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YourArt.com >> Encyclopedia >> volatile   (Site not responding. Last check: 2007-10-06) Volatility is a measure of the risk in a financial instrument Volatile acidity is a term used in winemaking to indicate an unacceptably high level of acid or vinegar Volatiles are the volatile compounds of magma (mostly water vapor) that play an important part in the appearance and strength of volcanoes www.yourart.com /research/encyclopedia.cgi?subject=/volatile   (175 words)

General anaesthetic - Wikipedia, the free encyclopedia Inhalational anaesthetic substances are either volatile liquids or gases and are usually delivered using an anaesthesia machine. Injection anaesthetics are used for induction and maintenance of a state of unconsciousness. It is now known that general anaesthetics act on the central nervous system by modifying the electrical activity of neurons at a molecular level by modifying the function of ion channels. en.wikipedia.org /wiki/General_anaesthetic   (415 words)

Volatile anaesthetics in paediatric anaesthesia The uptake and distribution of volatile anaesthetics differ between infants, children and adults, depending to a considerable extent on age-related factors such as solubility, respiration, and circulation. In children, the solubility of volatile anaesthetics is inversely proportional to age [2], and the tissue/blood coefficient is about 50% lower in infants than in adults [3], presumably because of the greater water content and the smaller protein and lipid concentrations. Eger reported that the pharmacokinetics of a volatile anaesthetic during the first 15–20 min of anaesthesia depend on the characteristics of the vessel-rich group and during the following 20–200 min on uptake by the muscle group [1]. www.euroanesthesia.org /education/rc_vienna/10rc4.HTM   (2338 words)

ebme.co.uk - Anaesthesia Inhalation Agents and reactions with absorbents Previous studies, in which volatile anaesthetics were exposed to small amounts of dry soda lime, generally controlled at or close to ambient temperatures, have demonstrated a large carbon monoxide (CO) production from desflurane and enflurane, less from isoflurane, and none from halothane and sevoflurane. Consequences of volatile anaesthetic degradation by carbon dioxide absorbents that contain strong base include formation of compound A from sevoflurane, formation of carbon monoxide (CO) and CO toxicity from desflurane, enflurane and isoflurane, delayed inhalation induction, and increased anaesthetic costs. Anaesthetic concentrations in the fresh (preabsorber), inspired (postabsorber), and end-tidal gas were measured, as were inspired CO and compound A concentrations and blood oxyhemoglobin and COHb concentrations. www.ebme.co.uk /arts/anaes2/part2.htm   (1424 words)

OV - Hazards and risk factors - Anaesthetics The halogenated anaesthetic, initially in the liquid state, is vaporized in a thermocompensated device, where it mingles with a gaseous current which usually comes from a centralized system and is made up of 40% Oxygen and 60% nitrous oxide. The concentration of the halogenated anaesthetic in the mixture may reach 4-5% depending on which substance is used and on the type of surgical operation that is going to be performed. This biotransformation is important not only because it ends the anaesthetic's action but also because some of the metabolites that originate during the reaction may be held responsible for some of the anaesthetic's acknowledged toxic effects. www.medlav.unimo.it /ov/fdrEanes.htm   (1152 words)

Anaesthetics, volatile (IARC Summary & Evaluation, Supplement7, 1987) In one of the studies [ref: 4], a higher rate of cancer was reported among dental assistants with relatively heavy exposure to anaesthetics, reflecting a higher prevalence of cervical and uterine cancer in women with heavier exposure to anaesthetics than in those with a lighter exposure (significant only for cancer of the cervix). It is not possible to consider exposure to different volatile anaesthetics separately, although the study of US anaesthesiologists working during 1930-1946 [ref: 10] concerned the period before fluorinated anaesthetic agents were introduced in the 1950s. Anaesthetics, volatile are not classifiable as to their carcinogenicity to humans (Group 3). www.inchem.org /documents/iarc/suppl7/anaesthetics_vol.html   (981 words)

JPMA :::   (Site not responding. Last check: 2007-10-06) On recovery from anaesthesia, nearly all factors governing the rate of increase in the alveolar anaesthetic concentration during induction are reversed and are equally important in determining the rate of elimination of adjunct inhalational agent and thus recovery. Solubility of the anaesthetic agent is one of the most important factors in determining the rate of induction and recovery of volatile anaesthetic. The duration of inhalational anaesthetic administration is one of the determinants of the elimination of alveolar anaesthetic. jpma.org.pk /jpma/6june06/fulltex4.htm   (1915 words)

Effects of volatile anaesthetics on the membrane potential and ion channels of cultured neocortical astrocytes. Effects of volatile anaesthetics on the membrane potential and ion channels of cultured neocortical astrocytes. In less than 10% of the membrane patches, volatile anaesthetics either increased or decreased the mean open time of K+-selective ion channels without altering single-channel conductances. In summary, it seems unlikely that the actions of volatile anaesthetics described here are involved in the state of general anaesthesia. www.kyb.tuebingen.mpg.de /de/publication.html?publ=356   (342 words)

[No title]   (Site not responding. Last check: 2007-10-06) In the early postoperative period (0—2 h), the leading risk factor for vomiting was the use of volatile anaesthetics, with similar odds ratios (OR (95% CI)) being found for isoflurane (19.8 (7.7—51.2)), enflurane (16.1 (6.2—41.8)) and sevoflurane (14.5 (5.6—37.4)). According to the presented data, the use of volatile anaesthetics was the strongest risk factor for the development of PV. The pro-emetogenic effect of volatile anaesthetics must therefore be considered to be a main cause of PONV in the early postoperative period. www.aneo.com /sidor/news.asp?newsid=54   (363 words)

Altweb: ATLA This system was used to evaluate the biotransformation and toxicity of different volatile anaesthetics (halothane, enflurane, isoflurane and sevoflurane), and compare their effects to those of new anaesthetics (desflurane). Volatile anaesthetics were delivered by volatilization after pre-incubation for 1 hour to produce a constant concentration in the medium. Halothane is the anaesthetic which is metabolized furthest and has the most toxic effect, while desflurane is the least metabolised anaesthetic and has the least toxicity. altweb.jhsph.edu /publications/journals/atla/18/atla18s.htm   (324 words)

Halothane, isoflurane and sevoflurane inhibit NADH:ubiquinone oxidoreductase (complex I) of cardiac mitochondria -- ... Volatile anaesthetics increase NADH fluorescence of ventricular myocytes The ability of volatile anaesthetics to reduce the rate of NADH oxidation by submitochondrial particles suggested that NADH:ubiquinone oxidoreductase is inhibited. The estimated concentrations of the anaesthetics corresponding to 2 MAC are indicated by arrows. jp.physoc.org /cgi/content/full/544/3/687   (4513 words)

How do volatile anaesthetics work The AD is the anaesthetic dose required to prevent response to surgical stimulus in 95% of subjects. Blood/gas coefficient is the ratio of the amount of anaesthetic in blood and gas when the two phases are of equal volume and pressure and in equilibrium at 37oC. The action of anaesthetic agents is suggested to be related to the lipid solubility (Meyer-Overton theory). www.creaghbrown.co.uk /anae/volatiles.htm   (922 words)

Inhalation anaesthesia according to the B The application of volatile anaesthetics and anaesthetic gases in general follows  quite different rules: The desired gas and anaesthetic concentration has to be established not only in the lung and tissues of the patient, but also in all gas containing parts of the anaesthetic machine. Even if the volatile anaesthetics could be delivered indipendently from the fresh gas flow, the use of high flow would be the only wash-in technique when intending to use precisely composed gas mixtures consisting either of nitrogen or of nitrous oxide with oxygen. Rapid increase of the anaesthetic concentration can be realized by injecting a small additive bolus of 0.5 mL into the system to rapidly enhance transfer, rapid decrease of the anaesthetic, however, only can be gained by switching to high fresh gas flow, between 2.0 to 4.0 L/min to enhance elimination. www.alfanaes.freeserve.co.uk /Session043-2.htm   (857 words)

Data Sheet ISOFLURANE is a halogenated volatile anaesthetic which induces and maintains general anaesthesia by depression of the central nervous system and resultant loss of consciousness. The pharmacokinetics of ISOFLURANE are those of inhaled gaseous or volatile anaesthetics for which blood concentrations are related to alveolar concentrations through the established partition coefficients, and the distribution to tissues is also determined by solubility coefficients which are relatively constant under a wide variety of circumstances. As with all halogenated anaesthetics, repeat anaesthesia within a short period of time should be approached with caution since the risk of hepatotoxicity is not fully understood. www.medsafe.govt.nz /Profs/datasheet/i/Isofluraneliqgas.htm   (1830 words)

Types of Anaesthetic Agents Anaesthetic agents should produce a loss of sensation with a minimum of side effects and they should have a calming effect on the animal during the recovery phase. For general anaesthesia inhalant anaesthetics are highly preferred as the anaesthesia is much easier to control and the agent quickly cleared from the body. Injectable anaesthetics are easily administered requiring little more than a needle and syringe, but once they have been injected it is very difficult to control their effects. www.ccac.ca /en/CCAC_Programs/ETCC/Module11/05.html   (598 words)

The Hindu Business Line : A volatile market should be left to professionals   (Site not responding. Last check: 2007-10-06) Volatile means "easily evaporated at normal temperature", and when that happens to your gains, a mini-tragedy is at hand. Volatile anaesthetics are a class of anaesthetics which vapourise easily. Volatile acidity is an unacceptably high level of acid or vinegar, in winemaking." As a computing term, volatile is use for memory and variables. www.thehindubusinessline.com /2005/09/23/stories/2005092300961100.htm   (995 words)

Data Sheet Desflurane is one of a family of halogenated methylethylethers which is administered by inhalation producing a dose-related, reversible loss of consciousness and of pain sensations, suppression of voluntary motor activity, modification of autonomic reflexes and sedation of respiration and the cardiovascular system. SUPRANE should not be used as the sole agent for anaesthetic induction in patients at risk of coronary artery disease or in patients where increases in heart rate or blood pressure are undesirable. The symptoms of overdosage of SUPRANE are anticipated to be similar to those of other volatile agents with a deepening of anaesthesia, cardiac and/or respiratory depression in spontaneous breathing patients, and hypotension in ventilated patients in whom hypercarbia and hypoxia may occur only at a late stage. www.medsafe.govt.nz /Profs/datasheet/s/Supraneliq.htm   (2215 words)

Animal Factors in Anaesthesia The volatile anaesthetics are more consistent in their application between species. The mean alveolar concentration of the anaesthetic agent required for anaesthesia is similar among species and this is controlled by the concentration of the agent in the inspired gases. For those anaesthetics that are extensively metabolized as part of the excretory process, a second anaesthetic may result in more rapid metabolism of the drug than the first, with a shorter period of anaesthesia. www.ccac.ca /en/CCAC_Programs/ETCC/Module11/06.html   (513 words)

E-Doc INTERACTIVE - General Anaesthesia: Induction and Maintenance   (Site not responding. Last check: 2007-10-06) Inhalational anaesthetics are particularly useful in the induction of paediatric patients unwilling to accept an intravenous line or in patients of any age group with potentially difficult airways. The relative solubility of an anaesthetic in blood and air is expressed as the blood/gas partition coefficient (Table 1). Patients exposed to multiple halothane anaesthetics at short intervals, middle-aged obese women, and persons with a familial predisposition to halothane toxicity, or a personal history of toxicity, are considered to be at increased risk for halothane hepatitis, although this condition is extremely rare (1 in 35000 cases). www.edoc.co.za /modules.php?name=News&file=print&sid=55   (4140 words)

Post-operative nausea and vomiting (PONV) after general anaesthesia with volatile anaesthetics   (Site not responding. Last check: 2007-10-06) There is now strong evidence that volatile anaesthetics are emetogenic and that there are no meaningful differences between halothane, enflurane, isoflurane, sevoflurane, and desflurane in this respect. Of course, the most logical approach for prevention would be the omission of volatile anaesthetics and nitrous oxide using a total intravenous anaesthesia with propofol. However, since volatile anaesthetics are probably not the most important risk factors, it might be even better--if appropriate--to avoid general anaesthesia by using a regional, opioid-free anaesthesia if PONV is a serious problem. www.anaesthetized.com /ponv.html   (400 words)

Influence of volatile anaesthetics on hypercapnoeic ventilatory responses in mice with blunted respiratory ... Influence of volatile anaesthetics on hypercapnoeic ventilatory responses in mice with blunted respiratory drive{dagger} -- Groeben et al. Fig 4 Changes in respiratory rate (RR) and pressure amplitude (Amp), as an expression of tidal volume, to 8% carbon dioxide in 11 male C3H/HeJ mice measured at baseline and during isoflurane, sevoflurane or desflurane anaesthesia at 0.5, 1.0 and 1.5 MAC and at the end of recovery. In recovery, the response to carbon dioxide was significantly suppressed for all three anaesthetics and did not differ from the blockade during deep anaesthesia at 1.5 MAC (P<0.0001). bja.oxfordjournals.org /cgi/content/full/92/5/697   (3124 words)

Effects of anaesthesia and surgery on the solubility of volatile anaesthetics in blood -- Lerman et al. 34 (1): 14 -- ... Effects of anaesthesia and surgery on the solubility of volatile anaesthetics in blood -- Lerman et al. Effects of anaesthesia and surgery on the solubility of volatile anaesthetics in blood volatile anaesthetics in blood, we measured the blood/gas partition www.cja-jca.org /cgi/content/abstract/34/1/14   (184 words)

Volatile anaesthetics may be the main cause of early but not delayed postoperative vomiting: a randomized controlled ... Volatile anaesthetics may be the main cause of early but not delayed postoperative vomiting: a randomized controlled trial of factorial design -- Apfel et al. Volatile anaesthetics may be the main cause of early but not delayed postoperative vomiting: a randomized controlled trial of factorial design and volatile anaesthesia is caused mainly by the emetogenic bja.oxfordjournals.org /cgi/content/full/88/5/659   (4798 words)

GNS | Abstracts 3/95   (Site not responding. Last check: 2007-10-06) Volatile Anästhetika entfalten ihre Wirkung durch Bindung an lipophile Bereiche von Proteinen, nicht durch die Lösung in den Lipiden der Zellmembran. Volatile anaesthetics operate by binding to lipophilic regions of proteins, not by dissolving in the lipids in the cell membrane. Studies of anaesthetized patients have shown that with certain anaesthetics the state of anaesthesia (loss of consciousness) can be achieved even though cortical activity (evoked potentials of intermediate latency) is still present. nwg.glia.mdc-berlin.de /nf-abstracts.php/en/ie-default/abstract395   (1083 words)

2004 Finalist - Health Innovation Awards An improved system for administering anaesthetics is saving money and may mean more rapid recovery for patients at Christchurch Hospital. Too little anaesthetic risks awareness or undue stress for the body; too much anaesthetic can delay recovery and may have adverse long-term effects. Brain levels are calculated and future anaesthetic levels in the blood and the brain are estimated and displayed. www.healthinnovationawards.co.nz /06profilefinal17.html   (260 words)

Effects of volatile anaesthetics on spontaneous action potential firing of cerebellar Purkinje cells in vitro do not ... Effects of volatile anaesthetics on spontaneous action potential firing of cerebellar Purkinje cells in vitro do not follow the Meyer-Overton rule. We have investigated in rat brain slices the effects of the volatile anaesthetics enflurane, isoflurane and halothane on spontaneous discharge patterns and mean firing rates of cerebellar Purkinje cells. In the absence of these anaesthetics, Purkinje cells fired bursts of action potentials separated by quiescent periods lasting less than 2 s. www.kyb.tuebingen.mpg.de /publication.html?publ=352   (173 words)

The Biochemical Basis of Coma   (Site not responding. Last check: 2007-10-06) General anaesthetics have been shown to increase rates of desensitization at the nicotinic ACh receptor (Raines et al, 1995; Scheller et al, 1997; Liu et al, 1995), and to act as antagonists (Andoh et al, 1997; Franks and Lieb, 1997). In conclusion, it appears that one important role for volatile anaesthetics is to potentiate GABA-mediated inhibition at the receptor level and to inhibit NMDAr-mediated conduction at the level of the post-synaptic signaling cascade (Zou et al, 1996). As the molecular targets of general anaesthetics (in either the classical or the receptor-based theories) are widely distributed in the brain, it seems likely that anaesthesia would affect all brain systems in a rather unselective manner. psycprints.ecs.soton.ac.uk /archive/00000661/01/psyc.99.10.026.coma-biochemistry.1.smythies.xml   (6520 words)

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