Local anaesthesia for your eye operation

Transcription

1 Local anaesthesia for your eye operation This is a short guide about local anaesthesia for your eye operation. You can find out more from the leaflet Anaesthesia Explained from Local Anaesthesia Local anaesthetics are drugs that stop you feeling pain. For eye operations they can be given either as eye drops or as injections around the eye depending on the requirement of the surgery. Once you have been given the local anaesthetic, you should not be able to feel pain in the eye during the operation. You might however be able to feel some sensation such as touch around your forehead, face and the lids. What is the difference between local and general anaesthesia? General anaesthesia: you are in a state of controlled unconsciousness during the operation and will not be aware of what is happening. Local anaesthesia: you will be awake and aware of your surroundings. What are the benefits of local anaesthesia? Some people may be at a higher risk from a general anaesthetic as compared to local anaesthetic. Local anaesthesia is useful because it generally has fewer risks and side effects than a general anaesthetic. Local anaesthetic blocks usually don t affect other parts of your body, such as your breathing or your heart. People recover more quickly following surgery under local anaesthetic and can go home on the same day. It also offers pain relief after the operation. You will also be able to eat and drink as normal after the operation. You will be advised about food and drink during your preoperative check up. I would really prefer a general anaesthetic, do I have a choice? If you do have a preference for a general anaesthetic, you should inform and discuss this with your surgeon and anaesthetist. You may need to wait a little longer for your operation for some additional tests to be carried out. The decision to proceed with a general anaesthetic will rest with your anaesthetist who will make the decision depending upon your medical fitness. Nothing will however happen to you until you understand and agree with what has been planned for you. Page 1

2 How is a local anaesthetic given? Your anaesthetist or eye surgeon will give you your local anaesthetic. Local anaesthetic eye drops are used first to make the surface of the eye numb. After disinfection of the eye with an antiseptic, a fine needle is used to inject more local anaesthetic. The injection is made in the area between the inner corner of the eye and the nose. Following the injection, a controlled pressure will be applied to the eye to help the spread of the local anaesthetic. The anaesthetist will check the eye to ensure that the local anaesthetic has worked. Will you be giving the injection into my eyeball? No. The injection is not given into the eyeball. It is given in the tissues between the inner corner of the eye and the nose for peribulbar injections, or around the eyeball in case of sub-tenon s. Sub-Tenon s Injection The sub-tenon s injection is chosen for the patients who are not suitable for the fine needle peribulbar injection technique. This involves a minor surgical procedure which is well tolerated. Usually a single injection is made around the eyeball. Are there any risks to local anaesthesia? Eye surgery under local anaesthesia is very safe. Sometimes the tissues around the eye can swell after the injection of the local anaesthetic drug. Occasionally a small amount of bleeding may occur following the injection. This is more common if you are on medication that thins the blood such as aspirin, clopidogrel or warfarin. The swelling usually settles within a day or two. If bleeding is severe, your operation may be postponed. Serious complications are very rare Complications such as damage to the eye, blood vessels or muscles or spread of local anaesthetic drugs to other areas of the body are known to occur. These complications are difficult to predict. The anaesthetist will be able to go into detail about the rare complications of local anaesthesia, should you wish to know about them. The following tables outline the risk of serious complications following local anaesthetic injection around the eye: Page 2

3 1. National reported complications of all types of local ophthalmic anaesthetics: UK data (2007) Type of anaesthetic Incidence of complications Sub-conjunctival, Topical 0 per 10,000 cases Peribulbar 2.4 per 10,000 cases (0.024%) Sub-Tenon 0.6 per 10,000 cases (0.006%) Retrobulbar 4.5 per 10,000 cases (0.045%) Please note that we do not practice retrobulbar blocks in this Trust. 2. Details of complications of peribulbar blocks [Infero-temporal and medial canthal injections (USA data)] Complication Incidence Injury to the eye ball % ( in patients) Loss of consciousness 0.006% (0.6 in patients) Damage to the main nerve of the eye % (0.6 4 in patients) Bleeding around the eye structures % ( in patients) Serious expulsive haemorrhage % ( in patients) Is there anything that makes people unsuitable for a local anaesthetic to the eye? Yes. Local anaesthetic is not normally recommended if you: cannot lie still during local anaesthetic injection cannot lie on the back and be reasonably still for between 30 minutes and an hour for the operation have an illness (e.g. Parkinson s) that makes being still difficult have a cough you cannot control have difficulty in understanding what is being said Page 3

4 are unable to follow simple instructions have severe claustrophobia have a known allergy to local anaesthetic drugs have severe hearing difficulties not relieved by hearing aids have infection or inflammation around the eye have some uncontrolled bleeding and clotting problems If any of these points apply to you it is important that you talk or write to your GP, surgeon or anaesthetist before the day of your operation. Can I have something to help calm me down during the operation? Although it is possible to give sedatives, sometimes they can make you very sleepy and slow your breathing. This can lead to difficulty during the operation. Please discuss your wishes with the person doing your preoperative check up and with your anaesthetist on the day of surgery. Before the operation Health Check: The Pre-Assessment Clinic You will be asked to attend a pre-operative assessment clinic to assess your fitness for the operation. Nurses usually conduct these clinics with a doctor available for immediate advice. A full medical history is taken. During the preoperative check up you will be asked about: General health and fitness Previous operations Heart disease High blood pressure Pain in the chest during exercise or at rest Ability to lie flat Lung disease Liver or kidney disease Diabetes Epilepsy Your current medication Page 4

5 Allergies Smoking Alcohol intake Help you have at home You will be advised about the any tests that you need. The tests will be arranged at the clinic before the operation. You may need an additional blood test to check your clotting on the day of operation. If you are taking aspirin, clopidogrel, or warfarin you may need to stop them a few days before your operation. Please check this with your specialist. You will be given instructions about: Medication to take on the day of surgery Food and drink Clothing to bring to the hospital The day of the operation Please bring any medication you are taking to the hospital on the day of operation so that the doctors and nurses may check them. You should wear comfortable clothing. If you have a heavy cold/cough on the day of operation, please telephone the ward for advice, your operation may need to be re-scheduled. In hospital You will be seen by your eye specialist and an anaesthetist. Your eye specialist will check and mark the eye that is being operated on and discuss the operation with you. Your anaesthetist will explain the anaesthetic technique, its risks and benefits. What happens next? You will be asked to put on a hospital gown. The ward nurses may give you some eye drops to dilate your pupil depending on the type of operation you are having. These may make your sight slightly blurred. Page 5

6 The operating theatre staff will accompany you to theatre. They will ask you some questions to check who you are and that you have signed a consent form. You will be brought to the anaesthetic room by a trolley, wheelchair or, if you prefer, you can walk. What happens in the anaesthetic room? Your anaesthetist may need to give you drugs into a vein. A needle will be used to put a thinplastic tube (a cannula) into a vein in the back of your hand or arm. This is taped down to stop it slipping out. To monitor you during your operation, your anaesthetist may attach you to machines to watch: 1. Your heart: sticky patches will be placed on your chest or arms. (electrocardiogram or ECG). 2. Your blood pressure: blood pressure cuff will be placed on your arm (a sphygmomanometer). 3. The oxygen level in your blood: a clip will be placed on your finger (pulse oximeter). Anaesthetic eye drops will be instilled in your eye. An injection around the eye through a fine needle or a tube will be made as described before. A small weight or a balloon may be placed on your closed eyelids and secured with a strap. This helps the anaesthetic drug to work evenly. Once your eye begins to feel numb it will be kept closed to prevent any damage. Will the local anaesthetic injection hurt? This varies from person to person. There is usually some discomfort during injection. Occasionally, a stinging and burning sensation may be felt. The anaesthetic drops used before the injection help to reduce the discomfort, however they do not stop all sensation. How do I know that the anaesthetic is working? Your anaesthetist will check your eye to make sure it is numb. You will be asked to look in different directions to assess the effects of the anaesthetic. Once you and the anaesthetist are happy that the anaesthetic has worked, the monitors will be temporarily detached and you will be taken into the operating theatre. Page 6

7 The operation What happens in the operating theatre? The nurse will check you are lying comfortably on the operating table and that your head is supported. A pillow may also be placed under your knees to help reduce the strain on your back. A sterile surgical sheet will be placed over your face to keep the area around your eye clean. The sheet will have a hole in it so the surgeon can see your eye to be operated on. Your other eye is protected under the sheets with a tape or you can close it yourself. A tube may be placed under the surgical sheet which will blow fresh air around your mouth and nose. This is to help you breathe easily during the operation and to feel comfortable. The heart and pulse monitors and the blood pressure cuff will be reattached. You may be aware of the area around your eye being cleaned with a cold fluid to keep it sterile. You may feel a bit of water running down your face. This is quite normal as the surgeon uses a very weak salt-water solution to keep your eye moist. You will hear buzzing sounds and other noises made by the operating machines. Will I see anything during the operation? It is not unusual to see flashing lights, colours, movements and shadows of the instruments with the operated eye during the surgery. These perceptions vary amongst the patients. Generally, these visual perceptions are not frightening. You will be able to see as normal with your good eye. It may be covered with the drapes though. Can I wear my hearing aid during the operation? It is usual practice to remove a hearing aid from the side of the surgery because, no matter how careful your surgeon is, water can enter the ear and the hearing aid may start to make noises. However it may be possible to leave a hearing aid in the opposite ear to the eye which is being operated on. Page 7

8 Can I speak during the operation? It is best not to speak whilst the surgeon is operating on your eye as this will make your face move and could affect the surgery. If you want to say something, please indicate with your hand or speak out briefly and the eye surgeon will stop operating. You can then say what you need to. How long does the operation take? The cataract and laser treatment surgery takes approximately 30 minutes. Other types of procedures involving operations on the back of the eye and retina can take longer (60-90 minutes). Will you take my eye out to do the operation? No. The eye is not taken out. What happens if my anaesthetic wears off during the operation? The local anaesthetic drugs are chosen to match the projected length of the operation. If for some reason the operation is prolonged, a supplementary injection of the local anaesthetic will be given by the surgeon well in time. The supplementary injection is usually not painful. After the operation The operation for cataracts usually lasts approximately 30 minutes, other operations for example retina surgery takes longer. Your eye may be covered with a shield or pad until the following day to protect it and stop you from rubbing it whilst asleep. You may experience double vision for a time, due to the after effects of the anaesthetic. A nurse will escort you back to the ward in a wheelchair. What about going home? Once you have recovered and your transport arrives, you may go home. Before you go the ward nurse will give you written instructions about recovering from your operation, for example what activities to avoid. You will also be told about any medication you need to take and will be shown how to put the eye drops in. Drops are used following surgery to stop inflammation (swelling) and help prevent infection. You will be asked to attend the ward or the outpatient clinic for a further check up. Please note: Special instructions will be given for procedures involving retina of the eye. This will involve specific posturing and medications. Page 8

9 How long does the anaesthetic last? The local anaesthetic usually lasts for 2-3 hours, although it can last longer, (up to 6-8 hours) depending upon the type of anaesthetic drug used. The double vision may persist for several hours. Will I be in pain after the operation? You may feel some discomfort when the anaesthetic wears off and a mild painkiller such as paracetamol may be required. It is good if you can have someone to help you at home and stay with you for the first night following surgery. The hospital will advise you about the painkiller medication before you are discharged. The discomfort usually disappears within 24 hours. Should you experience prolonged or severe pain you must contact your GP or the hospital immediately. When can I drive? You will need to ask the surgeon how long you should wait before driving, as each case is different. Do I need to take any special care? You will receive individual instructions about the care of your eye, but you should think about the following: Avoid rubbing your eye. Contact your hospital if your eye becomes painful or you develop a problem with your vision. Keep your hands clean. Avoid getting water into your eye whilst showering or bathing. If you are a restless sleeper wear an eye shield so you can t rub your eye without knowing when asleep. Avoid heavy lifting, strenuous exercise and swimming until you get the all-clear from the hospital. Take care in windy weather in case you get something in your eye. Page 9

10 Avoid looking directly at bright sunlight. Sunglasses can help to give some extra protection from dust, grit and bright light. Do not handle soil, plants etc. Avoid gardening until the eye has healed. Where can I get further information? If you want to ask any further questions about the type of anaesthetic planned for your operation please contact your local hospital or clinic before you come into hospital. Questions you may like to ask your anaesthetist: Q: Who will give my anaesthetic? Q: Do you use this type of anaesthetic often? Q: What are the risks of this type of anaesthetic? Q: Do I have any special risks? Q: How will I feel afterwards? Page 10

11 Useful organisations Association of Anaesthetists of Great Britain and Ireland 21 Portland Place London WC1 B1PY Phone: Fax: Website: This organisation works to promote the development of anaesthesia and the welfare of anaesthetists and their patients in Great Britain and Ireland. Royal College of Anaesthetists Churchill House 35 Red Lion Square London WC1 R4SG Phone: Fax: Website: This organisation is responsible for standards in anaesthesia, critical care and pain management throughout the UK. Royal College of Ophthalmologists 17 Cornwal Terrace London NW1 4QW Tel: Fax: Website: This organisation is responsible for the standards, education and research for ophthalmology, throughout the UK. It has a series of information leaflets about different types of eye surgery. Page 11

12 Royal National Institute of Blind People (RNIB) 105 Judd Street London WC1 H 9NE Telephone: Fax: Website: RNIB s work helps anyone with a sight problem - not just with Braille, talking books and computer training, but with imaginative and practical solutions to everyday challenges. If you or someone you know has a sight problem, RNIB can help. Call the RNIB Helpline on (Monday to Friday 8.45am to 6.00pm and Saturday 9.00am to 4.00pm. Calls charged at local rates to UK callers). The RNIB can provide a confidential interpreter in your language within minutes of your call. Simply state in English the language you prefer to use. A Teaching Trust of The University of Birmingham Incorporating City, Sandwell and Rowley Regis Hospitals ML2145 Issue Date: June 2010 Review Date: June 2012 Page 12