| An evaluation of the contributions by fresh gas flow rate, carbon dioxide concentration and desflurane partial pressure to carbon monoxide concentration during low fresh gas flows to a circle anaesthetic breathing system. | |
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MedLine Citation:
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PMID: 18339215 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND AND OBJECTIVE: Numerous in vitro studies have shown that volatile anaesthetics react with desiccated carbon dioxide (CO2) absorbents to produce carbon monoxide (CO). The effects of anaesthetic concentration, fresh gas flow rate, and the hydration of absorbent or the excretion of CO2 by patients on CO production have also been investigated. This work aims to identify the most significant one of these factors on CO concentration in a low-flow anaesthesia system, without control of the hydration of the absorbents. METHODS: A simulated clinical circle anaesthetic breathing system was used to study the CO concentration under various conditions. Desflurane was used at three different concentrations. Two CO2 flow rates and three fresh gas flow rates were used. The absorbent temperatures and hydration were measured simultaneously. RESULTS: Desflurane degraded to produce CO in the breathing tube, when the CO2 absorbents were not dried beforehand. In this imitation clinical low-flow setting, fresh gas flow affected the CO production more than the CO2 did (31.7% vs. 9.5%). The actual desflurane partial pressure was not a significant factor. The CO2 flow rate explained 18.2% and 54.0% of the variation of the absorbent hydration changes (%) and temperature, respectively. CONCLUSIONS: In clinical practice, the CO2 production varies among patients and is uncontrollable, but markedly affects CO production. The only controllable factor is the fresh gas flow rate if the ultimate goal is to reduce the undesirable exposure of patients to CO from the breathing tube according to this bench model without counting the oxygen consumption. |
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Authors:
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S-Z Fan; Y-W Lin; W-S Chang; C-S Tang |
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Publication Detail:
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Type: Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't Date: 2008-03-13 |
Journal Detail:
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Title: European journal of anaesthesiology Volume: 25 ISSN: 1365-2346 ISO Abbreviation: Eur J Anaesthesiol Publication Date: 2008 Aug |
Date Detail:
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Created Date: 2008-07-01 Completed Date: 2008-08-14 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8411711 Medline TA: Eur J Anaesthesiol Country: England |
Other Details:
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Languages: eng Pagination: 620-6 Citation Subset: IM |
Affiliation:
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National Taiwan University, College of Medicine, Department of Anesthesiology, Taiwan, ROC. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Absorption Anesthesia, Closed-Circuit* Anesthetics, Inhalation / chemistry* Carbon Dioxide / chemistry* Carbon Monoxide / analysis* Humidity Isoflurane / analogs & derivatives*, chemistry Oxygen / metabolism Partial Pressure Regression Analysis Temperature |
| Chemical | |
Reg. No./Substance:
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0/Anesthetics, Inhalation; 124-38-9/Carbon Dioxide; 26675-46-7/Isoflurane; 57041-67-5/desflurane; 630-08-0/Carbon Monoxide; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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