Procedures › General anaesthetic

Having a general anaesthetic

This page covers what to expect from a general anaesthetic for any operation: preparing, going off to sleep, waking up, and the common side effects and risks. If your operation has its own page in Procedures, read that too - it adds detail specific to your surgery. Your own plan is always agreed with you before surgery.

What is a general anaesthetic?

A general anaesthetic is a carefully controlled, medication-induced state of unconsciousness. You are fully asleep, feel nothing, and remember nothing of the operation. It is not like normal sleep - your anaesthetist stays with you the whole time, continuously adjusting the medications and monitoring your breathing, heart, blood pressure and oxygen levels.

Before surgery

Fasting

• No food for 6 hours before surgery.
• You may drink clear fluids (water, black tea/coffee without milk, clear apple juice) until 2 hours before.

More information: see our fasting guidance.

Medications

• Most regular medications can be taken as usual, with a sip of water if needed.
• Blood thinners, diabetes medicines and some others need changes - these will be discussed individually.

Use the medicine timing tool to check when to take or stop individual medicines, and see medicines before surgery for the full guidance.

Ozempic, Wegovy, Mounjaro, Trulicity or similar

These medicines slow stomach emptying, so special fasting rules apply:

• 24-6 hours before surgery: clear fluids only.
• 6-2 hours before: water only (max 200 ml per hr).
• 2 hours before: nothing by mouth.

See GLP-1 medicines before surgery for details. If you did not follow these instructions, please tell me - your surgery may need to be delayed or modified.

Pre-operative consultation

You may be contacted by the pre-op nursing team or a peri-operative physician. I may also contact you before surgery to discuss your plan and answer questions. See consent and assessment.

On the day

After you are admitted, we will meet before your operation. I will go through your health, medicines and fasting, answer your questions, and confirm the plan with you. In the operating suite:

• A small drip (cannula) is placed in your hand or arm - a brief sting, then no further needles that you will feel.
• Monitoring is attached: ECG dots, a blood pressure cuff and an oxygen clip on your finger.
• You breathe oxygen through a soft mask while the anaesthetic medicine is given through the drip. Going off to sleep takes less than a minute and is not unpleasant.

See day of surgery for the full timeline, including arrival times and what to bring.

While you are asleep

• I remain with you for the entire operation - this is my only job while you are asleep.
• A soft breathing device is usually placed in your airway once you are asleep, and removed before you are fully awake.
• Pain relief, anti-nausea medicines and fluids are given during surgery so you wake as comfortable as possible.
• Depending on your operation, local anaesthetic or a nerve block may be added for pain relief afterwards - this is discussed with you beforehand.

Waking up

You wake in the recovery room with a nurse beside you. Most people are drowsy for 30-60 minutes. It is normal to feel:

• Sleepy, a little disoriented, or emotional for a short time.
• A dry mouth or mildly sore throat from the breathing device.
• Cool or shivery - warm blankets help and it settles quickly.

Pain and nausea are treated straight away in recovery - tell your nurse early rather than waiting.

Going home (day surgery)

• You must have a responsible adult take you home and stay with you overnight.
• For 24 hours: do not drive, operate machinery, sign important documents, or drink alcohol.
• Anaesthetic medicines can affect judgement and reflexes even when you feel normal.

For pain relief at home, see the pain relief tool.

Side effects and risks

Anaesthesia in Australia is very safe, but like any medical procedure, risks can occur.

• Common (5-25%): Nausea, sore throat, dizziness, drowsiness, headache, sleep disturbance.
• Uncommon (<5%): Severe pain immediately after surgery, confusion (more common in older patients), dental injury, eye irritation, muscle aches.
• Rare (<1%): Awareness during anaesthesia, airway emergency, aspiration of stomach contents, severe allergic reaction, nerve injury from positioning, heart attack or stroke.

Death directly related to anaesthesia is extremely rare (about 1 in 60,000). Your individual risks depend on your health and your operation - we discuss anything relevant to you before surgery.

When to call after you go home

• Pain that is getting worse despite your pain relief plan.
• Vomiting that will not settle, or you cannot keep fluids down.
• Fever, or redness/swelling that is spreading.
• Feeling very unwell in any way - call 000 or go to your nearest emergency department.