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Anaesthesia - What it is

Anaesthesia means 'loss of sensation'. Medications that cause anaesthesia are called anaesthetics, which is given to you to so that you do not feel pain or induce sleep during the surgery or procedure. After the anaesthetics has worn off, you will regain consciousness and the normal sensations. 

Anaesthesia - Symptoms

Anaesthesia - How to prevent?

Anaesthesia - Causes and Risk Factors

Anaesthesia - Diagnosis

Anaesthesia - Treatments

Anaesthesia - Preparing for surgery

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 into your windpipe to help you breathe while under anaesthetic. The tube is removed as you wake up after surgery.

Regional Anaesthesia 
Regional Anaesthesia numbs one region of your body. Patients are usually sedated for the procedure itself and throughout surgery. Sometimes, regional anaesthesia is combined with  general anaesthetic. Regional anaesthesia may be performed as a single shot or with a continuous catheter through, which medication is given over a prolonged period.
Epidural Anaesthesia
Local anaesthetic and other pain medicines are given using an epidural catheter (a small tube or line) that is inserted into your back to block pain during surgery and/or after your operation. Epidural analgesia is commonly used to help reduce labour pain.
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.

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. Blocks lasting longer than this are extremely rare. 
Local Anaesthesia with Monitored Anaethesia 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 sedative medicines to help you to remain calm during the surgery. One effect of the sedative is drowsiness.

Anaesthesia - Post-surgery care

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 Score

Methods for Pain Relief
  • Oral medications e.g. paracetamol, opioids
  • Intravenous medications including narcotics like morphine
  • Epidural analgesia
  • Nerve blocks
Patient Controlled Analgesia 
Patient Controlled Analgesia (PCA) is delivered using a computerised pump. The PCA pump is programmed by the doctor and is activated by you using a handset attached to the pump. Medication is kept in the pump and the pump is locked at all times. It is important to note that ONLY YOU are allowed to press the handset to activate the pump for the medication. This is to avoid overdosing. Some of the common side effects include nausea, vomiting and drowsiness. An intravenous access is required for the pump. 

Anaesthesia - Other Information

What are the risks of Anaesthesia?

The practice of anaesthesia is very safe; however the risk of complications with any anaesthesia rendered remains. Death or permanent disability related to anaesthesia is extremely rare. 

Risks associated with all forms of Anaesthesia
Common Risks
  • Pain or bruising at the site of injections or drips
  • Shivering
  • Dizziness
  • Post-operative nausea and vomiting
  • Temporary headache
Rare Risks
  • Breathing difficulties
  • Heart attack
  • Chest infection
  • Allergy to drugs
  • Stroke
  • Death
Additional risks associated with General Anaesthesia
Common Risks
  • Sore throat
  • Damage to teeth or dental work
  • Damage to lips or tongue
  • Facial abrasions
  • Body aches
  • Eyelid abrasions
Rare Risks
  • Inherited muscle sensitivity to particular anaesthetic drugs (malignant hyperthermia)
  • Awareness of activity in the operating room during anaesthesia
Risks associated with Epidural, Spinal and Regional Anaesthesia
Common Risks
  • Headache
  • Bleeding
  • Inadequate pain relief
  • Prolonged nerve blockade
Rare Risks
  • Infection
  • Seizures
  • Allergic reactions
  • Damage to nerves, spine, skin, muscles or other internal structures

The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth