Section 8: Awareness Risks associated with your anaesthetic Section 8: Awareness during general anaesthesia hen you have a general anaesthetic, you become unconscious. The Wanaesthetist decides how much anaesthetic you need to keep you unconscious during your operation. Awareness is when you become conscious during your operation and can remember things that happened. This is an uncommon event, but it can be very distressing. This article tells you more about how it can occasionally happen, what steps are taken to prevent it and what to do if you think it has happened to you. What is awareness? for you. For some operations these drugs Awareness is becoming conscious during are essential as they allow the surgeon some part of your operation. The majority access to parts of your body that he/ she could not reach without muscle of patients who are aware do not feel any relaxants. These drugs also allow lighter pain, but may have memories of events in levels of anaesthetic to be used, and this the operating theatre. reduces dangerous side effects. Muscle Dreaming around the time of an operation relaxants also prevent movement, and is very common (6 in 100) but this is your anaesthetist uses information coming not awareness.1 Some patients recall from monitors (heart rate, blood pressure, events from the recovery room after their anaesthetic gas levels etc) to judge whether operation and mistakenly believe them to you are unconscious or not. be memories from during the surgery. Awareness occurs if your anaesthetist misjudges the amount of anaesthetic How and why does it happen? needed to keep you unconscious. It You are not receiving enough anaesthetic can also happen if the equipment that to keep you unconscious. delivers the anaesthetic to your body Anaesthetics have side effects that is malfunctioning, or there may be a combination of these. increase as more anaesthetic is given. These include falling blood pressure and How likely is it? reduced breathing. Your anaesthetist is present throughout the whole operation. Careful studies, which include interviews He/she uses clinical judgement and with many thousands of patients, have 1,2 experience to ensure that you are been done. Most studies suggest receiving enough anaesthetic to keep you that between 1 and 2 people per 1,000 anaesthetics experience some kind of unconscious, but not so much that you awareness. Only a third of these people suffer serious side effects. feel pain, although the experience can still Anaesthetists sometimes use muscle be very distressing. However, a recent relaxing drugs as part of the anaesthetic. survey3 of over 80,000 patients, published These drugs stop your breathing and your in 2007 found that only 1 in 14,000 people anaesthetist will use a ventilator (breathing having a general anaesthetic experience machine) to do the breathing awareness. Most of the cases they found 1 Risks associated with your anaesthetic v Information for Patients: The Royal College of Anaesthetists Section 8: Awareness happened to people who had certain risk He/she will talk to you about your factors. If no risk factor is present, the risk memories and try to work out if you was 1 in 42,000 anaesthetics. Awareness have been aware or if your memories are is more likely, (but still rare) if you are dreams or relate to things that happened having open heart surgery, obstetric while your anaesthetist is allowing you to surgery (childbirth) or surgery after a wake up. If you have been aware when major accident. you should not have been aware, your anaesthetist will explain to you how this What does it feel like if it happens might have happened. You will be offered to me? counselling. Help is available on the Over half of aware patients recollect sounds internet.6 and conversations within the operating theatre.1,2,4 You may be unable to move and How can awareness be avoided have feelings of anxiety and panic.1,4 totally? Approximately a quarter of aware patients If you do not have a general anaesthetic, are aware of the insertion or presence of then you cannot have unintentional the endotracheal (breathing) tube in their awareness. Some operations can be throats.1,4,5 carried out using a local or regional Pain is experienced by about one third of anaesthetic to numb part of the body. You aware patients.1,2,4,5 will not need a general anaesthetic and you will be awake during the operation. Are there any long-term effects? You can find out more about these anaesthetics in the booklet ‘Anaesthesia Many people who have been aware Explained’ on the Royal College of during a general anaesthetic suffer long- Anaesthetists website (www.rcoa.ac.uk). term effects.2,4 These include anxiety, Your anaesthetist will be able to tell you if fear of anaesthesia, sleep disturbances, these anaesthetics are suitable for you. nightmares, flashbacks and in some cases post-traumatic stress disorder. You can choose to have sedation with a local or regional anaesthetic. Sedation If I think I have been aware, what is medicine that makes you drowsy and should I do? mentally relaxed, but not unconscious. Your anaesthetist should be informed You will probably remember events in the as soon as possible. You can ask your operating theatre. nurses, or, if you are already at home, your GP, to contact him/her. Your How is awareness prevented during anaesthetist will want to know about it, a general anaesthetic? and you will benefit from talking about At the start of the day, your anaesthetist it and understanding how it might have will check all equipment to ensure it is happened. functioning properly. Misconnections and Studies have shown that some people do disconnections of the breathing tubes can not realise that they have been aware until cause awareness. All anaesthetists are several days later. You can still report the trained to spot these problems, hopefully fact that you think you have been aware, before awareness occurs. even days later. Before the start of your anaesthetic you The anaesthetist who conducted the will be connected to a monitor that tells anaesthetic will talk to you. He/she will ask the anaesthetist how you are responding you to explain exactly what you remember. during the operation. Another monitor 2 Risks associated with your anaesthetic v Information for Patients: The Royal College of Anaesthetists Section 8: Awareness will usually be used which shows the types of sleeping tablets and morphine- amount of anaesthetic in your body. like drugs. It is very important that you This monitoring equipment helps the inform the anaesthetist of all your regular anaesthetist judge whether you are having medications. the right amount of anaesthetic. Some types of general anaesthetic Monitors, which try to detect awareness are more likely to be associated with by analysing brain activity, have been awareness than others. There is not developed. These have been studied in usually any choice in which kind of a number of trials of varying size and anaesthetic you have – it depends on what quality.7,8 The results of the different operation you are having and on your trials do not agree. At the present time general health. Most cases of awareness these monitors are not in routine use in leading to serious psychological upset British hospitals nor are they generally occur in people who have received muscle 9 recommended for routine use in America. relaxants. Only one study in the last 50 years has shown awareness in people If I have had an episode of who were breathing for themselves.2 awareness, is it more likely None of these people suffered serious to happen during my next psychological upset as a result. anaesthetic? In some types of surgery the side Yes, you are at a slightly increased risk effects of anaesthetic drugs may be during your next anaesthetic. It is very particularly dangerous to you (or, if you important you tell your anaesthetist about are pregnant, to your unborn child). The your previous episode of awareness. He/ risk of awareness is increased because she will try to ensure that you receive your anaesthetist may need to use less adequate doses of anaesthetic throughout anaesthetic. For example: surgery. If available, he/she may make use of additional monitors that help to 4 cardiac surgery (the risk may be decrease the likelihood of awareness. 1 in 100) Many hospitals in this country do not yet 4 emergency surgery for major trauma provide this kind of equipment. (1 in 20) 4 emergency Caesarean section under a Are there any circumstances in general anaesthetic (4 in 1,000).5 which awareness is more or less likely? Is there anything I can do to prevent it from happening? If you are very ill, awareness is more common.1 Very ill patients have a low Ask your anaesthetist if it is possible to blood pressure and anaesthetics can avoid having a general anaesthetic and decrease the blood pressure further have your operation performed with a which may cause harm (e.g. heart attack local anaesthetic. You can have sedation or stroke). The anaesthetist may use as well to help you feel drowsy and a lighter general anaesthetic to reduce mentally relaxed. the risks to you. However, the risk of Tell the anaesthetist about all your regular you being aware of what is going on is medications or drugs, especially those increased. mentioned above, and about your alcohol If you take certain medications you will intake. Also tell him/her if you think you require more anaesthetic. These include may have been aware during any previous alcohol (prolonged, heavy use), some anaesthetic.