Understanding Anaesthetic

General Medical

Dr. Sam Hay

Most people will have an anaesthetic at some stage in their lives. From the safe and happy birth of a baby to stitches to colonoscopies, appendectomies to knee replacements or nose jobs to breast reconstructions, an anaesthetist will be called upon.  Surgeries might be short and sweet or they may be long and complex, requiring rapid decisions to keep the patient safe. Either way, it's important to understand the different types of anaesthesia, and what to expect when you go under.

Firstly, the word anaesthesia means "without sensation", a term referring to the administration of medications that block sensation and the feeling of pain, and it may even induce a deep state of unconsciousness. Anaesthesia has come a long way since the dark ages when a decent swig of ale was the only thing on offer.  Over the years, opium, bromide, ether, and chloroform emerged as more formal anaesthetics, before modern medicine pioneered current practices and drugs.

The purpose of anesthesia is to allow for the safe conduct of medical or surgical procedures, without causing undue stress or discomfort to the patient, and it's the job of the anaesthetist to keep you safe. They are with you for the entire journey, from the preoperative assessment right through the procedure or surgery, to ensure a smooth and comfortable recovery. The pre-operative assessment allows them to do a full assessment prior to your surgery, ensuring they know everything about you so there are no surprises further down the track.

But what are the differences between the anaesthetics on offer, you might be wondering? Here's a quick rundown of the different types of anaesthesia you might need one day...

Local Anaesthetic
Doctors talk about "giving you a local" when you need simple small procedures such as a stitching up a kitchen knife wound, or cutting out a mole.  The anaesthetic is injected straight into the affected ("local") area, making it numb within minutes.  Depending on the drug used, local anaesthetics generally last for a few hours. There are also jelly and cream versions which are simply rubbed on, as an alternative to having an injection.

Twilight Anaesthetic (also known as Conscious Sedation)
Some procedures require the patient to respond to commands so to do that, a conscious sedation is used. Sedative medications reduce the level of consciousness just enough to make the patient comfortable and pain free, but responsive enough to interact with the doctors as required.

General Anaesthetic
General anaesthetics, or ‘GA's, are designed to knock you out. You're unconscious so you don’t respond to pain or stimuli, and you're completely reliant on the trusty anaesthetist to look after you. The type and doses of medications used are adjusted on an individual basis, often minute by minute during surgery.  Ultimately they are adjusted to wear off just at the right time for the end of the surgery. Few people know that subconscious hearing remains during most GAs.  However, few remember the horrible music surgeons play in theatre as memory is wiped out with even small doses of anaesthetics.  Most people don’t remember a thing from just before they go to sleep, to some time after they wake up. Administering a safe and effective anaesthetic can be difficult.  There’s actually no perfect way to be certain a patient is actually asleep during a procedure, which is why anaesthetists must practice with a combination of technical skill, experience, compassion and science (far more important than knowledge alone).

Regional Anaesthetic
General anaesthetics can be dangerous or unnecessary for some patients or procedures; but sometimes, there’s still the need to perform large or complex procedures on specific areas of the body. To achieve this, anaesthetists can administer a regional anaesthetic, allowing for complete ‘blockade’ of pain and sensation to an area, such as the arm, ankle, both legs, hand, or shoulder.  All this can be done with the patient awake, or can be used with a general anaesthetic to enhance pain relief. Nerve blocks, epidurals, and spinal blocks are different types of regional anaesthesia. A local anaesthetic is injected into the vicinity of major nerve bundles that supply the specific body needed. Nerve locating devices or ultrasounds can help locate the selected nerve so that local anaesthetics can be delivered with improved accuracy. Once a body region is ‘blocked’, pain relief is complete; however patients may feel numbness and tingling, and it can be impossible to move that part of the body.

BMedSci, MBBS(Hons), FRACGP, GDipSpMed, DCH
Director Your Doctors®


Please note: Dr. Sam's blog is general advice only. For further information on this topic please consult your healthcare professional.


Nicola posted at 3:04 PM 18-Jan-2017

Such an interesting article! I recently had a minor procedure which required twilight sedation; I'd never heard of it before so wasn't really sure what to expect. The main difference I experienced between that and a previous general anaesthetic was that I came out of the twilight sedation much quicker than the GA, it was almost instant like "boom, I'm awake" - no grogginess or nausea on that occasion. Thanks Dr. Sam for the article anyway, it'll be a good one to revisit in the future.

Add a Comment

  1. Enter your comments


Your details