Anaesthesia means ‘loss of sensation’. Medications that cause anaesthesia are called anaesthetics. Anaesthetics are used for pain relief during tests or surgical operations so that you do not feel:
- pain,
- touch,
- pressure, and
- temperature.
How do anaesthetics work?
Anaesthetics work by blocking the signals that pass along your nerves to your brain.
Your nerves are bundles of fibres that use chemical and electrical signals to pass information around your body. If you cut your finger, the pain signal travels from your finger to your brain through your nerves. When the signal reaches your brain, you realise that your finger hurts.
Anaesthetics stop the nerve signals reaching your brain, allowing procedures to be carried out without you feeling anything. When the anaesthetic wears off, the signals will work again and your feelings will come back.
Types of anaesthesia
There are several different types of anaesthesia. Most types do not make you unconscious, but they stop you feeling pain in a particular area of your body.
The different types of anaesthetic are described below.
- Local anaesthetic - used for minor procedures and tests to numb the nerves in the area where the procedure is taking place. During the procedure, you stay conscious but you do not feel any pain.
- Regional anaesthetic - is used for larger or deeper operations where the nerves are harder to reach. Local anaesthetic is injected near the nerves in order to numb a larger area, but you remain conscious.
- Epidural anaesthetic - a regional anaesthetic to numb the lower half of your body, which is often used for childbirth.
- Spinal anaesthesia - a regional anaesthetic that is used to numb your spinal nerves so that surgery can be carried out in this area.
- General anaesthetic - used for more extensive operations when you need to be unconscious. The anaesthetic stops your brain recognising any signals from your nerves so that you cannot feel anything.
- Sedation - for minor painful or unpleasant procedures. Sedation makes you feel sleepy and relaxes you both physically and mentally.
Different types of anaesthesia can be used at the same time. For example:
- a regional anaesthetic can be used with a general anaesthetic to relieve pain after an operation, or
- sedation may be used with a regional anaesthetic to make you relaxed during the operation as well as pain free.
Anaesthesia may be given to you in the form of:
- ointment, spray, or drops that are rubbed onto your skin,
- an injection into a vein, or
- a gas that you breathe in.
Anaesthetists
Anaesthetists are specialist doctors who are trained in anaesthesia. Before your procedure, they will discuss with you what anaesthetic methods are appropriate, plus any risks or side effects. You should raise any queries that you have with them.
You anaesthetist will make sure that you are safe throughout the surgery, and that you wake up comfortably after the procedure. They may also help with any pain relief that you need after the procedure.
Side effects
Anaesthetics consist of a number of medications, which can cause side effects in some people. Your anaesthetist will let you know what side effects you may feel for your specific anaesthetic.
Some of the more common side effects include:
- feeling sick or vomiting - about one in three people may feel sick after an operation,
- dizziness and feeling faint,
- feeling cold and shivering for up to half an hour - this is possible after a general anaesthetic, or during, or after, a regional anaesthetic,
- headache,
- itchiness, and
- bruising and soreness.
The side effects do not usually last for very long and, if necessary, they can be treated with further medication. You should let the healthcare professionals who are treating you know if you experience any of the above side effects, or if you are in any pain after your procedure.
Complications and risks
There are a number of more serious complications that are associated with anaesthesia but, fortunately, they are very rare (occurring in less than one case for every 10,000 anaesthetics given). Complications include:
- permanent nerve damage (causing paralysis or numbness),
- a serious allergic reaction to the anaesthetic (anaphylaxis), and
- death - which is extremely rare (there is approximately one death for every 100,000 general anaesthetics given).
Whether you are at any risk of these complications will depend on:
- your medical history - for example, whether you have any other illness,
- personal factors - for example, whether you smoke or are overweight,
- the type of surgery needed - for example, whether it is planned, or carried out in an emergency, or whether it is a major, or minor, procedure, and
- the type of anaesthetic needed - general anaesthetic can have more side effects and complications than local anaesthetic.
Before you have the procedure, your anaesthetist will explain your risk of developing possible complications or side effects. Usually, the benefit of being pain-free will outweigh the risks, but you should discuss any concerns that you have with your anaesthetist.
