Diff: Anaesthesia
Comparing revision #1 (2023-08-18 12:27:03) with revision #2 (2026-06-22 12:41:02).
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'''Anaesthesia''' is the deliberate use of medicines to prevent pain and distress during surgery, investigations or other medical procedures. It can involve loss of sensation in one small area, numbness across a larger region of the body, sedation, or controlled unconsciousness. |
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Anaesthesia is a medical practice that involves inducing a reversible state of unconsciousness and insensitivity to pain, allowing for surgical procedures, medical interventions, or diagnostic tests to be performed without causing discomfort or distress to the patient. It encompasses a range of techniques and medications designed to ensure the patient's safety, comfort, and well-being during medical procedures. |
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Anaesthesia is normally planned and delivered by an anaesthetist, supported by trained theatre and recovery staff. The choice of anaesthetic depends on the procedure, the patient's health, the urgency of treatment and the risks and benefits of each option. |
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== History == |
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The history of anaesthesia dates back to ancient times, with early methods relying on herbal remedies, alcohol, and even physical restraints to dull pain during medical procedures. The modern era of anaesthesia began in the 19th century with the discovery and development of various anaesthetic agents, leading to significant advancements in surgical practice and patient care. |
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== Main Types == |
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The main forms of anaesthesia are: |
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== Types of Anaesthesia == |
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Anaesthesia can be broadly classified into three main categories: |
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* '''Local anaesthesia''': numbs a small area while the patient remains awake. |
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* '''Regional anaesthesia''': numbs a larger part of the body, such as an arm, leg or lower half of the body. |
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* '''General anaesthesia''': produces controlled unconsciousness so the patient is asleep and feels nothing during the procedure. |
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* '''Sedation''': uses medicines to reduce anxiety and awareness, and may be combined with local or regional anaesthesia. |
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=== General Anaesthesia === |
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General anaesthesia involves rendering the patient unconscious and unresponsive to pain by administering a combination of intravenous medications and inhaled gases. It results in a complete loss of sensation and consciousness, allowing for extensive surgical procedures to be performed. |
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These methods can be combined. For example, a patient may have a general anaesthetic for an operation and a nerve block for pain relief afterwards. |
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=== Regional Anaesthesia === |
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Regional anaesthesia focuses on numbing a specific region of the body, such as an arm or a leg, using local anaesthetic agents. Common techniques include epidural and spinal anaesthesia. While the patient remains awake, they do not experience pain in the targeted area. |
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== Local Anaesthesia == |
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Local anaesthesia is used for smaller procedures such as dental work, skin procedures, minor surgery and some diagnostic tests. The anaesthetic is usually injected or applied to the area being treated. |
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=== Local Anaesthesia === |
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Local anaesthesia involves the injection of anaesthetic agents directly into a small area of the body, such as the skin or underlying tissues. It results in temporary numbness and loss of sensation in the treated area, making it suitable for minor surgical procedures or medical interventions. |
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The NHS describes local anaesthetics as generally safe, with serious side effects being very rare. The patient usually stays awake and can go home sooner than after a general anaesthetic, depending on the procedure. |
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== Anaesthetic Agents == |
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Various anaesthetic agents are used to induce and maintain anaesthesia. These agents can be categorised into intravenous agents (administered through a vein) and inhaled agents (inhaled through a breathing mask or tube). Commonly used intravenous agents include propofol and thiopental, while inhaled agents include nitrous oxide and sevoflurane. |
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== Regional Anaesthesia == |
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Regional anaesthesia blocks sensation from a larger part of the body. Spinal anaesthesia, epidural anaesthesia and nerve blocks are common examples. |
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== Anaesthesia Process == |
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The administration of anaesthesia involves a carefully orchestrated process to ensure the patient's safety and comfort: |
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Regional techniques may allow surgery without full unconsciousness. They can also reduce pain after an operation. The Royal College of Anaesthetists notes that regional anaesthesia has benefits and risks that should be discussed as part of an individual anaesthetic plan. |
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# Preoperative Assessment: The anaesthesiologist evaluates the patient's medical history, current health status, and any potential risks associated with anaesthesia. |
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# Induction: Anaesthesia is induced by administering the chosen anaesthetic agents. For general anaesthesia, this leads to unconsciousness and loss of sensation. |
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# Maintenance: The patient's anaesthetic state is carefully maintained throughout the procedure using a combination of medications. |
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# Monitoring: Vital signs, such as heart rate, blood pressure, and oxygen levels, are continuously monitored to ensure the patient's well-being. |
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# Emergence: At the end of the procedure, anaesthesia is gradually discontinued, and the patient is carefully brought back to consciousness. |
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== General Anaesthesia == |
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General anaesthesia uses medicines given through a vein, breathed in as gases, or both. The patient is unconscious and does not feel pain during the operation or procedure. |
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== Risks and Complications == |
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While anaesthesia is generally safe, there are potential risks and complications, including: |
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During general anaesthesia, breathing, oxygen levels, heart rate, blood pressure and other signs are monitored. Some patients need help with breathing while they are anaesthetised. The anaesthetist adjusts medicines and monitors the patient until the procedure is finished and recovery begins. |
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* Allergic Reactions: Some patients may be allergic to anaesthetic agents, leading to adverse reactions. |
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* Respiratory Problems: Anaesthesia can depress the respiratory system, leading to breathing difficulties. |
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* Nausea and Vomiting: Some patients may experience post-operative nausea and vomiting. |
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== Before and After == |
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Before anaesthesia, the anaesthetist or pre-assessment team reviews relevant medical history, allergies, medicines, previous anaesthetic problems and the planned procedure. Patients may be asked about smoking, alcohol, pregnancy, loose teeth, fasting and long-term conditions. |
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== Advances in Anaesthesia == |
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Advancements in medical technology and research have led to safer and more effective anaesthetic techniques. The field continues to evolve, with ongoing efforts to improve patient outcomes and reduce risks associated with anaesthesia. |
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After the procedure, recovery staff monitor the patient as the anaesthetic wears off. Common short-term effects can include sleepiness, nausea, sore throat, shivering or temporary confusion. The expected recovery depends on the type of anaesthetic and procedure. |
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== See Also == |
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== Risks == |
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Modern anaesthesia is usually safe, but it is not risk-free. Risk varies by age, general health, urgency of surgery, airway difficulty, allergies, heart or lung disease, pregnancy, obesity and the type of operation. |
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Possible complications include nausea, vomiting, sore throat, dental injury, breathing problems, allergic reaction, nerve injury after some regional techniques, awareness under general anaesthetic, and rare life-threatening reactions. Serious events are uncommon, but they are the reason assessment, monitoring and trained anaesthetic care matter. |
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== See Also == |
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* [[Surgery]] |
* [[Surgery]] |
* [[Anaesthetic Agents]] |
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* [[Medical Procedures]] |
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* [[Pharmacology]] |
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* [[Common_Medical_Terms]] |
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* [[NHS]] |
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== References == |
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* [https://www.nhs.uk/tests-and-treatments/general-anaesthesia/ NHS: General anaesthetic] |
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* [https://www.nhs.uk/tests-and-treatments/local-anaesthesia/ NHS: Local anaesthetic] |
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* [https://www.nhsinform.scot/tests-and-treatments/medicines-and-medical-aids/types-of-medicine/anaesthetics/ NHS inform: Anaesthetics] |
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* [https://www.rcoa.ac.uk/patients/patient-information-resources/patient-information-leaflets-video-resources Royal College of Anaesthetists: Patient information resources] |
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* [https://rcoa.ac.uk/gpas/chapter-8 Royal College of Anaesthetists: Regional anaesthesia] |
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* [https://anaesthetists.org/Home/Public-info/Patient-information Association of Anaesthetists: Patient information] |
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[[Category:Medicine]] |
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[[Category:Surgery]] |
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[[Category:Pharmacology]] |