What is Anaesthesia?
Anaesthesia is best described by the two Greek words used to derive its name - "an" meaning "without" and "aethesis" meaning "sensation". Anaesthetic, the drug that causes anaesthesia, enables the painless performance of medical procedures. Without it, complex operations would not be possible. Modern anaesthesia is also relatively safe due to the continued developments in anaesthetics, anaesthesia protocols and training of anaesthetists. Due to the emphasis on high standards, Australia has one of the best patient safety records in the world.
Types of anaesthesia
There are four broad categories of anaesthesia.
1. Local anaesthesia
2. Regional anaesthesia
4. General anaesthesia
Different types of anaesthesia will be used, either individually or in combination, depending on the nature and duration of the procedure as well as your past medical and surgical history. The anaesthetist will consult with you and the surgeon to offer the safest and most appropriate type of anaesthesia for the surgical situation.
Local anaesthesia is where a small area or patch of the body is made numb with the injection of local anaesthetic drugs into the tissues near the surgical site. Minor surgery can then be performed pain free in that area whilst you are awake, thus avoiding the need for general anaesthetic drugs. Local anaesthesia is also commonly combined with light sedation. Examples of procedures where local anaesthesia may be used include having a cut stitched or having a wisdom tooth taken out.
Regional anaesthesia is where a region of the body is made numb with the injection of local anaesthetic drugs around the major nerve bundles. Many areas of the body such as the abdomen, eyes, arm/hand and legs/feet can be operated on under regional anaesthesia whilst you are awake. The anaesthetic usually lasts about 12 to 18 hours and so you will be free of pain for that duration post surgery. As the anaesthetic wears off, surgical pain may return, in which case alternate methods of pain relief will be prescribed. You may also experience numbness and tingling in the area supplied by the nerves and it may be difficult or impossible to move that part of the body whilst the anaesthetic drug is present. Common examples of regional anaesthesia are epidurals used in labour, spinal/epidural anaesthetics used in caesarean section, spinal/epidural anaesthetics for hip and knee replacement, axillary blocks in shoulder, arm or hand surgery and eye blocks for cataract and vitreous surgery.
Sedation is used on procedures where light anaesthesia is required. You are induced into a low level of consciousness, which is sometimes called twilight sleep or intravenous sedation. The anaesthetist will administer a combination of drugs that will make you feel relaxed, drowsy and comfortable during the procedure. Common examples of procedures where sedation is used include eye surgery, plastic surgery, gastroenterological and colonoscopy. Sedation is also commonly used in combination with other anaesthetic techniques such as regional and local anaesthesia.
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 anaesthesia is normally commenced intravenously via a needle placed in a vein in your arm by the anaesthetist, and is maintained with the intravenous drug or a mixture of gases which you will breathe. While you remain unaware of what is happening around you, your anaesthetist will stay with you throughout the procedure, constantly monitoring and ensuring your wellbeing. Common examples of procedures where general anaesthesia is used include neurosurgical, abdominal and chest surgeries.