Types of anaesthesia

Broadly, anaesthesia can be categorised as follows.  You may have a combination of anaesthetic techniques, for example regional anaesthesia with sedation.  Click on the links below to find out more about the anaesthetic you may receive.

General Anaesthesia

General anaesthesia is when you are ‘put under’ for your surgery. You will be put into an anaesthetic state using powerful intravenous drugs and/or inhaled anaesthetic agents, where you are unable to feel pain, or be aware of anything occurring during surgery. Under general anaesthesia you are fully unconscious. Prior to going to sleep you will be given oxygen to breath on through a clear mask, which smells a little rubbery. This process of preoxygenation is important for increasing the safety of your anaesthetic during placement of an airway (breathing tube) that will occur once you are asleep. You will have an IV cannula inserted into your arm (drip), which is the only painful thing that will occur prior to going to sleep.

Your vital functions will be fully monitored, as well as the depth of your anaesthetic, which will be continuously adjusted to ensure you are receiving the right amount. The surgery will commence usually within 10-20 minutes of going to sleep, depending on the preparation and positioning required. You will usually be woken up within 15 minutes of your surgery ending, but this can vary greatly depending on the procedure. You will often not recall anything until you are in the recovery room, and sometimes later.

General anaesthesia affects people differently, so individual post operative responses to the same dosages can vary greatly. In general most people are a little groggy after a general anaesthetic but completely unaffected by the anaesthetic the following day. Anaesthesia is very safe, but like your surgery, complications can occur, ranging from minor to serious.

Local Anaesthesia

Local anaesthetics area group of medications that numb nerves, meaning that you feel no pain. Local anaesthetics are usually administered by injection, but can also be topical or inhaled. Either your anaesthetist or surgeon will inject the local anaesthetic into the tissues around the surgery site. Local anaesthesia may be the only anaesthetic given (you are otherwise awake but numb), or used in conjunction with sedation, or as an adjunct to a general anaesthetic, where you are put to sleep but then given local anaesthetic anyway to help with post anaesthesia pain.

Local anaesthetics when properly administered, work brilliantly to remove pain from surgery. The nerves that supply light touch are difficult to anaesthetise, so despite not feeling pain you are often left with some sensation. The injection of local anaesthetics is uncomfortable for a short time, and can be more sensitive if being injected into a sensitive area such as the hands, feet, face, nose. The local anaesthetic will also provide you with some post operative pain relief, but eventually wears off, leaving you with some pain that may require medication. The offset of local anaesthetic is usually rapid.

Regional Anaesthesia

Regional anaesthesia is where your anaesthetist identifies a particular group of nerves that supplies sensation and movement to a particular body part, and administers local anaesthetic to numb that nerve plexus. The resulting numbness can vary from light to intense, depending on the purpose. Otherwise known as a ‘block’, this form of anaesthetic when very dense can be used to avoid general anaesthesia, or when lighter, can be used inconjunction with general anaesthesia for post operative pain relief.An epidural or spinal anaesthetic is another example of a block, used for many abdominal or lower limb operations.

The most common form of regional anaesthetic is an eye block for cataract surgery, but other body parts commonly numbed are parts of the arm or hand, parts of the leg or foot, and the abdominal wall. An epidural is most commonly used for pain relief during labour, or caesarean section, but is also commonly used in abdominal or thoracic procedures, and many urological procedures.

The local anaesthetic is usually administered using needles, but after smaller numbing needles are used to reduce the discomfort of the block. Blocks may be performed while you are still awake, or after you have gone to sleep. When performed on an awake patient, intravenous sedation is usually also used. Blocks can be technically challenging to perform, and therefore can take some time. Your anaesthetist will discuss the options for regional anaesthesia that are available to you.

Sedation

Intravenous sedation is when you are given powerful sedatives to reduce your anxiety levels, and to induce a state of ‘twilight’ where you are sleepy, but not fully unconscious. Despite being able to respond, it is very likely that you will have very limited recall of your procedure, and in fact most patients recall nothing. Because it is not general anaesthesia, some recall is considered normal, however you should not recall anything unpleasant such as pain during surgery. Usually recall is of some voices and other sounds.

The sedation is usually administered through an iv drip (cannula) which can hurt a little when being inserted. You will usually also be given supplemental oxygen to breath through a mask or nasal prongs, which can dry your mouth and nose a little. Once you are adequately sedated, usually either local anaesthesia or regional anaesthesia will occur at this stage. You may have some recollection of the numbing needles being inserted, but only for a very brief time. It is important to both the surgeon and your anaesthetist that your level of sedation is just right. Being over sedated can cause problems because patients tend to become unpredictable in their movements, and can sometimes have difficulty breathing because of airway obstruction. It is for this reason most anaesthetists will titrate sedation slowly to achieve the correct depth where you are sedated, but not overly so. Please be patient with us if this takes some time to achieve.

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