Anaesthesia - NHS Skip to main content the NHS website Anaesthesia Anaesthesia means "loss of sensation". Medicines that cause anaesthesia are called anaesthetics. Anaesthetics are used during tests and surgical operations to numb sensation in certain areas of the body or induce sleep. This prevents pain and discomfort, and enables a wide range of medical procedures to be carried out. Local anaesthetics and general anaesthetics are 2 commonly used types of anaesthetics:local anaesthesia is where a small area of the body is numbed and you remain fully conscious – often used during minor proceduresgeneral anaesthesia is where you're totally unconscious and unaware of the procedure – often used for more serious operations Types of anaesthesia As well as local and general anaesthetic, there are a number of other types of anaesthesia. Unlike general anaesthetic, these do not make you unconscious – they just stop you feeling pain in a particular area of your body. The different types of anaesthetic are:regional anaesthetic – a local anaesthetic given to a specific region of your body, leading to numbness or pain relief for deeper operations where more extensive numbness is neededepidural anaesthetic – a type of regional anaesthetic usually used to numb the lower half of the body; for example, as pain relief during labour and childbirthspinal anaesthetic – a type of regional anaesthetic used to give total numbness, lasting about 3 hours, to the lower parts of the body, such as in the base of your spine or in your lower back, so surgery can be safely carried out in this areasedation – medicine that makes you feel sleepy and relaxes you both physically and mentally; it's sometimes used to keep you calm during minor, painful or unpleasant procedures Different types of anaesthesia can be used in combination. For example, a regional anaesthetic can be used with a general anaesthetic to relieve pain after an operation. A sedative is also sometimes used with a regional anaesthetic to help you feel relaxed and calm, as well as pain-free, during an operation. How anaesthetics are given An anaesthetic can be given in a number of ways:as an ointment, spray or dropsas an injection into a veinas a gas you breathe in Anaesthetists Anaesthetists are doctors who have received specialist training in anaesthesia. They'll give you your anaesthetic and be responsible for your safety and wellbeing during your procedure. Before the procedure, your anaesthetist will discuss a number of things with you, including:the types of anaesthetic appropriate for the procedure you're havingany risks or side effects associated with different types of anaesthetic They'll plan your anaesthetic and pain control with you, taking into account any preferences you have for a particular type of anaesthetic. You should ask your anaesthetist to clarify anything you're unsure about. If you have a general anaesthetic, your anaesthetist will carefully monitor you throughout your operation and make sure you wake up comfortably afterwards. They may also help with any pain relief you might need after the procedure. Side effects Anaesthetics consist of a number of medicines that can cause side effects in some people. Your anaesthetist will tell you about any side effects you may experience after having a specific type of anaesthetic and measures that will be taken to reduce these. Some common side effects that can occur after a general anaesthetic or some regional anaesthetics include:feeling or being sickdizziness and feeling faintfeeling cold or shiveringheadachesitchinessbruising and sorenessdifficulty peeingaches and pains The side effects of anaesthetic usually do not last very long and, if necessary, some of them can be treated. Tell the healthcare professionals treating you if you experience any of the above side effects, or if you're in pain after your procedure. Risks and complications In recent years, having anaesthesia has become very safe. Advances in equipment, medicine and training mean serious problems are rare. However, as with any type of surgery or medical procedure, there's a potential risk of complications. The benefits and risks of surgery and anaesthesia will be carefully weighed up and explained to you before you have any operation. The complications of anaesthesia listed below are very rare. Permanent nerve damage This can cause numbness or paralysis (inability to move a part of the body), although this may be a result of the surgery itself. If the damage is slight, you may get better in a few days to a few weeks. Permanent damage to the peripheral nerves, which run between the spinal cord and the rest of the body, occurs in around 1 in 1,000 people having a general anaesthetic. An allergic reaction to an anaesthetic medicine Although an allergic reaction (anaphylaxis) can be severe, appropriate treatment is on hand to enable the best chance of dealing with this immediately and effectively. It's not clear exactly how often anaesthetics cause anaphylaxis, but the best estimate is that a life-threatening allergic reaction occurs in 1 in 10,000 anaesthetics. More than 95 per cent of these will survive and generally recover well. Death If you're a healthy patient having non-emergency surgery, death is very rare at around 1 in 100,000 people having general anaesthetic. However, this may increase depending on certain factors. Factors affecting risk of complications Your risk of developing complications will depend on a number of factors, including:your medical history – for example, whether you have any other serious medical conditions or illnessespersonal factors – for example, whether you smoke or are overweight; if you smoke, stopping several weeks before your operation will reduce your risk of having breathing problems, and losing weight will also help reduce your riskthe type of procedure – for example, whether it's a planned or an emergency procedure, or whether it's a major or minor procedurethe type of anaesthetic – local anaesthesia can have advantages over general anaesthesia in the right circumstances Before your procedure, your anaesthetist will explain if there are any particular risks of developing possible complications. In most cases, the benefits outweigh the risks. Any concerns you have should be discussed with your anaesthetist before surgery. More information You can find out more about specific types of anaesthesia:local anaesthesiageneral anaesthesiaepidural Also see the Royal College of Anaesthetists' patient information. Page last reviewed: 23 September 2021 Next review due: 23 September 2024