The Experts below are selected from a list of 1059 Experts worldwide ranked by ideXlab platform
Tim Mcculloch - One of the best experts on this subject based on the ideXlab platform.
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environmental and economic impact of using increased fresh gas flow to reduce Carbon Dioxide Absorbent consumption in the absence of inhalational anaesthetics
BJA: British Journal of Anaesthesia, 2020Co-Authors: George Zhong, Joseph Jones, Sarah Kong, Tim Mcculloch, Ali AbbasAbstract:Abstract Background Increasing fresh gas flow (FGF) to a circle breathing system reduces Carbon Dioxide (CO2) Absorbent consumption. We assessed the environmental and economic impacts of this trade-off between gas flow and Absorbent consumption when no inhalational anaesthetic agent is used. Methods A test lung with fixed CO2 inflow was ventilated via a circle breathing system of an anaesthetic machine (Drager Primus or GE Aisys CS2) using an FGF of 1, 2, 4, or 6 L min−1. We recorded the time to exhaustion of the CO2 Absorbent canister, defined as when inspired partial pressure of CO2 exceeded 0.3 kPa. For each FGF, we calculated the economic costs and the environmental impact associated with the manufacture of the CO2 Absorbent canister and the supply of medical air and oxygen. Environmental impact was measured in 100 yr global-warming potential, analysed using a life cycle assessment ‘cradle to grave' approach. Results Increasing FGF from 1 to 6 L min−1 was associated with up to 93% reduction in the combined running cost with minimal net change to the 100 yr global-warming potential. Most of the reduction in cost occurred between 4 and 6 L min−1. Removing the CO2 Absorbent from the circle system, and further increasing FGF to control CO2 rebreathing, afforded minimal further economic benefit, but more than doubled the global-warming potential. Conclusions In the absence of inhalational anaesthetic agents, increasing FGF to 6 L min−1 reduces running cost compared with lower FGFs, with minimal impact to the environment.
Richard B Weiskopf - One of the best experts on this subject based on the ideXlab platform.
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dehydration of baralyme increases compound a resulting from sevoflurane degradation in a standard anesthetic circuit used to anesthetize swine
Anesthesia & Analgesia, 1997Co-Authors: Eugene Steffey, Edmond I Eger, Michael J Laster, Pompilliu Ionescu, Diane Gong, Richard B WeiskopfAbstract:In a model anesthetic circuit, dehydration of Baralyme[registered sign] brand Carbon Dioxide Absorbent increases degradation of sevoflurane to CF2=C(CF3)OCH2 F, a nephrotoxic vinyl ether called Compound A.In the present study, we quantified this increase using "conditioned" Baralyme[registered sign] in a circle Absorbent system to deliver sevoflurane anesthesia to swine. Mimicking continuing oxygen delivery for 2 days after completion of an anesthetic, we directed a conditioning fresh gas flow of 5 L/min retrograde through fresh Absorbent in situ in a standard Absorbent system for 40 h. The conditioned Absorbent was subsequently used (without mixing of the granules) in a standard anesthetic circuit to deliver sevoflurane to swine weighing 78 +/- 2 kg. The initial inflow rate of fresh gas flow was set at 10 L/min with the vaporizer at 8% to achieve the target end-tidal concentration of 3.0%-3.2% sevoflurane in approximately 20 min. The flow was later decreased to 2 L/min, and the vaporizer concentration was decreased to sustain the 3.0%-3.2% value for a total of 2 h (three pigs) or 4 h (eight pigs). Inspired Compound A increased over the first 30-60 min to a peak concentration of 357 +/- 49 ppm (mean +/- SD), slowly decreasing thereafter to 74 +/- 6 ppm at 4 h. The average concentration over 2 h was 208 +/- 25 ppm, and the average concentration over 4 h was 153 +/- 19 ppm. Pigs were killed 1 or 4 days after anesthesia. The kidneys from pigs anesthetized for both 2 h and 4 h showed mild inflammation but little or no tubular necrosis. These results suggest that dehydration of Baralyme[registered sign] may produce concentrations of Compound A that would have nephrotoxic effects in humans in a shorter time than would be the case with normally hydrated Baralyme[registered sign]. Implications: The vapor known as Compound A can injure the kidney. Dehydration of Baralyme[registered sign], a standard Absorbent of Carbon Dioxide in inhaled anesthetic delivery systems, can cause a 5- to 10-fold increase in Compound A concentrations produced from the inhaled anesthetic, sevoflurane, given at anesthetizing concentrations in a conventional anesthetic system. (Anesth Analg 1997;85:1382-6)
Eugene Steffey - One of the best experts on this subject based on the ideXlab platform.
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dehydration of baralyme increases compound a resulting from sevoflurane degradation in a standard anesthetic circuit used to anesthetize swine
Anesthesia & Analgesia, 1997Co-Authors: Eugene Steffey, Edmond I Eger, Michael J Laster, Pompilliu Ionescu, Diane Gong, Richard B WeiskopfAbstract:In a model anesthetic circuit, dehydration of Baralyme[registered sign] brand Carbon Dioxide Absorbent increases degradation of sevoflurane to CF2=C(CF3)OCH2 F, a nephrotoxic vinyl ether called Compound A.In the present study, we quantified this increase using "conditioned" Baralyme[registered sign] in a circle Absorbent system to deliver sevoflurane anesthesia to swine. Mimicking continuing oxygen delivery for 2 days after completion of an anesthetic, we directed a conditioning fresh gas flow of 5 L/min retrograde through fresh Absorbent in situ in a standard Absorbent system for 40 h. The conditioned Absorbent was subsequently used (without mixing of the granules) in a standard anesthetic circuit to deliver sevoflurane to swine weighing 78 +/- 2 kg. The initial inflow rate of fresh gas flow was set at 10 L/min with the vaporizer at 8% to achieve the target end-tidal concentration of 3.0%-3.2% sevoflurane in approximately 20 min. The flow was later decreased to 2 L/min, and the vaporizer concentration was decreased to sustain the 3.0%-3.2% value for a total of 2 h (three pigs) or 4 h (eight pigs). Inspired Compound A increased over the first 30-60 min to a peak concentration of 357 +/- 49 ppm (mean +/- SD), slowly decreasing thereafter to 74 +/- 6 ppm at 4 h. The average concentration over 2 h was 208 +/- 25 ppm, and the average concentration over 4 h was 153 +/- 19 ppm. Pigs were killed 1 or 4 days after anesthesia. The kidneys from pigs anesthetized for both 2 h and 4 h showed mild inflammation but little or no tubular necrosis. These results suggest that dehydration of Baralyme[registered sign] may produce concentrations of Compound A that would have nephrotoxic effects in humans in a shorter time than would be the case with normally hydrated Baralyme[registered sign]. Implications: The vapor known as Compound A can injure the kidney. Dehydration of Baralyme[registered sign], a standard Absorbent of Carbon Dioxide in inhaled anesthetic delivery systems, can cause a 5- to 10-fold increase in Compound A concentrations produced from the inhaled anesthetic, sevoflurane, given at anesthetizing concentrations in a conventional anesthetic system. (Anesth Analg 1997;85:1382-6)
David M Gratch - One of the best experts on this subject based on the ideXlab platform.
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economic and environmental considerations during low fresh gas flow volatile agent administration after change to a nonreactive Carbon Dioxide Absorbent
Anesthesia & Analgesia, 2016Co-Authors: Richard H Epstein, Franklin Dexter, David P Maguire, Niraj K Agarwalla, David M GratchAbstract:BACKGROUND:Reducing fresh gas flow (FGF) during general anesthesia reduces costs by decreasing the consumption of volatile anesthetics and attenuates their contribution to greenhouse gas pollution of the environment. The sevoflurane FGF recommendations in the Food and Drug Administration package ins
Tetsuo Satoh - One of the best experts on this subject based on the ideXlab platform.
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compound a concentrations during low flow sevoflurane anesthesia correlate directly with the concentration of monovalent bases in Carbon Dioxide Absorbents
Anesthesia & Analgesia, 2000Co-Authors: Hideyuki Higuchi, Yushi U Adachi, Shinya Arimura, Masuyuki Kanno, Tetsuo SatohAbstract:UNLABELLED: Sevoflurane degrades to Compound A, which is nephrotoxic in rats. Potassium hydroxide (KOH) and sodium hydroxide (NaOH) are primary determinants of this degradation reaction. To address this, new Carbon Dioxide Absorbents, such as Amsorb((R)) (A; Armstrong Medical, Coleraine, Northern Ireland), which contains neither KOH nor NaOH, Dragersorb 800 Plus((R)) (D; Drager, Luebeck, Germany), and Medisorb((R)) (M; Datex-Ohmeda, Bromma, Sweden), which contain some NaOH (1% to 2%) and only trace amounts of KOH (0.003%), were recently developed. We compared Compound A concentrations using these three CO(2) Absorbents during low-flow (1 L/min) sevoflurane anesthesia in surgical patients, with those using a conventional CO(2) Absorbent, Dragersorb 800 (C). The mean Compound A concentrations +/- SD using C, A, D, and M were 18.7 +/- 2.5, 1.8 +/- 0.7, 13.3 +/- 3.5, and 11.2 +/- 2.6 ppm, respectively, with significant differences (P < 0.001; A versus C, A versus D, A versus M, C versus D, C versus M). Amsorb prevented the degradation of sevoflurane to Compound A, whereas Dragersorb 800 Plus and Medisorb decreased the degradation to Compound A. IMPLICATIONS: Sevoflurane degradation to Compound A is decreased by lowering the concentration of monovalent bases in the Carbon Dioxide Absorbent (Dragersorb 800 Plus) [Drager, Luebeck, Germany] and Medisorb) [Datex-Ohmeda, Bromma, Sweden]) and is virtually eliminated in the absence of these bases (Amsorb) [Armstrong Medical, Coleraine, Northern Ireland]).