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Anaesthesia During Your Surgery

Anaesthesia During Your Surgery - What it is

Anaesthesia plays a major role to ensure your comfort and safety during your surgery. The following information will help prepare you to receive anaesthetic and know what to expect when you wake up after surgery.

    Anaesthetists are doctors with specialized training who:
    • Discuss types of anaesthesia and risks with you
    • Plan your anaesthetic and pain control
    • Are responsible for administering your anaesthesia, monitor your wellbeing and safety throughout the operation
    • Plan and manage your stay in the Intensive Care Unit (if needed)
    • Make your experience as pleasant and pain free as possible

    • General Anaesthesia
    • Regional Anaesthesia
    • Local Anaesthesia
    • Sedation

    The type of anaesthesia you will receive depends on the type of surgery, medical conditions you may have and the length of the operation. Your anaesthetist will discuss with you the options.

    Sometimes your anaesthetist will use a combination of anaesthetics. It depends on what is best for you.

    Your anaesthetist will meet you before your operation to check on your health, perform relevant examinations and discuss your anaesthetic in detail. They may also send you for blood or other tests. The anaesthetist would need to know:
    1. If you have a history of high blood pressure, heart problems, thyroid problems, diabetes, asthma, history of reflux or heartburn, or any other medical conditions
    2. The past operations you have had and if there were any problems with anaesthesia
    3. If you had any abnormal reactions to any drugs or if you have any allergies
    4. If you are currently taking any medications. If you are taking aspirin, non-steroidal anti-inflammatory agents or other blood thinning drugs, consult your surgeon or anaesthetist on whether you should stop taking them before your surgery. Please bring with you all your current medications in their original packaging
    5. If you have any loose or capped teeth, browns, or wear dentures
    6. If you smoke. Giving up smoking for several weeks before the operation reduced the risks of breathing problems. If you cannot stop smoking, cutting down on smoke will help

    Nil by mouth = Nothing to eat or drink

    The doctors or nurses will advise you how long to fast. Is it important to follow these instructions. Food or fluid in the stomach may enter your lungs while you are unconscious. If you don’t follow this rule of fasting, the operation may be postponed in the interests of your safety.

    If you are taking medications, you should continue to take them, e.g. high blood pressure or asthmatic medications, unless your anaesthetist or surgeon tells you not to.

    If you feel unwell on the day that you are coming into the hospital for an elective operation, please call and inform your doctor.

    General anaesthesia
    You get an injection or breathe a gas that makes you unconscious. A tube may be placed in your windpipe to help you breathe. This is essential for some operations. Your anaesthetist stays with you throughout the operation to ensure you are receiving the correct amount of anaesthetic.

    There are two ways of starting a general anaesthesia:
    • Anaesthesia drugs are injected into your body through a cannula placed in a vein
    • You will be asked to breathe in oxygen or anaesthesia gases through a mask

    Once you are unconscious, anaesthesia can be maintained with intravenous drugs or a mixture of gases, which you will breathe. While you remain unaware of what is happening around you, the anaesthetist monitors your condition closely and constantly adjusts the level of anaesthesia.

    As soon as the operation ends, the drugs will be stopped or reversed so that you regain consciousness.

    Regional anaesthesia
    This involves injections to numb the nerves around the area of the body where the surgeon needs to operate. This may make the area numb for several hours. You can remain awake, or your anaesthetist may give you an injection to make you relaxed and drowsy. Examples of regional anaesthetics include epidurals, for labour and spinal anaesthesia for caesarean section or vaginal hysterectomy.

    Local anaesthesia
    This involves injections that numb only the site of operation. You will be awake but feel no pain.

    The anaesthetist administers drugs to make you relaxed and drowsy. This is often used for gastroscopy, colonoscopy, some plastic surgery and IVF procedures.

    You will be observed after surgery to ensure your recovery is as smooth and trouble-free as possible. Your anaesthetist, assisted by the recovery room staff will continue to monitor your condition closely.

    You will feel drowsy for a little while after you wake up from the anaesthetic. You may have a sore or dry throat, feel sick or have a headache. These are temporary and you will recover from them soon.

    To help the recovery process, you may be given oxygen to breathe, usually by a clear plastic facemask, and encouraged to take deep breaths and to cough.

    Only when you are fully conscious and comfortable will you be transferred back to your room/ward or waiting area before returning home.

    You may also experience some dizziness, blurred vision or short-term memory loss, but these will pass quickly. If you have any concerns, you should contact your anaesthetist.

    If you are having “day surgery”, make sure there is someone to accompany you home. For the next 24 hours do not:
    • Drive a car/motorcycle
    • Make important decisions
    • Use any dangerous equipment or tools
    • Sign any legal documents
    • Drink alcohol or take sedatives

    Modern anaesthesia is very safe. There are however risks and side effects. While most are minor and temporary, some can be serious and long term. Certain conditions increase the risks/complications such as heart and kidney disease, diabetes, high blood pressure, being overweight, colds/flu, and smoking. Complications are also more likely if you are having a major or an emergency surgery.

    Common side effects: Feeling sick and vomiting, headache, dizziness, shivering, sore/dry throat, pain and bruising at injection sites.

    Less common side effects: Muscle aches, weakness, itching or rash.

    Uncommon side effects: Awareness under general anaesthesia, damage to teeth/dental prosthesis, temporary damage to the voice, allergic reactions, damage to nerves.

    Very uncommon side effects: Severe allergy causing heart failure, very high temperature, heart attack or stroke, paralysis, vomit in the lungs (causing pneumonia), blood clots in the lungs, brain injury or death.

    Reactions or allergy to local anaesthetics are extremely rare. Regional anaesthesia very rarely cases nerve damage due to infection, bleeding and imflammation. This can cause weakness and/or numbness that is usually temporary.

    There are specific risks with epidural and spinal anaesthesia. These are:
    Headache: The risk is about 1 in 100; the headache is severe, although temporary and can be treated if it occurs
    Backache: usually temporary and due to bruising from the injection
    Nerve damage: This is extremely rare, but can range from mild, temporary numbness to severe and permanent paralysis

    We encourage you to ask questions. Your anaesthetist will be happy to answer them and discuss the best way to work with you for the best possible outcome.
Useful telephone numbers
​Pre-anaesthetic clinic
​Appointment / Specialist 
Outpatient Clinics
Enquiries Hotline

Anaesthesia During Your Surgery - Symptoms

Anaesthesia During Your Surgery - How to prevent?

Anaesthesia During Your Surgery - Causes and Risk Factors

Anaesthesia During Your Surgery - Diagnosis

Anaesthesia During Your Surgery - Treatments

Anaesthesia During Your Surgery - Preparing for surgery

Anaesthesia During Your Surgery - Post-surgery care

Anaesthesia During Your Surgery - Other Information

The information above is also available for download in pdf format.
The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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