What is Anaesthesia?

Anaesthesia is the absence of pain and other sensation in all or part of your body. There are a number of different anaesthetics and their use depends on factors such as the type of surgery or procedure you are having and your past medical and surgical history. Your anaesthetist will discuss the type of anaesthetic with you prior to your surgery. The most common are:


This is commonly referred to as "going off to sleep." A combination of drugs and anaesthetic agents are administered placing you in a carefully controlled medical state of unconsciousness with muscular relaxation and the absence of pain. A general anaesthetic is normally commenced intravenously via a needle placed in a vein in your arm by the anaesthetist. The anaesthetic is then maintained throughout surgery by breathing anaesthetic gases. Your anaesthetist will stay with you throughout the procedure, constantly monitoring and ensuring your wellbeing. General anaesthetics are used for many surgical procedures ranging from short day case surgery to major operations. For example, the majority of neurosurgical, abdominal and chest surgery will be done with the aid of general anaesthesia.


Some procedures only require a light anaesthetic. This is referred to as sedation or sometimes called twilight anaesthesia. Your anaesthetist will administer a combination of drugs that make you feel relaxed, drowsy and comfortable during the procedure. Many smaller procedures such as colonoscopy and gastroscopy are routinely performed with the patient under sedation. Sedation is also commonly used in combination with other anaesthetic techniques such as regional and local anaesthesia.


Regional anaesthesia is where a region of the body is numbed or ‘put to sleep’. Many areas of the body such as the shoulder, arm, hip and leg can be operated on under regional anaesthesia. Regional anaesthesia is achieved when an anaesthetist performs a nerve block to a particular area of the body. Most often you are awake during the surgery, however you will be free of pain. The regional technique can also be combined with sedation. Common examples of regional anaesthetics are epidurals for labour or caesarean section, spinal block for hip and knee replacement, and eye blocks for cataract surgery.


Local anaesthesia is where a small area of the body is numbed with the injection of local anaesthetic drugs. Surgery can then be performed pain free on the numb area while the patient is awake, thus avoiding the need to administer other drugs. Local anaesthesia is also commonly combined with light sedation. The removal of skin cancers and many other minor skin operations are frequently performed using the local anaesthetic technique.