Anaesthesia and Sedation
For most surgical procedures it is necessary to have some form of anaesthetic or sedation to ensure that no pain is felt and to ensure optimal operating conditions. Anaesthetics can be divided into:
- Local and Regional anaesthetics
- General anaesthetics.
In addition some procedures are performed under sedation
Local and regional Anaesthesia.
A local anaesthetic drug blocks the passage of painful stimuli along the nerves that carry these sensations to the brain. Accordingly with a local anaesthetic you can be awake but have no sensation of pain at the operating site. Furthermore the effect of the anaesthetic lasts for sometime after the operation and therefore reduces the need to take pain killers.
Local anaesthetics may be:
- Injected directly into the area to be operated on.
- Injected away from the operating site but around a nerve supplying that area.
- This is known as a regional anaesthetic. Examples are a spinal or epidural – where anaestheticic agents are injected into the back and numb the area supplied.
- Applied topically. This includes throat spray applied during an endoscopy or cream applied to the skin.
In all cases the treated area will rapidly become numb but you may still be aware of movement in and around the anaesthetised area.
Preparation for local anaesthetic
For minor procedures performed under local anaesthetic there is no specific preparation and no need to fast.
For regional anaesthetics and procedures which may take longer it is usual to ask patients to fast for 6 hours prior to the procedure. In addition, you will frequently be attached to a monitor during the procedure. As you will be awake during the operation the surgeon and nurses are able to speak with you and ensure that you are comfortable throughout. Some patients like to bring their own choice of music to listen to during the procedure.
After care
One of the great advantages of a local anaesthetic is that the area anaesthetised remains numb for a variable period after the operation. How long depends upon the specific drug used and your surgeon will explain this to you. It is important that you are given oral painkillers to take (as required) as feeling starts to return and the anaesthetic wears off.
When someone has had a regional anaesthetic there is often a weakness in the muscles which lasts for several hours – this may limit your mobility initially.
In most cases it is possible to eat and drink shortly after a local anaesthetic – the exception is if throat spray has been used. In this case your mouth and pharynx will be numb and it is best to fast for an hour after the procedure to stop you biting your tongue or burning yourself on hat drinks.
General Anaesthesia
A general anaesthetic involves giving drugs to ensure that a patient is asleep during the length of a specific procedure. There are many different ways in which this can be achieved and modified for different operations / patient requirements. Your anaesthetic will discuss this with you in more detail.
Preparation for General Anaesthesia
It is essential that the surgeon and anaesthetist are aware of your previous medical history as this may have a bearing on how the anaesthetic is delivered. In particular they will want to know:
- If you are on any medications – if so what and how often do you take them
- Have you had any anaesthetics before and if you have had any adverse reactions
- Are you known to be allergic to anything
- Do you have any dental crowns or loose teeth
- Have you had any recent coughs and sore throats etc- in this case it may be advisable to postpone your operation until you are fully recovered.
Depending upon the procedure and your general state of health it may be necessary to obtain some blood tests, X-rays and / or cardiographs before the operation. Your surgeon and anaesthetist will explain further if this is required.
Fasting
It is important that your stomach is empty prior to any anaesthetic – accordingly you will be asked to fast for 6 hours before an operation. The exception may be if you have to take important medications with a sip of water – however the anaesthetist will discuss this with you.
The Operation
Transfer to the operating theatre can be an unsettling time as it is likely to be an environment to which most people are strange. When you enter the operating theatre you will be met by one of the nurses who will do their best to explain everything that is going on. There will be a number of checks and questions asked to you to ensure that all of the preparation is complete.
As above the exact form that the anaesthetic takes will vary from patient to patient and your anaesthetist will have explained what is going to happen. In general a drug will be injected to put you to sleep.
To keep you asleep during the main part of the operation you will generally be given a mixture of oxygen and anaesthetic gasses. These will be supplemented by drugs to control pain and cause muscle relaxation to allow the operation to take place.
Throughout you operation you will be very closely monitored by the anaesthetist and nurses. Usually, clinical observation is supplemented by the use of machines which monitor oxygen levels, monitor heart rate continuously and measure blood pressure.
Recovery and Aftercare
Once the drugs keeping you asleep are stopped you will start to regain consciousness. It is important that you are still monitored closely during this period and this will take place in the recovery area of the operating theatre. During this period it will be possible to ensure that you have adequate pain relief before returning to the ward.
In the ward you will continue to receive close nursing care to ensure that your recovery is complete.
Before your operation your anaesthetist will have discussed your pain control with you and this will vary according to the magnitude of your operation.
After a period of 2-3 hours it is likely that you will be fully awake however some of the anaesthetic drugs and pain killers may affect your co-ordination. Accordingly you should not drive, operate machinery or take any important decisions for a period of 48 hours after a general anaesthetic.
3. Sedation
It is possible to give drugs to relieve the anxiety associated with a surgical procedure. This is not the same as a general anaesthetic as you will not be fast asleep and sedatives have no effect on pain. They are therefore commonly combined with local anaesthetics and help patients to relax during the procedure.
After sedation most patients will sleep for a period of time and many will be completely unaware of what has happened. This period of amnesia may extend beyond that of the operation so if you do not remember any post operative instructions etc you should contact the ward and or surgeon for clarification.
Although most of the effects of sedation are relatively short lived others may have a prolonged duration, accordingly you should not drive, operate machinery or undertake any complex tasks for a period of 24 hours after the sedation.
The choice of an anaesthetic for any procedure is dependent upon:
- Patient wishes. For many procedures it is possible to perform the same operation under a general anaesthetic or local. In which case the choice is often that of the patient’s. If you feel very anxious about the procedure and do not feel that you would be able to stay still more the required period of time than a local anaesthetic is probably not for you. A local anaesthetic does avoid many of the risks of a general anaesthetic and does mean that you will avoid the recovery period of a general anaestetic.
- The site and magnitude of the operation. There is a limit to the amount of local anaesthetic that can be administered as a result more extensive procedures do require a general anaestetic. Similarly there is a limit to the amon
- Fitness of the patient
