Anaesthesia refers to loss of pain sensation and absence of other sensations, which is induced by administration of gases (breathing in) or injection of drugs to allow surgical procedures to be performed without undue discomfort of distress. There are different types of anaesthesia and the type you receive will be determined by various factors like the type of procedure, your health, and your preference.
Types of Anaesthesia
- Local Anaesthesia is produced by application of a local anaesthetic to numb a small part of the body. The superficial nerves are blocked using drops; sprays, ointments or injections while you stay conscious but free of pain. Common examples of surgery under local anaesthesia include removal of stitches, having teeth removed and common eye operations.
- Regional anaesthesia is an umbrella term used to describe injection of local anaesthetic near to the nerves supplying a larger or deeper area of the body to render that area numb. Types of regional anaesthesia are nerve blocks (surgery on arm, shoulder, leg), epidural blocks and spinal blocks (operations on lower body e.g. caesarean section, bladder surgery, hip and knee surgery).
- Sedation is used for minimally invasive procedures like gastroscopies and colonoscopies. It involves using small amounts of anaesthetic drugs to produce a ‘sleep like’ state that makes you physically and mentally relaxed.
- General anaesthesia is a drug-induced state of controlled unconsciousness where you will not respond to any stimulus including pain. A general anaesthetic is essential for major operations like heart surgery and abdominal surgery. General anaesthesia induced unconsciousness is different from natural sleep in that you can only be woken from an anaesthetic once the drugs are stopped and their effects wear off.
Your anaesthesiologist does a pre-operative assessment to formulate an anaesthetic plan for you.
The objectives of having an anaesthetic plan are to ensure your safety, comfort and the best outcome possible from your surgery, and minimise the risks of complications and side-effects. This plan takes into account the patient, their medical and surgical conditions, and the type of surgery planned.
Every patient is unique with regard to their health, previous experiences and expectations.
Anaesthesiologists are specialists at perform pre-operative assessments, including physical examination, that look for patient specific risk factors. A physical examination helps confirm good health or existing disease, and the severity thereof.
Certain chronic diseases, if not well controlled can increase your risk of having a major complication during or after your surgery. Your anaesthesiologist may decide that further medical evaluation or treatment is necessary before surgery to mitigate your risk of complications.
Also, certain patient–specific physical features directly influence the type of anaesthetic you receive. Your anaesthesiologist will examine you for these, and consider the safest options available based on the assessment.
Once your anaesthetist has considered your medical history and performed a physical examination, they will formulate a provisional anaesthetic plan and discuss this with you.
This is your opportunity to ask questions and let you anaesthetist address any concerns you may have.
**If you only expect to meet your anaesthetist on the day of surgery, please try to write down a summary of your medical history, and bring in a copy of the prescription of any medication you may be on.
It is the primary role of the Anaesthetist to manage and treat changes in your critical life functions--breathing, heart rate, and blood pressure--as they are affected by the surgery being performed. They are furthermore responsible to diagnose and treat any medical problems that might arise during and immediately after surgery. The following is important information the anaesthetist needs to know, before surgery, this will enable them to evaluate your medical condition and formulate an anaesthetic plan that takes your physical condition into account.
- Medical history. All current and previous medical conditions that you have received treatment for.
- Surgical history. All operations that you have had in the past.
- Any known allergies. Allergies to both foods and drugs should be identified.
- Reactions to previous anaesthetics. This includes mild reactions and adverse effects to significant complications, including if you felt nauseated or the amount of time you took to wake up.
- Family history of reactions to anaesthetics. There are a few genetically inherited life-threatening conditions that, if aware of, you need to tell your anaesthetist about.
- Sleep apnoea or heavy snoring. These conditions can be exaggerated by anaesthesia. Always speak to your anaesthetist about this and bring any machines or devices for the medical treatment of apnoea with you when you come for surgery.
- Current herbal or fitness supplements. Certain supplements may cause changes in heart rate and blood pressure, and may even increase the chance of bleeding.
- All recent and current prescription and over-the-counter medicines. Certain prescription medicines, especially blood thinners, might have to be discontinued for some time before surgery.
- Cigarette smoking and drinking alcohol. It is important to be honest about your past, recent, and current consumption as well as recent cessation.
- Use of street drugs (such as marijuana, cocaine, or amphetamines) as well as past and present addiction to prescription medication. All conversations between you and anaesthetists are confidential. It is crucial to know about your past, recent, and current use of these substances.
- Restorative dental work or loose teeth. Crowns, bridges, veneers and false teeth or dentures.
- History of heartburn or reflux.
- Exercise tolerance. How far and at what pace can you walk? How many flights of stairs would you be able to climb comfortably? This provides an estimation of your heart and lungs ability to cope with the demands or stress of surgery and anaesthesia.
You should continue to take your usual medication up to and including the day of your operation, unless you have been told not to. Please check this with the prescribing doctor, or contact our rooms to clarify any uncertainty.
Look out for specific instruction to take:
- drugs to thin your blood, e.g. warfarin, dabigatran, rivaroxaban, clopidogrel (Clopiwin/Plavix), aspirin (Disprin/Ecotrin)
- drug for diabetes
- blood pressure pills
- herbal remedies
Remember to bring all your medication with you to hospital, or your full prescription including the drug name and dose and timing.
Your anaesthetist is highly trained in the safe administration of medication and the performance of several techniques to minimize your pain, these are adjusted to suit your changing requirements as you recover from surgery. Your anaesthetist will discuss various options of minimising your pain experience to allow greater levels of comfort, these interventions can be done before, during and after surgery.
Everyone experiences pain differently. Even though pain after surgery is normal and in some instances common, it will already be reduced significantly by the anaesthetists pre-emptive interventions. Should you experience pain on awakening or in the recovery room, rest assured that this will be promptly attended to, and controlled before you leave the theatre complex.
We appreciate, and are sensitive to, the fact that some patients experience significant anxiety over needles and drips. Sometimes you may experience discomfort at an area different to your surgical site, we call this referred pain. The most intense discomfort may be felt around the site of surgery. Throat discomfort is common after general anaesthesia and is due to the breathing tube inserted while you are asleep. So you see...whatever pain concerns you may have, we have several methods of helping you.
Whatever your concerns, we would like to discuss these with you and together we can formulate a plan to safely keep you comfortable.
No, you do not necessarily have to go to sleep for your surgery.
Going to sleep is termed General Anaesthesia, for which your anaesthetist will administer drugs to render you totally unconscious. Much surgery is able to be performed without you being unconscious, either using local or regional anaesthesia.
Local anaesthesia involves infiltrating the area around the surgical site with local anaesthetic drugs , which numb the area. This form of anaesthesia is suitable for surface surgery such as removing lumps, skin lesions, and also larger operations such as many cosmetic surgeries.
Regional anaesthesia involves numbing a region of your body such as your limbs or even the whole lower half of your body. This is achieved by injecting local anaesthetic drugs around large nerves supplying the limb, or around the nerves as they leave the lower part of the spinal cord, which will numb the lower half of your body.
Both local and regional anaesthesia may be accompanied by Conscious Sedation, where the anaesthetist will administer a combination of drugs to remove any anxiety and let you feel totally relaxed. These drugs may also make you very drowsy, so that you fall asleep, but you will be rousable and NOT unconscious.
Conscious sedation may also be used alone for unpleasant procedures such as colonoscopy, gastroscopy and invasive radiological procedures.
General anaesthesia is overall very safe; most people, even those with significant health conditions, are able to undergo general anaesthesia itself without serious problems. Anaesthesia is however not without risk. Adverse events can occur during any anaesthetic, which can range from trivial to brain damage or death. Your risk of complications is more closely related to the type of procedure you're undergoing and your general physical health, rather than to the type of anaesthesia. Older adults or patients with significant medical problems, particularly those undergoing more extensive procedures, may be at increased risk of perioperative complications. Anaesthetists are trained to manage these complications should they occur. If a complication persists for more than 48 hours, please inform your anaesthesiologist or surgeon.
The following list covers some of the complications that may occur under anaesthesia or post operatively.
|Common Complications||Rare Complications||Very Rare Complications||Brain Damage or Death|
|(1 - 10% of cases) |
Minimal treatment usually
|(Less than 1 in 1000 cases) |
May require further treatment
|(1 in 10,000 to 1 in 200,000 cases) Often serious with long-term damage||(Less than 1 in 250,000 cases)|
Side effects or interactions of medications vary and may cause complications above across the spectrum
Complications arising due to procedures that may be performed during your anaesthetic:
|Intravenous Line||Pain, swelling, bleeding, inflammation, infection, clots, repeated insertions.|
|Central line for specialised monitoring||Pain, swelling, bleeding, inflammation, infection, repeated insertions, puncture of lung, artery or nerve, clots.|
|Arterial line for specialised monitoring||Pain, swelling, bleeding, inflammation, infection, repeated insertions, loss of blood flow to the hand leading to death of fingers.|
|Airway management||Damage to lips, teeth, tongue, palate, throat, vocal cords, hoarseness, inhalation of stomach contents (aspiration), pneumonia, obstruction of breathing, failure to maintain the airway requiring an operative procedure.|
|Nerve blocks, spinal or epidural injection||Back pain, non-resolving headache, nerve damage, paralysis, headache, nausea, vomiting, dizziness, shortness of breath, chest pain, pneumothorax, seizures, drug toxicity.|
Specific conditions that can increase your risk of complications during surgery include: smoking, seizures, obstructive sleep apnoea, obesity, high blood pressure, diabetes, stroke, other medical conditions involving your heart, lungs or kidneys, medications (e.g. asprin that can increase bleeding), heavy alcohol use, drug allergies, previous reactions to anaesthesia.
Awareness during general anaesthesia is a distressing thought to many people about to undergo an operation. The combination of being both aware and in pain under general anaesthesia is even more distressing. Fortunately, awareness is a very rare event. In 2014, a large study from the United Kingdom showed that accidental awareness under general anaesthesia only occurred in approximately 1 in 20 000 people. Some groups of patients, however, had higher risks. These included: patients where paralysing drugs were used, general anaesthesia for Caesarean Section, and cardiothoracic surgery. Your attending anaesthesiologist will make use of certain equipment and monitors in theatre to help reduce the risk of awareness whilst you are under general anaesthesia. The monitors will help your anaesthesiologist to give the correct amount of anaesthetic required for your procedure, thereby nearly eliminating the risk.
Nausea and vomiting is unfortunately not uncommon after surgery. The cause is multifactorial, involving patient risk factors, the drugs used for anaesthesia and the type of surgery itself. That said, all anaesthetists are aware of these risks and can tailor their anaesthetic technique to minimise this unpleasant side effect as needed. Be sure to tell your anaesthetist before the operation if you’ve experienced this before, or if you are prone to nausea or motion sickness, and he or she can discuss a management plan with you. Although unpleasant, nausea and vomiting are usually mild and self-limiting if they occurs.
An empty stomach reduces the chances of an aspiration and its complications. An aspiration is when stomach contents are expelled up the oesophagus (food pipe) into the lungs (wind pipe). An aspiration can cause significant damage. You can protect yourself from an aspiration by strictly following the no food/no drink rule. The only exception is that you may take necessary medications the morning of surgery with a sip of water. Your surgeon, or anaesthesiologist can help you determine which of your medications, if any, are necessary the morning of surgery.
If you are requiring a general anaesthetic, or some forms of sedation, the anaesthetist will be required to place an airway device to ensure that you will receive ongoing oxygen and anaesthetic gasses, and continue to breathe safely. Your anaesthetist may also have to use a plastic sucker to clear secretions in your mouth.
Damage to your lip, tongue or teeth as a result of these procedures is overall an uncommon event, occurring in less than 1 in 1000 anaesthetics. But the likelihood of this occurring is more if you have pre-existing loose or weak teeth, especially in the setting of a small mouth or jaw, or a stiff neck. You must inform your anaesthetist of the state of your dentition (loose teeth, caps, crowns, bridges) so that it can be recorded pre-operatively. Despite the care that your anaesthetist takes, these loose teeth, caps or crowns can break or dislodge and fall into your lungs, so it is important to know of their presence so that extra care can be taken to mitigate this risk.
An 'epidural' is a type of regional anaesthetic in which a needle is positioned between the bones of the spine to allow the anaesthesiologist to insert a small plastic tube (or catheter) into the epidural space. The needle is then removed and local anaesthetic is injected through the catheter. This local anaesthetic moves (or diffuses) across the dura into the spinal canal, and temporarily stops the spinal nerves from working, so that sensation and movement in the area supplied by the nerves does not occur. When the effect of the local anaesthetic wears off, sensation and movement will return. If a weaker solution of local anaesthetic is used, then only painful sensations will be blocked. This is very useful for controlling pain and is called epidural analgesia. Often continuous infusions of local anaesthetic solutions are used, which allows the effect to be maintained as long as required. The catheter may be placed in the upper back (thoracic spine) or the lower back (lumbar spine), depending on where the effect is needed. This is a very useful and safe procedure, when performed with appropriate care by an experienced anaesthesiologist.
No one can tell you when you will be fit to resume normal activities. This is a very subjective question that only you and your surgical team will be able to answer. It will depend on the surgical procedure, your general state of health, your age and what you regard as normal.
Before undergoing any surgical procedure it is important to discuss with the surgeon exactly what the surgery entails and how this may affect you in returning to normal activity. Once this has been done, have the same discussion with the anaesthesiologist to verify that you understand what the post-operative implications will be for you to resume normal activity. (Second opinion.)
You may not drive for at least 24 hours after an anaesthetic:
- It takes 24 hrs for the body to get rid of the effects of the anaesthetic drugs.
- You may not be 100% functional in making the right decisions and responding to sudden changes whilst driving.
- It is illegal to drive “under the influence” and you may not be covered by your insurance company should you be involved in an accident. Even if you are not the guilty driver.
- Depending on the type of surgery you have had it may be physically very difficult to control your vehicle and respond in an emergency situation.
Having waited 24 hours and you feel ready to drive. Get into your motor vehicle. Do not start the engine. Buckle up and close the doors. Pretend that you are about to start and drive off. Go through all the motions of driving the vehicle. Ensure that you have good and easy vision in both the side and rear view mirrors. Apply brakes suddenly as if a child or dog has run into your path. If you can do this without any pain or discomfort start the engine and take a very slow drive around your area. If comfortable with this you are most probably ready to drive. It may be advisable to have some responsible company on your first road trip. Do not take any chances.
After an anaesthetic you should be accompanied by a responsible adult in case you need assistance. This is typically advised for the first 24 hours after an anaesthetic.
During a procedure, conscious sedation lets you stay awake and aware, without feeling discomfort and without the stronger side effects and dangers of general anesthesia. Some patients may experience brief periods of sleep. Patients who receive conscious sedation are usually able to speak and respond to verbal cues throughout the procedure, communicating any discomfort they may experience to the provider. A brief period of amnesia may erase any memory of the procedures. Conscious sedation does not last long, but it may make you drowsy.