Surgery is a common reason for you to be in hospital. The first step in having a safe surgery is to understand about anaesthesia. This is a much neglected aspect. In this article we will attempt to explain about the various types of anaesthesia and the steps that should be taken, before and after surgery.
The word anaesthesia is used to describe a state when you feel no pain, either in the whole of your body or just in part of it. The word comes from two Greek words meaning loss of feeling or sensation. This is a specialised form of medicine which is administered by specially trained doctors who are called anaesthesiologists.
There are three types of anaesthesia. The three types are-
1. General anaesthesia
During general anaesthesia you are put into a state of unconsciousness and you will be unaware of anything during the time of your operation. Your anaesthetist achieves this by giving you a combination of drugs. Usually the first step is to inject medication intravenously (ie into a vein) through a small plastic tube, placed usually in your arm or hand. This is known as induction of anaesthesia. An example of a commonly used drug is Thiopentone. Induction is occasionally achieved by breathing gases. To maintain you in this state of unconsciousness, you will breathe a mixture of anaesthetic gases or vapours with oxygen. If the surgery or other factors requires your muscles to be relaxed, eg in surgery on the abdomen, then a muscle relaxant drug is given and a tube is inserted into your throat and down your windpipe to help you to breathe.
While you are unconscious and unaware your anaesthetist remains with you at all times, monitoring your condition and controlling your anaesthetic, replacing fluid or blood. At the end of the operation, your anaesthetist will reverse the anaesthetic and you will regain awareness and consciousness in the recovery room, or as you leave the operating theatre.
2. Regional Anaesthesia
For regional anaesthesia a local anaesthetic drug is injected around a bundle of nerves so that a part of the body, such as an arm or a leg, is made numb.
Examples of regional anaesthesia are the use of an epidural for pain relief during childbirth; a spinal for an operation on the bladder; a brachial plexus block for upper limb surgery; and an eye block for cataract surgery. Sometimes regional and general anaesthesia are combined, particularly for major surgery, to provide pain relief after the operation.
Just as for general anaesthesia, your anaesthetist remains with you throughout the operation under regional anaesthesia, monitoring and controlling your anaesthetic state throughout in the same way.
3. Local anaesthesia
In local anaesthesia the local anaesthetic drug is injected into the skin and tissues at the site of the operation. The area of numbness will be restricted and some sensation of pressure may be present, but there should be no pain. Local anaesthesia is used for minor operations such as stitching a cut. Usually a local anaesthetic will be given by the doctor doing the operation.
Before your Operation
Before your operation your anaesthetist will visit you in the ward, although occasionally this will happen in a pre-anaesthetic assessment clinic. If you are a day-case patient it may not be until just before your operation. The anaesthetist who looks after you on the day of your operation is the one who is responsible for making the final decisions about your anaesthetic. He or she will need to understand about your general health, any medication that you are taking and any past health problems that you have had. Your anaesthetist may examine your heart and lungs and may also prescribe medication that you will be given shortly before your operation, the pre-medication or ‘pre-med.’
Pre-medication is the name given to medication (drugs) given to you some hours before your operation. These drugs may be given as tablets, injections or liquids (to children). They relax you and may send you to sleep.
During your operation
While you are unconscious and unaware your anaesthetist remains with you at all times. He or she monitors your condition and administers the right amount of anaesthetic drugs to maintain you in the correct level of unconsciousness for the period of the surgery. Your anaesthetist is constantly aware of your condition and trained to respond. Your anaesthetist will be monitoring such factors as heart rate, blood pressure, heart rhythm, body temperature and breathing. He or she will also constantly watch your need for fluid or blood replacement. If you have any other medical conditions, your anaesthetist will know of these from your pre-operative assessment and be able to treat them during surgery.
After your operation
After your operation your anaesthetist continues to monitor your condition carefully. You will probably be transferred to a recovery ward where specially trained nurses, under the direction of anaesthetists, will look after you. Your anaesthetist and the recovery nurses will ensure that all the anaesthetic effects are reversed and that you are closely monitored as you return to full consciousness. You may be given some oxygen to breathe in the recovery area, and may find that intravenous drips have been inserted whilst you are unconscious in theatre and that these will be replacing fluids that you might require. You will be given medication for any pain that you might feel. Some patients feel sick, others may have a sore throat related to the insertion of the breathing tube during surgery. During this time it is important that you relax as much as you can, breathe deeply, do not be afraid to cough, and do not hesitate to ask the nursing staff for any pain relief. You are likely to have hazy memories of this time and some patients experience vivid dreams. Once you are fully awake you will be returned to the ward, and if you are a day patient will be allowed to go to the waiting area to fully recover before you are accompanied home. Do not expect to feel completely normal immediately!
Why am I told not to eat and drink before my operation?
This is essential! Nothing means nothing, including water. The reason why you are asked not to eat and drink before your operation is because your body reflexes are suppressed and if your stomach contains food and drink there is a danger of vomiting or regurgitation silently. This can easily spill into your lungs and affect your breathing with the risk of infection. Even if there is no plan for you to have a general anaesthetic, your anaesthetist needs this option to be open in the interests of your own safety. Your anaesthetist, or the nurses on the ward, will specifically tell you for how long before your operation you must not eat or drink.