151
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Maiorino RM, Gandolfi AJ, Sipes IG. Gas-chromatographic method for the halothane metabolites, trifluoroacetic acid and bromide, in biological fluids. J Anal Toxicol 1980; 4:250-4. [PMID: 7442137 DOI: 10.1093/jat/4.5.250] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A simple and rapid method is presented for the quantitative determination of bromide and trifluoroacetic acid in urine, plasma or serum. The biological fluid is treated with dimethyl sulfate in an acidic medium, resulting in the formation of the methyl ester of trifluoroacetic acid and methyl bromide. The volatile derivatives are then isolated from the samples via a head-space technique, separated and resolved by gas chromatography, and detected by flame ionization. Detection of the two metabolites is linear within the sample concentrations studied. The method is reproducible and applicable to the determination of the two metabolites in biological fluids in the 0.1-10 mM concentration range. The method is comparable to previous techniques but is less time consuming, and both bromide and trifluoroacetic acid can be determined simultaneously. Preliminary pharmacological studies of urine and blood metabolite levels in rats and human patients anesthetized with halothane agree with existing results determined by other methods. In addition, the results indicate that bromide concentrations in human blood remain elevated for a much longer period of time than those in rat blood.
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152
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Campbell D, Davis PD, Halliday MM, MacDonald I. Comparison of personal pollution monitoring techniques for use in the operating room. Br J Anaesth 1980; 52:885-92. [PMID: 7437227 DOI: 10.1093/bja/52.9.885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Three personal pollution monitors (adsorption tubes, diffusion dosimeters and evacuated bottles) have been tested, in routinely used operating rooms and under controlled laboratory conditions, for their accuracy and reproducibility relative to one another and to measurements by infra-red spectroscopy. All the techniques provide time-weighted average measurements of pollutant concentrations. Tubes and dosimeters measure halothane with greater accuracy than that required by N.I.O.S.H. regulations, but neither technique can measure inorganic pollutants such as nitrous oxide. The prototype evacuated bottles tested are unsatisfactory at their present stage of development for the measurement of both halothane and nitrous oxide concentrations. We believe that, at the present time, surveys of operating room pollution can best be carried out using adsorption tubes of diffusion dosimeters for personal halothane concentrations and a portable infra-red spectrometer for measurement of background nitrous oxide concentrations.
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153
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Blanck TJ, Thompson M. Measurement of halothane by ultraviolet spectroscopy. Anesth Analg 1980; 59:481-3. [PMID: 7190783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Halothane absorbs strongly in the ultraviolet region of the spectrum. This property has been employed to measure the concentration of halothane in samples in which the effect of halothane on enzyme kinetics was being studied. Halothane can be completely extracted into heptane, displays a concentration-dependent linear increase in absorbance over a broad concentration range, and has a molar extinction coefficient of 447 M cm-1 at 208 nm. The procedure described for the measurement of halothane will enable other investigators who do not have a gas chromatograph to measure the concentration of halothane.
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154
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Mazur JF, Podolak GE, Esposito GG, Rinehart DS, Glenn RE. Evaluation of a passive dosimeter for collection of 2-bromo-2-chloro-1, 1, 1-trifluoroethane and 2-chloro-1, 1, 2-trifluoroethyl difluoromethyl ether in hospital operating rooms. AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL 1980; 41:317-21. [PMID: 7415956 DOI: 10.1080/15298668091424816] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Operationally, passive dosimeters are ideally suited for monitoring organic vapors in hospital operating rooms as they are compact, lightweight and do not require tubing or pumps. In this study, a recently developed passive diffusion sampler was used to collect 2-bromo-2-chloro-1, 1, 1-trifluoroethane (Halothane) and 2-chloro-1, 1, 2-trifluoroethyl difluoromethyl ether (Enflurane) in standard air mixtures over the range of 0.2-10 ppm. Additionally, exposures to known concentrations were conducted for various lengths of time. A side-by-side comparison of charcoal tubes (CT) and passive dosimeter collection characteristics were made on known air mixtures and samples collected in operating rooms. The material adsorbed on charcoal from dosimeters and CT was desorbed with carbon disulfide and quantified using gas-liquid chromatography. The overall efficiency of the dosimeters along with quality control data are presented.
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155
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Valenta HL. Real time estimate of end-expired halothane concentration for surgical anesthesia. BIOMEDICAL SCIENCES INSTRUMENTATION 1980; 16:15-9. [PMID: 7407299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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156
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Davenport HT, Halsey MJ, Wardley-Smith B, Bateman PE. Occupational exposure to anaesthetics in 20 hospitals. Anaesthesia 1980; 35:354-9. [PMID: 7435894 DOI: 10.1111/j.1365-2044.1980.tb05116.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The nitrous oxide and halothane contamination in the inspired air of anaesthetists and in the atmospheres of operating theatres, anaesthetic induction and recovery rooms, were measured during normal unmodified working sessions in 20 hospitals using integrated personal samplers. The nitrous oxide (and halothane) levels ranged from < 10 to 3000 ppm (< 0.1 to 60 ppm) in the different areas with an average of 388.5 ppm (2.8 ppm) for the inspired air of the anaesthetists during 2 hour sampling periods. There was no correlation between the levels of the anaesthetists' exposures and those in the static air samples and this appeared to be due primarily to a wide variation in work practices and techniques. Thus it is potentially misleading to assess anaesthetists' occupational exposure by collecting ambient air samples in the operating rooms. Comparisons with more prolonged measurements in one hospital indicated that the installation of relatively simple active scavenging devices will be effective in most hospitals.
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157
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Kavanagh S, Miller SL, Seal J, Stevens AJ, Swale J, Reaveley DA. An evaluation of the Porton diffusion sampler for long-term monitoring of halothane vapour concentrations. THE ANNALS OF OCCUPATIONAL HYGIENE 1980; 23:133-46. [PMID: 7436227 DOI: 10.1093/annhyg/23.2.133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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158
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Halliday MM, Anderson J. Determination of halothane in operating theatre air by using a passive organic vapour dosimeter. Analyst 1980; 105:289-92. [PMID: 7396217 DOI: 10.1039/an9800500289] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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159
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Prins L, Strupat J, Clement J, Knill RL. An evaluation of gas density dependence of anaesthetic vaporizers. CANADIAN ANAESTHETISTS' SOCIETY JOURNAL 1980; 27:106-10. [PMID: 6767537 DOI: 10.1007/bf03007770] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Four commonly used vaporizers were studied for the effect of carrier gas density on vaporizer output. Vapour concentrations from a halothane Cyprane (Fluotec) Mark 2 increased in relation to the density of carrier gas, whereas the concentrations delivered by an enflurane Ohio vaporizer decreased. The halothane Cyprane (Fluotec) Mark 3 and enflurane Cyprane vaporizers were largely independent of density. Of clinical importance, nitrous oxide/oxygen (75/25), compared with oxygen alone, increased the vapour concentration outputs of the halothane Mark 2 up to 30% and decreased the outputs of the enflurane Ohio unit up to 20%.
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160
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Bencsáth FA, Drysch K, Weichardt H. [Infrared spectrometry and gas chromatography for determination of halothane in operation rooms (author's transl)]. Anaesthesist 1980; 29:30-8. [PMID: 7396170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Chronic halothane intoxication is a health hazard to anaesthetic personnel and requires permanent control of the degree of exposure. Two different methods are described: a continuous infrared spectrometric and an intermittent gas chromatographic determination of airborne halothane. An elaborate instruction for the measuring procedure is given; calibration techniques and detection limits are discussed. Data from operating rooms with different security equipment are listed. For determining the total burden gas chromatography is the method of choice, as the concentration range to be detected is rather low in general. In addition infrared spectrometric concentration monitoring gives valuable information about concentration peaks caused by typical handling in an operation room.
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161
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Aono M, Matsuo T, Okazaki N, Yamauchi N, Sato T. [Efficiency of scavenging systems for exhaused anesthetic gases in OR (author's transl)]. MASUI. THE JAPANESE JOURNAL OF ANESTHESIOLOGY 1980; 29:49-54. [PMID: 7373832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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162
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Vean AH, King KJ. Measuring N2O levels in the dental operatory. ASDC JOURNAL OF DENTISTRY FOR CHILDREN 1979; 46:454-9. [PMID: 290639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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163
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Morris P, Tatnall ML, West PG. Breath-by-breath halothane monitoring during anaesthesia. A study in children. Br J Anaesth 1979; 51:979-82. [PMID: 518797 DOI: 10.1093/bja/51.10.979] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The use of a halothane meter in routine paediatric anaesthesia with controlled ventilation is described. The results demonstrate the accuracy achieved in the control of the alveolar halothane concentration. Measurement of the alveolar halothane concentration revealed responses to surgical stimulation otherwise obscured by neuromuscular blockade, and this may indicate insufficient depth of anaesthesia.
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164
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Thompson JM, Barratt RS, Hutton P, Robinson JS, Belcher R, Stephen WI. Ambient air contamination in a dental outpatient theatre. Br J Anaesth 1979; 51:845-55. [PMID: 508490 DOI: 10.1093/bja/51.9.845] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The extent of air contamination by halothane in an operating session was correlated with the number of patients, the total usage of halothane, refilling a vaporizer and the number of hyperventilating patients per session. Trichloroethylene content of theatre air correlated only with total usage and refilling a vaporizer. A very strong personal association (P smaller than 0.001) was found between the anaesthetist and the extent of air contamination with halothane. The association was weaker (0.05 less than P less than 0.1) for trichloroethylene. The median ambient air contamination with halothane in the vicinity of the faces of anaesthetists and dental surgeons was between six and nine times greater than the median air contamination at the fixed sampling sites (P smaller than 0.005).
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165
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Dateshidze KT, Kas'ianova AV. [Comparative evaluation of the operating room contamination by fluorothane vapors from semiclosed and closed respiratory circuits]. ANESTEZIOLOGIIA I REANIMATOLOGIIA 1979:32-4. [PMID: 507432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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166
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Halliday MM, Carter KB, Davis PD, MacDonald I, Collins L, McCreaddie G. Survey of operating room pollution within an N.H.S. district. Lancet 1979; 1:1230-2. [PMID: 87689 DOI: 10.1016/s0140-6736(79)91908-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pollution by waste anaesthetic gases was measured in all operating departments in a typical N.H.S. district. Methods were chosen to provide time-weighted average levels over the period of each operating session. The results showed that air-conditioning alone could not guarantee pollution levels below suggested maximum levels and that to meet those requirements air-conditioning plus scavenging was necessary. Background pollution levels were found to be representative of the personal exposure of nursing staff but approximated to only one third of the anaesthetists' personal exposure. Dental clinics presented special problems, namely the very high levels of pollution to which the dentist and his assistants were exposed.
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167
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Lauven PM, Hack G, Stoeckel H. [Gas chromatographic determination of the solubility coefficient for volatile anaesthetics (author's transl)]. Anaesthesist 1979; 28:104-6. [PMID: 434422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
For the determination of the solubility coefficient of volatile anaesthetics in Schindler's liquid culture, modified by Karzel, a gas-chromatographic analysis with direct-injection-method was used. A well defined volume with a known concentration of the anaesthetic was added to a vessel with known volume. After equilibration the concentration of the inhalational anaesthetics was determined in the liquid at various temperatures. The solubility coefficient and the temperature coefficient were then calculated from these data. We obtained the following solubility coefficients at -4 degrees C (37 degrees): for halothane 1,07 (0,77), for enflurane 1,14 (0,70), for methoxyflurane 4,92 (3,23) and for isoflurane 1,13 (0,82). In Schindler's liquid culture modified by Karzel the values at 24 degrees (37 degrees) were: for halothane 1,33 (0,92), for enflurane 1,32 (0,87), for methoxyflurane 6,61 (4,48) and for isoflurane 1,19 (0,98). The temperature coefficient for this temperature range were in water (in Schindler's liquid culture) for halothane: -2,31 . 10(-2) K(-1) (-3,15 . 10(-2) K(-1)), for methoxyflurane: -13,0 . 10(-2) K(-1) (-16,48 . 10(-2) K(-1)), for enflurane: -3,38 . 10(-2) K(-1) (-3,46 . 10(-2) K(-1)) and for isoflurane: -2,38 . 10(-2) K(-1) (-1,62 . 10(-2) K(-1)).
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168
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Krechkovskiĭ EA, Anisimova IG. [Determination of fluorothane in air by a gas-liquid chromatographic method]. GIGIENA I SANITARIIA 1979:58-9. [PMID: 761806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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169
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Abstract
The presence of two volatile halothane metabolites, 2-chloro-1,1,1-trifluoroethane (CF3CH2Cl) and 2-chloro-1,1-difluoroethylene (CF2CHCl), and a metabolite-decomposition product, 2-bromo-2-chloro-1,1-difluoroethylene (CF2CBrCl), were identified by gas chromatography-mass spectrometry in exhaled gases of 16 patients anesthetized with halothane in nonrebreathing, semiclosed and totally closed anesthesia circuits. No significant differences in concentrations of CF3CH2Cl and CF2CHCl were found relative to the anesthesia circuits used. CF2CBrCl could not be identified in the expired gases of patients anesthetized with a nonrebreathing circuit (Bain), but was present in gases recovered from both semiclosed and totally closed circuits. Under totally closed-circuit rebreathing conditions, the concentration of CF2CBrCl increased to 4-5 ppm, indicating significant breakdown of halothane by the soda lime. Possible pathways for formation of the two metabolites and the metabolite-decomposition product are presented, as well as clinical implications of these findings.
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170
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Abstract
The effects of halothane and enflurane on the polarographic measurement of oxygen with five platinum and three gold microelectrodes were examined. Oxygen microelectrodes were calibrated in saline solution equilibrated with either nitrogen (N2) or air, then either halothane, 1.0 per cent, or enflurane, 2.0 per cent, was added to the gas mixture. For each electrode, polarographic curves were determined during exposure to five equilibrating gas mixtures: N2, air, N2 plus halothane, air plus halothane, and N2 plus enflurane. Halothane variably increased the current produced (and therefore the estimated oxygen tension) at all polarizing voltages in saline solution equilibrated with either N2 or air. The effect was present in both conical platinum electrodes and recessed-tip gold electrodes and was not prevented by membrane coatings of polystyrol, Rhoplex or collodion. Enflurane did not alter the polarographic measurement of oxygen. It is concluded that tissue oxygen tension measurements, made with these microelectrodes and membranes, may be unreliable in the presence of halothane.
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171
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Hamm G, Apel G, Matthies J, Heuck U, Winter CG, Thieme A, Brennecke L. [Halothane working-site concentrations in operating rooms of the Magdeburg district]. ZEITSCHRIFT FUR DIE GESAMTE HYGIENE UND IHRE GRENZGEBIETE 1979; 25:14-8. [PMID: 425556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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172
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McIntyre JW, Purdham JT, Hosein HR. An assessment of operating room environment air contamination with nitrous oxide and halothane and some scavenging methods. CANADIAN ANAESTHETISTS' SOCIETY JOURNAL 1978; 25:499-505. [PMID: 728825 DOI: 10.1007/bf03007413] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This study was designed to assess operating room contamination with nitrous oxide and halothane when nitrous oxide 3 1/min and oxygen 2 1/min containing halothane one per cent were passed into a semiclosed circle absorber system from which the patients' lungs were ventilated with an Ohio ventimeter through a cuffed tracheal tube, with the exhaled gas vented to the floor. The normal room ventilation did not consistently maintain levels below the suggested amounts, which are nitrous oxide 25 ppm and halothane 2 ppm. Careful daily check for and correction of high and low pressure leaks combined with the use of a Foregger scavenging device (7--351--005) and continuous wall vacuum accepting approximately 22 1/min enabled geometric mean values below the suggested levels to be achieved. The Protection Filter Foregger 7--365--001 was only effective in removing halothane and only if the plastic holder provided was radically modified. Attention is drawn to the numerous factors influencing the magnitude of contamination, aspects of controlling it, and the necessity to cope with the problem of dealing with scavenged gases and vapours.
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173
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Lane GA. Measurement of anesthetic pollution in oral surgery offices. JOURNAL OF ORAL SURGERY (AMERICAN DENTAL ASSOCIATION : 1965) 1978; 36:444-6. [PMID: 274532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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174
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Abstract
The design and performance characteristics of an instrument for monitoring halothane concentrations which operates on the principle of the absorption of u.v. light are described. The innovation is that the entire exhaled breath passes through the sample cell, enabling the breath-by-breath halothane concentration to be measured accurately and instantaneously. Stablized power supplies, solid-state circuitry and filtering make the instrument stable and selective. A valve prevents rebreathing of gas exposed previously to u.v. light in the sample cell. Inspired and end-tidal concentrations are displayed digitally and an analog output is available also. Zero and gain drift were negligible after an initial settling period, and interference from other respiratory gases was not detectable. The monitor is suitable for use during anaesthesia for adults and children.
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175
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Salamonsen LA, Cole WJ, Salamonsen RF. Simultaneous trace analysis of nitrous oxide and halothane in air. Br J Anaesth 1978; 50:221-7. [PMID: 637994 DOI: 10.1093/bja/50.3.221] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
A gas chromatographic method for the simultaneous analysis of halothane and nitrous oxide in operating theatre atmospheres has been developed and evaluated. The flame ionization detector is suitable for the quantitative analysis of halothane in concentrations approaching one part per million. The frequency-modulated electron capture detector is highly sensitive to nitrous oxide but we have found it to be non-linear over the range 25--1000 p.p.m. The overall reproducibility of the gas chromatographic method based on the dynamic technique of standard preparation is approximately 4%. Effective exposure of personnel to pollutant anaesthetics is assessed by the analysis of end-expired gas.
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176
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Korttila K, Pfäffli P, Linnoila M, Blomgren E, Hänninen H, Häkkinen S. Operating room nurses' psychomotor and driving skills after occupational exposure to halothane and nitrous oxide. Acta Anaesthesiol Scand 1978; 22:33-9. [PMID: 76408 DOI: 10.1111/j.1399-6576.1978.tb01277.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Concentrations of halothane and nitrous oxide were assayed by gas chromatography throughout a working day in three operating theatres and in the end-tidal air of 19 nurses 15 and 60 min after leaving the theatres. Perceptual, psychomotor and driving skills were measured in these nurses and in 11 younger nurses working in the wards of the same hospital. A complicated psychomotor test battery and a driving simulator were used. End-tidal air concentrations of halothane and nitrous oxide were positively correlated with the exposure level of these gases in the operating theatres. Some of the operating room nurses had greater amounts of halothane in their end-tidal air (average 15 to 10 ppm) than student volunteers 4.5 h after 3.5 min of general anaesthesia with a combination of halothanenitrous-oxide oxygen (10 ppm halothane). These volunteers had worse psychomotor and driving performances when measured than controls who had not been anaesthetized. No correlations were found between the concentrations of halothane or nitrous oxide in end-tidal air and psychomotor or driving performance. Despite their higher age and exposure to the operating room environment, the driving skills of the operating room nurses were similar to those of the ward nurses. The results suggest that tolerance to anaesthetic gases develops among operating room personnel. No impairment of driving skills can be expected after daily exposure to halothan and nitrous oxide among long-term employees in operating theatres.
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177
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Berner O. Concentration elimination of anaesthetic gases in operating theratres. Influence of anaesthesia apparatus leakages. Acta Anaesthesiol Scand 1978; 22:46-54. [PMID: 76409 DOI: 10.1111/j.1399-6576.1978.tb01279.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Halothane and nitrous oxide (N2O) concentrations were measured in operating theatres, in the areas corresponding to theinhalation zones of the anaesthetists and operating nurses. The measurements were performed in an operating theatre with a non-recirculating air exchange rate of 20/h. This was performed partly in model experiments and partly during the administration of anaesthesia by intubation. In the model experiments. the measurements were taken both with and without a specially constructed scavenging system. During anaesthesia, the measurements were taken exclusively with the scavenging system, although well-defined leakages were fitted into the otherwise gas-tight anaesthetic system. The results were supplemented by smoke experiments which showed the air distribution patterns. The investigation showed that the gases were concentrated over and around the operating table. Activities during surgery diluted this concentration. Furthermore, it was shown that leakage in the anaesthetic system significantly influences the achieving of a low gas-air mixture. Halothane concentrations in the inhalation zone of the anaesthetist and operating nurse can be reduced to 0.02 and 0.01 p.p.m. respectively, if the anaesthetic system is completely gas-tight.
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178
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Holmes CM. Pollution in operating theatres: Part 2: The solution. THE NEW ZEALAND MEDICAL JOURNAL 1978; 87:50-4. [PMID: 273795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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179
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Holmes CM. Pollution in operating theatres. Part 1: The problem. THE NEW ZEALAND MEDICAL JOURNAL 1978; 87:18-20. [PMID: 273789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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180
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Best JL, McGrath CJ. Trace anesthetic gases: an overview. J Am Vet Med Assoc 1977; 171:1268-9. [PMID: 342467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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181
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Steffey EP, Howland D. Rate of change of halothane concentration in a large animal circle anesthetic system. Am J Vet Res 1977; 38:1993-6. [PMID: 596697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The slow rate of change of inspired halothane concentration which results in a conventional large animal circle anesthetic delivery system when low carrier gas flow rates are used was confirmed, using a model system. To obtain a 63% change in inspired halothane concentration in the 32-L large animal circle anesthetic machine at fresh gas inflow rates of 3, 6, and 12 L/minute required 10.7, 5.3, and 2.7 minutes, respectively. At a given inflow rate, increasing the rebreathing bag size from 20 to 40 L prolonged the time for equilibration between the gas flowing into the anesthetic circuit and the inspired gas. The extent to which an adult horse further slowed the rate of rise of inspired anesthetic concentration was also demonstrated.
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182
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Holaday DA. Absorption, biotransformation, and storage of halothane. ENVIRONMENTAL HEALTH PERSPECTIVES 1977; 21:165-9. [PMID: 348455 PMCID: PMC1475353 DOI: 10.1289/ehp.7721165] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Current knowledge of the quantitative aspects of biotransformation of halothane and the fate of its metabolites are reviewed. Absorbed quantities of the inhalation anesthetic average 12.7 and 18 g during 1 and 2 hr, respectively, of anesthesia. Reported fractions of halothane recovered as urinary metabolites range from 10 to 25%. An analysis of reports of bromide ion accumulation in plasma during and following anesthesia suggests that metabolism of halothane continues for 20-40 hr after exposure and that 22-24% of absorbed halothane is metabolized following 8 hr of anesthesia. Half-times for excretion of trifluoroacetic acid (TFA), a principal urinary metabolite of halothane, tend to confirm that biotransformation proceeds for 2 to 3 days following exposure. Other urinary metabolites which occur in small amounts include a dehydrofluorinated metabolite of halothane conjugated with L-cysteine and N-trifluoroacetyl-n-ethanolamine, both of which are evidence of the occurrence of reactive intermediates during the metabolism of halothane. Support for free radical formation has come from in vivo and in vitro demonstrations of stimulation of lipoperoxidation of polyenoic fatty acids by halothane. Irreversible binding of halothane metabolites to microsomal proteins and phospholipids has been shown to depend on the microsomal P-450 cytochrome system. Irreversible binding is increased by microsomal enzyme induction and by anaerobic conditions. Hypoxia increases irreversible binding to phospholipids, augments the release of inorganic fluoride and is followed by centrilobular hepatic necrosis. It is concluded that one-fourth to one-half of halothane undergoes biotransformation in man. One fraction is excreted as trifluoroacetic acid, chloride and bromide. A second fraction is irreversibly bound to hepatic proteins and lipids. Under anaerobic conditions fluoride is released, binding to phospholipids is increased, and hepatic necrosis may occur.
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183
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Abstract
Air monitoring, an essential feature of the waste gas control program, is best based on measurement of total leakage in time-weighted sampling of N2O present in the anesthetist's breathing zone during clinical anesthesia. Leakage in the high-pressure N2O system is measured separately in a survey of the empty rooms. The infrared N2O analyzer used for these measurements is also useful as a teaching device and in enhancing the safety of the patient.
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184
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Abstract
We found that both variable bypass (Tec-type) and measured flow (Kettle type) vaporizers that nominally are turned off may permit anesthetic to leak into the bypass or the diluent stream. The contamination ranges from 1 to 3,300 parts per million of halothane (0.0001 to 0.33 percent). It appears to result either from diffusion of agent from the liquid reservoir into the bypass or diluent stream or from a reservoir in the piping connecting vaporizer to the diluent stream.
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185
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Whitcher CE, Zimmerman DC, Tonn EM, Piziali RL. Control of occupational exposure to nitrous oxide in the dental operatory. J Am Dent Assoc 1977; 95:763-76. [PMID: 143480 DOI: 10.14219/jada.archive.1977.0493] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Methods were developed for controlling the dental team's occupational exposure to nitrous oxide. The most applicable and effective use of these methods included the use of properly maintained gas delivery equipment, a double-walled scavenging nosepiece and vented suction machine, and minimizing speech by the patients. These methods were evaluated by measuring concentrations of nitrous oxide present in the air inspired by dental personnel. Before their use, the dentist inhaled 900 ppm nitrous oxide; their application reduced his inhaled concentration to 31 ppm, representing a 97% reduction. These methods were well accepted during 157 procedures completed by a group of eight dentists engaged in private practice (four general practitioners, two pedodontists, and two oral surgeons).
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186
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Robinson JS, Thompson JM, Barratt RS. Inadvertent contamination of anaesthetic circuits with halothane. Br J Anaesth 1977; 49:745-54. [PMID: 889661 DOI: 10.1093/bja/49.8.745] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
All halothane vaporizers tested for leakage when turned off, leaked significant amounts of halothane and this may represent a hazard to patients liable to develop halothane hepatitis or malignant hyperpyrexia. The hazard from leaking vaporizers may be reduced considerably by the use of well-designed bypass units. Circuit contamination by halothane may still result from such sources as neoprene seals around flowmeters, breathing bags and anaesthetic hose which have had previous contact with halothane vapour, whether or not an apparatus is in use. The hazard from contaminated hoses and bags may be reduced considerably by washing and then hanging in a halothane-free atmosphere for a day. The hazard from contamined rubber or plastic components of the anaesthetic machine can be eliminated only by using one apparatus without the vaporizers having been attached at any time during its working life. Similarly, hazards may arise from trichloroethylene vaporizers and from circuit components contaminated with trichloroethylene.
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187
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Campbell RL, Hannifan MA, Reist PC, Gregg JM. Exposure to anesthetic waste gas in oral surgery. JOURNAL OF ORAL SURGERY (AMERICAN DENTAL ASSOCIATION : 1965) 1977; 35:625-30. [PMID: 267187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Exposure to nitrous oxide and halothane during oral surgery was monitored using a Miran infrared analyzer. A "typical" time-weighted analysis exposure was established for the surgeon, assistant, and anesthetist. Values for halothane ranged from 7.5 to 59 ppm, and for nitrous oxide, from 280 to 90,000 ppm.
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188
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189
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Bushman JA, Enderby DH, Al-Abrak MH, Askill S. Closed circuit anaesthesia. A new approach. Br J Anaesth 1977; 49:575-87. [PMID: 871354 DOI: 10.1093/bja/49.6.575] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A logical development of the closed circuit is described, from a basic resuscitation device, through various modifications, to a circle system incorporating an oxygen demand valve, adsorbers for both carbon dioxide and halothane, and some specific safety features. The behaviour of the circuits has been investigated in relation to elimination of nitrogen, concentrations of halothane and circuit leaks.
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190
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Abstract
Response time (RT) of the Narkotest anesthetic gas monitor was measured for 7 inhalation anesthetics, using a 5 L/min fresh gas flow (FGF). Time to 63 percent of maximum response (RT63) and to 95 percent of maximum response (RT95) was directly related to rubber/gas and oil/gas partition coefficients. RT95 ranged from 7 seconds for N2O to 843 seconds for methoxyflurane. RT measured at 0.5 L/min FGF was markedly prolonged over RT at 5 L/min. When the Narkotest was placed on the expiratory limbs of circle-absorber breathing circuits, the difference between the calibrated Narkotest reading (Fn) and the mixed expired circuit concentration (Fc) was shown to depend on the rate of increase of the circuit concentration.
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191
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Halliday MM, MacDonald I, MacGregor MH. Gas chromatographic determination of Ostwald solubility coefficients for cyclopropane, halothane and trichloroethene (trichloroethylene). Br J Anaesth 1977; 49:413-7. [PMID: 861107 DOI: 10.1093/bja/49.5.413] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Gas chromatographic methods using solvent extraction for the analysis of cyclopropane and and trichloroethene (trichloroethylene) are described and evaluated; cyclopropane was extracted into carbon tetrachloride and trichloroethene into carbon disulphide, using chloroform and toluene respectively as the internal standards. Ostwald solubility coefficients were measured for cyclopropane, halothane and trichloroethene in Krebs solution: at 310 K the respective values +/- SEM of the Ostwald coefficients are 0.181 +/- 0.009, 0.78 +/- 0.02 and 1.54 +/- 0.02; over the temperature range 295-310 K the respective temperature coefficients of solubility are -2.27, -4.18 and -3.81 in units of per cent/K at 310 K.
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192
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Cottrell JE, Chalon J, Turndorf H. Faulty anesthesia circuits: a source of environmental pollution in the operating room. Anesth Analg 1977; 56:359-62. [PMID: 559434 DOI: 10.1213/00000539-197705000-00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Commonly used disposable anesthesia circuits were studied for leak and gas spillage. Trace anesthetic gas concentrations produced by these circuits in the anesthesiologist's breathing zone were analyzed by a Hewlett-Packard Gas Chromatograph. These measurements demonstrated ambient halothane (3.29 +/- 0.1 ppm) and N2O (333.5 +/- 2.31 ppm) concentrations well above target levels, when swivel-type disposable anesthesia circuits were used, despite the presence of standard gas-scavenging devices and appropriate operating room fresh air exchange rates. Lower ambient concentration levels (0.38 +/- 0.03 ppm halothane and 31.3 +/- 1.49 ppm N2O) were measured when Y-type disposable anesthesia circuits were used.
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193
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Salamonsen RF, Cole WJ. Effect of polarity on the response of the flame ionization detector to halothane. Br J Anaesth 1977; 49:387-90. [PMID: 889653 DOI: 10.1093/bja/49.4.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Prepared standards of halothane in oxygen were analysed using a Pye Series 104 gas chromatograph equipped with a heated head flame ionization detector and gas sampling valve. The adoption of a positive jet voltage expanded the linear dynamic range of the detector to cover the 0.5-9.0% by volume range, provided that a small (0.5-ml) sample loop was used.
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194
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[Survey of anesthetic pollution in the operating room]. MASUI. THE JAPANESE JOURNAL OF ANESTHESIOLOGY 1977; 26:369-86. [PMID: 325241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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195
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MacKenzie JE. Determination of MAC for halothane, cyclopropane and ether in the rabbit. Br J Anaesth 1977; 49:319-22. [PMID: 889646 DOI: 10.1093/bja/49.4.319] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Rabbits have a high rate of ventilation which makes it difficult to obtain a sample of end-tidal gas by the usual procedures. An occlusion technique was developed which provided a gas sample equivalent to an end-tidal gas sample. MAC values were determined using this sampling method. The values obtained +/- SEM were: cyclopropane 15.6 +/- 1.7%, halothane 0.63 +/- 0.06% and ether 2.7 +/- 0.2%.
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196
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Koehler LS, Cruley W, Koehler KA. Solvent effects on halothane: 19F nuclear magnetic resonance in solvents and artificial membranes. Mol Pharmacol 1977; 13:113-21. [PMID: 834180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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197
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Piziali RL, Whitcher C, Sher R, Moffat RJ. Distribution of waste anesthetic gases in the operating room air. Anesthesiology 1976; 45:487-94. [PMID: 973705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Epidemiologic and animal studies identify a strong relationship between chronic exposure to anesthetic gases and health hazards. Efforts to reduce exposure of personnel require an understanding of the distribution of anesthetic waste gases in the operating room air. Concentrations of nitrous oxide and halothane were measured at numerous stations throughout an operating room and a delivery room in the absence of personnel. Air conditioning flow rates and flow patterns were varied, as was the height of the anesthetic gas source. Air flow patterns were found to dominate the anesthetic gas distribution, while buoyancy effects were negligible. Venting waste gases at the floor does not significantly reduce exposure of personnel. Areas of high concentration were observed; their occurrences and locations varied strongly with air flow patterns. The exhaust grille is the best location for a single measurement of the average room concentration. Recirculating air-conditioning systems reduce energy costs; however, only the non-recirculating portion of the air exchanges reduces waste gas concentrations.
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198
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Abstract
This approach to programmed anaesthesia uses a pharmakokinetic model to predict the rate at which halothane must be administered to achieve and maintain a preselected tension within the brain. 'In-course' corrections are also applied to this predictive regime on the basis of variations in the respired minute volume which is taken as an indicator of the depth of anaesthesia. Experimental data on the accuracy of the model and the performance of the corrective control unit are presented.
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199
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Tanifuji Y, Eger EI. Effect of arterial hypotension on anaesthetic requirement in dogs. Br J Anaesth 1976; 48:947-52. [PMID: 990148 DOI: 10.1093/bja/48.10.947] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In the dog a reduction of mean arterial pressure to 40-50 mm Hg decreased MAC by 20+/--EM 4% in the 1st hour. No further change resulted during the ensuing 3 h of hypotension (40-50 mm Hg). Arterial and cerebrospinal fluid lactate and pyruvate concentrations were not affected by hypotension, nor did cerebrospinal fluid pH decrease. In a separate group of dogs, we reduced arterial pressure to 40-50, 30-40 and 20-30 mm Hg successively. MAC decreased concomitantly, being 58+/-11% of control value at the lowest pressure. MAC increased following the restoration of normal pressure, but hysteresis was evident. In a third group of dogs, arterial pressure was reduced rapidly to 10-30 mm Hg. MAC decreased to 29+/-5% of control. This decrease was significantly greater than that associated with the three-stage reduction.
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200
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Turnbull MJ, Watkins JW. Determination of halothane-induced sleeping time in the rat: effect of prior administration of centrally active drugs. Br J Pharmacol 1976; 58:27-35. [PMID: 987820 PMCID: PMC1667137 DOI: 10.1111/j.1476-5381.1976.tb07689.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A method is described for the determination of halothane-induced sleeping time in the rat. 2 The sleeping time exhibited a diurnal variation which was due, at least in part, to a change in the sensitivity of the central nervous system (CNS) to the anaesthetic. 3 Tolerance to halothane did not develop in rats repeatedly exposed to the anaesthetic over a period of over 48 hours. 4 Repeated sleeping time determinations have been used to follow changes in the sensitivity of the CNS to the anaesthetic occurring with time. 5 A tolerance to halothane was induced by pretreatment of rats with doses of amylobarbitone, pentobarbitone or meprobamate sufficient to keep animals anaesthetized for approximately 12 hours. This tolerance was followed by a period of halothane-hypersensitivity. 6 Halothane-tolerant animals awakened with higher brain halothane concentrations and were also tolerant to intracerebroventricularly administered pentobarbitone. 7 Halothane-hypertensive rats awakened with lower brain halothane concentrations and were also hypersensitivity to intracerebroventricularly administered pentobarbitone. 8 The possibility that the induction of cross-tolerance to halothane may be indicative of a drug's potential to produce dependence is discussed.
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