Using Amsorb to Detect Dehydration of CO2Absorbents Containing Strong Base

2002 ◽  
Vol 97 (2) ◽  
pp. 454-459 ◽  
Author(s):  
Erich Knolle ◽  
Wolfgang Linert ◽  
Hermann Gilly
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Water Content ◽  
Color Change ◽  
Anesthesia Machine ◽  
Strong Base ◽  
Carbon Monoxide Formation ◽  
The Mean ◽  
Indicator Dye

Background Because Amsorb changes color when it dries, the authors investigated whether Amsorb combined with different strong base-containing carbon dioxide absorbents signals dehydration of such absorbents. Methods Five different carbon dioxide absorbents (1,330 g) each topped with 70 g of Amsorb were dried in an anesthesia machine (Modulus CD, Datex-Ohmeda, Madison, WI) with oxygen (Amsorb layer at the fresh gas inflow site). As soon as a color change was detected in the Amsorb, the authors tested the samples for a change in weight and carbon monoxide formation from 7.5% desflurane or 4% isoflurane. In a different experiment with the five absorbents, Amsorb was layered at the drying gas outflow site. In further experiments, the authors tested for a color change in Amsorb from drying and rehydrating and from drying with nitrogen. Finally, they dried a mixture of Amsorb and 1% NaOH and examined it for color change. Results In the experiments with Amsorb layered at the inflow, the Amsorb changed color when the water content of the samples was only marginally reduced (to a mean 13.6%), and no carbon monoxide formed. With Amsorb layered at the outflow, it changed color when the mean water content of the samples was reduced to 8.8%, and carbon monoxide formation was detected to varying degrees. The color change was independent of the drying gas and could be reversed by rehydrating. Adding NaOH to Amsorb prevented a color change. Conclusions Dehydration in strong base-containing absorbents can reliably be indicated before carbon monoxide is formed when Amsorb is layered at the fresh gas inflow. The authors assume that the indicator dye in Amsorb changes color on drying because of the absence of strong base in this absorbent.

High Carboxyhemoglobin Concentrations Occur in Swine during Desflurane Anesthesia in the Presence of Partially Dried Carbon Dioxide Absorbents 

1997 ◽  
Vol 87 (2) ◽  
pp. 308-316 ◽  
Author(s):  
Edward J. Frink ◽  
Wallace M. Nogami ◽  
Scott E. Morgan ◽  
Roger C. Salmon
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Water Content ◽  
Flow Rate ◽  
Gas Flow ◽  
Flow Direction ◽  
Anesthesia Machine ◽  
Oxygen Flow Rate ◽  
Oxygen Flow

Background Increased carboxyhemoglobin concentrations in patients receiving inhalation anesthetics (desflurane, enflurane, and isoflurane) have been reported. Recent in vitro studies suggest that dry carbon dioxide absorbents may allow the production of carbon monoxide. Methods The authors used high fresh oxygen flow (5 or 10 l/min) through a conventional circle breathing system of an anesthesia machine for 24 or 48 h to produce absorbent drying. Initial studies used 10 l/min oxygen flow with the reservoir bag removed or with the reservoir bag left in place during absorbent drying (this increases resistance to gas flow through the canister). A third investigation evaluated a lower flow rate (5 l/min) for absorbent drying. Water content of the absorbent and temperature were measured. Pigs received a 1.0 (human) minimum alveolar concentration desflurane anesthetic (7.5%) for 240 min using a 1 l/min oxygen flow rate with dried absorbent. Carbon monoxide concentrations in the circuit and carboxyhemoglobin concentrations in the pigs were measured. Results Pigs anesthetized with desflurane using Baralyme exposed to 48 h of 10 l/min oxygen flow (reservoir bag removed) had extremely high carboxyhemoglobin concentrations (more than 80%). Circuit carbon monoxide concentrations during desflurane anesthesia using absorbents exposed to 10 l/min oxygen flow (reservoir bag removed, 24 h) reached peak values of 8,800 to 13,600 ppm, depending on the absorbent used. Carboxyhemoglobin concentrations reached peak values of 73% (Baralyme) and 53% (soda lime). The water content of Baralyme decreased from 12.1 +/- 0.3% (mean +/- SEM) to as low as 1.9 +/- 0.4% at the bottom of the lower canister (oxygen flow direction during drying was from bottom to top). Absorbent temperatures in the bottom canister increased to temperatures as high as 50 degrees C. With the reservoir bag in place during drying (10 l/min oxygen flow), water removal from Baralyme was insufficient to produce carbon monoxide (lowest water content = 5.5%). Use of 5 l/min oxygen flow (reservoir bag removed) for 24 h did not reduce water content sufficiently to produce carbon dioxide with desflurane. Conclusions An oxygen flow rate of 10 l/min for 24 h in a conventional anesthesia circuit can dry carbon dioxide absorbents sufficiently to produce extremely high levels of carbon monoxide with high carboxyhemoglobin concentrations in desflurane-anesthetized pigs. When the reservoir bag is in place on the anesthesia machine or when a lower oxygen flow rate (5 l/min) is used, carbon dioxide absorbent drying still occurs, but 24-48-h exposure time is insufficient to allow for carbon monoxide production with desflurane.

Rehydration of Desiccated Baralyme Prevents Carbon Monoxide Formation from Desflurane in an Anesthesia Machine 

1997 ◽  
Vol 86 (5) ◽  
pp. 1061-1065 ◽  
Author(s):  
Pamela J. Baxter ◽  
Evan D. Kharasch
Keyword(s):  
Carbon Monoxide ◽  
Water Content ◽  
Effective Means ◽  
Soda Lime ◽  
Anesthesia Machine ◽  
Gas Chromatography Mass Spectrometry ◽  
Constant Weight ◽  
Normal Water ◽  
Carbon Monoxide Formation

Background Desiccated carbon dioxide absorbents degrade desflurane, enflurane, and isoflurane to carbon monoxide (CO) in vitro and in anesthesia machines, which can result in significant clinical CO exposure. Carbon monoxide formation is highest from desflurane, and greater with Baralyme than with soda lime. Degradation is inversely related to absorbent water content, and thus the greatest CO concentrations occur with desflurane and fully desiccated Baralyme. This investigation tested the hypothesis that rehydrating desiccated absorbent can diminish CO formation. Methods Baralyme was dried to constant weight. Carbon monoxide formation from desflurane and desiccated Baralyme was determined in sealed 20.7-ml vials without adding water, after adding 10% of the normal water content (1.3% water), and after adding 100% of the normal water content (13% water) to the dry absorbent. Similar measurements were made using an anesthesia machine and circle system. Carbon monoxide was measured by gas chromatography-mass spectrometry. Results Carbon monoxide formation from desflurane in vitro was decreased from 10,700 ppm with desiccated Baralyme to 715 ppm and less than 100 ppm, respectively, when 1.3% and 13% water were added. Complete rehydration also decreased CO formation from enflurane and isoflurane to undetectable concentrations. Desflurane degradation in an anesthesia machine produced 2,500 ppm CO in the circuit, which was reduced to less than 180 ppm when the full complement of water (13%) was added to the dried absorbent. Conclusions Desflurane is degraded by desiccated Baralyme in an anesthesia machine, resulting in CO formation. Adding water to dried Baralyme is an effective means of reducing CO formation and the risk of intraoperative CO poisoning. Although demonstrated specifically for desflurane and Baralyme, rehydration is also applicable to enflurane and isoflurane, and to soda lime.

Comparison of Emission Levels of Motor Cars, Motorcycles, and Tricycles Using Petrol Engines in Southwestern Nigeria

2021 ◽  
Vol 900 ◽  
pp. 183-187
Author(s):  
Odunlami Olayemi Abosede ◽  
Akeredolu Funso Alaba
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Carbon Dioxide Emissions ◽  
Mean Value ◽  
Southwestern Nigeria ◽  
Mean Values ◽  
Mobile Sources ◽  
Southwest Nigeria ◽  
The Mean ◽  
European Standards

The emissions of carbon monoxide, carbon dioxide, and hydrocarbon from four stroke-powered motorcars and two stroke-powered motorcycles and tricycles in Southwest Nigeria were examined using an automotive 4-gas analyer. Results show that tricycles produced more hydrocarbon and carbon monoxide emissions than motorcycles, while motorcycles emitted more of these pollutants than the gasoline fueled motor cars. (The gasoline fueled motorcars produced lowest hydrocarbon and carbon monoxide while the tricycles produced the highest hydrocarbon and carbon monoxide emissions). On the contrary, motor cars had the highest mean value of carbon dioxide followed by the motorcycles, while tricycles had the least. This could be attributed to the presence of the catalytic converters in some of the motor cars oxidizing carbon monoxide to carbon dioxide. The mean values of hydrocarbon, carbon monoxide and carbon dioxide emissions from motorcars are 630ppm, 10200ppm and 59900ppm. This is much higher than the NESREA (National Environmental standards and Regulations Enforcement Agency) standards as well as Euro II and Euro III (European standards) for vehicular emission. The mean values for hydrocarbon, carbon monoxide and carbon dioxide emissions from motorcycles and tricycles are (2150ppm, 21530ppm and 31200ppm) and (2820ppm, 24880ppm and 38710ppm) respectively. These results do not comply with Nigeria and European emission standards for hydrocarbon, and carbon monoxide. Tricycles and motorcycles account for higher concentrations of hydrocarbon and carbon monoxide pollutants from mobile sources, while they emit carbon dioxide minimally.

scholarly journals Co-pyrolysis of rubberwood sawdust (RWS) and polypropylene (PP) in a fixed bed pyrolyzer

2019 ◽  
Vol 13 (1) ◽  
pp. 4636-4647 ◽  
Author(s):  
N. I. Izzatie ◽  
M. H. Basha ◽  
Y. Uemura ◽  
M. S. M. Hashim ◽  
M. Afendi ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Water Content ◽  
Fixed Bed ◽  
Oil Yield ◽  
Pyrolysis Oil ◽  
Pyrolysis Process ◽  
Increasing Trend ◽  
Different Temperatures

Co-pyrolysis of rubberwood sawdust (RWS) waste and polypropylene (PP) was carried out at different temperatures (450,500,550, and 600°C) with biomass to plastics ratio 1:1 by using fixed bed drop-type pyrolyzer. The yield of pyrolysis oil has an increasing trend as the temperature increased from 450°C to 550°C. However, the pyrolysis oil yield dropped at a temperature of 600°C. Co-pyrolysis of RWS and PP generated maximum pyrolysis oil with 36.47 wt.% at 550°C. The result is compared with the pyrolysis of RWS only without plastics, with the same feedstock, and the maximum pyrolysis oil yield obtained was 33.3 wt.%. The water content in pyrolysis oil of co-pyrolysis RWS with PP is lower than RWS only with 54.2 wt.% and 62 wt.% respectively. Hydrocarbons, acyclic olefin, alkyl, and aromatic groups are the major compound in the pyrolysis oil from the co-pyrolysis process. Carbon monoxide (52.2 vol.%) and carbon dioxide (38.2 vol.%) are the major gas components.

Mass Spectrometry Provides Warning of Carbon Monoxide Exposure Via Trifluoromethane

1996 ◽  
Vol 84 (6) ◽  
pp. 1489-1493 ◽  
Author(s):  
Harvey J. Woehlck ◽  
Marshall Dunning ◽  
Kasem Nithipatikom ◽  
Alexander H. Kulier ◽  
Daniel W. Henry
Keyword(s):  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Gas Chromatography ◽  
Carbon Monoxide ◽  
Water Content ◽  
Charge Ratio ◽  
Patient Exposure ◽  
Mass Spectrometers ◽  
Clinical Anesthesia

Background The chemical breakdown of isoflurane, enflurane, or desflurane in dried carbon dioxide absorbents may produce carbon monoxide. Some mass spectrometers can give false indications of enflurane during anesthetic breakdown. Methods During clinical anesthesia with isoflurane or desflurane, the presence of carbon monoxide in respiratory gas was confirmed when enflurane was inappropriately indicated by a clinical mass spectrometer that identified enflurane at mass to charge ratio = 69. In vitro, isoflurane, enflurane, or desflurane in oxygen was passed through dried carbon dioxide absorbents at 35, 45, and 55 degrees C. Gases were analyzed by gas chromatography and by mass spectrometry. Results Mass spectrometry identified several clinical incidents in which 30-410 ppm carbon monoxide was measured in respiratory gas. Trifluoromethane was produced during in vitro breakdown of isoflurane or desflurane. Although these inappropriately indicated quantities of "enflurane" correlated (r2 > 0.95) to carbon monoxide concentrations under a variety of conditions, this ratio varied with temperature, anesthetic agent, absorbent type, and water content. Conclusions Trifluoromethane causes the inappropriate indication of enflurane by mass spectrometry, and indicates isoflurane and desflurane breakdown. Because the ratio of carbon monoxide to trifluoromethane varies with conditions, this technique cannot be used to quantitatively determine the amount of carbon monoxide to which a patient is exposed. If any warning of anesthetic breakdown results from this technique then remedial steps should be taken immediately to stop patient exposure to carbon monoxide. No warning can be provided for the breakdown of enflurane by this technique.

Sign in / Sign up

Export Citation Format

Share Document