Contribution of airway closure to chronic postbronchiolitis airway dysfunction in rats

Genetically susceptible Brown Norway rats develop a chronic asthmalike syndrome after recovering from viral bronchiolitis at an early age. We hypothesized that airway closure is an important mechanism of airflow obstruction in postbronchiolitis rats. Rats were studied 8–12 wk after inoculation with Sendai virus or sterile vehicle at 3–4 wk of age. Under light pentobarbital anesthesia, rats were instrumented with an orotracheal catheter and an esophageal pressure monitor and placed in a total body plethysmograph. Lung volumes and forced-expiratory maneuvers were measured using the Boyle's law method and software-controlled valving of positive and negative pressures to elicit lung inflations and rapid deflations; pulmonary resistance was measured during spontaneous tidal breathing; and quasi-static pressure-volume curves were obtained with passive inflations and deflations in fully anesthetized, paralyzed rats. Compared with controls, the postbronchiolitis rats had elevated pulmonary resistance and reduced forced-expiratory volume in 0.2 s. Most of the reduced forced-expiratory volume in 0.2 s was associated with reduced forced vital capacity, indicating premature airway closure as a prominent mechanism. The reduced airflow in postbronchiolitis rats was highly dependent on lung volume, being nearly normal at 70% lung capacity, but sevenfold less than normal at 30% lung capacity. Increased respiratory system hysteresis between functional reserve capacity and total lung capacity was evidence for increased airway closure at normal end-expiratory lung volumes in postbronchiolitis rats. We conclude that airway instability and closure is a prominent mechanism of the chronic airway dysfunction in rats that have recovered from viral bronchiolitis at an early age.

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Effect of previous volume history on airway closure

Journal of Applied Physiology ◽

10.1152/jappl.1983.55.2.294 ◽

1983 ◽

Vol 55 (2) ◽

pp. 294-299

Author(s):

H. W. Greville ◽

L. J. Slykerman ◽

P. A. Easton ◽

N. R. Anthonisen

Keyword(s):

Regional Distribution ◽

Lung Parenchyma ◽

Breath Hold ◽

Closing Volume ◽

Airway Closure ◽

Lung Volumes ◽

Lung Capacity ◽

Normal Humans ◽

Volume History ◽

Previous Volume

We studied the effect of volume history on airway closure in six healthy males ranging from 32 to 67 yr of age. The method used was to compare the regional distribution of 133Xe boluses distributed according to N2O uptake during open-glottis breath-hold maneuvers with the regional distribution of boluses of intravenously injected 133Xe. Measurements were made at two lung volumes, one close to residual volume (RV) and the other just below closing volume. The required volume was reached either by expiring from total lung capacity or by inspiring from RV. Although there was considerable airway closure in the basal regions of the lungs at both lung volumes studied, the degree of airway closure was not dependent on the previous volume history. We conclude that the airways concerned with closure have a volume-pressure hysteresis similar to that of the lung parenchyma. Furthermore in normal humans the volume-pressure hysteresis of the lung is not secondary to airway closure.

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Effects of chest wall strapping on mechanical response to methacholine in humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.00379.2005 ◽

2006 ◽

Vol 101 (2) ◽

pp. 430-438 ◽

Cited By ~ 29

Author(s):

Roberto Torchio ◽

Carlo Gulotta ◽

Claudio Ciacco ◽

Alberto Perboni ◽

Marco Guglielmo ◽

...

Keyword(s):

Chest Wall ◽

Mechanical Response ◽

Airflow Obstruction ◽

Deep Inspiration ◽

Contractile Apparatus ◽

Pulmonary Resistance ◽

Lung Volumes ◽

Airway Narrowing ◽

Maximal Expiratory Flow ◽

Before And After

We examined the effects of chest wall strapping (CWS) on the response to inhaled methacholine (MCh) and the effects of deep inspiration (DI). Eight subjects were studied on 1 day with MCh inhaled without CWS (CTRL), 1 day with MCh inhaled during CWS (CWSon/on), and 1 day with MCh inhaled during temporary removal of CWS (CWSoff/on). On the CWSon/on day, MCh caused greater increases in pulmonary resistance, upstream resistance, dynamic elastance, residual volume, and greater decreases in maximal expiratory flow than on the CTRL day. On the CWSoff/on day, the changes in these parameters with MCh were not different from the CTRL day. Six of the subjects were again studied using the same protocol on CTRL and CWSon/on days, except that, on a third day, MCh was given after applying the CWS, but the measurements before and after the inhalation were made without CWS (CWSon/off). The latter sequence was associated with more severe airflow obstruction than during CTRL, but less than with CWSon/on. The bronchodilator effects of a DI were blunted when CWS was applied during measurements (CWSon/on and CWSoff/on) but not after it was removed (CWSon/off). We conclude that CWS is capable of increasing airway responsiveness only when it is applied during the inhalation of the constrictor agent. We speculate that breathing at low lung volumes induced by CWS enhances airway narrowing because the airway smooth muscle is adapted at a length at which the contractile apparatus is able to generate a force greater than normal.

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Pulmonary function in young and older athletes and untrained men

Journal of Applied Physiology ◽

10.1152/jappl.1988.65.1.101 ◽

1988 ◽

Vol 65 (1) ◽

pp. 101-105 ◽

Cited By ~ 54

Author(s):

J. M. Hagberg ◽

J. E. Yerg ◽

D. R. Seals

Keyword(s):

Pulmonary Function ◽

Vital Capacity ◽

Older Men ◽

Forced Expiratory Volume ◽

Endurance Athletes ◽

Lung Volumes ◽

Lung Capacity ◽

Older Athletes ◽

Younger Men ◽

Maximal Voluntary Ventilation

This study compared the lung volumes and pulmonary functions of older endurance-trained athletes with those of healthy sedentary age-matched controls, young athletes, and young untrained men to determine whether training affects the age-associated changes in these variables. Despite large differences in maximal 02 consumption (VO2max), the older athletes and their sedentary peers had similar values for all pulmonary variables when expressed as absolute values. However, because the older athletes were shorter than the older sedentary men, their vital capacity, total lung capacity (TLC), and forced expiratory volume in 1 s were significantly larger than those of the older sedentary men when normalized for age and height; the average values for maximal voluntary ventilation and residual volume (RV) were also larger in the older athletes when normalized for age and height, but the differences were not significant. The young trained and untrained men did not differ in any of these measures. TLC was the only pulmonary variable that was the same in the young and older men; RV and the RV-to-TLC ratio were larger, whereas all other pulmonary function and volume measures were lower in the older men compared with the younger men. The older athletes were the only group whose lung volumes and pulmonary function measures were all, except for RV, substantially greater than expected based on their age and height. Thus prolonged strenuous endurance training in these older highly trained endurance athletes appears to have altered the decline in pulmonary function and volumes associated with aging.

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Airflow obstruction in sarcoidosis

Medicinski pregled ◽

10.2298/mpns13s1039d ◽

2013 ◽

Vol 66 (suppl. 1) ◽

pp. 39-41

Author(s):

Aleksandra Dudvarski-Ilic ◽

Spasoje Popevic ◽

Mihailo Stjepanovic ◽

Branislav Gvozdenovic ◽

Branislava Milenkovic ◽

...

Keyword(s):

Pulmonary Fibrosis ◽

Pulmonary Function ◽

Airflow Obstruction ◽

Lung Parenchyma ◽

Forced Expiratory Volume ◽

Airflow Limitation ◽

Small Airways ◽

Lung Capacity ◽

Late Stages ◽

Expiratory Flow Rates

Introduction. Aberrations in pulmonary function test are present in about 20% of patients with radiographic stage I sarcoidosis, whereas the pulmonary function is damaged in 40-80% of patients with parenchymal infiltrates (stages II, III or IV). Discussion and Review of Literature. Reductions in lung volumes (vital capacity and total lung capacity) are characteristic. The diffusing capacity of lungs is often reduced, but it is less pronounced in sarcoidosis than in idiopathic pulmonary fibrosis. Oxygenation is usually preserved until late in the course of sarcoidosis. Airflow obstruction (reduced forced expiratory volume in one second and expiratory flow rates) and bronchial hyper-reactivity occur in 30-50% of sarcoidosis patients with pulmonary parenchymal involvement. Conclusion. While restrictive spirometry pattern could easily be explained by fibrous changes in lung parenchyma, especially in late stages of the lung disease, pathogenesis of airflow limitation can be attributed mostly to endobronchial involvement (intraluminal granuloma or fibrous scars formation), airway compression due to enlarged lymph nodes and to distortion of small airways due to established pulmonary fibrosis.

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Chronic airflow obstruction after successful treatment of multidrug-resistant tuberculosis

ERJ Open Research ◽

10.1183/23120541.00026-2017 ◽

2017 ◽

Vol 3 (3) ◽

pp. 00026-2017 ◽

Cited By ~ 9

Author(s):

Anthony L. Byrne ◽

Ben J. Marais ◽

Carole D. Mitnick ◽

Frances L. Garden ◽

Leonid Lecca ◽

...

Keyword(s):

Forced Vital Capacity ◽

Vital Capacity ◽

Airflow Obstruction ◽

Multidrug Resistant ◽

Chronic Respiratory Disease ◽

Forced Expiratory Volume ◽

Cross Sectional ◽

Lung Volumes ◽

Lower Lung ◽

Mdr Tb

Cross-sectional studies reveal an association between tuberculosis (TB) and chronic airflow obstruction, but cannot adequately address confounding. We hypothesised that treated pulmonary TB is an independent risk factor for chronic airflow obstruction.The Pulmones Post TB cohort study enrolled participants from Lima, Peru, aged 10–70 years with a history of drug-susceptible (DS)- or multidrug-resistant (MDR)-TB who had completed treatment and were clinically cured. Unexposed participants without TB were randomly selected from the same districts. We assessed respiratory symptoms, relevant environmental exposures, and spirometric lung function pre- and post-bronchodilator.In total, 144 participants with DS-TB, 33 with MDR-TB and 161 unexposed participants were fully evaluated. Compared with unexposed participants, MDR-TB patients had lower lung volumes (adjusted mean difference in forced vital capacity −370 mL, 95% CI −644– −97) and post-bronchodilator airflow obstruction (adjusted OR 4.89, 95% CI 1.27–18.78). Participants who had recovered from DS-TB did not have lower lung volumes than unexposed participants, but were more likely to have a reduced forced expiratory volume in 1 s/forced vital capacity ratio <0.70 (adjusted OR 2.47, 95% CI 1.01–6.03).Individuals successfully treated for TB may experience long-lasting sequelae. Interventions facilitating earlier TB treatment and management of chronic respiratory disease should be explored.

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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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Household Food Insecurity, Lung Function, and COPD in US Adults

Nutrients ◽

10.3390/nu13062098 ◽

2021 ◽

Vol 13 (6) ◽

pp. 2098

Author(s):

Francisca de Castro Mendes ◽

Kirstie Ducharme-Smith ◽

Gustavo Mora-Garcia ◽

Saleh A. Alqahtani ◽

Maria Stephany Ruiz-Diaz ◽

...

Keyword(s):

Lung Function ◽

Food Insecurity ◽

Representative Sample ◽

Airflow Obstruction ◽

Forced Expiratory Volume ◽

Chronic Obstructive ◽

Obstructive Pulmonary Disease ◽

The Us ◽

Nationally Representative ◽

Lung Health

Increasing epidemiological evidence suggests that optimal diet quality helps to improve preservation of lung function and to reduce chronic obstructive pulmonary disease (COPD) risk, but no study has investigated the association of food insecurity (FI) and lung health in the general population. Using data from a representative sample of US adults who participated in the National Health and Nutrition Examination Survey (NHANES) 2007–2012 cycles, we investigated the association between FI with lung function and spirometrically defined COPD in 12,469 individuals aged ≥ 18 years of age. FI (high vs. low) was defined using the US Department of Agriculture’s Food Security Scale). Population-weighted adjusted regression models were used to investigate associations between FI, and forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), their ratio, and spirometrically defined restriction (FVC below the lower limit of normal) and airflow obstruction (COPD). The prevalence of household FI was 13.2%. High household FI was associated with lower FVC (adjusted β-coefficient −70.9 mL, 95% CI −116.6, −25.3), and with higher odds (OR) of spirometric restriction (1.02, 95% CI 1.00, 1.03). Stratified analyses showed similar effect sizes within specific ethnic groups. High FI was associated with worse lung health in a nationally representative sample of adults in the US.

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Pulmonary Function Testing in Pediatric Practice

Pediatrics in Review ◽

10.1542/pir.15.10.403 ◽

1994 ◽

Vol 15 (10) ◽

pp. 403-411

Author(s):

Gary A. Mueller ◽

Howard Eigen

Keyword(s):

Pulmonary Function ◽

Pulmonary Function Tests ◽

Airflow Obstruction ◽

Disease Process ◽

Pulmonary Function Testing ◽

Response To Therapy ◽

Lung Volumes ◽

Arterial Blood Gas ◽

Arterial Blood ◽

Function Testing

Pulmonary function testing is an important tool in the evaluation of children who have or are suspected of having lung disease. Of particular importance, pulmonary function testing provides objective and reproducible measurements, which then can be used to follow the response to therapy. The measurements of air flow and lung volumes are the mechanical pulmonary function tests used most commonly. However, measurements of the efficiency of gas exchange also are considered a test of pulmonary function and can be assessed by such methods as arterial blood gas and oximetry. This article focuses on those tests readily available to the pediatrician in the office or hospital. Measuring pulmonary function regularly is analogous to measuring blood pressure in patients who have hypertension, allowing the physician to follow a measurement directly associated with the pulmonary disease process. As with other clinical tests, pulmonary function measurements are most effective when used to answer a specific question about the patient. For example, in a child who presents having a persistent cough and a family history of asthma, the diagnosis may be asthma, and the question "Does the child have airflow obstruction consistent with asthma?" can be answered by spirometry. Spirometry The parameters commonly measured in the assessment of respiratory function are lung volumes, air flows and timed volumes, and airway reactivity.

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STUDIES OF RESPIRATORY PHYSIOLOGY IN CHILDREN

PEDIATRICS ◽

10.1542/peds.24.2.181 ◽

1959 ◽

Vol 24 (2) ◽

pp. 181-193

Author(s):

C. D. Cook ◽

P. J. Helliesen ◽

L. Kulczycki ◽

H. Barrie ◽

L. Friedlander ◽

...

Keyword(s):

Tidal Volume ◽

Respiratory Rate ◽

Vital Capacity ◽

Total Lung Capacity ◽

Lung Compliance ◽

Respiratory Physiology ◽

Residual Volume ◽

Lung Volumes ◽

Lung Capacity ◽

Residual Capacity

Tidal volume, respiratory rate and lung volumes have been measured in 64 patients with cystic fibrosis of the pancreas while lung compliance and resistance were measured in 42 of these. Serial studies of lung volumes were done in 43. Tidal volume was reduced and the respiratory rate increased only in the most severely ill patients. Excluding the three patients with lobectomies, residual volume and functional residual capacity were found to be significantly increased in 46 and 21%, respectively. These changes correlated well with the roentgenographic evaluation of emphysema. Vital capacity was significantly reduced in 34% while total lung capacity was, on the average, relatively unchanged. Seventy per cent of the 61 patients had a signficantly elevated RV/TLC ratio. Lung compliance was significantly reduced in only the most severely ill patients but resistance was significantly increased in 35% of the patients studied. The serial studies of lung volumes showed no consistent trends among the groups of patients in the period between studies. However, 10% of the surviving patients showed evidence of significant improvement while 15% deteriorated. [See Fig. 8. in Source Pdf.] Although there were individual discrepancies, there was a definite correlation between the clinical evaluation and tests of respiratory function, especially the changes in residual volume, the vital capacity, RV/ TLC ratio and the lung compliance and resistance.

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Persistent airflow obstruction in inner-city children with asthma

Allergy and Asthma Proceedings ◽

10.2500/aap.2021.42.210043 ◽

2021 ◽

Vol 42 (4) ◽

pp. 310-316

Author(s):

Kenny Y. Kwong ◽

Yang Z. Lu ◽

Emilio Jauregui ◽

Lyne Scott

Keyword(s):

Lung Function ◽

Inner City ◽

Airway Remodeling ◽

Airflow Obstruction ◽

Later Life ◽

Forced Expiratory Volume ◽

Initial Visit ◽

Asthma Care ◽

Increased Risk ◽

Children With Asthma

Background: Airway remodeling has been shown to be persistent in patients with asthma despite treatment with controller medications. Patients with early airflow obstruction may continue to experience poor lung function despite treatment. Objectives: To determine whether early airflow obstruction in inner-city children with asthma persists despite guideline-based asthma care. Methods: In a retrospective study that used a cohort of inner-city children with asthma treated by using an asthma-specific disease management system, the patients were stratified into “low” or “high” lung function groups at the time of the initial visit (high, forced expiratory volume in the first second of expiration [FEV1] % predicted and FEV1/forced vital capacity [FVC] ≥ 80%; and low, FEV1% predicted and FEV1/FVC < 80%). These patients then received National Heart, Lung, and Blood Institute guideline‐based asthma treatment at regular follow-up intervals with spirometry performed at these visits as part of regular care. FEV1% predicted and FEV1/FVC were followed up for up to 10 years for both the high and low cohorts. Results: Over 10 years, the patients initially in the “high” group maintained FEV1% predicted and FEV1/FVC at values similar to the initial visit (94 to 96% and 87 to 89%, respectively), whereas those in the low group had only slight increases of FEV1% predicted and FEV1/FVC over the same time (77 to 82% and 78 to 82%, respectively). Low FEV1% predicted and FEV1/FVC at the time of the first visit was significantly associated with an increased risk of low values of these lung functions over the next 3‐5 years despite treatment. African American ethnicity and male gender were also associated with lower lung function over time. Conclusion: Early airflow obstruction in inner city children asthma is associated with poor lung function in later life despite guideline-based asthma care. Current asthma therapy may not affect pathways and leads to airway remodeling in children with asthma.

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