Information about anaesthesia
A general anaesthetic is given to make you unconscious and free of pain during your operation. It is a specialised medical procedure and only undertaken by doctors and Anaesthesia Associates who have been highly trained to do this. Afterwards you should have no memory of what happened while you were under the anaesthetic.
A general anaesthetic is essential for some operations and procedures where there is not an option of using a regional anaesthetic (e.g. spinal), a nerve block or local anaesthetic.
The anaesthetist will give you drugs or gas so that you are unconscious and feel no pain during surgery.
In most hospitals you will be invited to a preoperative assessment clinic before the date scheduled for your operation. Currently with the pandemic many appointments are taking place over the phone or using a video link. At this clinic you will see a preoperative assessment nurse specialist. An anaesthetist may also meet you then. This is especially likely if you are having a major operation or have any significant medical problems. Sometimes, for more minor surgery, a nurse will telephone you instead to ask you some questions.
Some hospitals may ask that you complete a health questionnaire. It is important that you include any medical issues you may have. The hospital needs to know about your general health, your regular medication, including over-the-counter medications and herbal medicines, and any allergies. Please bring a copy of your medication prescription and details about any allergies. If you have any letters or details of medical tests from other hospitals, these can be very helpful too.
They will also be interested in any anaesthetics you have had previously and how you felt afterwards. If you are aware of any family members who have had a serious reaction to anaesthetics, please ask your relative to tell you more about it so you can talk to the anaesthetist about this.
You may meet an anaesthetist in the preoperative assessment clinic if you are having planned major surgery or have medical conditions that need discussing in more detail before your procedure. You also have the opportunity to ask them any questions you might have (see ‘Questions to ask the anaesthetist’ below).
If you have not seen an anaesthetist at the preoperative assessment clinic, you will meet an anaesthetist before your operation. They will discuss any choices about your anaesthetic with you and will give you information about what they are planning to do. Where anaesthesia associates make up part of the anaesthetic team, the anaesthetist may, delegate some roles to them.
For a fit person of normal weight having a planned procedure under general anaesthetic the risks are very low. See our risk infographic for a summary of common events and risks.
Anaesthesia has been made safer by high standards of anaesthetists’ training and by improvements in drugs and monitoring equipment. An anaesthetist stays beside you all the way through the procedure. They will be adjusting the doses of the drugs being used so as to give you just the right amount to keep you both asleep, pain free and safe.
The Royal College of Anaesthetists has produced a series of leaflets on the risks of anaesthesia that can be viewed here if you want to look at risks in more detail.
It is very rare for anyone to be aware during a general anaesthetic. Rarely people may remember the feeling of a tube in the throat being taken out as they wake up and they may have a sore throat. Some people also have dreams around the time they wake up and are in recovery.
In 2014 the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland published a very large study of accidental awareness during general anaesthesia. This report showed that some awareness happens in only 1 in 20,000 patients during a general anaesthetic. Since then, advances in equipment and in monitoring the level of anaesthesia have helped to reduce the chances of this happening. An anaesthetist will be with you all the time during your surgery and watching all monitoring equipment closely to check you are getting the right amount of anaesthetic to keep you unaware and pain free.
An anaesthetist uses a combination of drugs to make you unconscious, pain free and unaware. Allergic reactions can happen with almost any drug. Anaphylaxis is the name given to a severe allergic reaction, also called anaphylactic shock.
Your anaesthetist uses equipment during the anaesthetic that helps to pick up any reaction at an early stage and where possible treat it before it becomes serious.
It is important to tell your anaesthetist about any allergies you have. If you have any allergies to anaesthetic drugs or antibiotics please check with your GP and bring in as many details with you as you can. Some rare serious reactions to anaesthetics run in families, so if any family member has had a serious reaction you should try and find out if they have been given any information on their reaction. Making the anaesthetist aware will allow them to use other drugs that have the same action but less chance of causing a reaction.
In 2018 a large study called NAP6 was carried out to investigate severe allergic reactions related to anaesthesia and surgery, see more details here.
There is normally no increased risk in having two anaesthetics close together. This applies whether they are general, local or regional anaesthetics (such as epidurals or spinals), sedation for procedures or a combination. However, it is important to tell your anaesthetist about any recent anaesthetics you have had and to discuss with them the options for your next anaesthetic.
Suxamethonium (Scoline™) is a muscle relaxant drug that is now only rarely used by anaesthetists in routine operations. However, there are some emergency situations in which it is still the most appropriate choice and it may be used in urgent surgery.
A few people suffer from ‘suxamethonium apnoea’. This is a rare inherited condition which makes the muscles stay relaxed for longer after an operation. If someone in your family is known to be affected, it may be wise for other members of the family to be screened for it by means of a blood test. Your GP should be able to arrange the blood test after discussion with the anaesthetic department at your local hospital.
This will depend on whether you have eye drops or injections to numb your eye. When anaesthetic eye drops are used, most people are just aware of a bright light from the microscope once the operation starts. You may see some moving shapes, but not the actual operation or what the surgeon is doing. If your eye is numbed with an injection, you may only see darkness until the injection wears off.
Your surgeon will place a sterile sheet over the eye they are not operating on, so you will not be able to see the operation. If you suffer from claustrophobia, they sometimes will use a clear sheet instead. You may then see people moving around you, but you will not be able to see the detail of your operation.
If you are anxious please discuss with your surgeon when you meet them to decide on surgery.
Regional anaesthesia and nerve blocks are techniques used to numb and area of your body so that you don’t feel pain. You still may be aware of some feelings of pressure or vibration. They can be used on their own or with some light sedation to help you relax during the procedure. Using regional anaesthesia and nerve blocks can be a good option if you have medical problems that make general anaesthesia more risky.
Regional anaesthesia is used to numb a whole region or large area of your body. Your anaesthetist will inject local anaesthetic around a large nerve or group of nerves. In the back, for example, this is called either an epidural or spinal injection, depending on where your anaesthetist injects the local anaesthetic. It can provide pain relief and numbness on its own for operations such as caesarean section, hip or prostate surgery. You may have it as well as a general anaesthetic to help with pain relief after an operation. For example, this may be helpful in major bowel surgery.
A nerve block is when local anaesthetic is injected around a single nerve. This numbs just the area controlled by that nerve during and after surgery. The other areas around that nerve will still have normal feeling and normal movement. Your anaesthetist will often use an ultrasound machine to see exactly where your nerves are. During some operations, your surgeon may place a thin plastic tube or catheter near your nerves. After your operation, this can continuously bathe your nerves in local anaesthetic for two or three days after your operation to keep your pain well controlled. For more details on regional anaesthesia please see our patient information resources.
An epidural catheter is a fine, flexible tube placed in the back near the nerves coming from the spinal cord, through which pain-killing drugs can be given. It is used during surgery (usually in addition to a general anaesthetic), after the operation for pain control, or both. If you would like information about epidurals and other methods of pain relief in labour, we would suggest that you read the information produced by the Obstetrics Anaesthetists’ Association.
Please also see our leaflet on epidural pain relief here.
Preparing for your operation
As soon as you know that you may be having an operation, it is helpful to think about how you can be as healthy and as fit as possible for surgery. Fitter patients recover from surgery more quickly and experience fewer complications.
If you have existing medical conditions such as high blood pressure and diabetes, you may wish to discuss with your GP how you can manage your condition as well as possible before your operation.
Many of the risks of having an operation are increased if you have obesity or are unfit. It is therefore important to reduce your weight, if you need to, and to do some exercise to increase your fitness level ahead of the operation.
If you smoke, you should consider quitting ahead of your operation. Smoking reduces the amount of oxygen in your blood and increases the risk of breathing and heart problems during and after the operation. On average, smokers stay in hospital longer than non-smokers.
Medical staff understand how hard it can be to give up smoking, particularly at a time when you are likely to be more stressed and anxious. However, if you can manage to do this you will greatly increase your chance of a speedy and successful recovery. You will have the best chance of success with the support of a specialist stop smoking service. You can get access to this through your GP.
Our Fitter Better Sooner resources will provide you with the information you need to become fitter and better prepared for your operation. Please see our website for more information here.
It is normal to have some anxiety about needles. Most people have concerns that they will feel pain when a needle is put into a blood vessel or other part of the body. That’s normal.
Some people can have more severe anxiety or a phobia. In most cases healthcare professionals can help people who are afraid of needles so they can have the procedure they need.
If you are having an operation or procedure it is likely that your healthcare team will need to use needles. You may need some blood tests before your surgery and you will also need a cannula (a thin plastic tube that goes into a blood vessel) for your operation. The anaesthetist will use this to give you the anaesthetic and medication you need during surgery.
It is important to try and manage your fear or phobia and seek help well in advance of your planned operation. You can speak with your GP about any support available in your area. Psychotherapy or support from a mental health professional may be recommended for those who have severe anxiety or phobia.
When you meet your preoperative assessment nurse at the hospital, it is important to think about what you are worried about and discuss your concerns with him/her. It’s a good idea to write your questions down so you don’t forget to ask.
If you worry about pain, you can discuss whether you could have some local anaesthetic cream to numb the area. Be aware though that this may take 40 minutes or so to work.
If healthcare professionals have found it difficult to take blood or put in a cannula in the past, it can be helpful to say which vein usually works best. Veins can be more difficult to find if you have had chemotherapy or have needed many cannulas in the past. Veins can be more difficult to find in people who have obesity. An anaesthetist might be able to use an ultrasound machine to see where the veins are, which can make inserting the needle easier and quicker.
If you are worried that you become very anxious or have a tendency to faint, you should tell the staff. They may suggest that you lie down, and they will talk to you to help you relax and to distract you. You might find that watching something on your phone/tablet may help. Try to take deep slow breaths and look away.
More rarely, if the fear or phobia cannot be easily managed, your anaesthetist may discuss the option for starting your anaesthetic by breathing the anaesthetic gas through a mask. They will then put the cannula in when you are anaesthetised. However, this option is not suitable for every patient. There can be risks when starting your anaesthetic this way, especially if you have obesity or acid reflux and your veins are not easy to find. You will need to discuss with your healthcare team if this option is possible for you well in advance of the operation.
Guy’s and St Thomas’ Hospital has a guidance leaflet for patients to help them overcome fear of needles which can be accessed here.
Please avoid wearing makeup on the day you come in for your operation.
Lipstick can make it more difficult for doctors and nurses to see the true colour of your lips. If the level of oxygen in your blood falls, it can change the colour of your lips, so it is important for the medical staff to be able see their natural colour.
Mascara could make your eyes sore if particles of it get into your eyes during the operation.
False eyelashes should be removed before you come into hospital – during an anaesthetic your eyes are kept gently shut using tape and false eye lashes may be damaged or displaced.
During an anaesthetic, your anaesthetist may need to secure monitoring equipment to your skin – body lotions, foundation and face cream can make this more difficult as they may prevent heart monitor pads and dressings from sticking properly.
You should also remove nail varnish and, usually, false nails. False nails and varnish may interfere with equipment monitoring the oxygen level in your blood. This is because a finger clip is used that shines a light through a nail.
During your anaesthetic your anaesthetist will look after your breathing. The anaesthetist will usually place a breathing tube in your throat when you are unconscious. This is not always straightforward and damage to your teeth is a possibility, especially if those at the front are already loose or you have crowns that are not as strong.
If you have any loose or damaged teeth, you should ask your dentist to look at them before your anaesthetic to reduce the risk of them becoming displaced.
Your anaesthetist will check how well you can open your mouth and assess your mouth opening. If you have any problems with your jaw, opening your mouth or have a stiff neck, make sure you tell your anaesthetist.
You should continue to take your usual medicines up to and including the day of the operation unless you are told not to. You should carefully follow the instructions you have been given by the preoperative assessment clinic.
Look out for specific instructions if you take:
- drugs to thin your blood like warfarin, dabigatran, rivaroxaban, clopidogrel, aspirin
- drugs for diabetes
- blood pressure pills
- herbal remedies.
If you have not been given instructions on the above medications, please contact your hospital. Remember to take your medication into hospital with you and ensure you have enough for when you return home.
If there is food or liquid in your stomach while you are anaesthetised, it could come up into the back of your throat and then go into your lungs. This would cause choking or serious damage to your lungs.
The hospital should give you clear instructions about eating and drinking, which you should follow carefully.
Recreational drugs such as cocaine, marijuana, heroin or the so called ‘legal highs’ can affect the way anaesthetics work, how you react to pain after your operation and can lead to withdrawal problems after your anaesthetic.
You should inform your anaesthetist/preoperative assessment clinic if you have used or regularly use recreational drugs. Ideally, you should make sure you do not take any recreational drugs in the days preceding your operation. Check with your anaesthetic department or GP if you need information on sources of support.
Unless very young, it is a good idea to talk with your child about the operation and what they can expect, including the anaesthetic.
The Royal College of Anaesthetists has a section on Information for children, parents and carers, which contains several useful resources to help you prepare your child for the operation, depending on the age of the child.
General anaesthetics do not normally have an effect on breastfed babies. It is recommended that you breastfeed up until your operation and continue breastfeeding as soon as you are awake and feel ready to do so afterwards. Very small amounts of anaesthetic may pass into breast milk but there is no need to ‘pump and dump’. Some painkillers can make your baby sleepy so it is important that your anaesthetist knows that you are breastfeeding so that they can prescribe the most appropriate medication.
Just as you should have a responsible adult with you for 24 hours following a general anaesthetic, it is also important that you are not the primary carer for your child for the first 24 hours. It is important to be aware that the risks of co-sleeping may be increased following anaesthesia due to residual sedation.
To download the Association of Anaesthetists 'Patient Information Leaflet', please click here.
It is very common to be anxious before an operation. There is much you can do, however, to help yourself at this time.
If it is your first time having an operation, it is usually helpful to find out more about going into hospital. There are many resources here on the patient information part of the website to help you.
You can also read some information about your operation. There is a lot of information you can read in leaflets or on the internet, as well as video clips you can watch online. It is important, though, to use reliable and evidence based information – internet browsers can bring up unreliable information on rare side effects that could scare you unnecessarily. The hospital will give you useful information to read. It will usually also suggest some recommended websites or links that you can visit. Organisations that have been awarded the Patient Information Forum tick logo (as we do at the RCoA) have been shown to produce reliable and well-researched information for patients.
You will usually be invited to see a nurse or anaesthetist for a preoperative assessment visit. This is your opportunity to ask questions and say what you are worried about. Consider writing your questions down before you go so you don’t forget them. Don’t worry if you think that your questions aren’t very good, as all questions are important and staff are very used to explaining what will happen and the choices you have.
Your nurse will give you an information sheet to remind you of what to do before you go into hospital, as it is easy to forget if you are anxious. If your anxiety is very severe, mention it to your anaesthetist who may sometimes be able to offer you a sedative before your operation.
If you have mental health problems, it is important that you talk to your nurse about these and anything that can affect this. If you are taking medication for mental health problems it is important to let the nurse at the hospital know about your medication. They will usually not want you to stop this. They can help organise any particular support you need for your time in hospital or return home.
In the time before your operation, it can help to exercise and eat healthily if you are able to. It is good to spend some time with friends or family and focus on planning for when you are home after the operation (so you do not need to worry when you are in hospital about, for example, childcare, paying bills). If you ask friends or family to help you with childcare, they may need to arrange time off work.
Many techniques including mindfulness, relaxation and breathing exercises or yoga could help you relax before and after your surgery. You can often find helpful information on line or on YouTube or a nurse at your surgery may be able to help you find some useful resources.
It is useful to plan ahead and organise things to take into hospital to keep your mind occupied. You might want to read a book, listen to music through headphones or take some magazines to read. Try to imagine yourself recovering calmly and doing well – perhaps reward yourself with something special to look forward to when you get home.
For more information, please see our Fitter Better Sooner resources.
What to expect after the operation
After most general anaesthetics, you will initially be cared for in a recovery room close to the operating theatre. Staff in the recovery room will usually give you extra oxygen through either a clear face mask or through soft plastic tubes that sit under your nostril. This is routine and does not mean that you are unwell. Staff in the recovery room are also responsible for monitoring your vital signs (such as pulse rate, blood pressure and temperature). They will also ask you how you feel and treat any sickness or pain that you may have. Sometimes you may feel a little cold or shivery – if this happens, they can give you a warm air blanket to quickly warm you. They will regularly check your wound to check there is no bleeding.
When you first arrive in recovery after a general anaesthetic, you will feel fairly drowsy. It is common at this stage to drift off to sleep and perhaps dream. You may be aware of other patients around and the noise of monitors beeping. As you become more alert, your nurse will sit you up and talk with you. It is common not to remember a great deal of your time in recovery afterwards.
When the person looking after you in the recovery area is happy that you are awake, comfortable and stable, you will be able to return to your bed on the ward. They will hand over all the important information and instructions to the nurse from the ward. They will continue to check all your vital signs, but less often. Depending on your surgery, they may allow you to have some sips of water before giving you something more to drink and eat. Try to rest and relax at this time. Your nurse will be experienced at knowing how you should progress and will call the ward doctor if they have any concerns. They will also know when you are likely to be ready to go home so you can let the person know who is collecting you.
If you had a regional or local anaesthetic you will usually still go to the recovery room but will be there for a shorter time as you do not have to recover from a full general anaesthetic.
After major surgery, you may need to go from theatre straight to the intensive care unit (ICU) or the high dependency unit (HDU). Your surgeon and anaesthetist will discuss with you beforehand if this is planned. Sometimes it can become necessary as a result of unexpected events during surgery. The length of time that you spend in ICU or HDU will depend on what type of operation you have had, any complications, and any other problems you may have.
Patients in HDU are normally awake and conscious but need more care and observation than staff can give on the normal ward. Patients in the ICU require close supervision at all times and may be given drugs to keep them unconscious or sedated and help with their breathing until they are stable. Your relatives will be able to come and visit you in both the HDU and ICU.
For more information, please see our patient resources.
Your anaesthetist will assess your risk of sickness when visiting you before your operation. There are various ways in which your anaesthetist can reduce your chance of suffering sickness. Many people have no nausea or sickness after surgery and some can feel very sick, but there is a wide range of drugs to treat this. Your anaesthetist will prescribe you drugs to help treat any sickness you develop after the operation.
If you have problems passing urine because of an enlarged prostate, sometimes drugs used during an anaesthetic can make things a little worse in the early period after your anaesthetic. If you are having a daycase operation, you will need to pass urine before you are allowed to go home. Occasionally it may be necessary to put a catheter (a flexible soft tube) into your bladder to drain urine before you can pass urine normally again. This may delay you going home. Occasionally, you may need to be seen by a urologist (a doctor who specialises in prostate problems) if difficulties continue.
Becoming confused is not uncommon after an operation and an anaesthetic, especially in older people. Behaviour and memory can be affected and there may be some deterioration in more complex mental functions such as the ability to get dressed or do crosswords. This can be temporary or permanent. Most people make a full recovery.
The effects of anaesthetic drugs may last for around 24 hours, longer for major operations. If the operation is to be done as a day case, you will need to have an able-bodied adult at home to be with you that night. People often underestimate the help that they may need after an operation as they recover.
You should not look after children during this time, use any dangerous equipment, drive or cook. If you think you will have significant difficulties looking after your children following an operation, talk to your local council or your health visitor. If you have pets, you should arrange for someone to look after them while you are in hospital and until you are able to look after them yourself.
You should also avoid making any important decisions and should be careful not to post anything on social media that you might later regret.
You may feel tired or even exhausted for some days after the operation. After major surgery, this can last for weeks or months. Healing after major surgery often leaves patients feeling exhausted.
If you ask a relative or friend to take care of you after you have undergone general anaesthetic or sedation, they may find it helpful to read this leaflet.
When you go home depends on how quickly you recover from your surgery and anaesthetic. Generally the quicker you become mobile again, the less likely you will be to get postoperative complications, such as blood clots in your legs and chest infections. It will also help your bowels recover faster and get you back to a normal diet.
You will usually sleep better and feel more relaxed in your own home. However, you will be discharged from hospital only when the doctors are happy that you are ready to go home. This is usually when you are mobile, are able to eat and drink, and can control your pain by taking tablets, if required. The decision to discharge you will also depend on the help you have at home and your other medical needs.
When you go home, it is important to have plenty of rest and allow your body to recover. You should begin gentle activity and carefully follow any exercises you are given. You should slowly increase your activity level until you are back to your normal fitness levels.
The hospital will give you a number to contact if you have any concerns about your recovery when you first go home.
For more information on how to manage pain after surgery, please see the leaflet from the British Pain Society: Understanding and managing pain after surgery.
Enhanced recovery is the name given to a programme that aims to get you back to your normal health as quickly as possible after a major operation. Hospital staff look at all the evidence of what you and they can do before, during and after your surgery to help give you the best quality recovery. This should get you home sooner.
The programme will vary depending on what operation you are having but may include:
- improving your fitness levels before your operation if there is enough time
- treating any other long-term medical conditions
- giving carbohydrate drinks before your surgery
- giving you drugs to prevent sickness after surgery
- considering the best ways of giving pain relief during the operation, and using local anaesthetic blocks or regional anaesthetics where possible
- giving the best pain relief afterwards to get you moving quicker
- allowing you to start drinking earlier
- reducing the time you have catheters and drips in
- teaching you exercises to help you recover after your operation.
By following an enhanced recovery programme, there are usually fewer complications after surgery. There is also less chance of you needing to go back into hospital.
Further information on recovering from surgery is available from the Royal College of Surgeons of England website.
The effects of anaesthetic drugs may last for around 24 hours; longer for major operations.
Following any general anaesthetic or sedation, you must not drive for at least 24 hours. This is because the drugs given during your anaesthetic or sedation can affect your reactions and how you think and make decisions. It takes at least 24 hours for your body to get rid of these medicines.
It may take longer to recover from your surgery than your anaesthetic. Your surgeon will give you advice on when it should be safe for you to drive after your procedure or operation.
Before getting back in the driving seat, you will need to be sure that you can use the brakes and drive safely without being distracted by pain.
If you are taking strong painkillers, you also need to be aware that these drugs can make you feel drowsy and can affect your driving.
By law it is illegal to drive while under the influence of drugs. You need to decide whether you think you can drive safely. If you feel drowsy, distracted by pain or generally unwell, you’ll need to wait a little longer until it is safe for you to drive.
You should check with your insurance company that you are covered to drive after your surgery.
Check with DVLA about any specific time periods recommended – information can be found on the DVLA website.
Enquiries to the Royal College of Anaesthetists
The RCoA cannot give advice to individuals about their personal treatment. If you are writing to the RCoA, please note that we may be unable to reply immediately. The RCoA often uses specialist advisors to answer enquiries and this may delay a response. For any immediate medical concerns, you should contact your GP, the NHS helpline by telephoning 111 or the emergency services without delay. Should you need more specific advice regarding your treatment, you are advised to contact the hospital where you are being treated.
The RCoA publishes a comprehensive series of patient information leaflets offering information on the different types of anaesthetics and the likely side effects and risks. We would advise you to take a look at these leaflets as they may contain the information you are looking for. You can see the full series here.
No. The RCoA does not hold lists of experts to provide a medicolegal opinion.
The role of the RCoA is to educate and train anaesthetists and to set the standards for the specialty.
The RCoA is not a regulator and cannot act on complaints raised by patients. For a list of regulators and advice on how to complain about your treatment, please visit the Complaints about your doctor or treatment page.
Questions you may want to ask your anaesthetist or the nurse at your preoperative assessment visit
It may be helpful to try and get the answers to any questions you might have well in advance of your scheduled surgery. Below is a list of questions that some may wish to discuss with their anaesthetist or nurse. If you have any further general requests or queries concerning anaesthesia, please contact email@example.com. However, please note that the College cannot give advice to individuals concerning their treatment.
- If I have a cold, should I let the hospital know before I come in?
- Should I take my normal medication on the day of the operation?
- When should I stop eating and drinking?
- I’m rather nervous; can I have medication to relieve my anxiety?
- I don’t like needles; do I have to have an injection?
- I’ve been told I have poor veins when I go for blood tests, will that be a problem?
- I am a diabetic. How do I control my blood sugar level before and afterwards?
- Are there any particular risks from the anaesthetic for me?
- May I leave my false teeth in?
- Do I need to remove my hearing aids, or decorative piercings?
- How soon will the feeling return after a regional anaesthesia or nerve block?
- What painkillers should I have at home?
- When can I drive after an operation?
- Can I go home alone following my anaesthetic?