Tuesday 28 January 2014

What exactly is Anaesthesia???

I had written this article a long time back, for bringing awareness about anaesthesia among patients...thought of sharing it for all those who wonder what anaesthesia actually is...

Q 1: What is Anaesthesia?
A : Anaesthesia is a word derived from the Greek, meaning 'without sensation'. Anaesthesia is given to patients who are undergoing painful procedures such as surgery. By means of various drugs, all sensations (including pain sensation) of a part or whole of body are temporarily and reversibly blocked.

Q 2 : Who are anaesthetists?
A : Anaesthetists are fully trained medical doctors who have had training in anaesthesia. The anaesthetists work in partnership with the surgeon, providing a team approach to surgical care.
Q 3: Are there different types of Anaesthesia?
A : There are four types of anaesthesia:
1.      General Anaesthesia - This is a state of deep unconsciousness, where you are free of all sensation, including pain, during the operation. In this type of anaesthesia, you will be in a controlled state of unconsciousness, with muscles paralysed reversibly, and in a state of amnesia (loss of memory). Your respiration will be controlled by a ventilator by means of a tube which the anaesthetist introduces inside your trachea after you have become unconscious. Anaesthesia is usually started by an injection of medicine into a vein. Sometimes, a  mixture of gases can be breathed in to give the same effect. Your anaesthetist will stay with you, monitoring your vital functions, (heart rate, blood pressure and oxygen levels in your blood) and maintaining the correct level of unconsciousness. The process of anaesthesia will be reversed at the end of the operation. After reversal, you will be fully awake, with complete muscle power, but without any memory of the operation or any pain.
2.      Regional Anaesthesia - This is a technique where a local anaesthetic drug is used, to numb a group of nerves, and make a large part of the body, such as the legs, numb and pain free. This is achieved by injecting an anaesthetic drug inside your spinal canal (space around your spinal cord, inside the vertebral column). This technique is known as ‘Spinal Anaesthesia’. When the drug is injected in the outermost layer around spinal cord, in a space called epidural space, it is known as ‘Epidural Anaesthesia’.This can be used on its own, or with sedation or a general anaesthetic. This type of Anaesthesia is useful for operations on lower limbs or lower part of abdomen. The numbness wears off sometime after the operation, when other forms of pain relief are used. As with a general anaesthetic, you anaesthetist will be monitoring you continuously.
3.      Local Anaesthesia - Here the local anaesthetic drug is injected near a few nerves, or into the site of the operation. As with regional anaesthesia, the painful sensation is removed, but there may be some sensation of pressure or movement. For e.g, eye surgeries are generally performed under local Anaesthesia.
4.      Sedation - This is where a sedative drug is used to make you sleepy and comfortable during surgery. You may not remember much of what happens at this time, although your anaesthetist will be able to talk to you to confirm you are comfortable. Sedation is used during procedures that are uncomfortable rather than painful. Sedation can be administered in combination with other techniques and by trained doctors other than anaesthetists.
The anaesthetist chooses the type of anaesthetic, but your wishes will always be taken into account. Nothing will be done without your agreement.
Q 4: What is pre-anaesthetic check up? Why is it necessary?
A : A pre-anaesthetic check up is your health assessment conducted by the anaesthetist prior to your scheduled surgery. The anaesthetist determines your fitness for surgery, for your safety. You will be asked about presence of any chronic health problem, such as Diabetes, high blood pressure, heart disease, asthama, tuberculosis. You will be asked if you have previously undergone any surgery, and the previous anaesthesia details. You will be asked about smoking and alcohol intake, medicines you are taking, any allergies to medicines you have had, and whether you have received a blood transfusion before. The anaesthetist will record your heart rate, your blood pressure. He will go through the necessary blood investigations to see whether they are in the normal range. This will also allow the anaesthetist to plan the anaesthetic to suit your health, and the needs of surgery.
Q 5:What is monitoring?
A : The anaesthetist constantly looks after your body’s function during the anaesthetic. This “monitoring” usually includes using special machines, which measures blood pressure, the heart rate (ECG), and the amount of oxygen in your blood. Depending upon the requirement as dictated by the surgery, the anaesthetist may use other monitors such as those for measuring the amount of carbon dioxide in your exhaled gas, your level of unconsciousness, the degree of your muscle relaxation etc.
Q 6: What can I do to prepare myself for an anaesthetic?
A : Following measures should be taken by the patient to ensure a safe anaesthesia :
1.      Confide everything to your anaesthetist. Do not hide any health problem or any drug you are consuming, as this can adversely affect the anaesthetic management.
2.      Do not eat or drink anything for at least six hours before surgery. This is important to prevent you from choking while you are unconscious and from vomiting after you are out of anaesthesia.
3.      Stop smoking and consuming alcohol at least a month before surgery. This is important for your post operative recovery.
4.      Glasses and contact lenses should be removed before surgery, to prevent them getting damaged by the anaesthetic equipment.
5.      Dentures or false teeth need to be removed just before the anaesthetic, and the anaesthetist should be informed about any loose or crowned teeth. This is because the anaesthetic will relax your neck and mouth, and the anaesthetists will need to use equipment to help keep you breathing safely.
6.      Follow the instructions given by the anaesthetist properly, especially regarding your routine medications. For e.g, the anaesthetist will advise you to take your antihypertensive medicine with sips of water on morning of surgery, while he will ask you to omit your diabetes medicine on the morning of surgery. This is important for your intraoperative safety.
Q 7: Where will I go to sleep? Where will I wake up?
A : When it is time for your operation, you will be moved from the ward to the anaesthetic room next to the operating theatre. It is here that you will have a cannula, a narrow plastic tube through which injections are made, put into a vein and you will go to sleep. Occasionally, you may be anaesthetized in theatre.
Usually you will wake up in the Recovery area, which is near to the theatre. Sometimes, you will wake up before you get there, but your anaesthetist will only wake you when it is safe to do so. The Recovery area has specially trained staff to look after you following you operation, and  to make sure that any nausea, pain or discomfort is treated. The Anaesthetist continues to have a role in keeping you pain free, and looking after your fluid and drug requirements, on the ward afterwards.
Q 8: Is Anaesthesia safe?
A : Yes it is, but all operations and anaesthetics have some risk. The risk depends on various factors, such as the age of the patient, associated diseases like heart disease or lung disease, the type of surgery, whether surgery is emergency or planned, the duration of surgery, the site of surgery (heart and brain surgeries obviously carry greater risk than surgery of toe). The risks of a particular procedure to a particular patient will vary, and your anaesthetist will discuss any risks that are relevant to you before the operation. There are side effects of having an anaesthetic, such as drowsiness, nausea, muscle pains, headaches or a sore throat. These symptoms are usually short lived, and can be relieved by relevant drugs.
Q 9: They say Anaesthesia is safer now than it was previously. Is it true?
A : Certainly. Anaesthesia has evolved over years from use of cold ice to cause numbness to a variety of safe and efficient drugs. Drugs like Thiopentone Sodium, which caused nausea and delayed recovery have been replaced by Propofol, which is short acting, helping in faster recovery, as well as non nauseating. Newer and shorter acting muscle relaxants are now available. Inhalation drugs such as Ether, which was used in the past and had lots of side effects have now been replaced by newer and safer as well as more potent drugs like Sevoflurane and Desflurane. Various new pain killers are now available which can be used alone or in combination for intra operative and post operative pain relief. Pain killers are now available in various forms such as skin patches and lollipops. Overall anaesthesia has now become a pleasant experience. All anaesthetists strive to give their patients a ‘Balanced Anaesthesia’, which is a combination of Analgesia (loss of response to pain), Amnesia (loss of memory), Immobility ( loss of motor reflexes), Hypnosis (loss of consciousness) and skeletal muscle relaxation.
Q 10: Where else will I require services of an Anaesthetist?
A : Apart from surgeries, Anaesthetist is required in the following scenarios-
1.      Labor analgesia – By giving a drug in the epidural space (mentioned above) anaesthetist can help you achieve a painless normal delivery. Here you will be able to move both legs but you will have no sensation, and hence no pain.
2.      Chronic pain – chronic pain conditions such as cancer pain, neuralgias can be relieved by various nerve blocks. The anaesthetist injects a nerve ablating agent such as absolute alcohol around the nerve responsible for causing intractable pain resulting in permanent irreversible blockede of that nerve resulting in relief from pain.
3.      Diagnostic procedures – Anaesthetist is required for giving sedation or anaesthesia for children and un-cooperative patients undergoing diagnostic procedures e.g CT scan, MRI, TEE etc.
4.      Critical care – Anaesthetists are trained in management of post operative patients in intensive care units.
5.      Trauma management – Anaesthetists are trained in cardio pulmonary resuscitation and emergency management.





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