Biomaterial Database

Elevated alveolar PCO2 relative to predicted values during normal gas exchange. 1977

H T Robertson, and M P Hlastala

A negative aADCO2 has been demonstrated during ventilation with hypercarbic gas mixtures and during rebreathing, but has never been demonstrated during normal gas exchange. This anomalous behavior of CO2 was studied by comparing it to the behavior of five infused inert gases during normal gas exchange in 10 anesthetized mongrel dogs. The distribution of VA/Q heterogeneity and the respiratory dead space in the animals was quantitated using excretion-solubility data from the five infused inert gases. The predicted excretion fraction (PACO2/PVCO2) for CO2 was obtained from the inert gas excretion-solubility curve, using a measured solubility for CO2. The measured excretion fraction for CO2 (PACO2/PVCO2), even after correction for Haldane effect, was significantly greater than the predicted fraction (P less than 0.001). This corresponded to an alveolar PCO2 that exceeded the predicted value by a mean of 5.0 Torr.

UI	MeSH Term	Description	Entries
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D011651	Pulmonary Artery	The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.	Arteries, Pulmonary,Artery, Pulmonary,Pulmonary Arteries
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
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
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
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
D014692	Ventilation-Perfusion Ratio	The ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung. (Stedman, 25th ed)	Ratio, Ventilation-Perfusion,Ratios, Ventilation-Perfusion,Ventilation Perfusion Ratio,Ventilation-Perfusion Ratios