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What is Anaesthesia?

 Anaesthesia means ‘loss of sensation’. Medications will be given to you so that you are unconscious and do not feel pain during the surgery or procedure. After the anaesthetics has worn off, you will regain consciousness and wake up.

What are the types of Anaesthesia?

General Anaesthesia

General Anaesthesia is a medically induced, reversible state of unconsciousness. This is achieved using a combination of drugs including pain-killers. Drugs are injected into your vein and/or breathed in as gases into the lungs. A breathing tube will be inserted to help you breathe while unconscious. The tube is removed after surgery when you wake up.

Regional Anaesthesia

Regional Anaesthesia numbs a specific part of your body. It may be combined with sedation or general anaesthesia. Regional anaesthesia may be performed as a single dose or with a continuous catheter through which medication is given over a period.
a) Epidural Anaesthesia
Local anaesthetic and other pain medicines are given using an epidural catheter (a small tube) that is inserted into your back to block pain during surgery and/or after operation. Epidural analgesia is commonly used to help reduce labour pain.
b) Spinal Anaesthesia
Local anaesthetics and other pain medicines are injected directly into your spinal canal to block pain during surgery. Generally during spinal anaesthesia, the patient is numbed from the chest or abdomen down to the legs for 6 to 8 hours.
c) Nerve Blocks
Local anaesthetics and other pain medicines are injected near a nerve or a group of nerves supplying sensation to the intended surgical site, hence numbing the region and blocking pain during surgery. Nerve blocks typically last 8 to 16 hours, although it may last for a few days in about 2% of people.
During your anaesthesia consult, the doctor will advise you on options suitable for you and your procedure.
d) Local Anaesthesia with Monitored Anaesthesia Care
Local anaesthetic are given to numb the area for surgery while the anaesthesia doctor monitors your vital functions such as heart rate, heart rhythm, blood pressure and breathing to ensure that you are safe and comfortable during surgery. You might also be given sedatives to help you to remain calm during the surgery.

Risks associated with all forms of Anaesthesia

Common Risks ​Rare Risks
  • ​Pain or bruising at the site of injections or drips
  • Shivering
  • Dizziness
  • Post-operative nausea and vomiting
  • Temporary headache
  • ​Breathing difficulties
  • Heart attack
  • Chest infection
  • Allergy to drugs
  • Stroke
  • Death

Additional risks associated with General Anaesthesia

Common Risks ​Rare Risks
  • ​Sore throat
  • Damage to teeth or dental work
  • Damage to lips or tongue
  • Facial abrasions
  • Body aches
  • Eyelid abrasions
  • ​Inherited muscle sensitivity to particular anaesthetic drugs (malignant hyperthermia)
  • Awareness of activityin the operating room during anaesthesia

Additional Risks associated with Regional Anaesthesia

Common Risks Rare Risks
  • Headache
  • Bleeding
  • Inadequate pain relief
  • Prolonged nerve blockade
  • Low blood pressure
  • ​Infection
  • Seizures
  • Allergic reactions
  • Damage to nerves, spine, skin, muscles or other internal structures

What can I expect after an operation involving Anaesthesia?

Post Surgery / Recovery

After surgery, you will be transferred to the Post Anaesthesia Care Unit (PACU) where your blood pressure, heart rate, breathing, temperature and pain will be monitored until you are stable enough to be discharged to the wards.


During recovery, we use the Numerical Rating Scale to score your pain (as illustrated below). Pain relief medications will be given to you to help reduce your pain.

Pain Factor

Methods for Pain Relief

  • Oral medications e.g. paracetamol, opioids
  • Intravenous medications e.g. morphine
  • Epidural analgesia
  • Nerve blocks

Patient Controlled Analgesia

Patient Controlled AnalgesiaPatient Controlled Analgesia (PCA) is delivered through your intravenous drip using a computerised pump. The PCA pump is programmed by the doctor and is activated by you using a handset attached to the pump. It is important that ONLY YOU are allowed to press the handset for the medication to avoid overdosing for your own safety. Some of the common side effects include nausea, vomiting and drowsiness.