<unk>  is a state of controlled, temporary loss of sensation or awareness that is induced for medical purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), amnesia (loss of memory), and unconsciousness. A person under the effects of<unk> thetic drugs is referred to as being<unk> thetized.<unk>  enables the painless performance of procedures that would otherwise cause severe or intolerable pain to a person who is not<unk> thetized, or would otherwise be technically unfeasible. Three broad categories of<unk>  exist: * General<unk>  suppresses central nervous system activity and results in unconsciousness and total lack of sensation, using either injected or inhaled drugs. * Sedation suppresses the central nervous system to a lesser degree, inhibiting both anxiety and creation of long-term memories without resulting in unconsciousness. * Regional and local<unk> , which blocks transmission of nerve impulses from a specific part of the body. Depending on the situation, this may be used either on its own (in which case the person remains fully conscious), or in combination with general<unk>  or sedation. Drugs can be targeted at peripheral nerves to<unk> thetize an isolated part of the body only, such as numbing a tooth for dental work or using a nerve block to inhibit sensation in an entire limb. Alternatively, epidural and spinal<unk>  can be performed in the region of the central nervous system itself, suppressing all incoming sensation from nerves supplying the area of the block. In preparing for a medical procedure, the clinician chooses one or more drugs to achieve the types and degree of<unk>  characteristics appropriate for the type of procedure and the particular person. The types of drugs used include general<unk> thetics, local<unk> thetics, hypnotics, dissociatives, sedatives, adjuncts, neuromuscular-blocking drugs, narcotics, and analgesics. The risks of complications during or after<unk>  are often difficult to separate from those of the procedure for which<unk>  is being given, but in the main they are related to three factors: the health of the person, the complexity (and stress) of the procedure itself, and the anaesthetic technique. Of these factors, the health of the person has the greatest impact. Major perioperative risks can include death, heart attack, and pulmonary embolism whereas minor risks can include postoperative nausea and vomiting and hospital readmission. Some conditions, like local<unk> thetic toxicity, airway trauma or malignant hyperthermia, can be more directly attributed to specific<unk> thetic drugs and techniques.
Anesthesia
Sedoanalgesia
Neuraxial blockade
Spinal anaesthesia
Sedation
Decompensation
Local anesthesia
Neurosurgical anesthesia