Influence of age on pulmonary diffusing capacity

Donevan, R. E.; Palmer, W. H.; Varvis, C. J.; Bates, David V.

doi:10.1152/jappl.1959.14.4.483

Cited by 60 publications

(19 citation statements)

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“…During the air diffusing capacity determination the measured mixed expired oxygen concentration was used in this calculation. Previous work from this laboratory (8) has supported the view of Asmussen and Neilsen (11) that the alveolar oxygen so calculated during exercise in normal subjects is reasonably accurate. The mean capillary oxygen tension (Pco2) was then calculated by the method described by Linderholm (10).…”

Section: Calculationssupporting

confidence: 57%

“…The apparatus used in this work has recently been described in full (8). A steady state measurement of diffusing capacity (DL) is made, the mean alveolar CO tension being calculated from an assumed value of respiratory dead space.…”

Section: Methodsmentioning

confidence: 99%

“…With the treadmill in the same position and at the same speed, the subject then resumed his exercise, the sequence of events being timed as before, but on this occasion he was switched into a mixture of air containing about 0.12 per cent CO. Following the determinations of the inspired and mixed expired CO concentrations, the oxygen uptake was calculated using the monitored mixed expired CO2 and oxygen in the manner previously described (8). The total experiment 1401 with the two measurements of diffusing capacity took about 25 minutes.…”

Section: Methodsmentioning

confidence: 99%

“…The pulmonary diffusing capacity was calculated from the DcO1A as previously described (8) except that the COHb correction was slightly modified. Early experience with the method showed that the calculated values of V, and DM were very sensitive to this correction, and it was found necessary to calculate the mean COHb during the exercise run, rather than to use the COHb level measured at the end of exercise as the pertinent value.…”

Section: Calculationsmentioning

confidence: 99%

“…A steady state measurement of diffusing capacity (DL) is made, the mean alveolar CO tension being calculated from an assumed value of respiratory dead space. Technical details and a study of the errors of this method have been presented previously (8). The determination of pulmonary capillary blood volume (Va) and membrane diffusion component (DM) involves the measurement of the pulmonary diffusing capacity at two different oxygen tensions.…”

mentioning

confidence: 99%

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Variations in the Pulmonary Capillary Blood Volume and Membrane Diffusion Component in Health and Disease*

Bates¹,

Varvis²,

Donevan³

et al. 1960

J. Clin. Invest.

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Forster, Roughton and their colleagues (1, 2) have reported a method of subdividing the components of the pulmonary diffusing capacity by measurement of the apparent diffusing capacity at different alveolar oxygen tensions. This development followed preparatory work by the same authors (3,4) in which the kinetic factors involved in CO and hemoglobin combination were reported. The principles underlying the measurements have been fully discussed by Forster in a recent review (5).Lewis, Lin, Noe and Komisaruk (6) reported on the measurement of pulmonary capillary blood volume in normal subjects, using the single breath method of determining the pulmonary diffusing capacity. They found average values of 65 ml for the pulmonary capillary blood volume at rest and 98 ml CO per minute per mm Hg for the membrane diffusion component. In four subjects both of these quantities increased somewhat during exercise. They did not report any results on patients. McNeill, Rankin and Forster (7), using a similar technique of measuring the pulmonary diffusing capacity by a single breath method, found similar values at rest for the pulmonary capillary blood volume, but a lower value for the membrane component, which was about 63.5 ml CO per minute per mm Hg in normal subjects at rest. These authors reported the results of this measurement in five patients with various types of pulmonary fibrosis, two with pulmonary hypertension, two with pulmonary congestion, and three with chronic obstructive emphysema. The most significant findings were the decrease in membrane diffusion component ib patients with pulmonary fibrosis, and the increase generally found in pulmonary capillary blood volume in patients with increased pressure in the lesser circulation.The present study reports the measurement of * Supported by a grant from the National Research Council of Canada.these two components of the pulmonary diffusing capacity by a steady state method during exercise in 14 normal subjects and in a group of 22 patients. This work was undertaken to study the reliability of the results obtainable with this technique, and to explore its usefulness in investigative work. METHODSThe apparatus used in this work has recently been described in full (8). A steady state measurement of diffusing capacity (DL) is made, the mean alveolar CO tension being calculated from an assumed value of respiratory dead space. Technical details and a study of the errors of this method have been presented previously (8). The determination of pulmonary capillary blood volume (Va) and membrane diffusion component (DM) involves the measurement of the pulmonary diffusing capacity at two different oxygen tensions. Each experiment whether on a normal subject or a patient consisted in the measurement of the diffusing capacity on either 60 or 100 per cent oxygen, followed by its determination on air. All estimates were made during moderate or light exercise.In a typical determination, the subject attained a steady state on the exercise treadmill for 5 minutes, and was then switch...

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Section: Calculationssupporting

confidence: 57%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

mentioning

confidence: 99%

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