitated and cause choking. You should have a bath or shower and remove make-up (including nail varnish) and any jewellery.

Can I take my normal medicines?

You should continue to take any normal medicines as usual, unless you have been told not to by your anaesthetist or your surgeon.

What happens if I get sick on the day?

You must let the hospital know. You will have been given a number to call at the pre-assessment clinic. Depending on what is wrong, the procedure may need to be put off until you are feeling better.

What is a pre-med?

Pre-medication (or pre-med) are drugs that can be given if you are nervous or distressed about the procedure. They are normally administered a few hours before the procedure and can make you fall asleep. Pre-med drugs can be in the form of tablets, injections or liquids.

How is the anaesthetic administered?

Before your procedure, you will usually be asked to put on a hospital gown and remove contact lenses, glasses, dentures and hearing aids. You will then be taken to the anaesthetic room where the general anaesthesia is started.

A general anaesthetic is normally given in two ways:

• Through a cannula (plastic tube) in the back of your hand
• By breathing anaesthetic gases and oxygen through a mask (this happens more often with children)

What other machines are used?

• A cuff will be put on your arm to check blood pressure during the procedure
• A pulse oximeter will be attached to measure the oxygen level in your blood. This is a small clip that is taped to your finger
• Sticky patches may be placed on your chest to monitor your heart on an electrocardiogram (ECG) machine

How quickly does a general anaesthetic work?

Once the anaesthetic drugs have been given, you will become unconscious within a few seconds. Your anaesthetist will continue to give you drugs during the operation to keep you anaesthetised.

What happens during the procedure?

Your anaesthetist stays with you in order to monitor you throughout the procedure, administer the correct amounts of drugs to keep you anaesthetised, as well as checking your heart rate, blood pressure, heart rhythm, body temperature, breathing and giving you any fluids you need.

For some surgical procedures, you will be given a muscle relaxant. As this stops you breathing, a tube attached to a ventilator will be passed down your throat and into your windpipe to help you breathe.

What happens after the operation?

When the procedure is finished, you will probably be taken to a recovery ward where your condition will continue to be monitored. There the anaesthetic drugs will be stopped and, if you have been given muscle relaxants, you will be given a drug to reverse their effects.

Specially trained nurses will monitor your progress and make sure you return to full consciousness comfortably. You may be given some oxygen and, if you need extra fluids, you may find you are attached to a drip.

You may also find you have had a urine catheter inserted during the course of the operation to drain your bladder.

How will I feel when I wake up?

Depending on the type of procedure you have had, you may feel awake and aware very quickly, or you could find yourself feeling drowsy.

Some people find they suffer from a few side-effects, such as nausea, shivering or headaches. If you had a breathing tube inserted, you may have a sore throat. If you are bothered by your side-effects or you are in pain, you should tell the nursing staff.

Once you are feeling wide awake and aware, you will be taken back to the ward. If you have had a procedure as a day case you will be taken to a waiting area so that you can recover fully before being escorted back home.

Infolinks:

• The Royal College of Anaesthetists
• Royal College of Anaesthetists: Having an anaesthetic