General Anaesthesia

An anaesthetic is a drug  or a combination of drugs that produce a complete or partial loss of feeling. There are three kinds of anaesthetic: general, regional and local. When a patient undergoes a general anaesthetic, they lose sensation and become unconscious. A variety of medications may be administered, with the overall aim of ensuring sleep, amnesia, analgesia, relaxation of skeletal muscles, and loss of control of reflexes of the autonomic nervous system.

What Happens When You Have A General Anaesthetic?

A couple of hours prior to surgery, you may be given a ‘pre-med’, which may be an injection or tablets that make you sleepy and relaxed. These drugs also help to dry up excessive saliva.

You are then wheeled into the operating theatre. The Anaesthetist administers the general anaesthetic. The Anaesthetist may administer the anaesthetic intravenously or by gas mask, or both. After a few seconds, you feel sleepy then lose consciousness.

Next, the Anaesthetist inserts a small tube connected to a ventilator into your airway. The Anaesthetist controls the length of time you are asleep, and constantly monitors your pulse, breathing and blood pressure. If necessary, your Anaesthetist will give you intravenous fluids before, during and after surgery.

Once the surgery is over, you may have other drugs injected that will reverse the effect of the anaesthetic and any other drugs used during the operation (such as muscle relaxant). When the Anaesthetist is satisfied with your breathing and blood circulation, you are wheeled into the recovery room where specialised staff members look after you.

Side Effects And Risks Of A General Anaesthetic

Most healthy people don’t have any problems with general anaesthesia. Although many people may have mild, temporary symptoms, general anaesthesia itself is exceptionally safe, even for the sickest patients. In general, the risk of complications is more closely related to the type of procedure you are undergoing, and your general physical health, than to the anaesthesia itself. Some of the more common side effects experienced are:

  • Nausea and vomiting: Includes both the feeling of being sick as well as actually vomiting. Due to newer techniques and medications the incidence has decreased.
  • Damage to teeth: General anaesthesia involves the Anaesthetist carefully inserting a breathing tube which has the potential to cause damage to teeth. If you have false teeth, please wear them to hospital. Your Anaesthetist will decide whether it is best to either leave them in or remove them for your surgery.
  • Sore throat: This can be due to the presence of the breathing tube or just as a result of breathing in anaesthetic gases. It usually settles within 1-2 days.
  • Bruising:  At the site of the intravenous injections and nerve blocks and usually settles quickly.

Less Common And Rare Risks

Rare complications, which may occur more frequently in older adults or in people with serious medical problems and include:

  • Regurgitation and aspiration is where the stomach contents are brought back up in to the back of the throat and then inhaled into the lungs during a general anaesthetic.  In very rare circumstances, this may cause a life threatening lung infection. Therefore, it is very important to adequately fast prior to an anaesthetic according to the instructions you are provided with.
  • Awareness: Very occasionally a patient can become conscious during the operation and remember things that happened during this time. This is very rare (1 in 14,000 general anaesthetics).  Awareness is due to the patient receiving too little anaesthetic, however with advances in monitoring and equipment the chance of this occurring is becoming even more unlikely.
  • Allergy: It is possible to have an allergic reaction to an anaesthetic drug without a prior history of allergies . Some people may be allergic to particular medications used during anaesthesia, the skin preparations or to latex (rubber) that is present in the operating theatre. It is important that you advise your Anaesthetist of any known allergies to medications or rubber products.
  • Nerve Damage: Causing loss of feeling or movement in parts of the body is very uncommon as a result of anaesthesia. Your Anaesthetist takes great care in positioning you during surgery and constantly monitors and maintains your blood pressure to try and minimise this occurring.
  • Death and brain damage: Death related to anaesthesia is extremely rare.

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