Articles: enflurane-analysis.
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[The effect of anesthetic method on enflurane air pollution in non-air conditioned operating rooms].
Pollution of work areas by volatile anaesthetics and nitrous oxide occurs during general anaesthesia. Short anaesthesia procedures are often carried out in operating theatres that are not equipped with air-conditioning systems. Methods of lowering exposure during short procedures, where mask anaesthesia is the usual procedure, are double masks and the laryngeal mask. The aim of our investigation was to determine the possibility of lowering the pollution of the environment to below national and international thresholds in a non-air-conditioned work area and to find out which method of anaesthesia is the most effective in environmental protection, i.e. which has the lowest leakage rate. ⋯ In unventilated work areas, it was not possible to lower the exposure of the personnel by changing the method of anaesthesia. The application of procedures like double or laryngeal masks does not avoid the need for installation of air-conditioning systems in all work areas were anaesthesia is performed.
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Infrared analysis can determine exhaled concentrations of the three volatile anesthetics in common use because each absorbs infrared light. Many infrared analyzers use a single source of infrared light at a wavelength of 3.3 microns for measurements of all three agents but cannot identify which agent is in use. Organic gases such as ethanol also absorb infrared light. ⋯ Conversely, with the monitor set for isoflurane, 1 vol% halothane mixed with isoflurane resulted in readings 0.2 vol% too high. In a model simulating alveolar gas, ethanol vapor corresponding to blood alcohol levels of 0.10, 0.30, and 0.50% had a slight but not clinically significant effect on readings for enflurane and isoflurane but increased readings with the halothane setting 3.5 times the corresponding level of blood alcohol. Clinicians can test for an interfering gas such as ethanol before induction by checking the reading in the halothane setting during preoxygenation.
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J. Am. Vet. Med. Assoc. · May 1983
Minimal alveolar concentrations for halothane, enflurane, and isoflurane in the cat.
The minimal alveolar concentrations for halothane, enflurane, and isoflurane in the domestic cat were found to be 1.19 +/- 0.05 (SEM)%, 2.37 +/- 0.06%, and 1.61 +/- 0.04%, respectively. During the potency studies, it was observed that enflurane and isoflurane resulted in shorter wake-up times, compared with halothane. However, enflurane and isoflurane produced electroencephalographic (EEG) and clinical signs of CNS irritability (EEG spiking, myoclonus) in normocapnic or mildly hypocapnic cats. In addition, enflurane and isoflurane caused greater airway irritability (coughing, salivation) than did halothane.
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Anesthesia and analgesia · Jan 1979
Nitrous oxide increases enflurane concentrations delivered by Ethrane vaporizers.
Delivered enflurane concentrations from two calibrated Ethrane vaporizers were determined with total gas flows of 3,5 and 8 L/min. Regardless of total gas flow the presence of 60% nitrous oxide increased enflurane concentrations by 20 to 40% above those concentrations present when only oxygen was flowing through the vaporizer. This nitrous oxide effect was present at all dial settings studied except the lowest engraved (0.25) concentration. ⋯ A similar mechanism has been proposed to explain increased halothane concentrations delivered by Fluotec Mark 2 vaporizers in the presence of nitrous oxide. Clinically, central system stimulation and anesthetic overdose may occur from increased enflurane concentrations delivered when nitrous oxide is added to the gases flowing through the Ethrane vaporizer. The ability to deliver low enflurane concentrations is limited since the measured concentration at the lowest dial setting was nearly 0.4%.