The Rate of Carbon Monoxide Uptake by Normal Men

Forbes, W. H.; Sargent, Frederick; Roughton, F. J. W.

doi:10.1152/ajplegacy.1945.143.4.594

Cited by 161 publications

(61 citation statements)

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“…The rate of CO uptake in men breathing low concentrations of CO (0.01 to 0.2 per cent in air) has previously been measured (4,5,15) by methods based on analyses of inspired gas and venous blood and determinations or estimations of the blood volume. It has been found that under these conditions the CO uptake remains constant until the blood is approximately one-third saturated with CO. Three empirical formulae for predicting the increase in per cent COHb have been derived from such data.…”

Section: Discussionmentioning

confidence: 99%

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Carbon Monoxide Uptake and Pulmonary Diffusing Capacity in Normal Subjects at Rest and During Exercise 1

Filley¹,

Macintosh²,

Wright³

1954

J. Clin. Invest.

329

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It is generally accepted that the exchange of pulmonary gases between "alveolar air" and pulmonary blood takes place by simple diffusion across the "pulmonary membrane." 2 Two properties of this membrane, namely, its permeability to gases and its surface area, are of considerable interest since a decrease in either could limit the rate of gaseous diffusion. There is no known physiological method for measuring specifically the permeability as contrasted to the area of the pulmonary diffusing surface in man. In 1915, M. Krogh (1), using carbon monoxide, made the first determinations of the pulmonary "diffusion constant" in human beings. This constant was considered to be proportional to both permeability and area of the diffusing surface and was expressed in cc. of CO diffusing per mm. Hg of CO partial pressure difference on either side of the pulmonary membrane. Roughton (2) has viewed the diffusion constant of normal persons as a measure of the number and size of patent pulmonary capillaries. Several investigators (3), in considering the diffusion constant for oxygen, have recommended that it be referred to as the "diffusing capacity" because its magnitude is greater during exercise than at rest.Carbon monoxide is peculiarly suitable for studies of gas diffusion across the pulmonary membrane because of the tenacity with which it is bound by hemoglobin after it has diffused into the red cells. For this reason, CO is taken up from respired gas for considerable periods of time (4) without there being a significant change in the Pco, or "escaping tendency," in the pulmonary capillary blood. The driving force responsible for CO transport across 1 These studies were aided by a contract between the Office of Naval Research, Department of the Navy, and the Trudeau Foundation

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Section: Discussionmentioning

confidence: 99%

“…the pulmonary membrane can, therefore, be considered to be equal to the partial pressure of CO in the alveoli. Forbes, Sargent, and Roughton (5) have used these facts to estimate the pulmonary diffusing capacity in man at rest during the steady state of CO uptake.…”

mentioning

confidence: 99%

Carbon Monoxide Uptake and Pulmonary Diffusing Capacity in Normal Subjects at Rest and During Exercise 1

Filley¹,

Macintosh²,

Wright³

1954

J. Clin. Invest.

329

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“…For example, exposure to 20 ppm of CO (such as might still be encountered in the most confined and heavily trafficked areas of European Cities, such as road tunnels, and which still commonly occurs in many cities in developing countries) will cause blood levels of carboxyhaemoglobin to rise to an equilibrium level of 3.2% in about 8 hours if a person is carrying out light activity, or four hours during more strenuous exercise (Forbes et al (1945) in EPAQS (1994). For lead, a blood sample reveals the level of exposure over a longer time period, and a rise from 10 to 20 µg dl -1 has been found to be associated with a loss of up to two Intelligence Quotient points (EPAQS, 1998).…”

Section: Road Traffic and Effects Of Urban Air Quality (Especially Pamentioning

confidence: 99%

The transport sector as a source of air pollution

Colvile

Hutchinson

Mindell

et al. 2001

Atmospheric Environment

607

228

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Transport first became a significant source of air pollution after the problems of sooty smog from coal combustion had largely been solved in western European and North American cities. Since then, emissions from road, air, rail and water transport have been partly responsible for acid deposition, stratospheric ozone depletion and climate change. Most recently, road traffic exhaust emissions have been the cause of much concern about the effects of urban air quality on human health and tropospheric ozone production. This article considers the variety of transport impacts on the atmospheric environment by reviewing three examples: urban road traffic and human health, aircraft emissions and global atmospheric change, and the contribution of sulphur emissions from ships to acid deposition. Each example has associated with it a different level of uncertainty, such that a variety of policy responses to the problems are appropriate, from adaptation through precautionary emissions abatement to cost-benefit analysis and optimised abatement. There is some evidence that the current concern over the transport contribution to urban air quality is justified, but aircraft emissions should also give cause for concern given that air traffic is projected to continue to increase. Emissions from road traffic are being reduced substantially by the introduction of technology especially three-way catalysts and also, most recently, by local traffic reduction measures especially in western European cities. In developing countries and Eastern Europe, however, there remains the possibility of great increase in car ownership and use, and it remains to be seen whether these countries will adopt measures now to prevent transport-related air pollution problems becoming severe later in the 21 st century.Key words: Vehicle emissions, Aerosol urban, Health impact, Ship emissions, Aircraft emissions 1 Introduction Transport is widely recognised to be a significant and increasing source of air pollution world wide. Several previous reviews have focused on individual modes of transport and/or single environmental impacts of transport. For example, OECD (1988) briefly considers regional and global impacts of transport emissions of air pollution, but is mostly concerned with the impact of emissions on local urban air quality, and considers only road transport. The Third International Symposium on Transport and Air Pollution (Joumard, 1996) also has an emphasis on road traffic and urban air quality, but the Special Edition of Science of the Total Environment presenting highlights of the symposium also includes a few papers covering air and sea transport. Joumard comments on the value of the contributions from developing countries including Africa and Latin America; a review of road transport emissions and their impact on the environment at all scales from local to global was also published a couple of years earlier by Faiz (1993). One of the most comprehensive recent reviews of the environmental impacts of transport is that of the Royal Commi...

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“…Furthermore, chemical reaction between formic and sulphuric acid is very rapid, producing carbon monoxide almost instantaneously. Experimental data demonstrate that with concentrations of 3000 ppm of carbon monoxide in the air, it takes approximately 30 minutes to reach 30% of carboxyhemoglobin in the blood [22]. Histology analyses revealed complete lack of inflammatory reaction in the tissues.…”

Section: Resultsmentioning

confidence: 93%