Anaesthesia is one of the greatest discoveries of modern medicine. In fact, many of today’s operations, especially for the very young, very old, or very ill would not be possible without it.
The word anaesthesia is coined from two Greek words: “an” meaning “without” and “aesthesis” meaning “sensation”. There are various types of anaesthesia. Throughout their lives, most people will undergo anaesthesia either during the birth of their baby or for a surgical procedure, which could range from relatively short, simple surgery on a day-stay basis through to major surgery requiring complex, rapid decisions to keep them safe. Many of today’s operations are made possible as a result of developments in anaesthesia and training of specialist anaesthetists.
Patients having anaesthesia will have an anaesthetist with them all the way from the preoperative assessment of their medical conditions and planning of their medical care, to closely monitoring their health and wellbeing throughout their procedure to ensure a smooth and comfortable recovery.
Relief of pain and suffering is central to the practice of anaesthesia. Despite an increase in the complexity of surgical operations, modern anaesthesia is relatively safe due to high standards of training that emphasise quality and safety. In addition, there have been improvements in drugs and equipment. Increased support for research to improve anaesthesia has resulted in Australia and New Zealand having one of the best patient safety records in the world.
What is anaesthesia?
Anaesthesia refers to the practice of administering medications either by injection or by inhalation (breathing in) that block the feeling of pain and other sensations, or that produce a deep state of unconsciousness that eliminates all sensations, which allows medical and surgical procedures to be undertaken without causing undue distress or discomfort. Download an information brochure here.
Types of anaesthetic given
1. Procedural sedation
Procedural sedation is used for procedures where general anaesthesia is not required and allows patients to tolerate procedures that would otherwise be uncomfortable or painful. It may be associated with a lack of memory of any distressing events.
2. Conscious sedation
Conscious sedation is defined as a medication-induced state that reduces the patient’s level of consciousness during which the patient can respond purposefully to verbal commands or light stimulation by touch.
Analgesia is the reduction or elimination of the patient experiencing pain by medications that act locally, such as local anaesthetics (which interfere with nerve conduction) or generally, such as opioid medications (which decrease the patient’s experience of pain in the central nervous system).
4. Regional anaesthesia
Regional anaesthesia is an umbrella term used to describe nerve blocks, epidural blocks pain relief and having a baby and spinal blocks. Regional anaesthesia involves the injection of local anaesthetic in the vicinity of major nerve bundles supplying body areas, such as the thigh, ankle, forearm, hand or shoulder.
Regional anaesthesia is sometimes achieved by using a nerve-locating device, such as a nerve stimulator, or by using ultrasound, which is a painless procedure used to demonstrate internal body structures using sound waves to create an image. These devices help to locate the selected nerve(s) so that local anaesthetics can be delivered with improved accuracy.
Regional anaesthesia may be used on its own or combined with general anaesthesia.
Once local anaesthetic is injected in the desired region, patients may experience numbness and tingling in the area supplied by the nerves and it may become difficult or impossible to move that part of the body.
5. General anaesthesia
General anaesthesia produces a drug-induced state where the patient will not respond to any stimuli, including pain. It may be associated with changes in breathing and circulation.
6. Spinal Anaesthesia
Spinal anaesthesia also known as subarachnoid anaesthesia is a form of local or regional anaesthesia, which involves injection of a anaesthetic drug into the subarachnoid cerebrospinal fluid space (CFS). The injection is usually made in the lumbar region at the L2/3 or L3/4 space
Spinal anaesthesia has the advantage of simplicity, rapid onset of action, low failure rate, minimum drug dose, and excellent muscle relaxation, which makes it the technique of choice for both elective and emergency caesarean section when a functioning epidural catheter is not in place. Therefore, it is used for:
- Surgeries below the umbilicus such as genitourinary surgery, hernial repair procedures or surgeries performed on the lower extremities (lower limbs).
- Caesarean surgeries
- Spinal anaesthesia provides rapid and comprehensive anaesthesia for surgery or caesarean section by reversibly blocking nerves in the spinal canal serving both superficial and deep tissues. In doing so, the pain transmission is not delivered to the brain, thus decreasing the brain’s awareness of the pain during procedures and provides pain relieve to the patient.
- If spinal anaesthesia is used during childbirth, a midwife or trained medical staff must be continuously present for at least 20 minutes after each bolus dose to record the maternal blood pressure, pulse and the foetal heart every 5 minutes and assess the height of the block. Alternatively if spinal anaesthesia is used during surgeries, the same protocols of close monitoring of respiration, blood pressure and pulse should be followed.