Anesthesia Recovery Period: The period of emergence from general anesthesia, where different elements of consciousness return at different rates.Anesthesia: A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures.Anesthesia, General: Procedure in which patients are induced into an unconscious state through use of various medications so that they do not feel pain during surgery.Anesthesia, Local: A blocking of nerve conduction to a specific area by an injection of an anesthetic agent.Anesthesia, Epidural: Procedure in which an anesthetic is injected into the epidural space.Anesthesia, Spinal: Procedure in which an anesthetic is injected directly into the spinal cord.Anesthesia, Inhalation: Anesthesia caused by the breathing of anesthetic gases or vapors or by insufflating anesthetic gases or vapors into the respiratory tract.Anesthesia, Conduction: Injection of an anesthetic into the nerves to inhibit nerve transmission in a specific part of the body.Anesthesia, Intravenous: Process of administering an anesthetic through injection directly into the bloodstream.Recovery of Function: A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.Anesthesia, Obstetrical: A variety of anesthetic methods such as EPIDURAL ANESTHESIA used to control the pain of childbirth.Anesthesia, Dental: A range of methods used to reduce pain and anxiety during dental procedures.Anesthetics, Intravenous: Ultrashort-acting anesthetics that are used for induction. Loss of consciousness is rapid and induction is pleasant, but there is no muscle relaxation and reflexes frequently are not reduced adequately. Repeated administration results in accumulation and prolongs the recovery time. Since these agents have little if any analgesic activity, they are seldom used alone except in brief minor procedures. (From AMA Drug Evaluations Annual, 1994, p174)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Anesthetics, Inhalation: Gases or volatile liquids that vary in the rate at which they induce anesthesia; potency; the degree of circulation, respiratory, or neuromuscular depression they produce; and analgesic effects. Inhalation anesthetics have advantages over intravenous agents in that the depth of anesthesia can be changed rapidly by altering the inhaled concentration. Because of their rapid elimination, any postoperative respiratory depression is of relatively short duration. (From AMA Drug Evaluations Annual, 1994, p173)Propofol: An intravenous anesthetic agent which has the advantage of a very rapid onset after infusion or bolus injection plus a very short recovery period of a couple of minutes. (From Smith and Reynard, Textbook of Pharmacology, 1992, 1st ed, p206). Propofol has been used as ANTICONVULSANTS and ANTIEMETICS.Adjuvants, Anesthesia: Agents that are administered in association with anesthetics to increase effectiveness, improve delivery, or decrease required dosage.Isoflurane: A stable, non-explosive inhalation anesthetic, relatively free from significant side effects.Methyl Ethers: A group of compounds that contain the general formula R-OCH3.Anesthetics, Local: Drugs that block nerve conduction when applied locally to nerve tissue in appropriate concentrations. They act on any part of the nervous system and on every type of nerve fiber. In contact with a nerve trunk, these anesthetics can cause both sensory and motor paralysis in the innervated area. Their action is completely reversible. (From Gilman AG, et. al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed) Nearly all local anesthetics act by reducing the tendency of voltage-dependent sodium channels to activate.Anesthesiology: A specialty concerned with the study of anesthetics and anesthesia.Anesthetics, Combined: The use of two or more chemicals simultaneously or sequentially to induce anesthesia. The drugs need not be in the same dosage form.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Nitrous Oxide: Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.Monitoring, Intraoperative: The constant checking on the state or condition of a patient during the course of a surgical operation (e.g., checking of vital signs).Anesthetics: Agents that are capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act to induce general ANESTHESIA, in which an unconscious state is achieved, or may act locally to induce numbness or lack of sensation at a targeted site.Halothane: A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)Methotrimeprazine: A phenothiazine with pharmacological activity similar to that of both CHLORPROMAZINE and PROMETHAZINE. It has the histamine-antagonist properties of the antihistamines together with CENTRAL NERVOUS SYSTEM effects resembling those of chlorpromazine. (From Martindale, The Extra Pharmacopoeia, 30th ed, p604)Lidocaine: A local anesthetic and cardiac depressant used as an antiarrhythmia agent. Its actions are more intense and its effects more prolonged than those of PROCAINE but its duration of action is shorter than that of BUPIVACAINE or PRILOCAINE.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Exercise: Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.Fentanyl: A potent narcotic analgesic, abuse of which leads to habituation or addiction. It is primarily a mu-opioid agonist. Fentanyl is also used as an adjunct to general anesthetics, and as an anesthetic for induction and maintenance. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1078)Anesthesia, Closed-Circuit: Inhalation anesthesia where the gases exhaled by the patient are rebreathed as some carbon dioxide is simultaneously removed and anesthetic gas and oxygen are added so that no anesthetic escapes into the room. Closed-circuit anesthesia is used especially with explosive anesthetics to prevent fires where electrical sparking from instruments is possible.Anesthetics, General: Agents that induce various degrees of analgesia; depression of consciousness, circulation, and respiration; relaxation of skeletal muscle; reduction of reflex activity; and amnesia. There are two types of general anesthetics, inhalation and intravenous. With either type, the arterial concentration of drug required to induce anesthesia varies with the condition of the patient, the desired depth of anesthesia, and the concomitant use of other drugs. (From AMA Drug Evaluations Annual, 1994, p.173)Flurothyl: A convulsant primarily used in experimental animals. It was formerly used to induce convulsions as a alternative to electroshock therapy.Bupivacaine: A widely used local anesthetic agent.Ambulatory Surgical Procedures: Surgery performed on an outpatient basis. It may be hospital-based or performed in an office or surgicenter.Physical Exertion: Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.Preanesthetic Medication: Drugs administered before an anesthetic to decrease a patient's anxiety and control the effects of that anesthetic.Ketamine: A cyclohexanone derivative used for induction of anesthesia. Its mechanism of action is not well understood, but ketamine can block NMDA receptors (RECEPTORS, N-METHYL-D-ASPARTATE) and may interact with sigma receptors.Nerve Block: Interruption of NEURAL CONDUCTION in peripheral nerves or nerve trunks by the injection of a local anesthetic agent (e.g., LIDOCAINE; PHENOL; BOTULINUM TOXINS) to manage or treat pain.Thiopental: A barbiturate that is administered intravenously for the induction of general anesthesia or for the production of complete anesthesia of short duration.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Oxygen Consumption: The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.Anesthesia, Caudal: Epidural anesthesia administered via the sacral canal.Body Temperature: The measure of the level of heat of a human or animal.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Electroencephalography: Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.Lactic Acid: A normal intermediate in the fermentation (oxidation, metabolism) of sugar. The concentrated form is used internally to prevent gastrointestinal fermentation. (From Stedman, 26th ed)Skin Temperature: The TEMPERATURE at the outer surface of the body.Pentobarbital: A short-acting barbiturate that is effective as a sedative and hypnotic (but not as an anti-anxiety) agent and is usually given orally. It is prescribed more frequently for sleep induction than for sedation but, like similar agents, may lose its effectiveness by the second week of continued administration. (From AMA Drug Evaluations Annual, 1994, p236)Anesthetics, Dissociative: Intravenous anesthetics that induce a state of sedation, immobility, amnesia, and marked analgesia. Subjects may experience a strong feeling of dissociation from the environment. The condition produced is similar to NEUROLEPTANALGESIA, but is brought about by the administration of a single drug. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed)Phosphocreatine: An endogenous substance found mainly in skeletal muscle of vertebrates. It has been tried in the treatment of cardiac disorders and has been added to cardioplegic solutions. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1996)Enflurane: An extremely stable inhalation anesthetic that allows rapid adjustments of anesthesia depth with little change in pulse or respiratory rate.Xylazine: An adrenergic alpha-2 agonist used as a sedative, analgesic and centrally acting muscle relaxant in VETERINARY MEDICINE.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Intubation, Intratracheal: A procedure involving placement of a tube into the trachea through the mouth or nose in order to provide a patient with oxygen and anesthesia.Conscious Sedation: A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway. (From: American Society of Anesthesiologists Practice Guidelines)Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Anesthesia Department, Hospital: Hospital department responsible for the administration of functions and activities pertaining to the delivery of anesthetics.Pain, Postoperative: Pain during the period after surgery.Intraoperative Complications: Complications that affect patients during surgery. They may or may not be associated with the disease for which the surgery is done, or within the same surgical procedure.Anesthesia, IntratrachealRest: Freedom from activity.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Organ Size: The measurement of an organ in volume, mass, or heaviness.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Postoperative Complications: Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.Anoxia: Relatively complete absence of oxygen in one or more tissues.Cold Temperature: An absence of warmth or heat or a temperature notably below an accustomed norm.Body Temperature Regulation: The processes of heating and cooling that an organism uses to control its temperature.Lactates: Salts or esters of LACTIC ACID containing the general formula CH3CHOHCOOR.Respiration: The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Energy Metabolism: The chemical reactions involved in the production and utilization of various forms of energy in cells.Hemarthrosis: Bleeding into the joints. It may arise from trauma or spontaneously in patients with hemophilia.Bicycling: The use of a bicycle for transportation or recreation. It does not include the use of a bicycle in studying the body's response to physical exertion (BICYCLE ERGOMETRY TEST see EXERCISE TEST).Exercise Test: Controlled physical activity which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used.No-Observed-Adverse-Effect Level: The highest dosage administered that does not produce toxic effects.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Intraoperative Period: The period during a surgical operation.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Muscle Fatigue: A state arrived at through prolonged and strong contraction of a muscle. Studies in athletes during prolonged submaximal exercise have shown that muscle fatigue increases in almost direct proportion to the rate of muscle glycogen depletion. Muscle fatigue in short-term maximal exercise is associated with oxygen lack and an increased level of blood and muscle lactic acid, and an accompanying increase in hydrogen-ion concentration in the exercised muscle.Regional Blood Flow: The flow of BLOOD through or around an organ or region of the body.