Acid–base kinetics during hemodialysis using bicarbonate and lactate as dialysate buffer bases based on the H+ mobilization model

2020 ◽  
Vol 43 (10) ◽  
pp. 645-652
Author(s):  
John K Leypoldt ◽  
Mauro Pietribiasi ◽  
Anna Ebinger ◽  
Michael A Kraus ◽  
Allan Collins ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Concentration ◽  
Compartment Model ◽  
Total Carbon ◽  
Bicarbonate Concentration ◽  
Plasma Bicarbonate ◽  
Hemodialysis Treatment ◽  
Daily Hemodialysis ◽  
Acid Generation ◽  
Carbon Dioxide Concentrations

Background: The H+ mobilization model has been recently reported to accurately describe intradialytic kinetics of plasma bicarbonate concentration; however, the ability of this model to predict changing bicarbonate kinetics after altering the hemodialysis treatment prescription is unclear. Methods: We considered the H+ mobilization model as a pseudo-one-compartment model and showed theoretically that it can be used to determine the acid generation (or production) rate for hemodialysis patients at steady state. It was then demonstrated how changes in predialytic, intradialytic, and immediate postdialytic plasma bicarbonate (or total carbon dioxide) concentrations can be calculated after altering the hemodialysis treatment prescription. Results: Example calculations showed that the H+ mobilization model when considered as a pseudo-one-compartment model predicted increases or decreases in plasma total carbon dioxide concentrations throughout the entire treatment when the dialysate bicarbonate concentration is increased or decreased, respectively, during conventional thrice weekly hemodialysis treatments. It was further shown that this model allowed prediction of the change in plasma total carbon dioxide concentration after transfer of patients from conventional thrice weekly to daily hemodialysis using both bicarbonate and lactate as dialysate buffer bases. Conclusion: The H+ mobilization model can predict changes in plasma bicarbonate or total carbon dioxide concentration during hemodialysis after altering the hemodialysis treatment prescription.

scholarly journals Relationship between serum total carbon dioxide concentration and bicarbonate concentration in patients undergoing hemodialysis

2020 ◽  
Vol 39 (4) ◽  
pp. 441-450
Author(s):  
Keiji Hirai ◽  
Susumu Ookawara ◽  
Junki Morino ◽  
Saori Minato ◽  
Shohei Kaneko ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Concentration ◽  
Total Carbon ◽  
Bicarbonate Concentration

scholarly journals Organic Acids Interfere in the Measurement of Carbon Dioxide Concentration by the Kodak Ektachem 700

1992 ◽  
Vol 29 (1) ◽  
pp. 105-108 ◽  
Author(s):  
Nader Rifai ◽  
John Hyde ◽  
Mariet Iosefsohn ◽  
Allen M. Glasgow ◽  
Steven J Soldin
Keyword(s):  
Carbon Dioxide ◽  
Organic Acids ◽  
Carbon Dioxide Concentration ◽  
Total Carbon ◽  
Blood Gas ◽  
Total Plasma ◽  
Bicarbonate Concentration ◽  
Significant Discrepancy ◽  
Maple Syrup ◽  
Urine Disease

A significant discrepancy was noted in our laboratory between the total plasma carbon dioxide concentration measured by the Kodak Ektachem 700 and the bicarbonate concentration derived from the Corning 170 pH/Blood Gas analyser in an 8-day-old patient. The concentration of total carbon dioxide was 18 mmol/L while the derived bicarbonate was 13 mmol/L. The patient was eventually diagnosed as maple syrup urine disease. This finding led us to examine the effect of various organic acids on the measurement of carbon dioxide by the Ektachem 700. Several interfered significantly. Clinicians should be aware that when organic acid concentrations are increased, the Ektachem 700 total carbon dioxide result may be falsely raised.

scholarly journals Technical Note: Long-term memory effect in the atmospheric CO<sub>2</sub> concentration at Mauna Loa

2006 ◽  
Vol 6 (6) ◽  
pp. 11957-11970 ◽  
Author(s):  
C. Varotsos ◽  
M.-N. Assimakopoulos ◽  
M. Efstathiou
Keyword(s):  
Carbon Dioxide ◽  
Time Series ◽  
Power Law ◽  
Carbon Dioxide Concentration ◽  
Global Climate Models ◽  
Fluctuation Analysis ◽  
Original Time Series ◽  
Mauna Loa ◽  
Carbon Dioxide Concentrations ◽  
Original Time

Abstract. The monthly mean values of the atmospheric carbon dioxide concentration derived from in-situ air samples collected at Mauna Loa Observatory, Hawaii, during 1958–2004 (the longest continuous record available in the world) are analyzed by employing the detrended fluctuation analysis to detect scaling behavior in this time series. The main result is that the fluctuations of carbon dioxide concentrations exhibit long-range power-law correlations (long memory) with lag times ranging from four months to eleven years, which correspond to 1/f noise. This result indicates that random perturbations in the carbon dioxide concentrations give rise to noise, characterized by a frequency spectrum following a power-law with exponent that approaches to one; the latter shows that the correlation times grow strongly. This feature is pointing out that a correctly rescaled subset of the original time series of the carbon dioxide concentrations resembles the original time series. Finally, the power-law relationship derived from the real measurements of the carbon dioxide concentrations could also serve as a tool to improve the confidence of the atmospheric chemistry-transport and global climate models.

Comparison of two analyzers for measurement of plasma total carbon dioxide concentration in horses

2013 ◽  
Vol 74 (8) ◽  
pp. 1091-1102
Author(s):  
Peter D. Constable ◽  
Stacy H. Tinkler ◽  
Laurent. L. Couëtil
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Concentration ◽  
Total Carbon

An Investigation of the Sources of Blowby in Single-Cylinder Supercharged Diesel Engines

1978 ◽  
Vol 192 (1) ◽  
pp. 39-48 ◽  
Author(s):  
B. Bull ◽  
M. A. Voisey
Keyword(s):  
Carbon Dioxide ◽  
Diesel Engines ◽  
Piston Ring ◽  
Carbon Dioxide Concentration ◽  
Operating Conditions ◽  
Exhaust Valve ◽  
Simple Method ◽  
Single Cylinder ◽  
Carbon Dioxide Concentrations ◽  
Wide Range

Measurements of carbon dioxide concentrations in the exhaust and in the crankcase of two different types of single-cylinder, supercharged diesel engines have been used to determine the amount of exhaust gas reaching the crankcase as piston ring blowby and as leakage through the exhaust valve stem-to-guide clearance. Over a wide range of operating conditions in both engines the carbon dioxide concentration was found to be more dependent on engine fuelling rate per hour than on fuel input per stroke. It was established that blowby through the exhaust valve guide was a major contributor to crankcase contamination. A simple method has been devised, requiring only minor modifications to the engine, that permits the blowby through the piston ring pack and the exhaust valve guides to be determined separately in turbocharged production engines.

Respiration in cropped and fallow soil

1979 ◽  
Vol 92 (1) ◽  
pp. 45-51 ◽  
Author(s):  
D. T. Pritchard ◽  
N. J. Brown
Keyword(s):  
Carbon Dioxide ◽  
Gas Chromatography ◽  
Soil Moisture ◽  
Moisture Content ◽  
Temperature Effects ◽  
Root Respiration ◽  
Soil Moisture Content ◽  
Carbon Dioxide Concentration ◽  
Carbon Dioxide Concentrations ◽  
Fallow Soil

SummarySoil air was sampled daily at depths of 5, 10, 20 and 30 cm in fallow and cropped plots, which had either been rolled or cultivated. Carbon dioxide was measured by gas chromatography.Carbon dioxide concentrations were greater in the cropped than in the fallow plots. The rolled plots were wetter than the cultivated plots and carbon dioxide concentrations were also greater.In the fallow plots, carbon dioxide was correlated with soil temperature but variations in soil moisture content had little immediate effect.In the cropped plots, temperature effects were overshadowed by the response to irrigation which immediately increased the carbon dioxide concentration. These increases were attributed to enhanced root respiration, rather than to restricted diffusion or increased microbial activity.

scholarly journals Detecting causality signal in instrumental measurements and climate model simulations: global warming case study

2019 ◽  
Author(s):  
Mikhail Y. Verbitsky ◽  
Michael E. Mann ◽  
Byron A. Steinman ◽  
Dmitry M. Volobuev
Keyword(s):  
Carbon Dioxide ◽  
Time Series ◽  
Atmospheric Carbon Dioxide ◽  
Climate Model ◽  
Carbon Dioxide Concentration ◽  
Anthropogenic Forcing ◽  
Carbon Dioxide Concentrations ◽  
Climate Model Simulations ◽  
Earth’S Climate

Abstract. Detecting the direction and strength of the causality signal in observed time series is becoming a popular tool for exploration of distributed systems such as Earth's climate system. Here we suggest that in addition to reproducing observed time series of climate variables within required accuracy a model should also exhibit the causality relationship between variables found in nature. Specifically, we propose a novel framework for a comprehensive analysis of climate model responses to external natural and anthropogenic forcing based on the method of conditional dispersion. As an illustration, we assess the causal relationship between anthropogenic forcing (i.e., atmospheric carbon dioxide concentration) and surface temperature anomalies. We demonstrate a strong directional causality between global temperatures and carbon dioxide concentrations (meaning that carbon dioxide affects temperature stronger than temperature affects carbon dioxide) in both the observations and in (CMIP5) climate model simulated temperatures.

Environment in stone chamber of an unexcavated tumulus and preservation of buried relics: Part 1. Environmental monitoring for simulated tumulus

2020 ◽  
pp. 174425912091390
Author(s):  
Huarong Xie ◽  
Daisuke Ogura ◽  
Hiroyuki Yasui ◽  
Nobumitsu Takatori ◽  
Shuichi Hokoi ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Environmental Monitoring ◽  
Oxygen Concentration ◽  
Carbon Dioxide Concentration ◽  
Metal Corrosion ◽  
Small Temperature ◽  
Carbon Dioxide Concentrations ◽  
Hygrothermal Environments ◽  
Term Monitoring

Japan has many unexcavated tumuli, most of which were buried along with artifacts of precious cultural heritage. For such a tumulus, it is essential to understand how changes in its exterior environment affect its interior environment, and how those interior changes affect the deterioration of the relics buried in the stone chamber. In this study, an underground space was constructed in the forest of the Katsura Campus of Kyoto University to simulate the environment of an unexcavated tumulus, and long-term monitoring was implemented in the simulated stone chamber, including the temperature, humidity, water potential, wetness, and oxygen and carbon dioxide concentrations, along with metal corrosion tests. This article is focused on environmental monitoring, and the results demonstrate that the simulated tumulus has the general characteristics of the hygrothermal environments of an unexcavated tumulus that has small temperature fluctuation and near-saturation humidity. The ceiling of the simulated chamber condensed significantly from October to April, which is related to the variations of the ceiling and floor temperatures. Also, the wetness of the walls in the simulated chamber was affected by rainfall. The oxygen concentration in the simulated stone chamber varied in the range of 13%–19% in 2015, and the variation of carbon dioxide concentration in the simulated stone chamber was contrary to the oxygen concentration and varied in the range of 3%–9% in 2016. The oxygen concentration in the stone chamber was similar to that in the surrounding soil that decreased at times of rainfall, contrary to the fluctuations in the soil water content.

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