AIRWAY RESISTANCE AND CARBON MONOXIDE DIFFUSING CAPACITY TO PREDICT THE NEED FOR HOSPITAL ADMISSION IN COPD PATIENTS

To achieve a multidimensional evaluation of chronic obstructive pulmonary disease (COPD) patients, the spirometry measures are supplemented by assessment of symptoms, risk of exacerbations, and CT imaging. However, the measurement of diffusing capacity of the lung for carbon monoxide (DLCO) is not included in most common used models of COPD assessment. Here, we conducted a meta-analysis to evaluate the role of DLCO in COPD assessment. The studies were identified by searching the terms “diffusing capacity” OR “diffusing capacity for carbon monoxide” or “DLCO” AND “COPD” AND “assessment” in Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Scopus, and Web of Science databases. The mean difference of DLCO % predict was assessed in COPD patient with different severity (according to GOLD stage and GOLD group), between COPD patients with or without with frequent exacerbation, between survivors and non-survivors, between emphysema dominant and non-emphysema dominant COPD patients, and between COPD patients with or without pulmonary hypertension. 43 studies were included in the meta-analysis. DLCO % predicted was significantly lower in COPD patients with more severe airflow limitation (stage II/IV), more symptoms (group B/D), and high exacerbation risk (group C/D). Lower DLCO % predicted was also found in exacerbation patients and non-survivors. Low DLCO % predicted was related to emphysema dominant phenotype, and COPD patients with PH. The current meta-analysis suggested that DLCO % predicted might be an important measurement for COPD patients in terms of severity, exacerbation risk, mortality, emphysema domination, and presence of pulmonary hypertension. As diffusion capacity reflects pulmonary ventilation and perfusion at the same time, the predictive value of DLCO or DLCO combined with other criteria worth further exploration.

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COPD patients with severe diffusion defect in carbon monoxide diffusing capacity predict a better outcome for pulmonary rehabilitation

Revista Portuguesa de Pneumologia (English Edition) ◽

10.1016/j.rppnen.2016.03.003 ◽

2016 ◽

Vol 22 (6) ◽

pp. 323-330

Author(s):

H. Sahin ◽

I. Naz ◽

Y. Varol ◽

N. Aksel ◽

F. Tuksavul ◽

...

Keyword(s):

Carbon Monoxide ◽

Pulmonary Rehabilitation ◽

Diffusing Capacity ◽

Copd Patients

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Can Asymptomatic or Non-Severe SARS-CoV-2 Infection Cause Medium-Term Pulmonary Sequelae in Children?

Frontiers in Pediatrics ◽

10.3389/fped.2021.621019 ◽

2021 ◽

Vol 9 ◽

Author(s):

Ilaria Bottino ◽

Maria F. Patria ◽

Gregorio P. Milani ◽

Carlo Agostoni ◽

Paola Marchisio ◽

...

Keyword(s):

Carbon Monoxide ◽

Airway Resistance ◽

Pulmonary Complications ◽

Diffusing Capacity ◽

Medium Term ◽

Female Ratio ◽

Immune Assays ◽

Male To Female ◽

Ig G ◽

Fondazione Irccs

Pulmonary complications in adults who recovered from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported even in minimally symptomatic patients. In this study, lung ultrasound (LUS) findings and pulmonary function of children who recovered from an asymptomatic or mildly symptomatic SARS-CoV-2 infection were evaluated. We prospectively followed up for at least 30 days patients younger than 18 years who recovered from SARS-CoV-2 infection at the Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan (Italy). All enrolled patients underwent LUS. Airway resistance measured by the interrupter technique test was assessed in subjects aged 4–6 years, whereas forced spirometry and measurement of diffusing capacity of the lungs for carbon monoxide were performed in subjects older than 6 years. To evaluate a possible correlation between pulmonary alterations and immune response to SARS-CoV-2, two semiquantitative enzyme immune assays were used. We enrolled 16 out of 23 eligible children. The median age of enrolled subjects was 7.5 (0.5–10.5) years, with a male to female ratio of 1.7. No subject presented any abnormality on LUS, airway resistance test, forced spirometry, and diffusing capacity of the lungs for carbon monoxide. On the other hand, all subjects presented Ig G against SARS-CoV-2. In contrast in adults, we did not detect any pulmonary complications in our cohort. These preliminary observations suggest that children with an asymptomatic or mildly symptomatic SARS-CoV-2 infection might be less prone to develop pulmonary complications than adults.

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Reduced exercise tolerance in mild chronic obstructive pulmonary disease: The contribution of combined abnormalities of diffusing capacity for carbon monoxide and ventilatory efficiency

Respirology ◽

10.1111/resp.14045 ◽

2021 ◽

Author(s):

Devin B. Phillips ◽

Matthew D. James ◽

Amany F. Elbehairy ◽

Kathryn M. Milne ◽

Sandra G. Vincent ◽

...

Keyword(s):

Chronic Obstructive Pulmonary Disease ◽

Carbon Monoxide ◽

Pulmonary Disease ◽

Exercise Tolerance ◽

Chronic Obstructive ◽

Diffusing Capacity ◽

Obstructive Pulmonary Disease ◽

Ventilatory Efficiency

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Ventilation Heterogeneity in Asthma and COPD: The Value of the Poorly Communicating Fraction as the Ratio of Total Lung Capacity to Alveolar Volume

Respiration ◽

10.1159/000513954 ◽

2021 ◽

pp. 1-7

Author(s):

Roberta Pisi ◽

Marina Aiello ◽

Luigino Calzetta ◽

Annalisa Frizzelli ◽

Veronica Alfieri ◽

...

Keyword(s):

Total Lung Capacity ◽

Airflow Obstruction ◽

Diffusing Capacity ◽

Body Plethysmography ◽

Alveolar Volume ◽

Asthmatic Patients ◽

Lung Capacity ◽

Copd Patients ◽

Ventilation Heterogeneity ◽

Patient Groups

Background: The ventilation heterogeneity (VH) is reliably assessed by the multiple-breath nitrogen washout (MBNW), which provides indices of conductive (Scond) and acinar (Sacin) VH as well as the lung clearance index (LCI), an index of global VH. VH can be alternatively measured by the poorly communicating fraction (PCF), that is, the ratio of total lung capacity by body plethysmography to alveolar volume from the single-breath lung diffusing capacity measurement. Objectives: Our objective was to assess VH by PCF and MBNW in patients with asthma and with COPD and to compare PCF and MBNW parameters in both patient groups. Method: We studied 35 asthmatic patients and 45 patients with COPD. Each patient performed spirometry, body plethysmography, diffusing capacity, and MBNW test. Results: Compared to COPD patients, asthmatics showed a significantly lesser degree of airflow obstruction and lung hyperinflation. In asthmatic patients, both PCF and LCI and Sacin values were significantly lower than the corresponding ones of COPD patients. In addition, in both patient groups, PCF showed a positive correlation with LCI (p < 0.05) and Sacin (p < 0.05), but not with Scond. Lastly, COPD patients with PCF >30% were highly likely to have a value ≥2 of the mMRC dyspnea scale. Conclusions: These results showed that PCF, a readily measure derived from routine pulmonary function testing, can provide a comprehensive measure of both global and acinar VH in asthma and in COPD patients and can be considered as a comparable tool to the well-established MBNW technique.

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The effect of conductive ventilation heterogeneity on diffusing capacity measurement

Journal of Applied Physiology ◽

10.1152/japplphysiol.00917.2007 ◽

2008 ◽

Vol 104 (4) ◽

pp. 1094-1100 ◽

Cited By ~ 9

Author(s):

Sylvia Verbanck ◽

Daniel Schuermans ◽

Sophie Van Malderen ◽

Walter Vincken ◽

Bruce Thompson

Keyword(s):

Carbon Monoxide ◽

Vital Capacity ◽

Experimental Situation ◽

Normal Subjects ◽

Diffusing Capacity ◽

Capacity Measurement ◽

Alveolar Volume ◽

Estimation Errors ◽

Single Breath ◽

Ventilation Heterogeneity

It has long been assumed that the ventilation heterogeneity associated with lung disease could, in itself, affect the measurement of carbon monoxide transfer factor. The aim of this study was to investigate the potential estimation errors of carbon monoxide diffusing capacity (DlCO) measurement that are specifically due to conductive ventilation heterogeneity, i.e., due to a combination of ventilation heterogeneity and flow asynchrony between lung units larger than acini. We induced conductive airway ventilation heterogeneity in 35 never-smoker normal subjects by histamine provocation and related the resulting changes in conductive ventilation heterogeneity (derived from the multiple-breath washout test) to corresponding changes in diffusing capacity, alveolar volume, and inspired vital capacity (derived from the single-breath DlCO method). Average conductive ventilation heterogeneity doubled ( P < 0.001), whereas DlCO decreased by 6% ( P < 0.001), with no correlation between individual data ( P > 0.1). Average inspired vital capacity and alveolar volume both decreased significantly by, respectively, 6 and 3%, and the individual changes in alveolar volume and in conductive ventilation heterogeneity were correlated ( r = −0.46; P = 0.006). These findings can be brought in agreement with recent modeling work, where specific ventilation heterogeneity resulting from different distributions of either inspired volume or end-expiratory lung volume have been shown to affect DlCO estimation errors in opposite ways. Even in the presence of flow asynchrony, these errors appear to largely cancel out in our experimental situation of histamine-induced conductive ventilation heterogeneity. Finally, we also predicted which alternative combination of specific ventilation heterogeneity and flow asynchrony could affect DlCO estimate in a more substantial fashion in diseased lungs, irrespective of any diffusion-dependent effects.

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Nonlinear increases in diffusing capacity during exercise by seated and supine subjects

Journal of Applied Physiology ◽

10.1152/jappl.1981.51.4.858 ◽

1981 ◽

Vol 51 (4) ◽

pp. 858-863 ◽

Cited By ~ 31

Author(s):

D. L. Stokes ◽

N. R. MacIntyre ◽

J. A. Nadel

Keyword(s):

Carbon Monoxide ◽

Oxygen Consumption ◽

Healthy Subjects ◽

Vital Capacity ◽

Maximal Exercise ◽

Sitting Position ◽

Diffusing Capacity ◽

Heavy Exercise ◽

Lung Volumes ◽

Rate Of Increase

To study the effects of exercise on pulmonary diffusing capacity, we measured the lungs' diffusing capacity for carbon monoxide (DLCO) during exhalation from 30 to 45% exhaled vital capacity in eight healthy subjects at rest and during exercise while both sitting and supine. We found that DLCO at these lung volumes in resting subjects was 26.3 +/- 3.2% (mean +/- SE) higher in the supine than in the sitting position (P less than 0.001). We also found that, in both positions, DLCO at these lung volumes increased significantly (P less than 0.001) with increasing exercise and approached similar values at maximal exercise. The pattern of increase in DLCO with an increase in oxygen consumption in both positions was curvilinear in that the rate of increase in DLCO during mild exercise was greater than the rate of increase in DLCO during heavy exercise (P = 0.02). Furthermore, in the supine position during exercise, it appeared that DLCO reached a physiological maximum.

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