Risks of Anaesthesia


Side effects
General anaesthetics have some common side effects. Your anaesthetist should discuss these with you before your surgery.
Most side effects occur immediately after your operation and don’t last long.

Possible side effects include:
Feeling sick and vomiting – this usually occurs immediately, although some people may continue to feel sick for up to a day
Shivering and feeling cold – this may last a few minutes or hours
Confusion and memory loss – this is more common in elderly people or those with existing memory problems; it’s usually temporary, but occasionally can be longer lasting
Bladder problems –you may have difficulty passing urine
Dizziness – you will be given fluids to treat this
Bruising and soreness – this may develop in the area where you were injected or had a drip fitted; it usually heals without treatment
Sore throat – during your operation, a tube may be inserted either into your mouth or down your throat to help you breathe; afterwards, this can cause a sore throat
Damage to the mouth or teeth – a small proportion of people may have small cuts to their lips or tongue from the tube, and some may have damage to their teeth; you should tell your anaesthetist about any dental work you have had done
Complications and risks
A number of more serious complications are associated with general anaesthetics. These are very rare, occurring in less than 1 in every 10,000 cases.
Possible serious complications and risks include:
serious allergic reaction to the anaesthetic (anaphylaxis)
An inherited reaction to the anaesthetic that causes breathing difficulties (Suxamethonium apnoea)
Waking up during your operation – This is rare, with one episode known to anaesthetists in every 19,000 general anaesthetics. The amount of anaesthetic given will be continuously monitored to help ensure this doesn’t happen.
Death – this is very rare, occurring in 1 in every 100,000 to 1 in every 200,000 cases and very much depends on co-morbid conditions, complexity of surgery and postoperative care.
Serious problems are more likely to occur if you’re having major or emergency surgery, you have any other illnesses, you smoke, or you’re overweight.
Your anaesthetist will discuss the risks with you before your operation. You should try to stop smoking or drinking alcohol in the weeks before surgery, as doing so will reduce your risk of developing complications.
You may also be advised to lose weight, and if you can you should increase your activity levels in the weeks before surgery, as this is likely to reduce your risk as well.
In most cases, the benefits of being pain-free during an operation outweigh the risks.

Other risks are very uncommon and are enlisted below.

Damage to the eye during general anaesthesia

Equipment failure

Headache after a spinal or epidural injection

Mastocytosis and Anaesthesia

Nerve damage associated with a spinal or epidural injection

Post-operative chest infection