Biomaterial Database

Gas-to-blood PCO2 differences during severe hypercapnia. 1979

G H Gurtner, and R J Traystman

Five anesthetized dogs were made severely hypercapnic by stepwise addition of CO2 to their inspired air. Blood PCO2 levels greater than 400 Torr were reached. During hypercapnia, the steady-state end-tidal PCO2 (PaCO2) was always higher than the simultaneous measured arterial PCO2 (PaCO2). The mean ratio PaCO2/PACO2 was 0.861 +/- 0.01. These results are consistent with the predictions of the Charged Membrane Hypothesis, that gas-to-blood PCO2 differences should be directly proportional to the blood H+ activity. The results cannot be explained by delayed equilibration of CO2 between plasma and red blood cells. The latter hypothesis predicts that, under the conditions of these experiments, the PCO2 of arterial blood should be higher than the PCO2 of end-tibal gas. The blood HCO3- during hypercapnia did not increase as much as would be predicted if the blood were exposed to CO2 in vitro. This may reflect movement of blood HCO3- generated by the buffering of carbonic acid into intracellular compartments during hypercapnia.

UI	MeSH Term	Description	Entries
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D002021	Buffers	A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.	Buffer
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D002255	Carbonic Acid	Carbonic acid (H2C03). The hypothetical acid of carbon dioxide and water. It exists only in the form of its salts (carbonates), acid salts (hydrogen carbonates), amines (carbamic acid), and acid chlorides (carbonyl chloride). (From Grant & Hackh's Chemical Dictionary, 5th ed)	Acid, Carbonic
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D006935	Hypercapnia	A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.
D000136	Acid-Base Equilibrium	The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance.	Anion Gap,Acid-Base Balance,Acid Base Balance,Acid Base Equilibrium,Anion Gaps,Balance, Acid-Base,Equilibrium, Acid-Base,Gap, Anion,Gaps, Anion
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001639	Bicarbonates	Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.	Bicarbonate,Bicarbonate Ions,Hydrogen Carbonates,Bicarbonate Ion,Carbonic Acid Ions,Hydrogen Carbonate,Carbonate, Hydrogen,Carbonates, Hydrogen,Ion, Bicarbonate,Ions, Bicarbonate,Ions, Carbonic Acid