Carbon dioxide response

Like other volatile agents, sevoflurane causes dose-related respiratory depression. In healthy patients this results in a decrease in tidal volume and an increase in respiratory rate with a net decrease in minute ventilation. At anaesthetic concentrations the degree of depression is greater than that seen with halothane or isoflurane. There is a decline in the slope of the carbon dioxide response curve. Sevoflurane produces the same degree of bronchodilation as isoflurane and enflurane. 

Equipotent doses of etomidate and methohexitone produce a similar shift in the carbon dioxide-response curve but at any given carbon dioxide tension ventilation is greater after etomidate than after the barbiturate. 

Sharkey, T.D., Bemacchi, C.J., Farquhar, G.D., and Singsaas, E.L. 2007. Fitting photosynthetic carbon dioxide response curves for C3 leaves. Plant Cell Environ 30 1035-1040. 

Markedly lipid-soluble opioids have also been reported to cause respiratory depression. There was profound respiratory depression 100 minutes after the administration of fentanyl 100 micrograms epidurally (138), whilst epidural sufentanil caused apnea within a couple of minutes, reversed by nalbuphine (139). Epidural buprenorphine 150 micrograms produced prolonged time-dependent biphasic depression of carbon dioxide response in six healthy volunteers. The second maximum occurred at 8-10 hours after injection (140). Similar cases have been reported by others. 

Fig. 10. Carbon dioxide response at converter outlet, lean-to-rich transient.

Fig. 15. Measured and instantaneous carbon dioxide response, rich-to-lean transient.

Effects of Volatile Anesthetics on Cerbrocortical Laser Doppler Flow Hyperemia, Autoregulation, Carbon Dioxide Response, Flow Oscilliations, and Role of Nitric Oxide Antal G. Hudetz, Joseph G. Lee, Jeremy J. Smith, Zelijko J. Bosnjak, and John P. Kampine... 

Both fentanyl and Innovar depressed the slope of the rebreathing carbon dioxide response curve to 42% 6 of the values obtained in the same subjects when awake. After the last injection of fentanyl or the fentanyl/droperidol combination the slope of the curve increased to 77% 8 of the control level but after reaching a normal level the respiratory depression recurred, the slope of the curve falling to 55% + 5 of the control value. Subsequently the slope of the curve returned to near normal levels. 

A substantial fraction of the named enzymes are oxido-reductases, responsible for shuttling electrons along metabolic pathways that reduce carbon dioxide to sugar (in the case of plants), or reduce oxygen to water (in the case of mammals). The oxido-reductases that drive these processes involve a small set of redox active cofactors , that is, small chemical groups that gain or lose electrons. These cofactors include iron porjDhyrins, iron-sulfur clusters and copper complexes as well as organic species that are ET active. 

The solubility of the carbonate in water containing carbon dioxide causes the formation of caves with stalagtites and stalagmites and is responsible for hardness in water. Other important compounds are the carbide, chloride, cyanamide, hypochlorite, nitrate, and sulfide. 

The UK Environment Agency deals with over 6000 oil pollution incidents each year. One estimate suggests tliat tlie cheiTtical industry contributes to 50% of all ah pollution witli proportions approximating to sulphur dioxide (36%), carbon dioxide (28%), nitrogen oxides (18%), carbon monoxide (14%) and black smoke (10%). Motor spirit refining is responsible for ca 26% of emissions of volatile organic compounds to the atmosphere. In 1996 there were over 20 000 reports of water pollution incidents with 155 successful prosecutions. 

About 51 percent of solar energy incident at the top of the atmosphere reaches Earth s surface. Energetic solar ultraviolet radiation affects the chemistry of the atmosphere, especially the stratosphere where, through a series of photochemical reactions, it is responsible for the creation of ozone (O,). Ozone in the stratosphere absorbs most of the short-wave solar ultraviolet (UV) radiation, and some long-wave infrared radiation. Water vapor and carbon dioxide in the troposphere also absorb infrared radiation. 

Transportation is also the emissions leader. About 75 percent of carbon dioxide emissions and 45 percent of nitrogen oxide emissions come from the transportation sector. If rising levels of CO, are found to be responsible for global warming, and measures are put in place to severely curtail CO, emissions, the measures will have the greatest impact on the transportation sector. 

Power plant emissions result from the comhustion of fossil fuels such as coal, gas, and oil. These emissions include sulfur dioxide (SO,), nitrogen oxides (NO.,), particulate matter, and hazardous air pollutants, all of which are subject to environmental regulations. Another emission is carbon dioxide (CO,), suspected of being responsible for global warming. 

Natural gas will continue to be substituted for oil and coal as primary energy source in order to reduce emissions of noxious combustion products particulates (soot), unburned hydrocarbons, dioxins, sulfur and nitrogen oxides (sources of acid rain and snow), and toxic carbon monoxide, as well as carbon dioxide, which is believed to be the chief greenhouse gas responsible for global warming. Policy implemented to curtail carbon emissions based on the perceived threat could dramatically accelerate the switch to natural gas. 

Ethanol, C2H5OH, is responsible for the effects of intoxication felt after drinking alcoholic beverages. When ethanol burns in oxygen, carbon dioxide, and water are produced. 

Gal-Or and Hoelscher (G5) have recently developed a fast and simple transient-response method for the measurement of concentration and volumetric mass-transfer coefficients in gas-liquid dispersions. The method involves the use of a transient response to a step change in the composition of the feed gas. The resulting change in the composition of the liquid phase of the dispersion is measured by means of a Clark electrode, which permits the rapid and accurate analysis of oxygen or carbon dioxide concentrations in a gas, in blood, or in any liquid mixture. 

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