Published by Bupa’s Health Information Team, February 2011.
This factsheet is for people who are having local anaesthesia or sedation, or who would like information about it.
Anaesthesia describes a state or episode where there is a loss of feeling or sensation. Local anaesthesia completely blocks pain from the treated area. Sedation describes a state of calm. A sedative is the medicine or other agent used to produce this state.
You will meet the anaesthetist, doctor or dentist carrying out your procedure to discuss your care. It may differ from what is described here as it will be designed to meet your individual needs.
The word ‘anaesthesia’ comes from a Greek word meaning absence or loss of sensation. Anaesthesia blocks pain by stopping pain signals being carried by nerves to your brain. Anaesthesia is one of the most significant developments of modern medicine because it allows once unbearable medical procedures to be performed without discomfort.
Local anaesthesia can be used in many types of procedures and operations. It completely blocks pain from the area being treated and you will stay awake during the procedure. Local anaesthesia can also be used to completely block pain from a large part of the body, such as everything below the waist. This is called regional anaesthesia. Local and regional anaesthesia may also be used to provide postoperative pain relief.
Local anaesthetic is available in the form of drops, sprays, ointments or injections. For regional anaesthesia, the anaesthetic is usually injected into a bundle of nerves, using the following injection techniques.
Your anaesthetist can control how much feeling is lost and how long the effect lasts, depending on the amount, strength and type of solutions used. Typically, the effects of a local anaesthetic can last from two to eight hours.
A sedative relieves anxiety and helps you to relax. You may be offered a sedative if you’re having a procedure under local or regional anaesthesia or a test that may cause anxiety, such as a colonoscopy or an MRI scan.
A sedative can be:
The type and dose of sedative given depends on the procedure you are going to have and how anxious you are about it.
Instead of a local anaesthetic, you may be offered general anaesthesia. This means you will be asleep during your procedure.
Your anaesthetist will discuss with you which type of anaesthesia is most suitable for you.
You may be asked to follow fasting instructions. This means not eating or drinking, typically for about six hours beforehand. You will be told if this is necessary by the hospital.
Your doctor will discuss with you what will happen before, during and after your procedure, and any pain you might have. This is your opportunity to understand what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the procedure. This will help you to be informed, so you can give your consent for the procedure to go ahead, which you may be asked to do by signing a consent form.
You will start to lose feeling in the treated area within minutes of having a local anaesthetic.
Your procedure or operation won’t start until your doctor is absolutely sure that the area is numb. It’s important to realise that local anaesthesia takes away feelings of pain, but you may still feel pressure and movement during your operation.
You will start to feel calm and relaxed within minutes of having a sedative. Depending on the strength and type of sedative used, you may feel drowsy.
Sedatives can sometimes affect your breathing. While you’re sedated, your doctor will constantly monitor the amount of oxygen in your blood through a small device on your finger. You may be given extra oxygen through a mask or a plastic nasal tube.
After a local anaesthetic, it may take several hours before the feeling comes back into the treated area. Take care not to bump or knock the area.
You may need pain relief to help with any discomfort as the anaesthetic wears off.
You will remember very little about any treatment done under sedation.
If you need pain relief, you can take over-the-counter painkillers such as paracetamol or ibuprofen. Always read the patient information that comes with your medicine and if you have any questions, ask your pharmacist for advice.
Sedation temporarily affects your co-ordination and reasoning skills, so you must not drive, drink alcohol, operate machinery or sign legal documents for 24 hours afterwards. If you’re in any doubt about driving, contact your motor insurer so that you’re aware of their recommendations, and always follow your doctor’s advice.
There are some risks associated with having local anaesthesia and sedation. We have not included the chance of these happening as they are specific to you and differ for every person. Ask your surgeon to explain how these risks apply to you.
Side-effects are the unwanted but mostly temporary effects you may get after having local anaesthesia or sedation.
Side-effects of local anaesthesia may include your tongue feeling numb, dizziness, blurred vision, muscle twitching and temporary loss of muscle control.
Side-effects of sedation may include headache, feeling sick or vomiting and having difficulty in remembering what happened during the treatment.
Complications are when problems occur during or after local anaesthesia or sedation.
Specific complications of local anaesthesia and sedation are uncommon but can include the following.
For answers to frequently asked questions on this topic, see Common questions.
For sources and links to further information, see Resources.
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This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the About our Health Information page.
Publication date: February 2011
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