Anesthesia: Purpose and Types
Anesthesia is an artificially created decrease or lack of sensitivity in the process of medical manipulation.
Purpose of anesthesia:
The modern anesthesia solves the following problems:
* providing the surgeon with optimal working conditions during the surgery, which the quality of surgical treatment depends on,
* carrying out an effective and safe anesthesia of the patient during surgery,
* maintenance of the life of the patient’s organism before, during and after surgery,
* protection of the patient’s body from aggressive action – surgical, biological, physical, infectious, chemical, etc.
Anesthesia is used during medical procedures and surgeries on any part of the body in order to protect the patient from injury.
Anesthesia includes a wide range of tasks:
* preliminary assessment of the patient’s condition in order to detect anesthesia risk;
* if necessary, intensive care for the patient in order to prepare him for the surgery;
* premedication or drug preparation for anesthesia;
* choice of anesthesia and drugs;
* the use of anesthesia in emergency and planned surgical operations and diagnostic studies;
* control of the patient’s condition during anesthesia, drug correction to prevent life-threatening metabolic and functional disorders;
* awakening the patient after general anesthesia;
* elimination of pain syndrome in certain diseases (oncology and other incurable diseases) and other conditions.
Types of anesthesia:
a. general anesthesia;
b. local anesthesia;
c. combined anesthesia.
General anesthesia is a controlled drug coma, multi-component anesthesia with temporary disconnection of consciousness, reflexes, pain sensitivity and relaxation of skeletal muscles.
General anesthesia is carried out by several methods:
- inhalation anesthesia;
- non-anional anesthesia;
- combined anesthesia.
Inhalation anesthesia or “mask anesthesia” is carried out using inhalation anesthetics that enter the body through the -respiratory tract – volatile liquids or gaseous narcotic drugs.
The method is practically not used in its pure form, but is a component of combined anesthesia. Modern substances for inhalation anesthesia are safe for the patient’s body, the main part is quickly excreted from the body through the lungs, and the remnants are utilized by the liver cells. Inhaled anesthesia is a well-controlled method of anesthesia.
Non-anional anesthesia is a type of general anesthesia in which anesthetic solutions are administered intravenously. The advantage of the method is the rapid onset of anesthesia in the form of a pleasant sleep for the patient, the absence of a stage of excitation. The relative lack of intravenous anesthesia in the short-term effect, so it is not used in its pure form with prolonged surgeries.
Combined anesthesia is a consistent application of different methods of anesthesia: an initial intravenous anesthesia is maintained by inhalation of nitrous oxide followed by a fractional intravenous injection of anesthetics.
Combined anesthesia is the use of methods of local and general anesthesia.
Local anesthesia is the suppression of pain sensitivity in a limited area of the body, which is achieved by blockade of peripheral nerves at different levels. Local anesthesia is most often used in outpatient practice for surgery, bandaging, and diagnostic procedures.
There are several ways of local anesthesia:
* Surface treatment of skin and mucous membranes;
* the introduction of anesthetics into body tissues (infiltration anesthesia);
* the introduction of an anesthetic near the nerve trunk (regional anesthesia).
The infiltration method is the impregnation of tissues with an anesthetic solution with its layer-by-layer introduction.
The regional method of anesthesia is divided into spinal, conductive, epidural, intraosseous and intravascular anesthesia. The effect of anesthesia with this method is achieved by turning off the sensivity in a certain nerve or nervous plexus with the patient’s preserved consciousness.
Modern trends in the development of anesthesiology:
Newly introduced drugs for anesthesia are characterized by short-term action, which is an important condition. Modern anesthetics of ultrashort action have this tendency. Modern drugs are excreted from the body well, have no toxicity, no side effects, shortened sleep time of the patient after their use.
In modern anesthesia, combined methods of anesthesia are commonly used, which are characterized by the rational use and combination of the positive properties of modern anesthetics, eliminating side effects, complications and guaranteeing safe anesthesia.
Pain Relievers: Main Classes and Mechanisms of Action:
Pain is a protective reaction of the body to damage. This is a universal mechanism, through which the body can survive in difficult conditions. Any factor that provokes pain can be dangerous to health, so the pain is most unpleasant. An ancient way of protection did not not always serve good, bringing suffering. Therefore, pain relievers were created.
Local anesthetics:
Local anesthetics prevent the pain impulse from endings of sensitive neurons. The chemical blocks sodium channels in axons (neuronal endings), and information can not be transmitted further. This effect can be used to treat cardiac arrhythmia. The side effect of local anesthetics is the blocking of impulse transmission in all excitable tissues, which can occur during systemic administration. This can lead to cardiac arrest and respiratory depression. Therefore, such drugs are never used systematically. They are used in surgery, dentistry, for local and conductive anesthesia.
Antipyretic and analgesic agents:
Paracetamol, Phenazole, Metamizol
Paracetamol is more commonly used as an antipyretic, but also effective in dental and headaches. The mechanism of action consists in the blocking of cyclooxygenase 1 and cyclooxygenase 2, mainly acting on the centers of pain and thermoregulation in the brain. It can not have anti-inflammatory effects in tissues, as it is neutralized by cellular enzymes.
Paracetamol is considered one of the safest drugs for children, but an overdose causes damage to the kidneys and liver. The daily dose can not exceed 4 grams. Therefore, in case of a severe overdose, you should take acetylcysteine, which is the antidote of paracetamol.
Metamizole is used as an antipyretic and antispasmodic, often prescribed for severe colic in infants.
Nonsteroidal anti-inflammatory drugs:
Ibuprofen, Diclofenac, Aspirin, Indomethacin, Meloxicam
The strongest analgesic effect is provided by Ibuprofen.
The principle of action is based on inhibition of the activity of cyclooxygenase 1 and 2 – enzymes, which stimulate the formation of prostaglandins, prostacyclines, thromboxanes. NSAIDs have anti-inflammatory, analgesic and antipyretic effects.
Nonsteroidal anti-inflammatory drugs have a pronounced anti-edematous effect in inflammation, analgesic and antipyretic, and act in peripheral tissues. Therefore, they are widely used in the treatment of adults and children. They are relatively safe and at recommended doses do not have a negative effect. This group includes drugs for the basic treatment of joint diseases, such as rheumatoid arthritis, which are used for a long time, often throughout life.
Nonsteroidal anti-inflammatory drugs decrease the ability to thrombogenesis.
The drugs are contraindicated in inflammation of the stomach and intestines, liver and kidney failure, asthma.
Spasmolytics:
Papaverin, Drotaverin
They reduce the contractile activity of muscle fibers, removing the spasm and the pain associated with it. Spasmolytics are widely used in pediatrics, for the treatment of diseases of the stomach and intestines, with diseases of the gallbladder, urinary tract. It can also be part of the preparation for medical diagnostic procedures.
A high degree of safety allows to use these drugs for a long time.
Opioid pain relievers:
Morphine, Fentanyl, Methadone, Codeine, Tramadol
These drugs have a central effect, directly affecting the perception of pain. These are drugs for anesthesia and drugs for first aid and shock treatment. They have the most powerful analgesic and sedative effect, but also cause dependence when used regularly. The strongest drugs cause dependence even after the first dose. They are used regularly in palliative medicine.
Author: Sushanta Kumar Ghosh, Physiotherapy Specialist, DIU Medical Center
