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General Anaesthesia

What is a general anaesthetic?

A general anaesthetic (sometimes referred to as a “GA”) is a mixture of medicines to keep you unconscious and pain free during an operation or procedure. When you arrive to theatre, a drip will be inserted into one of your veins. Medicines are injected into a vein and/ or breathed in as gases into the lungs. To give the gases, the anaesthetist will use a face mask and/or a breathing tube which will be placed through your mouth or nose and into your throat. The tube is removed as you wake up after surgery. During the surgery, you will be attached to a ventilator to assist you with breathing as the drugs given to you often make it difficult for you to breath by yourself. Your anaesthesiologist will monitor you closely during the procedure, and react to any changes in your vital signs accordingly.

What are some of the risks of a general anaesthetic?

There are risks and complications with anaesthesia. There may also be risks specific to each person’s individual condition and circumstances. Please discuss these with the doctor/clinician and ensure you understand your risk before signing consent. Risks include but are not limited to the following:

Common risks and complications:

  • Nausea, vomiting, itching and shivering
  • Headache
  • Drowsiness
  • Pain, bruising and/or bleeding at the injection site
  • Bleeding is more common if you have been taking blood thinning drugs, such as warfarin, aspirin, clopidogrel
  • Sore or dry throat and lips
  • Minor damage to teeth, dental work, tongue and lips due to the breathing tube
  • Temporary blurred or double vision
  • Dizziness or feeling faint, especially when you start to move around
  • Mild allergic reaction to the medication, requiring further treatment
  • Problems in passing urine – you may require a catheter to be placed in your bladder
  • Leaking of stomach content into the lungs (aspiration)
  • Confusion and memory loss, usually in older people, usually recovers but may take weeks or months
  • Emotional distress
  • Small areas of the lung can collapse, increasing the risk of chest infection. This may need antibiotics and physiotherapy
  • Mild breathing problems requiring further treatment (laryngospasm/bronchospasm)
Your anaesthetist will monitor you closely while you are asleep

Uncommon risks and complications:

  • Significant allergic reaction to the medication, requiring further treatment
  • Significant breathing problems (laryngospasm and bronchospasm)
  • Muscle aches and pains
  • Temporary difficulty in breathing and/or slow breathing after waking up
  • Temporary nerve damage (paralysis or numbness)
  • The anaesthetic does not fully work (e.g. being conscious or aware whilst having a general anaesthetic)
  • Damage to the voice box and vocal cords, which may cause a temporary hoarse voice from the breathing tube
  • Damage to the eyes (small pieces of tape and/or eye ointment is used to keep the eyelids closed and lubricated)
  • Prolonged paralysis (mild) requiring breathing support
  • Worsening of an existing medical condition
  • Blood clot in the leg (DVT) causing pain and swelling. In rare cases part of the clot may break off and go to the lungs.

Rare risks and complications:

  • Serious allergic reaction or shock to the medication, requiring further treatment
  • Very high body temperature requiring emergency treatment
  • Heart attack or stroke could occur due to the strain on the heart
  • Severe and permanent nerve damage
  • Brain damage
  • Damage to the eyes including loss of vision
  • deafness (usually short-term)
  • Seizures may occur, requiring further medication and treatment
  • Equipment failure causing significant harm
  • Death as a result of this anaesthetic is rare

It is important to note that an anaesthesiologist is specifically trained to manage the above-mentioned complications.

The risk to you will depend on:

  • How simple or complex your surgery is
  • Whether your surgery takes a short or a long time
  • Whether your surgery is an emergency

Your risks are also increased if you:

  • Are elderly
  • Smoke
  • Are overweight
  • have the following:
    • A bad cold or flu, asthma or other chest disease
    • Diabetes
    • Heart disease
    • Kidney disease
    • High blood pressure
    • Other serious medical conditions
The above infographic describes what is meant by common, uncommon and rare risks

What is intubation?

Intubation is a procedure during which the anaesthesiologist will place a plastic tube into your trachea (windpipe) for the purposes of assisting you with breathing while you are under a general anaesthetic. The procedure can be done awake or asleep. If the procedure is done awake, it is usually because you have a significantly higher risk of breathing problems during intubation and this will be discussed with you in great detail. For the vast majority of patients, intubation is done asleep. After your drip is placed, the anaesthesiologist will inject medication into your drip to make you fall asleep. Thereafter, a paralytic agent is injected to facilitate a smooth intubation. The anaesthesiologist will place a metal instrument into your mouth to assist with visualizing the back of your throat. A plastic tube is placed under direct vision through your vocal cords and into your trachea. The plastic tube is then attached to a ventilator so that you may be assisted with breathing during your procedure.

The process of intubation: a metal instrument is placed into your mouth the assist with placing the plastic tube into your trachea

What can I expect after the general anaesthetic?

After the surgery, the nursing staff in the recovery area will watch you closely until you are fully awake. You will then be returned to the ward or day procedure area where you will rest until you are well enough to go home. Tell nursing staff if you have any side effects from the anaesthetic, such as headache, nausea, or vomiting. They will be able to give you some medication to help. The anaesthetist will arrange pain relief, any other medications and extra fluids by a drip, if needed. Some pain is normal after an operation, but you should still be comfortable.

Some ways of giving pain relief are:

  • Tablets or pills
  • Injections into the drip or into a muscle
  • Suppositories
  • Patient-controlled analgesia (PCA) pump – you control your own pain relief by pressing a button for your drip to give you a dose of strong pain relief medicines
  • Local/regional anaesthesia – Either local anaesthetic injection into the wound or a nerve block

A general anaesthetic will affect your judgment for about 24 hours or sometimes longer. For your own safety during this time:

  • Do NOT drive any type of car, bike or other vehicle
  • Do NOT operate machinery including cooking implements
  • Do NOT make important decisions (such as withdrawal of money from the ATM) or sign legal documents
  • Do NOT drink alcohol, take other mind-altering substances, or smoke, as they may react with the anaesthetic medicines
  • Have an adult with you on the first night after your surgery if you are being discharged on the same day as surgery

This information page has been adapted from the information pamphlets used by the Royal College of Anaesthesiologists in the United Kingdom ( https://www.rcoa.ac.uk/patients ) and the Government of Queensland, Australia.