Diffusing capacity at different lung volumes during breath holding and rebreathing

Rose, G. L.; Cassidy, S. S.; Johnson, Robert L.

doi:10.1152/jappl.1979.47.1.32

Cited by 45 publications

(25 citation statements)

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“…Estimates of DL CO by these two techniques agree well in conscious healthy human subjects at rest and during exercise (22,54). On the other hand, the SB technique is known to underestimate true DL CO in disease states in the presence of ventilatory inhomogeneity (28).…”

Section: Rb Technique In Rodentsmentioning

confidence: 78%

Fatty diabetic lung: functional impairment in a model of metabolic syndrome

Yilmaz

Ravikumar²,

Bellotto

et al. 2010

Journal of Applied Physiology

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The Zucker diabetic fatty (ZDF fa/fa) rat with genetic leptin insensitivity develops obesity and Type 2 diabetes mellitus (T2DM) with age accompanied by hyperplastic changes in the distal lung (Am J Physiol Lung Cell Mol Physiol 298: L392-L403, 2010). To determine the functional consequences of structural changes, we developed a rebreathing (RB) technique to simultaneously measure lung volume, pulmonary blood flow, lung diffusing capacity (Dl(CO)), membrane diffusing capacity (Dm(CO)), pulmonary capillary blood volume (Vc), and septal tissue volume in anesthetized tracheostomized male ZDF fa/fa and matched lean (+/+) control animals at 4, 8, and 12 mo of age. Results obtained by RB technique were compared with that measured by a single-breath (SB) technique and to that expected in a wide range of species. In fa/fa animals compared with +/+, lung volumes and compliance were 13-35% lower at different ages, and the normal age-related increase in lung compliance was no longer evident. Mean pulmonary blood flow declined with age in fa/fa but not in +/+ animals. Dl(CO) measured at a given pulmonary blood flow was 20-43% lower at different ages due to reductions in both Dm(CO) and Vc. Septal tissue volume was also reduced in older fa/fa rats. We conclude that obese rats with T2DM develop significant restrictive pulmonary defects with diffusion impairment in a pattern similar to that previously reported in obese human subjects with T2DM. Functional impairment became exaggerated with age and duration of T2DM. In both fa/fa and +/+ animals, Dl(CO) measured by RB was systematically higher than by SB technique whereas lung volume was similar, a finding consistent with heterogeneous distribution of ventilation in the rat lung.

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Section: Rb Technique In Rodentsmentioning

confidence: 78%

Fatty diabetic lung: functional impairment in a model of metabolic syndrome

Yilmaz

Ravikumar²,

Bellotto

et al. 2010

Journal of Applied Physiology

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“…The differences we found were statistically significant only for VA-corrected values (tables 4, 5). It is known that DLCO is directly correlated to lung volume [18], and that VA repre sents the greatest source of variability of the test [19], Hence, it is not surprising that data corrected for VA arc more sensitive indicators of differences in diffus ing capacity caused by changes in the position.…”

Section: Discussionmentioning

confidence: 99%

Factors Affecting Variations in Pulmonary Diffusing Capacity Resulting from Postural Changes

Pistelli

Fuso²,

Muzzolon³

et al. 1991

Respiration

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The relation of postural changes to the diffusing capacity of the lung for carbon monoxide (DLCO) was investigated in 12 normal nonsmokers in order to evaluate the influence of body position on several components of lung resistance to gas diffusion. The well-known increase in CO diffusing capacity in the supine position was obtained only for data corrected for alveolar volume (KCO: 6.18 ± 0.75 vs. 5.45 ± 0.67 ml/min/ mm Hg/l; p < 0.005). Moreover, only the membrane component (Dm) increased significantly in supine subjects (KDm = 2.81 ± 1.32 vs. 1.82 ± 0.54 ml/min/mm Hg/l; p < 0.05), the increase in capillary blood volume (Vc) being not significant (KVc = 12.54 ± 4.22 vs. 11.17 ± 3.79 ml/l; NS). These data could be interpreted as a demonstration of a more homogeneously distributed ventilation with respect to diffusion surface in healthy young people in a supine position. The amount of surface available for diffusion seems therefore to be a limiting factor to gas flow across the lungs in these subjects. Thus a straightforward attribution of posturally influenced changes in CO diffusing capacity exclusively to factors affecting Vc is not recommended, particularly in pathological conditions, if information about variation in distribution of ventilation is unavailable

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“…In sleeping infants, the respiratory system was inflated twice to a lung volume defined by an airway pressure of 30 centimeters H 2 O (V 30 ), which inhibited inspiratory effort and induced a respiratory pause at functional residual capacity (FRC). The inspiratory gas was switched from room air to the test gas (0.3% C 18 O, 5% He, 21% O 2 and balance N 2 ) and inflation to V 30 with the test gas induced a respiratory pause at V 30 , which was maintained for 4 seconds (breath-hold time), and then followed by passive exhalation to FRC. The helium and carbon monoxide concentrations were continuously measured with a respiratory gas mass spectrometer (Perkin Elmer MGA-1100, Waltham, MA).…”

Section: What This Study Adds To the Fieldmentioning

confidence: 99%

“…Following 60% of expired volume, the helium concentration remained constant, which reflects that alveolar equilibration had been achieved. DL CO was calculated from the inspired volume of test gas (0.3% C 18 O) and the alveolar concentration of carbon monoxide, which was calculated as the average C 18 O concentration between 60 and 80% of the passive expired volume following the breath-hold, and the calculated DL CO was corrected to an Hb of 13.4 using the subjects' measured Hb, as recommended by ATS standards (12,13). Following the completion of measurements of V A30 and DL CO , a finger-stick was used to obtain a blood sample for determining Hb concentration (Hemacue Hb201, Lake Forest, CA).…”

Section: What This Study Adds To the Fieldmentioning

confidence: 99%

Growth of the Lung Parenchyma Early in Life

Balinotti¹,

Tiller²,

Llapur³

et al. 2009

Am J Respir Crit Care Med

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Rationale: Early in life, lung growth can occur by alveolarization, an increase in the number of alveoli, as well as expansion. We hypothesized that if lung growth early in life occurred primarily by alveolarization, then the ratio of pulmonary diffusion capacity of carbon monoxide (DL CO ) to alveolar volume (V A ) would remain constant; however, if lung growth occurred primarily by alveolar expansion, then DL CO /V A would decline with increasing age, as observed in older children and adolescents. Objectives: To evaluate the relationship between alveolar volume and pulmonary diffusion capacity early in life. Methods: In 50 sleeping infants and toddlers, with equal number of males and females between the ages of 3 and 23 months, we measured DL CO and V A using single breath-hold maneuvers at elevated lung volumes. Measurements and Main Results: DL CO and V A increased with increasing age and body length. Males had higher DL CO and V A when adjusted for age, but not when adjusted for length. DL CO increased with V A ; there was no gender difference when DL CO was adjusted for V A . The ratio of DL CO /V A remained constant with age and body length. Conclusions: Our results suggest that surface area for diffusion increases proportionally with alveolar volume in the first 2 years of life. Larger DL CO and V A for males than females when adjusted for age, but not when adjusted for length, is primarily related to greater body length in boys. The constant ratio for DL CO /V A in infants and toddlers is consistent with lung growth in this age occurring primarily by the addition of alveoli rather than the expansion of alveoli.Keywords: pulmonary diffusion capacity; alveolar volume; lung development The lung, which provides surface area for gas exchange, begins alveolarization of the lung parenchyma in late gestation; however, the number of alveoli present at birth is estimated to be less than 20% of the number in adults (1-3). In addition, alveolar size of an infant is smaller than the alveolar size of an adult (1-3). Therefore, postnatal growth and development of the lung parenchyma includes increases in number as well as size of alveoli. Lung volume early in life is thought to occur primarily by the addition of alveoli during the rapid phase of somatic growth, and then, following alveolarization of the lung parenchyma, lung volume increases by the expansion of existing alveoli. However, from the limited number of morphometric studies of relatively few autopsied lungs from infants and toddlers, which have used differing morphometric techniques to estimate alveolar number, it remains unclear whether the addition of alveoli is complete by 6 months, 2 to 3 years, or 8 years of age (2, 4-6).In vivo physiologic measurements of alveolar volume (V A ) and pulmonary diffusing capacity for carbon monoxide (DL CO ) can provide a functional assessment of the volume and surface area available for gas exchange, which indirectly reflects the cumulative effects of alveolar number and size. In older subjects from 8 years of age to...

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Diffusing capacity at different lung volumes during breath holding and rebreathing

Cited by 45 publications

References 0 publications

Fatty diabetic lung: functional impairment in a model of metabolic syndrome

Fatty diabetic lung: functional impairment in a model of metabolic syndrome

Factors Affecting Variations in Pulmonary Diffusing Capacity Resulting from Postural Changes

Growth of the Lung Parenchyma Early in Life

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