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General anaesthesia

This leaflet is for people who are having or thinking of having a general anaesthetic. Your care may differ from what is described here because it is adapted to meet your individual needs, so it's important to follow your doctor's advice.

What is general anaesthesia?

General anaesthesia helps doctors put patients to sleep and keep them asleep for surgery or other medical procedures. When you have a general anaesthetic you will not feel or remember the operation.

Alternative treatment options

General anaesthesia may not be suitable for all patients. For some patients, regional anaesthesia is preferable. This completely numbs larger areas or deeper parts of the body but you stay awake. For more information, please see the separate BUPA Health factsheet, Local anaesthesia and sedation.

Your anaesthetist will discuss with you which type of anaesthesia is most suitable in your case.

Preparing for your operation

For certain operations you may be asked to attend a pre-admission clinic, where you may meet your anaesthetist. Otherwise you will usually meet your anaesthetist on the day of your operation. You will be asked about your health and about any previous experience you have had of hospital treatment. It's important that you tell your anaesthetist about any allergies that you have and whether you suffer from asthma, hayfever or eczema, and about any medicines that you are taking (whether prescribed, herbal, or over-the-counter).

You should tell your anaesthetist if you have any dental crowns, bridges or loose teeth. These can be vulnerable to damage because a tube is usually put in your mouth while you are unconscious.

If you smoke, you should give up a few weeks before surgery. This will significantly reduce your risk of breathing problems during and after general anaesthesia.

On the day of your operation

You should have a bath or shower at home on the day of your admission. You should also remove any make-up, nail varnish and jewellery. Rings and earrings that you prefer not to remove can usually be covered with sticky tape.

Eating and drinking

Follow the fasting instructions given in your admission letter. Typically, you must not eat or drink for about six hours before general anaesthesia. However, some anaesthetists allow occasional sips of water until two hours before your operation.

It is important to have an empty stomach when you have a general anaesthetic because you are less likely to be sick. Vomiting while you are unconscious can be dangerous because you can't cough, so fluid from the stomach may get into the lungs.

At the hospital

Your anaesthetist will usually visit you in your room, and will ask if there have been any changes to your health since your pre-admission visit.

Most people are anxious before an operation. Pre-medication drugs which help to relieve anxiety may be offered to you. You can discuss this with your anaesthetist beforehand.

You may be asked to wear compression stockings to help prevent blood clots forming in the veins in your legs (deep vein thrombosis, DVT). For more information, please see the separate BUPA health factsheet, Compression stockings.

If you wear contact lenses, glasses, dentures or hearing aids you will be asked to remove them. These will be kept safe for you during the operation.

The operating theatre

You will be taken from your room to the theatre suite where you will be met by a member of the theatre team. You may then be taken to the anaesthetic room, which connects with the operating theatre. In some hospitals you will be taken straight to the operating theatre.

An assistant will help your anaesthetist prepare you for the operation. You will have a narrow plastic tube (called a cannula) inserted into a vein, usually on the back of your right hand or in your arm. This causes a sharp sensation, like an injection, that passes quickly.

With the cannula in place, the anaesthetist can give the various drugs that put you to sleep and control pain and nausea, without repeated injections. You may also be put on a drip to keep you hydrated.

During the operation

The exact type of anaesthetic you are given depends on the procedure you are having. For most operations, anaesthesia is started with a drug injected through the cannula. Within seconds you will fall asleep and won't wake up again until after your operation is completed. This is known as the "induction" of anaesthesia. It's also possible to induce anaesthesia with anaesthetic gases, breathed through a mask. Your anaesthetist will stay with you during your operation.

To keep you asleep, you will be given a mixture of oxygen and anaesthetic gases through a flexible tube put into your windpipe. This part of anaesthesia is known as "maintenance".

To help control pain during and after surgery, your anaesthetist may give you strong painkillers. These can be injected through the cannula, or given as a suppository (tablet inserted into your back passage).

Depending on your particular operation you may also be given a drug to relax your muscles, so that the surgeon can operate more easily.

During the operation, you will be connected to machines that monitor the activity of your heart and other body systems. Your anaesthetist will keep a close check on your heart rate, blood pressure, and the amount of oxygen in your bloodstream.

Waking up

When the anaesthetic gases are stopped, you will begin to wake up or recover quite quickly. You will be given a drug to reverse the effects of any muscle relaxant.

You will be moved to the recovery room where a nurse will provide one-to-one care. If you have a tube in your throat this will be taken out as you wake up. It is routine to be given oxygen to breathe through a face mask. Your nurse will continue to monitor your heart rate, blood pressure and other vital body functions.

When you start to wake up, you may feel sleepy or disorientated for 15 minutes or so. You may have a sore throat caused by the tube that was used to keep your windpipe open. You may feel sick, but medicines are usually given to make this less likely.

Returning to your room

Once your anaesthetist is happy with your progress, you will be disconnected from the monitors and taken back to your room on a trolley or bed. When you no longer need intravenous medicines or fluids, the cannula and drip will be removed.

Pain control

Depending on the type of operation you have, you may need pain relief. There is a wide range of pain control drugs available which will be tailored to suit your needs. Controlling pain after an operation is very important because pain can interfere with your recovery, so please discuss any discomfort with your nurse, anaesthetist or doctor.

Sometimes, local or regional anaesthesia is used in combination with general anaesthesia to numb parts of the body which are painful. For more information, please see the separate BUPA Health factsheet, Local anaesthesia or sedation.

Patient-controlled analgesia (PCA) is used after some procedures. It consists of a pump connected to your cannula that allows you to control how much pain control medication you receive.

Before your operation, ask your anaesthetist what pain control options will be available to you.

Going home

If your operation is planned as a day case, you will need to rest on your bed for a few hours before going home.

Modern anaesthetics are quickly flushed out of your system. However, you should follow the advice of your anaesthetist and nurse about how much activity you should do. This will also depend on the type of operation you have. General anaesthesia can temporarily affect your co-ordination and reasoning skills, so you should not drink alcohol, operate machinery or sign legal documents for 48 hours afterwards.

For day-case procedures, you should try to arrange for somebody to stay with you at home for the first 24 hours.

You will need to get someone to drive you home. You should not drive for 48 hours after a general anaesthetic. However, depending on your operation, your doctor may recommend that you do not drive for a longer period. If in doubt, please contact your motor insurer so that you are aware of their recommendations, and always follow your doctor's advice.

Deciding to have general anaesthesia

The use of modern anaesthetic technology has made many types of surgery possible. For most people, the benefits in terms of controlled unconsciousness and removal of pain are much greater than the disadvantages. However, there is still the risk of side-effects and complications.

Side-effects are the unwanted but mostly temporary effects of successful treatment. After having a general anaesthetic, you may have a sore throat, a headache, or feel tired and confused for a couple of days.

Complications are unexpected problems that can occur during or after the procedure. Serious complications as a result of anaesthesia do occur, but they are extremely rare. It's estimated that serious complications result in four deaths for every million anaesthetics given.

Ask your anaesthetist to explain how these risks apply to you. The exact risks will differ for every person. This is one of the reasons why we have not included statistics here.

Further information

• Royal College of Anaesthetists
  020 7092 1500
  www.rcoa.ac.uk

Sources

• Brady M, Kinn S, Stuart P. Preoperative fasting for adults to prevent perioperative complications. The Cochrane Library.
  www.Cochrane.org
  accessed 16 August 2006
• Anaesthesia explained. Royal College of Anaesthetists.
  www.rcoa.ac.uk
  accessed December 2006

Published by BUPA's health information team, healthinfo@bupa.com, December 2006.

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