Sheffield Teaching Hospitals NHS Foundation Trust Advice for Patients Having MRI Investigation Under Sedation or General Anaesthetic Information for patients, relatives and friends
Contents How to contact us page 4 About Anaesthetics page 5 Having Sedation page 8 Having a General Anaesthetic page 10 What to do after the Scan page 15 Understanding Risks of Sedation and Anaesthesia page 17 3
You are coming to hospital for an MRI Scan for which you may need sedation or an anaesthetic. There may be questions you would like to ask about your anaesthetic or sedation. This booklet aims to answer most of the common questions. However, if after reading it you still have some questions please ask your anaesthetist on the day; or Telephone Mrs Julie Elliott in the Radiology Department at The Royal Hallamshire Hospital 0114 226 8926 between 10am and 4pm on normal working days 4
About Anaesthetics What is an anaesthetic? An Anaesthetic is a mixture of drugs that will help you feel relaxed, or make you unconscious so that you can have your scan safely and without any awareness of the procedure. Because everyone is different, the anaesthetic you have will be designed to suit you, and your particular scan. Why do I need an anaesthetic? You need an anaesthetic to make sure that you are comfortable, relaxed and unaware during your scan. The most common reason to require anaesthesia or sedation for MRI scanning is claustrophobia, which occurs in 1-5% of patients. Some patients need anaesthesia for movement disorders or because they are unable to lie flat or very still during the scan. Are all anaesthetics the same? No, there are two types of anaesthetics available for MRI scanning: Sedation - this relaxes you. You will be very sleepy and you will not be aware of or remember the procedure or scan. Sedation is only really suitable for patients needing scans of the lower and mid spine, as it can sometimes cause snoring and minor movements, making it difficult to get good pictures of the brain or neck. 5
Occasionally very light sedation may be all that is needed and you may feel that this is all you require. You will have the opportunity to discuss this with your anaesthetist on the day. General - this makes you unconscious. Under a general anaesthetic you will not be aware of what is happening to you and you will need an airway inserted when you are asleep, through which the anaesthetic will be given. At the end of the scan the anaesthetist will stop giving the anaesthetic drugs and you will regain consciousness quite quickly. Who are anaesthetists? Giving anaesthetics is a highly skilled and responsible job. Your anaesthetist is a doctor who has trained for at least six extra years to become a specialist in anaesthetics and is particularly experienced in providing you with appropriate sedation or anaesthesia for your scan. An anaesthetist gives all general anaesthetics and sedation in the MRI Unit. This hospital is a teaching hospital so you may be seen and cared for by a trainee anaesthetist who is already a qualified doctor. However, a consultant anaesthetist always supervises them. 6
What does my anaesthetist do? Your anaesthetist cares for you before, during and after your scan. They: Decide which is the best anaesthetic or sedation for you. Keep you safe through your scan. Monitor your pulse, ECG, blood pressure, oxygen levels in the blood and levels of anaesthetic agents. Make sure you are kept as healthy as possible through out your scan. What happens before I have an anaesthetic or sedation? Before being given an anaesthetic or sedation, your anaesthetist will talk to you and ask you questions about: Your previous health Your general health Any medicines you are taking Whether you smoke or drink alcohol Whether you are allergic to any medicines, or substances Whether you have had anaesthetic before and if so how it affected you 7
Your anaesthetist will have assessed your questionnaire which you completed and may have decided which technique will be best for you and which will enable the radiographers to obtain the best images which your doctor has asked for. You will also be asked to complete an MRI safety questionnaire prior to your scan. Having sedation How is sedation given? Sedation is given by injection into a vein. To do this, we put a needle covered in a tight fitting plastic tube into the vein. The needle is removed leaving the soft and bendy plastic tube, called a cannula in the vein. The cannula is taped in place and the sedative is then injected through this. Sedation works in a similar way to general anaesthetic and causes your breathing to become shallow. To ensure you get enough oxygen you will be given oxygen using a nasal cannula which is a fine tube placed under your nose. Will it hurt? Although sedative drugs themselves do not hurt, placing the cannula may hurt a little, but no more than having any other kind of injection. How will I feel? While you are sedated, you should feel comfortable, relaxed and very drowsy. Most people do not remember the scan. Occasionally the sedation gets a bit lighter and 8
people wake up during the scan. The anaesthetist will be monitoring you throughout the procedure and will increase the sedation to make you sleepy again. This is entirely normal. Most patients find that sedation works well for them and are happy to have it again if they need it. However, if you feel uncomfortable during the scan done under sedation we may: Give further drugs Be able to change to a general anaesthetic Is sedation safe? All anaesthetics have some risks. However, a trained doctor gives the sedation and you will be cared for in just the same way as if you were having a general anaesthetic (see page 10). Are any special preparations necessary? Sedation is treated just the same as general anaesthesia so we use the same fasting principles. We ask you to stop eating and drinking for at least 6 hours before the scan. This includes food and non-clear, pulpy and sugary drinks such as tea/coffee with milk or Lucozade. You can have water, diluted juice and tea/coffee without milk up to 2 hours before (and we encourage you to do so). It is ok to take some of your normal medications with a small amount of water. Chewing gum should be avoided up to an hour before your scan. What should I do after having sedation? If you have had sedation, you should: Have someone to take you home by car, or accompany you home in a taxi 9
Have a responsible adult to look after you overnight Have easy access to a telephone Not drink alcohol, take other sedatives or tranquillisers for 24 hours Not drive or operate machinery for 24 hours after your scan Avoid signing any important/legal documents for 24 hours Having a General Anaesthetic Is having a general anaesthetic safe? Yes it is. Of course, any anaesthetic carries a small risk but it is very slight. A survey in the United Kingdom showed that there were less than 5 deaths in every million anaesthetics given. Obviously people who are ill or have medical problems are at more risk than those who are fit and well. If you are concerned about this, talk to your anaesthetist who is an important member of the team of people that carry out your scan or discuss it with the doctor who has asked you to have the scan. When will I meet my anaesthetist? Everybody will meet their anaesthetist before their scan. Your anaesthetist will already have looked carefully at the questionnaire, which you have completed. You will normally meet your anaesthetist on the day of your scan, but it may be necessary for you to be seen in a 10
special clinic, arranged before your scan, to discuss your medical condition. The anaesthetist may ask you to have extra tests such as an ECG, chest Xray or blood tests, depending on your general fitness. Do I have any say in what happens to me? Your anaesthetist will talk to you about options for your care. Nothing will be done until you understand what is going to happen and agree with it. Are any special preparations necessary? You should follow preoperative fasting guidelines which are: No food, milk or pulpy drinks up to 6 hours prior to your scan Water, dilute clear juice and tea or coffee without milk can be consumed up to 2 hours before your scan and may make you feel less dehydrated. Most normal medications can be taken with a small amount of water Before your scan you will also be asked to remove your dentures, glasses or contact lenses, watch, and any jewellery. Make up and cosmetics are best left off. You may need to change into an operation gown if you are wearing anything with metal parts and before your scan you will need to complete a questionnaire about metal implants or objects in your body. 11
Why do I have to stop eating and drinking? This is because it takes this long for food and drink to pass through your system and having food in your stomach during your anaesthetic can be dangerous. Anaesthetics can make you sick. If you are sick when you are unconscious, your body cannot get rid of the vomit safely and you may choke, or drown because liquid has got into your lungs. Why do I have to take off my personal effects? You have to take your dentures out because general anaesthesia and sedation help you relax your whole body as well as making you unconscious. This includes your mouth and neck, which could make it difficult for you to breathe. To make sure you can breathe easily, your jaw may be supported or tubes used. Dentures or loose teeth can make it difficult to give you this help. We ask you to take off your glasses and contact lenses because during your scan you may need to have a mask on your face (usually to give you oxygen or an anaesthetic gas). Your glasses or contact lenses may get damaged or be in the way and make it difficult to do this properly. You need to remove your watch, jewellery and any other metallic objects to stop them getting damaged. If you have a pierced tongue or lip you will need to remove the metalwork because they may become loose and get stuck in your airway and they can cause interference with the scan. 12
Make-up, cosmetics and moisturisers can make it difficult to stick the monitors we use to the skin so they are best left off. How should I use prescribed drugs, tobacco, alcohol and other substances before the scan? Most prescribed drugs should be taken as normal. Your anaesthetist will give advice about any changes that are necessary around the time of the scan. Standard medical advice is to give up smoking. Tobacco smoke makes the lining of the lungs irritable, and contains carbon monoxide, which makes the blood less well able to carry oxygen. It is best to try to stop smoking 4 weeks before the scan, as this will let the lung lining return to normal. If you cannot do this it is helpful to reduce or stop smoking from 4 days before your scan so that any effects from carbon monoxide will be reduced. If you continue smoking you increase the risks from the anaesthetic or sedation, you may notice that you cough and produce more phlegm than usual in the first few days afterwards. Alcohol should not be used from 4 days before the scan. Alcohol will increase the effect of the anaesthetics used, adding to the risks of the anaesthetic. Patients used to high levels of alcohol can be resistant to anaesthetics and may require more anaesthetic drugs, which may add further to the risks. It is best to discuss these problems frankly and confidentially with your anaesthetist as early as possible. 13
Herbal remedies can affect anaesthetics. It is best to seek advice, or not to take them for 4 days before your scan. Occasional users of street drugs should abstain for 4 days before their scan. Regular users of street drugs can be resistant to anaesthetics and may have withdrawal problems after the anaesthetic, though as it is usually a relatively short procedure it is not usually a great problem. It is best to discuss these problems frankly and confidentially with your anaesthetist as early as possible. What happens during my scan? Once it is decided whether you will be having sedation or anaesthesia, the anaesthetist will give you drugs to make you sedated or unconscious. Your vital signs will be monitored throughout the procedure using highly specialised anaesthetic and monitoring equipment. Where will I wake up? After the scan you will wake up in the recovery bay where you will be looked after by a specially trained nurse. Your vital signs will be monitored for a short time and you will be given oxygen through a facemask. Your anaesthetist may not be with you when you wake up, but will be nearby if the nurse wants to check anything. Once you are recovered you will be taken back to your ward or discharged home. 14
How will I feel when I wake up? All anaesthetics and sedative drugs leave people needing some time to recover afterwards. Whilst you are waking up, you may feel muzzy and not remember much. In most cases you will be able to drink within 30 minutes of the end of the scan. It is very unlikely that you will feel sick, but if you do feel sick please tell the nurse, who will be able to give you drugs to make you feel less sick. Is there anything I should do after having a general anaesthetic? If you are gong home on the same day as having your general anaesthetic, you should: If you have had sedation, you should: Have someone to take you home by car, or accompany you home in a taxi Have a responsible adult to look after you overnight Have easy access to a telephone Not drink alcohol, take other sedatives or tranquillisers for 24 hours Not drive or operate machinery for 24 hours after your scan Avoid signing any important/legal documents for 24 hours 15
What if I need any help or information once I go home? If after you have gone home you are worried about anything to do with your procedure or anaesthetic, you should contact the: The MRI Unit on 0114 266 8661 Or The Anaesthetic Department on 0114 271 2381 16
Appendix Understanding Risk In modern anaesthesia serious problems are uncommon. Risk cannot be completely removed, but modern equipment, training and drugs have made it a much safer procedure in recent years. To understand a risk, you must know: how likely it is to happen how serious it could be how it can be treated The risk to you as an individual will depend on: whether you have any other illnesses personal factors such as smoking or being overweight procedures which are long or done in an emergency People vary in how they interpret words and numbers; this scale is provided to help Very Common Common Uncommon Rare Very Rare 1 in 10 1 in 100 1 in 1000 1 in 10,000 1 in 100,000 17
Very Common and Common Side Effects GA Feeling sick and vomiting GA Sore Throat GA Sedation Dizziness, blurred vision GA Headache GA Discomfort during injection of drugs GA Sedation Memory loss Uncommon side effects and complications GA Chest Infection GA Slow breathing (depressed respiration) GA Damage to teeth lips or tongue GA Sedation An existing medical condition getting worse GA Sedation Confusion GA Sedation Awareness (becoming conscious during your scan) GA Muscle pains Rare or very rare complications GA Sedation Damage to the eyes GA Sedation Serious allergy to drugs GA Sedation Equipment failure GA Burns from ECG electrodes GA Sedation Death Deaths caused by anaesthesia are very rare, and are usually caused by a combination of complications occurring together. There are probably about five deaths for every million anaesthetics in the UK. 18
We welcome any suggestions to improve this leaflet. You should send them to: Mrs Julie Elliott Radiology Department C Floor Royal Hallamshire Hospital Glossop Rd Sheffield S10 2JF 18
PD2957-PIL805 v4 Issue date: December 2016. Review date: December 2018