General anaesthetics | Better Health Channel
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General anaesthetics

Summary

An anaesthetic is a drug or agent that produces a complete or partial loss of feeling. There are three kinds of anaesthetic: general, regional and local. When a patient undergoes a general anaesthetic, they lose sensation and become unconscious. General anaesthetic may be given as an injection or as a gas. An anaesthetist will administer a general anaesthetic.

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An anaesthetic is a drug or agent that produces a complete or partial loss of feeling. There are three kinds of anaesthetic: general, regional and local. When a patient undergoes a general anaesthetic, they lose sensation and become unconscious.

General anaesthetics can be given in a number of ways. One method is by injecting drugs into your veins, and another method is by anaesthetic gas given by inhalation through a mask. Sometimes, injections and the anaesthetic mask can be used at the same time.

Issues to consider with general anaesthetics


Your anaesthetist will visit you before you go to theatre to assess if you are fit enough for surgery, and to explain the administration of a general anaesthetic. You need to discuss a range of issues with your anaesthetist including:
  • Medical history, including any pre-existing conditions, such as diabetes or heart problems
  • Surgical history
  • Allergies, for example, to drugs or foods
  • Drugs you may be taking, including cigarettes and alcohol.

Other issues which your doctor or nursing staff may discuss with you include:
  • Eating and drinking – usually you will be asked not to drink or eat for several hours before the operation.
  • Shaving - you may need hair shaved from the operation site,
  • Other procedures – you may need an enema or other pre-operative procedures.

Administration of general anaesthetic


A couple of hours prior to surgery, you may be given a ‘pre-med’, which may be an injection or tablets that make you sleepy and relaxed. These drugs also help to dry up excessive saliva.

You are then wheeled into the operating theatre. A qualified anaesthetist, who is a medical doctor with specialist training in anaesthetics, administers the general anaesthetic. The anaesthetist may administer the anaesthetic intravenously or by gas mask, or both. After a few seconds, you feel sleepy then lose consciousness.

Next, the anaesthetist inserts a small tube connected to a ventilator into your airway. The anaesthetist controls the length of time you are asleep, and constantly monitors your pulse, breathing and blood pressure. If necessary, your anaesthetist will give you intravenous fluids before, during and after surgery.

Once the surgery is over, you may have other drugs injected that will reverse the effect of the anaesthetic and any other drugs used during the operation (such as muscle relaxant). When the anaesthetist is satisfied with your breathing and blood circulation, you are wheeled into the recovery room where specialised staff members look after you.

Following surgery with general anaesthetic


After surgery, you can expect that hospital staff will:
  • Record your breathing, pulse and blood pressure.
  • Note your level of consciousness, as well as any special observations required for your type of surgery.
  • Record all intravenous fluids you are given.
Depending on the type of surgery you’ve had, you may find that when you wake up you:
  • Have a tube coming from your wound site to drain excess fluid.
  • Had a catheter inserted into your bladder while you are in theatre and your urine output is being noted.
  • Are encouraged to do deep breathing exercises and move your legs at least hourly following surgery, if you can.
  • Are given pain relief medication.
  • Feel drowsy and nauseous, with a headache and sore throat. These side effects pass relatively quickly.

Complications with general anaesthetics


Some of the rare but possible side effects from general anaesthetic include:
  • Injury at the injection site
  • Infection
  • Breathing problems
  • Short term damage to nerves
  • Allergic reaction, for example, asthma attack
  • Having sensation (and pain) during the operation
  • Damage to the mouth, teeth, lips or tongue
  • Damage to vocal cords or larynx
  • Lung damage
  • Heart attack
  • Brain damage
  • Stroke
  • Kidney failure
  • Liver failure
  • Paraplegia
  • Quadriplegia.

Taking care of yourself at home


Be guided by your doctor or anaesthetist, but general suggestions include:
  • If you are permitted to leave hospital within hours of the surgery, don’t try to drive home because your coordination may be affected by the medication. Ask a relative or friend to pick you up or take a taxi.
  • Don’t drive a car within 24 hours after the procedure.
  • Take it easy for the next day or two. Rest at home. Remember it may take several days before you feel back to normal.
  • Avoid taking herbal medicines in the days or weeks following surgery. Ask your doctor for further information.

Long term outlook after a general anaesthetic


Complications from general anaesthetic are rare. It is estimated that around one in every 10,000 people undergoing general anaesthetic die from an unforeseen complication, such as an allergic reaction or a heart attack.

Regional and local anaesthetics


Depending on the type of surgery, alternatives to general anaesthetic can include:
  • Regional anaesthetic – or ‘nerve block’. For example, a woman giving birth by caesarean section may have an epidural. This is an injection into the spine that numbs the body from the waist down.
  • Local anaesthetic – anaesthetic is injected into the immediate area to be operated on. For example, your dentist may inject local anaesthetic into your gum before removing a tooth.

Where to get help

  • Your doctor
  • Anaesthetist

Things to remember

  • An anaesthetic is a drug or agent that produces a complete or partial loss of feeling.
  • There are three kinds of anaesthetic: general, regional and local.
  • When a patient undergoes a general anaesthetic, they lose sensation and become unconscious.

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Last reviewed: September 2012

Content on this website is provided for education and information purposes only. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your doctor or other registered health professional. Content has been prepared for Victorian residents and wider Australian audiences, and was accurate at the time of publication. Readers should note that, over time, currency and completeness of the information may change. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions.


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An anaesthetic is a drug or agent that produces a complete or partial loss of feeling. There are three kinds of anaesthetic: general, regional and local. When a patient undergoes a general anaesthetic, they lose sensation and become unconscious. General anaesthetic may be given as an injection or as a gas. An anaesthetist will administer a general anaesthetic.



Content on this website is provided for education and information purposes only. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your qualified health professional. Content has been prepared for Victorian residence and wider Australian audiences, and was accurate at the time of publication. Readers should note that over time currency and completeness of the information may change. All users are urged to always seek advice from a qualified health care professional for diagnosis and answers to their medical questions.

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