Three types of anesthesia
Type of anesthesia used will depend on the nature and duration of the procedure, your general medical condition, and your preference and those of your anesthetist and surgeon or other doctor performing the procedure.
The three types of anaesthesia are general, regional and local. All three involve the administration of drugs to produce a change in sensation and they are frequently used in combination.
Confusion sometimes arises, because the term “ local anesthesia” is used to refer to what is properly called “ regional
You are put into a state of unconsciousness for the duration of the operation. This is usually achieved by injecting drugs through a cannula placed in a vein and maintained with intravenous drugs or a mixture of gases which you will breathe. While you remain unaware of what is happening around you, the anaesthetist monitors your condition closely and constantly adjusts the level of anaesthesia. You will often be asked to breathe oxygen through a mask just before your anaesthesia starts.
A nerve block numbs the part of the body where the surgeon operates and this avoids the need for general anesthesia. You may be awake or sedated (see below).
Examples of regional anesthesia include epidurals for
A local anaesthetic drug is injected at the site of the surgery to cause numbness. You will be awake but feel no pain. An obvious example of local anaesthesia is numbing an area of skin before having a cut stitched.
The anaesthetist administers drugs to make you relaxed and drowsy. This is sometimes called ‘twilight sleep’ or ‘intravenous sedation’ and may be used for some eye surgery, some plastic surgery and for some gastroenterological procedures. Recall of events is possible with ‘sedation’. Most patients prefer to have little or no recall of events. Please discuss your preference with your anaesthetist.
Factors that influence the choice of anesthetic include:
The procedure to be performed. Some procedures can only be performed under general anaesthesia. For example, a patient undergoing removal of the gallbladder, whether by means of a laparoscopic or key-hole technique or through a standard incision, needs a general anaesthetic. For other procedures it is reasonable to consider whether or not the operation should be carried out under local, regional or general anaesthesia, or if a combination of techniques should be used, such as combined regional and general anaesthesia. For example, a patient undergoing an examination of the knee using a special instrument called an arthroscope could be offered a choice of local, regional, or general anaesthesia. A patient undergoing an open-heart operation needs general anaesthesia, however some minimally invasive cardiac procedures can be performed with local anaesthesia and sedation.
The experience, expertise and preference of the anaesthetist can vary with different techniques.
Your own preference – whether or not you would prefer to be unconscious or wish to remain as conscious and in control as possible. Most patients prefer to be unconscious for major surgical procedures. For some procedures it is increasingly common for patients not to have a general anaesthetic—for example, caesarean section.
Age – It is common for children to have a general anaesthetic for procedures that might be done without any form of anaesthetic in an adult, for example, MRI (magnetic resonance imaging) scanning. This is because children may not understand the explanations or be able to lie still.