Anesthesia is etymologically a Greek word with roots an meaning without and aisthesis meaning sensation. The word anesthesia was coined by Oliver Wendell Holmes Sr. in 1846. It traditionally meant blocking any sensation. It implies the state where the body is put to sleep and any feeling is temporarily done away with. The feeling of pain is blocked and there is a loss of responsiveness, muscle reflexes and decreased stress response. Anesthesia is like an induced state of coma or it may be called a reversible lack of awareness. The lack of awareness may be total, like general anesthetic, or partial numbness of a part of a body, like spinal anesthetic. There are various kinds of anesthetics like local, regional, general and dissociative anesthesia. Regional anesthesia includes spinal and epidural anesthesia.
General anesthetic is a drug that brings reversible lost of consciousness. At the end, the patient would wake up with some pain, nausea and drowsiness and would be injected antibiotics or painkillers by drip. Drugs are given to induce anesthesia in the form of inhalational anesthetics like gases or vapors or intravenous anesthetics by injections. The anesthetic to be inhaled has substances which are volatile, liquids or gases and are delivered by a machine.
The history of general anesthetic usage can be traced back to 1842 when Crawford Long performed the first painless surgery administering diethyl ether to the patient. General anesthetics are believed to exert the effects of analgesia, amnesia and immobility. The elimination of general anesthesia of the volatile form in the terminal phase is via lungs.
Topical anesthetic is another kind of local anesthetic that is used to numb the surface of a body part like the skin, or the front of the eyeball, the inside of the nose, ear, throat, anus, genital area etc. Topical anesthetics are also available in the forms of creams, ointments, sprays, aerosols, lotions and jellies. The usage of such anesthetics is to relieve pain and itching by sunburns, insect bites or stings, cuts and scratches, poison ivy and poison oak. There has been liberal usage of this type in ophthalmology and optometry and even in dentistry. But when used excessively, it can cause severe and irreversible damage.
Spinal anesthesia is a form of regional anesthesia which includes an injection of local anesthesia. The onset of analgesia is approx 5 minutes and it must be injected below the lumbar region of the spine to avoid piercing the spinal cord. With successful spinal anesthetic, the surgery can be performed with the patient wide awake.
The risks or complications in administering anesthesia may be spinal shock, cardiac arrest, hypothermia, broken needle, infection; bleeding or post spinal head ache.