Estimates Of Diffusing Capacity Research Articles

Cardiac Sympathetic Dominance and Systemic Inflammation in COPD

Cardiac autonomic dysfunction is an independent determinant of adverse outcomes in many diseases. The available literature on the relative changes in sympathetic and parasympathetic components in chronic obstructive pulmonary disease (COPD) is equivocal, the clinical and physiological correlates are poorly defined and association with markers of systemic inflammation has not been explored. As both autonomic dysfunction and systemic inflammation may contribute to cardiovascular morbidity in COPD, we hypothesized that these may be associated. Sixty three stable patients of COPD and 36 controls underwent spirometry, estimation of diffusion capacity, six-minute walk test and measurements of serum interleukin-6 (IL-6) and high-sensitivity C-Reactive protein. Cardiac autonomic activity was evaluated by standard five-minute heart rate variability (HRV) recordings to obtain time- and frequency-domain indices and the averaged heart rate. We observed that HRV indices of overall autonomic modulation, the standard deviation of time intervals between consecutive normal beats (SDNN) and total power, were greater in patients with higher levels of indices of both parasympathetic and sympathetic activity. The heart rate was significantly higher in patients indicating an overall sympathetic dominance and was inversely correlated with diffusion capacity. Serum IL-6 was inversely correlated with pNN50, an index of parasympathetic activity, and positively with LF/HF ratio, a measure of sympathetic: parasympathetic balance. None of the HRV indices was significantly correlated with physiological measures of severity. It was concluded that patients with COPD have increased cardiac autonomic modulation with sympathetic dominance. This is associated with decreased lung diffusion capacity and systemic inflammation.

Comments on Point:Counterpoint: High altitude is/is not for the birds!

TO THE EDITOR: The debate between Scott et al. (6) and Llanos et al. (4) highlights the remarkable ability of birds and mammals to adapt and survive at high altitudes and cope with reduced oxygen (O2) availability. Scott and colleagues (6) make a compelling argument that birds are far superior to mammals at adapting and thriving in hypoxic environments, both at rest and during exercise. While their argument is supported by comparisons between birds and terrestrial mammals, it ignores marine mammals. Marine mammals such as seals are routinely exposed to and tolerate long bouts of hypoxia during breath-hold diving. For example, elephant seals may dive to depths of nearly 1,600 m and occasionally remain submerged for 2 h (3). Moreover, marine mammals can be exposed to partial pressures of arterial oxygen (PaO2) as low as 12 mmHg during free dives (5), which is less than the 20 mmHg observed in the bar-headed goose (6). Interestingly, a PaO2 of 12 mmHg observed in elephant seals corresponds to arterial saturations and O2 content of only 8% and 2.7 ml O2/dl (5). Thus marine mammals such as the elephant seal demonstrate a remarkable hypoxia tolerance. The integration of several key physiological adaptations including 1) substantially greater myoglobin concentrations compared to other mammals, 2) reductions in metabolism, 3) a greater reliance on aerobic metabolism (i.e., less lactate production), 4) a host of dramatic acute cardiovascular adjustments; and 5) an increased intrinsic cerebral hypoxia tolerance allow marine mammals to thrive in hypoxic environments and enable long deep dives (1–3).

Red cell distortion and conceptual basis of diffusing capacity estimates: finite element analysis.

To understand the effects of dynamic shape distortion of red blood cells (RBCs) as it develops under high-flow conditions on the standard physiological and morphometric methods of estimating pulmonary diffusing capacity, we computed the uptake of CO across a two-dimensional geometric capillary model containing a variable number of equally spaced RBCs. RBCs are circular or parachute shaped, with the same perimeter length. Total CO diffusing capacity (DLCO) and membrane diffusing capacity (DMCO) were calculated by a finite element method. DLCO calculated at two levels of alveolar PO2 were used to estimate DMCO by the Roughton-Forster (RF) technique. The same capillary model was subjected to morphometric analysis by the random linear intercept method to obtain morphometric estimates of DMCO. Results show that shape distortion of RBCs significantly reduces capillary diffusive gas uptake. Shape distortion exaggerates the conceptual errors inherent in the RF technique (J. Appl. Physiol. 79: 1039-1047, 1995); errors are exaggerated at a high capillary hematocrit. Shape distortion also introduces additional error in morphometric estimates of DMCO caused by a biased sampling distribution of random linear intercepts; errors are exaggerated at a low capillary hematocrit.

The effects of D/Q̇ and D/V̇ a inequalities on pulmonary oxygen diffusing capacity estimates

Bohr-integrated estimates of steady-state pulmonary diffusing capacity for oxygen (D l O 2 ) were calculated using lung compartments with different V̇ a/Q̇ rations. Compartmental diffusing capacity was distributed in proportion to either ventilation or blood flow. This method was applied to 115 gas exchange data sets previously collected from healthy human subjects during normoxic ( P i O 2 = 148 Torr ) or acute hypoxic ( P i O 2 = 80 Torr ) exercise. Ventilation-weighted estimates of oxygen diffusing capacity exceeded blood flow-weighted estimates by 10 and 78% during hypoxia and normoxia, respectively. While blood flow-weighted D l O 2 estimates during heavy exercise were greater in hypoxia than in normoxia (mean ± SEM of 87.1 ± 4.4 vs 53.0 ± 3.1 ml·min −1·Torr −1), ventilation-weighted estimates were not significantly different (93.2 ± 5.5 vs 96.3 ± 9.4 ml·min −1·Torr −1). These results show that the effect of D/Q̇ inequality on D l O 2 estimates is greater at higher levels of inspired oxygen. Furthermore, a D/Q̇ mismatch of similar magnitude as the V̇ a/Q̇ mismatch that is observed during heavy exercise can account for a previously observed discrepancy between normoxic and hypoxic oxygen diffusing capacity estimates.

Oxygen diffusing capacity estimates derived from measured V̇ A/Q̇ distributions in man

Data from eighteen subjects, studied in hypoxia ( minimum P I O 2 = 80 Torr ) both at rest and during exercise, were analyzed using computer models which estimate O 2 diffusing capacity from measured V̇ A/Q̇ distributions (obtained using the multiple inert gas elimination technique ‘MIGET’) and measured O 2 exchange. Two of these models assigned the distribution of the diffusing capacity (D) in proportion to either the perfusion (D L O 2 -Vwt) distributions from MIGET, and thus modeled the effects of V̇ A/Q̇ and D/Q̇β(where Q̇β is the perfusive conductance inequalities respectively. The third model (D L O 2 -3C) assigned all the diffusing capacity to a single homogeneous compartment. At rest D L O 2 was 41.1 ± 41.4 ± 5.4 and 30.2 ± 2.1 ml · min −1 · Torr −1 for the Qwt, Vwt and 3C models respectively. These rose to 93.7 ± 2.6, 109.3 ± 4.5 and 81.1 ± 1.9 ml · min −1 · Torr −1 respectively at maximal exercise, all significantly different from rest ( P < 0.001 for each). The effects of measured V̇ A/Q̇ and theoretical D/Q̇β inhomogeneities on diffusing capacity estimates were significant even in normal lungs. Both types of inequality caused an appreciable underestimation of D L O 2 . These multi-compartment model estimates, using real data, are consistent with published theoretical predictions of the effects of V̇, Q̇ and D inequalities. These results during exercise come close to morphometric predictions of maximal oxygen diffusing capacity in man.

Alveolar-arterial equilibration in the lung of sheep

In order to compare the efficiency of sheep lung with that of dog, gaseous exchange in hypoxia (F I O 2 0.12–0.13) with and without CO in the inspired air (F I CO 0.001) was measured in 12 sheep (mean body weight = 30.4 kg) under pentothal anesthesia and artificial ventilation. Alveolar-arterial pressure difference of O 2, % venous admixture and amount of V A/Q inhomogeneity were found to be substantially larger than in dog. Steady-state pulmonary diffusing capacity estimates, computed by three different procedures were, both for O 2 and for CO, about 40% smaller than in dog. The Dt O 2 /Dl CO ratio were not significantly different from those determined on dog data; thus the presumed benefecial effect of sheep small erythrocytes on O 2 transfer could not be demonstrated. Because its DL O 2 /M O 2 ratio is lower than that of dog, sheep appears to be more adequate than dog as a model for human alveolar-arterial gas exchange.

Simultaneous O 2 and CO diffusing capacity estimates from assumed lognormal V̇ A, Q̇ and D L distributions

O 2 and CO pulmonary transfer data obtained in dogs under steady-state conditions in hypoxia by Savoy et al. (Respir. Physiol. 42: 43–59, 1980) have been submitted to reevaluation and have yielded new estimates of the lung diffusing capacity, D L. For the proposed D L computation it has been assumed that functional inhomogeneity can be considered as resulting from lognormal distributions of the V̇ A/Q̇ and Ȧ A/D L ratios. The standard deviation, σ, of the V̇ A/Q̇ distribution is computed from the measured (P A - Pa) CO 2 , and the same σ value is assumed to prevail for the V̇ A/D L distributions.This is equivalent to assume constant D L/Q̇ ratios in the entire lung. With the so defined distributions, D L values, called D σ O 2 and D σ CO , were sought, for which the model calculations yielded O 2 partial pressures and CO fluxes equal to those measured. Compared with D L estimates computed with conventional procedures, these results show that D σ O 2 is twice as large as D L O 2 computed with ideal alveolar P O 2 and thatD σ CO lies between D L CO computed with the mean alveolar P CO and that computed with the ideal alveolar P CO. The D σ O 2 /D σ CO ratio was on the average 1.2, a value which, unlike the ratios obtained with conventional D L O 2 and D L CO estimates, is in good agreement with the characteristics of diffusion and of chemical association of O 2 and CO with blood.

Comparison of steady state pulmonary diffusing capacity estimates for O 2 and CO in dogs

In view of the fact that the inhomogeneity effects on pulmonary diffusing capacity (D l) estimates are quite different for O 2 and for CO, simultaneous determinations of steady-state D l CO and D l O 2 were attempted and compared. To this end, pulmonary gas exchange was measured in 17 anethetized and atificially ventilation dogs, in hypoxia with and without carbon monoxide in inspired gas (F i O 2 = 0.12, F i CO = 0.0009 to 0.0016). The diffusing capacity estimates were computed by tow conventional procedures, the firs (Dapp) taking into account the mean alveolar partial pressures and the second (D vda) the ideal alveolar partial pressures. It was found that the presence of COHb in blood, inevitable in the steady-state D l CO procedure, leads to a marked underestimation of D l O 2 ; therefore D l CO values could only be adequately compared to D l O 2 values obtained in the absence of CO from inspired gas. These D l O 2 were 18.5 and 33.4 ωmol·min −1·kg −1 for the mean Dapp O 2 and D vda O 2 , respectively, whereas the D l CO values obtained after 15 to 25 min CO inspiration were 30.0 and 83.4 ωmol·min −1·Torr −1·kg −1 for the mean Dapp CO and the mean D vda CO, respectively. The salient feature is that with both procedures the mean value of D l CO estimate is higher than the corresponding D l O 2 estimate. This finding suggests that in anesthetized, arttificially ventilated dogs Dapp O 2 estimates obtained by steady-state procedures in hypoxia are largely influenced by inhomogeneity effects and of limited value for assessment of the diffusing properties of the lung. Dapp CO and D vda O 2 are also affected by inhomogeneities but to a lesser degree.

The lung of shrews: Morphometric estimation of diffusion capacity

The lungs of 16 shrews from 8 species ( Sorex minutus, Neomys fodiens, Suncus etruscus, Crocidura russula, C. juvenetae, C. poensis, C. flavescens, C. giffardi) ranging in body weight from 2.2 to 100 g were studied by morphometry in order to compare the structural diffusion capacity for oxygen. D L O 2 , with the oxygen consumption, V̇ O 2 , measured on the same animals. V̇ O 2 was determined by short term measurements using a respirometer. D L O 2 was estimated morphometrically. Both parameters demonstrated good coincidence in their allometric behaviour, establishing further progress in structure-function relationship in the respiratory apparatus. Whereas V̇ O 2 as well as D L O 2 of shrews with a body weight W > 5 g follow the same allometric function established for mammals in general, the values for shrews with W < 5 g exhibit significantly higher values. It appears that the pulmonary gas exchange parenchyma of these smallest mammals is well suited to supply the organism with the comparatively high levels of O 2 required by the high metabolic rates, exhibiting a structural adaptation of the lung to higher V̇ O 2 .

Pulmonary O 2 diffusing capacity estimates from assumed Log-normal V̇ a/Q̇ distributions

Steady-state pulmonary gas exchange has been measured in hypoxia in 33 mongrel dogs with the aim of comparing D l O 2 estimates obtained with three procedures differing by the models assumed for functional inhomogeneity. In the first procedure the lung was assumed to be homogeneous and the corresponding D l O 2 estimate was 15 μmol · min −1 · Torr −1 · kg −1. In the second procedure, which is the one commonly used in respiratory physiology, alveolar dead space wasconsidered as the unique form of functional inhomogeneity and the corresponding D l O 2 estimate was 31 μmol · min −1 · Torr −1 · kg −1. In the third procedure, which has been specially worked out for this study, functional inhomogeneity was represented by a log-normal distribution of the V̇ a/Q̇ ratios and the corresponding D l O 2 estimate was 50 μmol · min −1 · Torr −1 · kg −1. The relation between the D l O 2 estimates by the second and by the third procedures was found to depend upon the blood pH. This could be explained on the basis of the effects of acidosis on the blood capacitances for O 2 and for CO 2. Analysis suggests that in hypoxia where normally the O 2 capacitance is about half the CO 2 one, the third procedure yields D l O 2 estimates about twice as large as those obtained by the second one.

Diffusion and chemical reaction in pulmonary gas exchange.

Diffusion and chemical reaction in pulmonary gas exchange.P D WagnerP D WagnerPublished Online:01 Apr 1977https://doi.org/10.1152/physrev.1977.57.2.257MoreSectionsPDF (9 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByHyperpolarized 129Xe magnetic resonance spectroscopy in a rat model of bronchopulmonary dysplasiaJordan D. Fliss, Brandon Zanette, Yonni Friedlander, Siddharth Sadanand, Andras A. Lindenmaier, Elaine Stirrat, Daniel Li, Martin Post, Robert P. Jankov, and Giles Santyr19 August 2021 | American Journal of Physiology-Lung Cellular and Molecular Physiology, Vol. 321, No. 3Single-Breath Diffusion Testing: Longevity is the Reward for VirtueArchivos de Bronconeumología (English Edition)Prueba de difusión por respiración única. La longevidad es la recompensa de la virtudArchivos de BronconeumologíaImage‐based computational fluid dynamics in the lung: virtual reality or new clinical practice?13 June 2017 | WIREs Systems Biology and Medicine, Vol. 9, No. 6Beyond just hemoglobin: Red blood cell potentiation of hemoglobin-oxygen unloading in fishColin J. Brauner and Till S. Harter26 October 2017 | Journal of Applied Physiology, Vol. 123, No. 4Role of the Cardiovascular System in Coupling the External Environment to Cellular RespirationAir to Muscle O 2 Delivery during Exercise at AltitudeHigh Altitude Medicine & Biology, Vol. 10, No. 2Positive end-expiratory pressure enhances development of a functional residual capacity in preterm rabbits ventilated from birthMelissa L. Siew, Arjan B. te Pas, Megan J. Wallace, Marcus J. Kitchen, Robert A. Lewis, Andreas Fouras, Colin J. Morley, Peter G. Davis, Naoto Yagi, Kentaro Uesugi, and Stuart B. Hooper1 May 2009 | Journal of Applied Physiology, Vol. 106, No. 5Hemoglobin P 50 during A Simulated Ascent of Mt. Everest, Operation Everest IIHigh Altitude Medicine & Biology, Vol. 8, No. 1Modeling kinetics of infused 13NN-saline in acute lung injuryK. O'Neill, J. G. Venegas, T. Richter, R. S. Harris, J. D. H. Layfield, G. Musch, T. Winkler, and M. F. Vidal Melo1 December 2003 | Journal of Applied Physiology, Vol. 95, No. 6A simulation model of the oxygen alveolo capillary exchange in normal and pathological conditions28 February 2003 | Physiological Measurement, Vol. 24, No. 2Sensitivity of CO2 excretion to blood flow changes in trout is determined by carbonic anhydrase availabilityPatrick R. Desforges, Stuart S. Harman, Kathleen M. Gilmour, and Steve F. Perry1 February 2002 | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Vol. 282, No. 2Impaired muscle oxygen transfer in patients with chronic renal failureErnest Sala, Elizabeth A. Noyszewski, Josep M. Campistol, Ramon M. Marrades, Steffi Dreha, Josep V. Torregrossa, Jennifer S. Beers, Peter D. Wagner, and Josep Roca1 April 2001 | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Vol. 280, No. 4Kinetics of absorption atelectasis during anesthesia: a mathematical modelC. J. Joyce, and A. B. Williams1 April 1999 | Journal of Applied Physiology, Vol. 86, No. 4Capillary recruitment and transit time in the rat lungRobert G. Presson, Thomas M. Todoran, Bracken J. De Witt, Ivan F. McMurtry, and Wiltz W. Wagner1 August 1997 | Journal of Applied Physiology, Vol. 83, No. 2Effect of the curvature of the O2 equilibrium curve on alveolar O2 uptake: theoryRespiration Physiology, Vol. 83, No. 3Pulmonary diffusing capacity: implications of two-phase blood flow in capillariesRespiration Physiology, Vol. 77, No. 1Velocity of red blood cell flow in capillaries of the guinea pig cochleaHearing Research, Vol. 27, No. 2Panting in the EMU causes arterial hypoxemiaRespiration Physiology, Vol. 54, No. 2Morphometrics of rapidly frozen goose lungsRespiration Physiology, Vol. 51, No. 3Diffusion of small ionic species in human saliva, plaque fluid and plaque residue in vitroArchives of Oral Biology, Vol. 28, No. 2Chloride-bicarbonate exchange and related transport processesBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, Vol. 694, No. 4Interpretation of inert gas retention and excretion in the presence of stratified inhomogeneityRespiration Physiology, Vol. 46, No. 3Inert gas elimination from lungs with stratified inhomogeneity: TheoryRespiration Physiology, Vol. 44, No. 3Predicted gas exchange on the summit of Mt. EverestRespiration Physiology, Vol. 42, No. 1Pulmonary O2 diffusing capacity estimates from assumed Log-normal V̇a/Q̇ distributionsRespiration Physiology, Vol. 37, No. 1Theory of gas exchange in the avian parabronchusRespiration Physiology, Vol. 35, No. 1Uneven perfusion and ventilation within lung regions studied with nitrogen-13Respiration Physiology, Vol. 34, No. 1 More from this issue > Volume 57Issue 2April 1977Pages 257-312 Copyright & PermissionsCopyright © 1977 by American Physiological Societyhttps://doi.org/10.1152/physrev.1977.57.2.257PubMed15292History Published online 1 April 1977 Published in print 1 April 1977 Metrics

Morphometric estimation of regional differences in the dog lung.

ArticleMorphometric estimation of regional differences in the dog lung.P Gehr, and E R WeibelP Gehr, and E R WeibelPublished Online:01 Nov 1974https://doi.org/10.1152/jappl.1974.37.5.648MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByRegional differences in alveolar density in the human lung are related to lung heightJohn E. McDonough, Lars Knudsen, Alexander C. Wright, W. Mark Elliott, Matthias Ochs, and James C. Hogg1 June 2015 | Journal of Applied Physiology, Vol. 118, No. 11Gas Exchange in the Respiratory Distress Syndromes1 July 2012Noninvasive quantification of heterogeneous lung growth following extensive lung resection by high-resolution computed tomographyCuneyt Yilmaz, Priya Ravikumar, D. Merrill Dane, Dennis J. Bellotto, Robert L. Johnson, and Connie C. W. Hsia1 November 2009 | Journal of Applied Physiology, Vol. 107, No. 5Diffusion of Gases Across the Alveolar Membrane1 January 2011Pulmonary Interstitial Spaces and Lymphatics1 January 2011Morphometry of the Alveolar Region of the LungApplication of Morphometric Methods to Study Diffuse and Focal Injury in the Lung Caused by Toxic Agents26 September 2008 | CRC Critical Reviews in Toxicology, Vol. 14, No. 1An ultrastructural morphometric comparison of the peripheral with the hilar air-blood barrier of dog lungThe Anatomical Record, Vol. 209, No. 4Simultaneous O2 and CO diffusing capacity estimates from assumed lognormal V̇A, Q̇ and DL distributionsRespiration Physiology, Vol. 52, No. 1An ultrastructural morphometric comparison of the right and left sides and lobes of the dog lungThe Anatomical Record, Vol. 204, No. 1Allometric analysis of the morphometric pulmonary diffusing capacity in dogsJournal of Morphology, Vol. 168, No. 1Design of the mammalian respiratory system. IV. Morphometric estimation of pulmonary diffusing capacity; Critical evaluation of a new sampling methodRespiration Physiology, Vol. 44, No. 1MORPHOLOGICAL BASIS FOR DISTRIBUTIONMorphometric estimation of pulmonary diffusion capacity in two horse lungsRespiration Physiology, Vol. 41, No. 2AtemphysiologieThe normal human lung: ultrastructure and morphometric estimation of diffusion capacityRespiration Physiology, Vol. 32, No. 2 More from this issue > Volume 37Issue 5November 1974Pages 648-53 https://doi.org/10.1152/jappl.1974.37.5.648PubMed4436188History Published online 1 November 1974 Published in print 1 November 1974 Metrics

Analysis of effect of the solubility on gas exchange in nonhomogenous lungs.

ArticleAnalysis of effect of the solubility on gas exchange in nonhomogenous lungs.W E Colburn Jr, J W Evans, and J B WestW E Colburn Jr, J W Evans, and J B WestPublished Online:01 Oct 1974https://doi.org/10.1152/jappl.1974.37.4.547MoreSectionsPDF (892 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByElucidating the roles of solubility and ventilation-perfusion mismatch in the second gas effect using a two-step model of gas exchangeBen Korman, Ranjan K. Dash, and Philip J. Peyton8 June 2020 | Journal of Applied Physiology, Vol. 128, No. 6Intravenous versus inhalational anaesthesia and lung ventilation–perfusion matching6 June 2019 | Anaesthesia and Intensive Care, Vol. 47, No. 3Effect of net gas volume changes on alveolar and arterial gas partial pressures in the presence of ventilation-perfusion mismatchBen Korman, Ranjan K. Dash, and Philip J. Peyton8 March 2019 | Journal of Applied Physiology, Vol. 126, No. 3Can Mathematical Modeling Explain the Measured Magnitude of the Second Gas Effect?Anesthesiology, Vol. 128, No. 6Ventilation-perfusion inhomogeneity increases gas uptake in anesthesia: computer modeling of gas exchangePhilip J. Peyton, Gavin J. B. Robinson, and Bruce Thompson1 July 2001 | Journal of Applied Physiology, Vol. 91, No. 1Simultaneous O2 and CO diffusing capacity estimates from assumed lognormal V̇A, Q̇ and DL distributionsRespiration Physiology, Vol. 52, No. 1Alveolar-capillary diffusion and ventilation-perfusion inhomogeneity: a mathematical modelMedical & Biological Engineering & Computing, Vol. 20, No. 3VENTILATION-PERFUSION INHOMOGENEITY AND EFFICIENCY OF ALVEOLAR GAS EXCHANGEMathematical Analysis of Compartmental Lung ModelsModele d'echanges gazeux pulmonaires: Influence de l'heterogeneite de distribution des rapports ventilation-perfusion et conductance-perfusion sur le transfert d'oxygeneInternational Journal of Bio-Medical Computing, Vol. 9, No. 4Measurement of the Distribution of Ventilation-Perfusion Ratios More from this issue > Volume 37Issue 4October 1974Pages 547-51 https://doi.org/10.1152/jappl.1974.37.4.547PubMed4412008History Published online 1 October 1974 Published in print 1 October 1974 Metrics

Gas mixing during inspiration.

Gas mixing during inspiration.

Diffusing capacity and anatomic dead space for carbon monoxide (C180).

ARTICLESDiffusing capacity and anatomic dead space for carbon monoxide (C180)P. D. Wagner, R. W. Mazzone, and J. B. WestP. D. Wagner, R. W. Mazzone, and J. B. WestPublished Online:01 Dec 1971https://doi.org/10.1152/jappl.1971.31.6.847MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByLow resting diffusion capacity, dyspnea, and exercise intolerance in chronic obstructive pulmonary diseaseAmany F. Elbehairy, Conor D. O'Donnell, Asmaa Abd Elhameed, Sandra G. Vincent, Kathryn M. Milne, Matthew D. James, Katherine A. Webb, J. Alberto Neder, Denis E. O’Donnell, and Canadian Respiratory Research Network14 October 2019 | Journal of Applied Physiology, Vol. 127, No. 4Effect of alveolar volume on the interpretation of single breath DlCORespiratory Medicine, Vol. 91, No. 5Inhalation toxicity of methyl n-amyl ketone (2-heptanone) in rats and monkeysToxicology and Applied Pharmacology, Vol. 58, No. 3Pulmonary function evaluation of cats after one year of exposure to diesel exhaustEnvironment International, Vol. 5, No. 4-6Comparison of steady state pulmonary diffusing capacity estimates for O2 and CO in dogsRespiration Physiology, Vol. 42, No. 1Pulmonary function in nonsmoking subjects with alpha1 antitrypsin deficiency (MZ phenotype)The American Journal of Medicine, Vol. 62, No. 1The Stable Isotopes of Oxygen in Research and Technical ApplicationsAngewandte Chemie International Edition in English, Vol. 13, No. 6 More from this issue > Volume 31Issue 6December 1971Pages 847-852 Copyright & PermissionsCopyright © 1971 the American Physiological Societyhttps://doi.org/10.1152/jappl.1971.31.6.847PubMed5123662History Published online 1 December 1971 Published in print 1 December 1971 Metrics

Inhomogeneity effects on O 2 and CO pulmonary diffusing capacity estimates by steady-state methods. Theory

The effects of pulmonary functional inhomogeneities (uneven distributions of a, D and ) on steady-state O 2 and CO diffusing capacity estimates were analysed in terms of gas transfer resistances for O 2 and for CO. To this end, a mathematical treatment was developed which is applicable to the transfer of any gas in non-homogeneous lungs. Quantitative comparisons of diffusing capacity, D, with its estimates, “D”, (as obtained by classical steady-state equations) were established on multi-compartmental lung models similar to those used by West (1969). Results show that, for inhomogeneous lungs, diffusing capacity estimates are lower than diffusing capacity. This divergence, which increases with the amount of inhomogeneity, is larger for D O 2 than for D CO. In contrast, it was also found that, in the particular case where D CO estimates are computed according to Filley, these can be higher than D CO. These findings can be adequately apprehended in terms of network analysis. They provide an explanation for the well-known discrepancy between morphometric and functional D estimates, as well as for the fact that D CO values higher than D O 2 values are encountered in the literature.

Effect of anemia, species, and temperature on CO kinetics with red blood cells.

ArticleEffect of anemia, species, and temperature on CO kinetics with red blood cells.W H Lawson JrW H Lawson JrPublished Online:01 Sep 1971https://doi.org/10.1152/jappl.1971.31.3.447MoreSectionsPDF (3 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByHigh-altitude exposure of three weeks duration increases lung diffusing capacity in humansPiergiuseppe Agostoni, Erik R. Swenson, Maurizio Bussotti, Miriam Revera, Paolo Meriggi, Andrea Faini, Carolina Lombardi, Grzegorz Bilo, Andrea Giuliano, Daniele Bonacina, Pietro A. Modesti, Giuseppe Mancia, and Gianfranco Paration behalf of the HIGHCARE Investigators1 June 2011 | Journal of Applied Physiology, Vol. 110, No. 6Rate of uptake of CO by hemoglobin in pig erythrocytes as a function of PO2Francis C. A. M. Te Nijenhuis, Lydia Lin, Gerko H. Moens, Adrian Versprille, and Robert E. Forster1 October 1996 | Journal of Applied Physiology, Vol. 81, No. 4Diffusion of Gases Across the Alveolar Membrane1 January 2011Alveolar-arterial equilibration in the lung of sheepRespiration Physiology, Vol. 55, No. 2Simultaneous O2 and CO diffusing capacity estimates from assumed lognormal V̇A, Q̇ and DL distributionsRespiration Physiology, Vol. 52, No. 1Pulmonary diffusing capacity in reptiles (Relations to temperature and O2-uptake)Journal of Comparative Physiology ? B, Vol. 142, No. 4Kinetics of Pulmonary Gas ExchangeTotal Body Haemoglobin Estimated with the Alveolar CO Method as Compared with a 51 Cr Technique18 January 2010 | Upsala Journal of Medical Sciences, Vol. 83, No. 1The biological effects of carbon monoxide on the pregnant woman, fetus, and newborn infantAmerican Journal of Obstetrics and Gynecology, Vol. 129, No. 1Kinetics of oxygenation and deoxygenation of erythrocytes containing hemoglobin SRespiration Physiology, Vol. 21, No. 1Influence of intracellular convection on the oxygen release by human erythrocytesPfl�gers Archiv European Journal of Physiology, Vol. 335, No. 1 More from this issue > Volume 31Issue 3September 1971Pages 447-57 https://doi.org/10.1152/jappl.1971.31.3.447PubMed5111864History Published online 1 September 1971 Published in print 1 September 1971 Metrics

A theoretical analysis of the alveolar-arterial O2 difference with special reference to the distribution effect.

SPECIAL COMMUNICATIONSA Theoretical Analysis of the Alveolar-Arterial O2 Difference With Special Reference to the Distribution EffectL. E. Farhi, and H. RahnL. E. Farhi, and H. RahnPublished Online:01 May 1955https://doi.org/10.1152/jappl.1955.7.6.699MoreSectionsPDF (850 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByFrom metabolism and behavior to respiratory physiology: an educational and research perspectiveEvelyn Heymann Schlenker3 September 2020 | Advances in Physiology Education, Vol. 44, No. 4Alveolar Air and O2 Uptake During Exercise in Patients With Heart FailureJournal of Cardiac Failure, Vol. 24, No. 10Hepatopulmonary Disorders: Gas Exchange and Vascular Manifestations in Chronic Liver Disease25 March 2018Alveolar air and oxidative metabolic demand during exercise in healthy adults: the role of single-nucleotide polymorphisms of the β2 AR gene23 October 2017 | Physiological Reports, Vol. 5, No. 20Pro: Hypoxic Pulmonary Vasoconstriction Is a Limiting Factor of Exercise at High AltitudeHigh Altitude Medicine & Biology, Vol. 12, No. 4Variability of indices of hypoxemia in adult respiratory distress syndromeCritical Care Medicine, Vol. 25, No. 1Pulmonary gas exchange during hypoxic exercise in the ratRespiration Physiology, Vol. 96, No. 2-3Hypoxic pulmonary vasoconstriction and pulmonary gas exchange in normal manRespiration Physiology, Vol. 68, No. 1Pulmonary function testing: Custom programs for manual equipmentComputers in Biology and Medicine, Vol. 14, No. 1Effect of shifts of the O2 dissociation curve upon alveolar-arterial O2 gradients in computer models of the lung with ventilation-perfusion mismatcingRespiration Physiology, Vol. 45, No. 2Analysis of chorioallantoic gas exchange in the chick embryoRespiration Physiology, Vol. 39, No. 3Distributions of V̇A/Q̇ in dog lungs obtained with the 50 compartment and the log normal approachRespiration Physiology, Vol. 38, No. 3Theoretical analysis of independent V̇a and Q̇ inequalities upon pulmonary gas exchangeRespiration Physiology, Vol. 29, No. 2Pulmonary gas exchange in dogs ventilated with mixtures of oxygen with various inert gasesRespiration Physiology, Vol. 28, No. 1The components of the alveolar-arterial oxygen tension difference in normal subjects and in patients with pneumonia and obstructive lung diseaseThe American Journal of Medicine, Vol. 52, No. 6Inhomogeneity effects on O2 and CO pulmonary diffusing capacity estimates by steady-state methods. TheoryRespiration Physiology, Vol. 13, No. 1A new lung model: An investigation with the aid of a digital computerComputers and Biomedical Research, Vol. 3, No. 3Pulmonary arteriovenous admixtureThe American Journal of Surgery, Vol. 119, No. 4Effect of slope and shape of dissociation curve on pulmonary gas exchangeRespiration Physiology, Vol. 8, No. 1Ventilation-perfusion inequality and overall gas exchange in computer models of the lungRespiration Physiology, Vol. 7, No. 1Apparent increase of the O2 diffusing capacity with increased O2 uptake in inhomogeneous lungs: TheoryRespiration Physiology, Vol. 6, No. 2Cirrhosis, cyanosis and polycythaemia: Multiple pulmonary arteriovenous anastomosesThe American Journal of Medicine, Vol. 45, No. 1Alveolar ventilation, diffusing capacity and the A-a Po2, difference in the newborn infantRespiration Physiology, Vol. 4, No. 2Alveolar-arterial O2 and CO2 pressure differences in the anesthetized, artificially ventilated dogRespiration Physiology, Vol. 3, No. 2Pulmonary diffusing capacity for oxygen in the anesthetized, artificially ventilated dog1Respiration Physiology, Vol. 3, No. 2VENOUS/ARTERIAL PULMONARY SHUNTING AS THE PRINCIPAL CAUSE OF POSTOPERATIVE HYPOXÆMIAThe Lancet, Vol. 289, No. 7480Causes of arterial hypoxemia in patients with obstructive pulmonary emphysemaThe American Journal of Medicine, Vol. 39, No. 3BLOOD-FLOW, VENTILATION, AND GAS EXCHANGE IN THE LUNGThe Lancet, Vol. 282, No. 7316Alveolar-arterial gas tension relationships in acute anterior poliomyelitisThe American Journal of Medicine, Vol. 30, No. 6 More from this issue > Volume 7Issue 6May 1955Pages 699-703 https://doi.org/10.1152/jappl.1955.7.6.699PubMed14381350History Published online 1 May 1955 Published in print 1 May 1955 Metrics

‘Ideal’ Alveolar Air and the Analysis of Ventilation-Perfusion Relationships in the Lungs

<i>‘Ideal’ Alveolar Air and the Analysis of Ventilation-Perfusion Relationships in the Lungs</i>