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Airway mucus plugs are frequently identified on CT scans of patients with COPD with a smoking history without mucus-related symptoms (ie, cough, phlegm [silent mucus plugs]). In patients with COPD, what are the risk and protective factors associated with silent airway mucus plugs? Are silent mucus plugs associated with functional, structural, and clinical measures of disease? We identified mucus plugs on chest CT scans of participants with COPD from the COPDGene study. The mucus plug score was defined as the number of pulmonary segments with mucus plugs, ranging from 0 to 18, and categorized into three groups (0, 1-2, and ≥ 3). We determined risk and protective factors for silent mucus plugs and the associations of silent mucus plugs with measures of disease severity using multivariable linear and logistic regression models. Of 4,363 participants with COPD, 1,739 had no cough or phlegm. Among the 1,739 participants, 627 (36%) had airway mucus plugs identified on CT scan. Risk factors of silent mucus plugs (compared with symptomatic mucus plugs) were older age (OR, 1.02), female sex (OR, 1.40), and Black race (OR, 1.93) (all P values <.01). Among those without cough or phlegm, silent mucus plugs (vs absence of mucus plugs) were associated with worse 6-min walk distance, worse resting arterial oxygen saturation, worse FEV 1 % predicted, greater emphysema, thicker airway walls, and higher odds of severe exacerbation in the past year in adjusted models. Mucus plugs are common in patients with COPD without mucus-related symptoms. Silent mucus plugs are associated with worse functional, structural, and clinical measures of disease. CT scan-identified mucus plugs can complement the evaluation of patients with COPD. [Display omitted] [ABSTRACT FROM AUTHOR]

A 71-year-old man with a history of recurrent tonsillar squamous cell carcinoma was admitted to the hospital with oropharyngeal bleeding. He received high-dose radiation therapy with curative intent. On day 4 of hospitalization, he demonstrated hypoxia resulting from an airway mucus plug and was brought to the medical ICU. [ABSTRACT FROM AUTHOR]

We previously showed in patients with poorly controlled eosinophilic asthma that a single dose of benralizumab resulted in significantly improved Asthma Control Questionnaire (ACQ-6) score and 129Xe MRI ventilation defect percent (VDP) 28 days postinjection, and 129Xe MRI VDP and CT airway mucus occlusions were shown to independently predict this early ACQ-6 response to benralizumab. Do early VDP responses at 28 days persist, and do FEV 1 , fractional exhaled nitric oxide, and mucus plug score improve during a 2.5 year treatment period? Participants with poorly controlled eosinophilic asthma completed spirometry, ACQ-6, and MRI, 28 days, 1 year, and 2.5 years after initiation of treatment with benralizumab; chest CT was acquired at enrollment and 2.5 years later. Of 29 participants evaluated at 28 days post-benralizumab, 16 participants returned for follow-up while on therapy at 1 year, and 13 participants were evaluable while on therapy at 2.5 years post-benralizumab initiation. As compared with 28 days post-benralizumab, ACQ-6 score (2.0 ± 1.4) significantly improved after 1 year (0.5 ± 0.6, P =.02; 95% CI, 0.1-1.1) and 2.5 years (0.5 ± 0.5, P =.03; 95% CI, 0.1-1.1). The mean VDP change at 2.5 years (−4% ± 3%) was greater than the minimal clinically important difference, but not significantly different from VDP measured 28 days post-benralizumab. Mucus score (3 ± 4) was significantly improved at 2.5 years (1 ± 1, P =.03; 95% CI, 0.3-5.5). In six of eight participants with previous occlusions, mucus plugs vanished or substantially diminished 2.5 years later. VDP (P <.001) and mucus score (P <.001) measured at baseline, but not fractional exhaled nitric oxide or FEV 1 , independently predicted ACQ-6 score after 2.5 years. In poorly controlled eosinophilic asthma, early MRI VDP responses at 28 days post-benralizumab persisted 2.5 years later, alongside significantly improved mucus scores and asthma control. [ABSTRACT FROM AUTHOR]

Background: Patients with eosinophilic asthma often report poor symptomatic control and quality of life. Anti-IL-5 therapy, including anti-IL-5Rα (benralizumab), rapidly depletes eosinophils in the blood and airways and also reduces asthma exacerbations and improves quality of life scores. In patients with severe asthma, eosinophilic inflammation-driven airway mucus occlusions have been measured using thoracic x-ray CT imaging. Pulmonary 129Xe MRI ventilation defect percentage (VDP) also sensitively measures asthma airway dysfunction caused by airway hyperresponsiveness, remodeling, and luminal mucus occlusions. Using 129Xe MRI and CT imaging together, it is feasible to measure both airway luminal occlusions and airway ventilation in relationship to anti-IL-5 therapy to ascertain the direct impact of therapy-induced eosinophil depletion on airway function.Research Question: Does 129Xe MRI detect airway functional responses to eosinophil depletion after a single benralizumab dose and do airway mucus occlusions mediate this response?Study Design and Methods: MRI, eosinophil count, spirometry, oscillometry, Asthma Control Questionnaire (ACQ), Asthma Quality of Life Questionnaire (AQLQ), and St. George's Respiratory Questionnaire were completed on day 0 and 28 days after a single 30-mg subcutaneous benralizumab dose. CT scan mucus plugs were scored on day 0, and MRI VDP was quantified on days 0 and 28.Results: Twenty-nine participants (27 with baseline CT imaging) completed day 0 and day 28 visits. On day 28 after a single benralizumab dose, significantly improved blood eosinophil counts, VDP, ACQ 6 scores, AQLQ scores (all P < .001), and peripheral airway resistance (P = .04) were found in all participants. On day 28, significantly improved VDP and ACQ 6 scores also were found in the subgroup of nine participants with five or more mucus plugs, but not in the subgroup (n = 18) with fewer than five mucus plugs. Based on univariate relationships for change in ACQ 6 score, multivariate models were generated and showed that day 0 VDP (P < .001) and day 0 CT scan mucus score (P < .001) were significant variables for change in ACQ 6 score on day 28 after benralizumab injection.Interpretation: 129Xe ventilation significantly improved in participants with uncontrolled asthma and in those with significant mucus plugging after a single dose of benralizumab.Trial Registry: ClinicalTrials.gov; No.: NCT03733535; URL: www.Clinicaltrials: gov. [ABSTRACT FROM AUTHOR]

Background: Improved understanding of the pathways associated with airway pathophysiologic features in COPD will identify new predictive biomarkers and novel therapeutic targets.Research Question: Which physiologic pathways are altered in the airways of patients with COPD and will predict exacerbations?Study Design and Methods: We applied a mass spectrometric panel of metabolomic biomarkers related to mucus hydration and inflammation to sputa from the multicenter Subpopulations and Intermediate Outcome Measures in COPD Study. Biomarkers elevated in sputa from patients with COPD were evaluated for relationships to measures of COPD disease severity and their ability to predict future exacerbations.Results: Sputum supernatants from 980 patients were analyzed: 77 healthy nonsmokers, 341 smokers with preserved spirometry, and 562 patients with COPD (178 with Global Initiative on Chronic Obstructive Lung Disease [GOLD] stage 1 disease, 303 with GOLD stage 2 disease, and 81 with GOLD stage 3 disease) were analyzed. Biomarkers from multiple pathways were elevated in COPD and correlated with sputum neutrophil counts. Among the most significant analytes (false discovery rate, 0.1) were sialic acid, hypoxanthine, xanthine, methylthioadenosine, adenine, and glutathione. Sialic acid and hypoxanthine were associated strongly with measures of disease severity, and elevation of these biomarkers was associated with shorter time to exacerbation and improved prediction models of future exacerbations.Interpretation: Biomarker evaluation implicated pathways involved in mucus hydration, adenosine metabolism, methionine salvage, and oxidative stress in COPD airway pathophysiologic characteristics. Therapies that target these pathways may be of benefit in COPD, and a simple model adding sputum-soluble phase biomarkers improves prediction of pulmonary exacerbations.Trial Registry: ClinicalTrials.gov; No.: NCT01969344; URL: www.Clinicaltrials: gov. [ABSTRACT FROM AUTHOR]

Background: Although mucus plugging is a well-reported feature of asthma, whether asthma and type 2 inflammation affect mucociliary clearance (MCC) is unknown.Research Question: Does type 2 inflammation influence mucus clearance rates in patients with mild asthma who are not receiving corticosteroids?Study Design and Methods: The clearance rates of inhaled radiolabeled particles were compared between patients with mild asthma with low (n = 17) and high (n = 18) levels of T2 inflammation. Fraction exhaled nitric oxide (Feno) was used to prospectively segregate subjects into T2 Lo (Feno < 25 ppb) and T2 Hi (Feno > 35 ppb) cohorts. Bronchial brush samples were collected with fiber-optic bronchoscopy, and quantitative polymerase chain reaction was performed to measure expression of genes associated with T2 asthma. MCC rate comparisons were also made with a historical group of healthy control subjects (HCs, n = 12).Results: The T2 Lo cohort demonstrated increased MCC when compared with both T2 Hi and historic HCs. MCC within the T2 Hi group varied significantly, with some subjects having low or zero clearance. MCC decreased with increasing expression of several markers of T2 airway inflammation (CCL26, NOS2, and POSTN) and with Feno. MUC5AC and FOXJ1 expression was similar between the T2Lo and T2Hi cohorts.Interpretation: Increasing T2 inflammation was associated with decreasing MCC. High rates of MCC in T2 Lo subjects may indicate a compensatory mechanism present in mild disease but lost with high levels of inflammation. Future studies are required to better understand mechanisms and whether impairments in MCC in more severe asthma drive worse clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: Cough characteristics vary between patients, and this can impact clinical diagnosis and care. The purpose of part two of this state-of-the-art review is to update the American College of Chest Physicians (CHEST) 2006 guideline on global physiology and pathophysiology of cough.Study Design and Methods: A review of the literature was conducted using PubMed and MEDLINE databases from 1951 to 2019 using prespecified search terms.Results: We describe the demographics of typical patients with cough in the clinical setting, including how cough characteristics change across age. We summarize the effect of common clinical conditions impacting cough mechanics and the physical properties of mucus on airway clearance.Interpretation: This is the second of a two-part update to the 2006 CHEST cough guideline; it complements part one on basic phenomenology of cough by providing an extended clinical picture of cough along with the factors that alter cough mechanics and efficiency in patients. A greater understanding of the physiology and pathophysiology of cough will improve clinical management. [ABSTRACT FROM AUTHOR]

Mucous exudates occluding the lumen of small airways are associated with reduced lung function and mortality in subjects with COPD; however, luminal plugs in large airways have not been widely studied. We aimed to examine the associations of chest CT scan-identified luminal plugging with lung function, health-related quality of life, and COPD phenotypes. We randomly selected 100 smokers without COPD and 400 smokers with COPD from the COPDGene Study. Luminal plugging was visually identified on inspiratory CT scans at baseline and 5-year follow-up. The relationships of luminal plugging to FEV 1 , St. George's Respiratory Questionnaire (SGRQ) score, emphysema on CT scan (defined as the percentage of low attenuation area < 950 Hounsfield units [%LAA-950]), and chronic bronchitis were assessed using linear and logistic multivariable analyses. Overall, 111 subjects (22%) had luminal plugging. The prevalence of luminal plugging was higher in subjects with COPD than those without COPD (25% vs 10%, respectively; P =.001). In subjects with COPD, luminal plugging was significantly associated with FEV 1 % predicted (estimate, −6.1; SE, 2.1; P =.004) and SGRQ score (estimate, 4.9; SE, 2.4; P =.04) in adjusted models. Although luminal plugging was associated with log %LAA-950 (estimate, 0.43; SE, 0.16; P =.007), its relationship with chronic bronchitis did not reach statistical significance (P =.07). Seventy-three percent of subjects with COPD with luminal plugging at baseline had it 5 years later. In subjects with COPD, CT-identified luminal plugging is associated with airflow obstruction, worse health-related quality of life, and emphysema phenotype. This imaging feature may supplement the current clinical assessment of chronic mucus hypersecretion in COPD. [ABSTRACT FROM AUTHOR]

Background: Postnasal drip (PND) is a common symptom associated with upper respiratory tract disorders. It occurs without other symptoms or combined with chronic rhinosinusitis. However, the pathophysiology of PND is debated to this day, and an objective definition of PND has not been established. Therefore, we aimed to elucidate whether the viscosity and volume of nasal secretions as well as the mucociliary clearance and sensitivity of the nasopharynx, or atopy could play a role in the pathophysiology of PND.Methods: A prospective case-control study of 30 patients (15 patients with PND and 15 healthy subjects) was conducted. The viscosity and volume of nasal secretions, the nasopharyngeal sensitivity, the mucociliary clearance, and allergic sensitization using a skin prick test were assessed in all subjects.Results: Viscosity of nasal secretions in patients with PND was significantly increased compared with healthy subjects. Two follow-up measurements in symptom-free intervals showed reversibility of increased viscosity. Analysis of nasopharyngeal sensitivity showed significant reductions in patients with PND. Furthermore, mucociliary clearance seems to be prolonged in patients with PND. The volume of nasal secretions and the atopy screening showed no significant differences in patients with PND compared with healthy individuals.Conclusions: Increased viscosity seems to play a relevant role in the pathophysiology of PND. Additionally, delayed mucociliary clearance and hyposensitivity of the nasopharynx may be further components. Earlier concepts of PND, regarding an increased volume of secretions and atopy, do not seem to hold true because our analyses showed no significant difference between cases and control subjects. [ABSTRACT FROM AUTHOR]

Background: Intraluminal contributor(s) to airflow obstruction in severe asthma are patient-specific and must be evaluated to personalize treatment. The occurrence and functional consequence of airway mucus in the presence or absence of airway eosinophils remain undetermined.Objective: The objective of this study was to understand the functional consequence of airway mucus in the presence or absence of eosinophils and to identify biomarkers of mucus-related airflow obstruction.Methods: Mucus plugs were quantified on CT scans, and their contribution to ventilation heterogeneity (using MRI ventilation defect percent [VDP]) was evaluated in 27 patients with severe asthma. Patients were dichotomized based on sputum eosinophilia such that the relationship between mucus, eosinophilia, and ventilation heterogeneity could be investigated. Fractional exhaled nitric oxide (Feno) and related cytokines in sputum were measured.Results: Mucus plugging was present in 100% of asthma patients with sputum eosinophils and 36% of those without sputum eosinophils (P = .0006) and was correlated with MRI VDP prebronchodilator (r = 0.68; P = .0001) and postbronchodilator (r = 0.72; P < .0001). In a multivariable regression, both mucus and eosinophils contributed to the prediction of postbronchodilator MRI VDP (R2 = 0.75; P < .0001). Patients with asthma in whom the mucus score was high had raised Feno (P = .03) and IL-4 (P = .02) values. Mucus plugging correlated with Feno (r = 0.63; P = .005).Conclusions: Both airway eosinophils and mucus can contribute to ventilation heterogeneity in patients with severe asthma. Patients in whom mucus is the dominant cause of airway obstruction have evidence of an upregulated IL-4/IL-13 pathway that could be identified according to increased Feno level. [ABSTRACT FROM AUTHOR]

The respiratory epithelium is lined by mucus, a gel consisting of water, ions, proteins, and macromolecules. The major macromolecular components of mucus are the mucin glycoproteins, which are critical for local defense of the airway. There are three classes of mucins in the airways: those that are secreted but do not polymerize (MUC7), those that are secreted and polymerize to form gels (MUC5AC, MUC5B), and those that have transmembrane domains and are cell surface associated (MUC1, MUC4, MUC16, MUC20). The mucins are regulated at the transcriptional, posttranscriptional, and epigenetic levels, and posttranslational modifications play an important role in mucin binding and clearance of microbes and pollutants. The development of mice deficient in specific mucins, and the cystic fibrosis pig, has greatly advanced our understanding of the role of mucins as innate immune mediators and how mucins and mucus contribute to lung disease. These observations suggest new strategies to ameliorate mucus obstruction by targeting mucociliary clearance and mucin hyperconcentration. Furthermore, a polymorphism in the promoter of MUC5B is strongly associated with risk of developing pulmonary fibrosis, supporting a novel function for MUC5B to influence interstitial lung disease. Exciting new data support the concept not only that mucins and mucus are important for lung homeostasis and protection from environmental threats but also that goblet cells play an important role as regulators of innate immune function. These insights into the innate immune properties of mucins and goblet cells support a shift from the current paradigm of repressing increased mucin expression to targeting regulation of specific mucins and the abnormal airway milieu. [ABSTRACT FROM AUTHOR]

Background: Diffuse airway mucus obstruction is an important feature of severe and fatal asthma. MUC5AC and MUC5B are the principal gel-forming mucins found in airway mucus. The mucin composition of airway mucus likely affects its functional properties.Methods: We quantified the principal airway mucins MUC5AC and MUC5B in the sputum of age-matched children with acute and stable asthma and healthy control subjects by using Western blotting.Results: Sputum samples from 38 children (13 with acute asthma, 15 with stable asthma, 10 control subjects) were obtained. Sputum MUC5AC concentrations were 7.6 μg/mL in control subjects, 22.4 μg/mL in those with stable asthma (P = .17), and 44.7 μg/mL in those with acute asthma (P < .05). MUC5B concentrations showed less variation, with 238.5, 208.4 and 165.9 μg/mL in control subjects, those with stable asthma, and those with acute asthma, respectively. The greater MUC5AC concentration in those with acute asthma resulted in a significantly altered MUC5B:MUC5AC ratio between control subjects and those with acute asthma (P < .05). Significant differences in MUC5B glycoforms were present between the groups, with the low-charge-only glycoform being found uniquely in those with acute asthma.Conclusions: Increased MUC5AC and the presence of a low-charge-only MUC5B glycoform significantly altered mucin composition in children with acute asthma. These changes may be important contributory factors to the airway mucus obstruction observed during acute asthma. [ABSTRACT FROM AUTHOR]

Although mucus is a normal product of the tracheobronchial tree, some diseases of the respiratory tract are characterized by unusually thick (inspissated) forms of mucus that accumulate within the airways. These are known as mucus plugs. The pathologic composition of these plugs is surprisingly diverse and, in many cases, correlates with distinctive clinical, radiologic, and bronchoscopic findings. The best-known conditions that involve mucus plugs are allergic bronchopulmonary aspergillosis, plastic bronchitis, and asthma. Other lung diseases occasionally associated with plugs within the airways include Aspergillus tracheobronchitis, hyper-IgE syndrome, exogenous lipoid pneumonia, pulmonary alveolar proteinosis, and chronic eosinophilic pneumonia. In this review, we describe and illustrate the bronchoscopic, pathologic, and imaging findings in respiratory disorders characterized by mucus plugs or plugs composed of other similar materials. Recognition of the characteristic appearance and differential diagnosis of mucus plugs will hopefully facilitate diagnosis and management of these diseases. [ABSTRACT FROM AUTHOR]

The article discusses the importance of recognizing secretory hyperresponsiveness as a distinct clinical condition for effective management of the disease including pulmonary mucus hypersecretion. It discusses the different types of patients with greater mucus secretory responses including those with middle lobe syndrome, cough-dominant asthma and severe asthma. It also discusses the possible causes of extreme forms of secretory hyperresponsiveness such as lung cancer and plastic bronchitis.

The article focuses on a randomized study which investigated the efficacy and safety of using inhaled dry powder mannitol over 12 weeks period for the symptomatic treatment of patients with non-cyctic fibrosis bronchiectasis. An overview is given on the pathophysiology and incidence of bronchiectasis and the mechanism of action of inhaled dry powder mannitol. It also examines the effect of mannitol on mucus clearance and quality of life of individuals with non-cystic fibrosis bronchiectasis.

Background: Patients with eosinophilic asthma often report poor symptomatic control and quality of life. Anti-IL-5 therapy, including anti-IL-5Rα (benralizumab), rapidly depletes eosinophils in the blood and airways and also reduces asthma exacerbations and improves quality of life scores. In patients with severe asthma, eosinophilic inflammation-driven airway mucus occlusions have been measured using thoracic x-ray CT imaging. Pulmonary 129 Xe MRI ventilation defect percentage (VDP) also sensitively measures asthma airway dysfunction caused by airway hyperresponsiveness, remodeling, and luminal mucus occlusions. Using 129 Xe MRI and CT imaging together, it is feasible to measure both airway luminal occlusions and airway ventilation in relationship to anti-IL-5 therapy to ascertain the direct impact of therapy-induced eosinophil depletion on airway function., Research Question: Does 129 Xe MRI detect airway functional responses to eosinophil depletion after a single benralizumab dose and do airway mucus occlusions mediate this response?, Study Design and Methods: MRI, eosinophil count, spirometry, oscillometry, Asthma Control Questionnaire (ACQ), Asthma Quality of Life Questionnaire (AQLQ), and St. George's Respiratory Questionnaire were completed on day 0 and 28 days after a single 30-mg subcutaneous benralizumab dose. CT scan mucus plugs were scored on day 0, and MRI VDP was quantified on days 0 and 28., Results: Twenty-nine participants (27 with baseline CT imaging) completed day 0 and day 28 visits. On day 28 after a single benralizumab dose, significantly improved blood eosinophil counts, VDP, ACQ 6 scores, AQLQ scores (all P < .001), and peripheral airway resistance (P = .04) were found in all participants. On day 28, significantly improved VDP and ACQ 6 scores also were found in the subgroup of nine participants with five or more mucus plugs, but not in the subgroup (n = 18) with fewer than five mucus plugs. Based on univariate relationships for change in ACQ 6 score, multivariate models were generated and showed that day 0 VDP (P < .001) and day 0 CT scan mucus score (P < .001) were significant variables for change in ACQ 6 score on day 28 after benralizumab injection., Interpretation: 129 Xe ventilation significantly improved in participants with uncontrolled asthma and in those with significant mucus plugging after a single dose of benralizumab., Trial Registry: ClinicalTrials.gov; No.: NCT03733535; URL: www., Clinicaltrials: gov., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

The article presents a case study of a 30-year-old woman presented with a mass-like opacity in the right upper lobe and with intermittent cough. A computed tomography (CT) scan of the chest showed a persistent anterior mediastinal mass that did not expand during the 2-year interval. There was big area of heterogenous consolidation where multiple enhancing vessels and mucus-filled dilated bronchi were found in the next anterior segment of the right upper lobe.

The article presents a study which examines the role of alternatively activate macrophages (AAMs) in the production of interleukins (IL). The study reveals that AAMs can also become a major source on the production of IL-13 and drive airway hyperactivity and increased mucus production that is characteristic of airway disease. It shows that markers of the immune cell subset can be useful to direct stratification and treating patients with chronic airway diseases.

The article presents a study which aims to examine the chronic bronchitic (CB) phenotype in chronic obstructive pulmonary disease (COPD). The study reveals that CB in patients having COPD is related with higher risk of exacerbations and with worse respiratory symptoms. It suggests that CB patients with COPD might require more directed therapy targeting smoking cessation and chronic mucus production to improve outcomes, improve quality of life and lessen risk.

The article discusses a study on the efficacy of three brands of 7.5-millimeter endotracheal tubes (ETTs), namely Hi-Lo Evac, Portex Blue Line Sacett and Teleflex Isis, in aspirating mucus and saliva simulants which are similar to human airway mucus. The study also examined the possible obstruction of the ETT suction port by a flexible tracheal membrane when vacuum pressure is applied. It was found that among the three ETTs, the Isis was the most effective in suctioning simulants through the tube orifice.

The article presents a study which examines the impact of interactions among airflow oscillation, tracheal inclination, and mucus elasticity in the improvement of simulated cough clearance. The study evaluates mucus stimulant aliquots displacement during simulated cough under several conditions in a rigid tracheal model. Results indicate that increased tracheal angle will result to increased cough efficiency which is attributed to increased frontal presentation facing the flow of cough.

The article highlights the most recent insights on mucus biology in health and disease. It provides information on mucin gene regulation and regulation of mucin secretion. It discusses how mucus biology is perturbed in disease and how insights concerning the biochemical and biophysical characteristics of mucus and sputum need to be considered to more effectively treat airway obstruction in chronic inflammatory airway diseases.

The article reports on the stimulation of mucin secretion and mucociliary transport velocity (MCTV) in the lipopolysaccharide (LPS)-inflammed ferret airway using Vicks VaporRub (VVR) from Proctor & Gamble Co. In an animal model of airway inflammation, mucin secretion was increased by 63% over the controls in the VVR in vitro grop. Ciliary beat frequency was decreased by 35%. Neither LPS nor VVR increased lung water, but LPS decreased MCTV in normal airways and VVR-exposed airways.

The article describes how the discrete anatomic components of the respiratory system work in concert to produce an effective cough. The capacity to drive gas at high linear velocities through the airways determines an effective cough. It also depends on an effective interaction between the flowing gas and mucus lining the airways. By way of considering the timing of the varied events that constitute cough, the mechanics of cough can be calculated. The inhalation of gas characterize the initial phase of cough. The initial inspiratory phase is followed by the compressive phase of cough.

The article focuses on a case study related to mucus properties in children with primary ciliary dyskinesia. Primary ciliary dyskinesia (PCD) is a form of bronchiectasis that is quiet similar to cystic fibrosis (CF) in many ways and is caused by congenital defects in mucociliary clearance. The main purpose of the study was to compare the biophysical properties of CF and PCD sputa in patients with lung function impairment. It was found upon thorough examination that inflammation was three times greater in the PCD sputa. No significant differences were found in the sputum biophysical or transport properties.

The article evaluates the effectiveness of endotracheal suction catheters. These catheters are used to remove mucus from an endotracheal tube and reduce the risk of hypoxemia. The suction catheter design had a significant effect on the amount of mucus simulant removed at each simulant concentration. An accurate evaluation of suction catheters requires mucus simulants with surface and viscoelastic properties similar to human tracheal mucus. The results of this study indicate that the viscoelastic and surface properties of secretions and suction catheter side hole positioning and size were the most significant factors that affected mucus removal effectiveness.

This article presents a study conducted to determine the benefits of daily use of high-frequency chest wall oscillation in familial dysautonomia (FD) patients with lung disease. FD, also known as the Riley-Day syndrome, is a genetic disorder commonly associated with pulmonary disease. Fifteen FD patients who had a history of recurrent lung disease and for whom chest physiotherapy, i.e., daily inhalations with bronchodilators and percussion, had been prescribed were enrolled into the clinical trial. Pulmonary function measures were obtained using an office-based spirometry system. Over a 1-year period, scheduled longitudinal evaluations were performed at 1, 3, 6, 9, and 12 months.

This article focuses on a study conducted to examine the antiprotease function of airway secretions in purulent tracheobronchitis. The aim of this study was to examine the compartmentalization of human leukocyte elastase (HLE) activity in the liquid sol phase and the solid gel phase of airway secretions. HLE is a serine protease that is synthesized in neutrophils. HLE amidolytic activities in the above two phases were measured using chromogenic substrates. It was found that the activity of HLE was 95% inhibited when bound to the gel phase.

This article focuses on a study related to airway narrowing measured by spirometry and impulse oscillometry following room temperature and cold temperature exercise. The knowledge that respiratory symptoms alone do not predict the presence of exercise-induced bronchoconstriction (EIB) justifies the need for objective testing methods for diagnosis. EIB, a transient narrowing of the airways during or shortly following the termination of exercise in susceptible individuals, exceeds the estimated 10 to 12% prevalence of asthma in both the general population and in the elite athlete population. The symptoms and observable signs of EIB are varied and disparate in nature, commonly including cough, wheeze, dyspnea, chest tightness, and/or excess mucus.

This article focuses on a study related to dornase alfa that reduces air trapping in children with mild cystic fibrosis (CF) lung disease. The predominant cause of morbidity and mortality in CF lung disease is progressive obstructive lung disease resulting from reduced mucociliary clearance, airway obstruction, recurrent endobronchial infections, and persistent inflammation and destruction of the airways. Early manifestations of CF lung disease include submucosal gland hypertrophy, inspissated airway mucus, inflammatory infiltrates, and bronchiectasis.

Study objective: To assess the effects of tiotropium on lung mucociliary clearance in COPD. Design: Randomized, double-blind, placebo-controlled, parallel-group study. Setting: Outpatients of an urban-area university teaching hospital. Patients: Thirty-four patients with COPD aged 40 to 75 years classified equally into two groups. Intervention: Single (18 µg) daily dose of tiotropium inhalation capsules or of placebo for 21 days. Methods: Six-hour tracheobronchial clearance of inhaled 99mTc-labeled polystyrene particles using a 48-h retention measurement to determine the "nontracheobronchial" deposition fraction. Results: Test radioaerosol penetration into the lungs increased significantly (p < 0.003) as did FEV1 (p < 0.006) in the tiotropium-treated patients, but measured mucociliary clearance was not significantly changed despite the increased pathway length for clearance (mean ± SE area under the tracheobronchial retention curve changed from 442 ± 22 to 453 ± 20%/h). Smaller (nonsignificant) decreases of radioaerosol penetration and FEV1 occurred in the placebo group together with a small (nonsignificant) decrease in the area under the retention curve. Conclusion: Twenty-one days of inhaled tiotropium, 18 µg/d, as a dry powder does not retard mucus clearance from the lungs. [ABSTRACT FROM AUTHOR]

Study Objectives: Inhalation of hypertonic saline or mannitol solutions acutely increases mucociliary clearance. Because increased clearance is often coupled with increased mucus secretion, we hypothesized that hyperosmolar agents would stimulate mucus secretion.Setting and Subjects: The isolated tracheae of healthy young adult ferrets were studied in a basic research laboratory.Measurements and Results: We demonstrated that there was a dose-dependent increase in mucin secretion by enzyme-linked lectin assay after incubation with 1.69 g/dL (597 mOsm/L), 3.69 g/dL (1,192 mOsm/L), 5.69 g/dL (1,823 mOsm/L), and 10.69 g/dL (3,612 mOsm/L) of saline solution over Krebs-Henseleit solution control (288 mOsm/L) [p < 0.01 for 1.69 g/dL of saline solution and p < 0.0001 for others]. Mannitol solution, 15 g/dL (1,040 mOsm/L), also significantly increased mucin secretion (n = 4, p < 0.005). There was a 47% and 54% increase in secretion of the serous cell product lysozyme after exposure to 3.69 g/dL (1,192 mOsm/L) and 10.69 g/dL (3,612 mOsm/L) saline solutions, respectively (n = 5, p < 0.05). Secretion was only stimulated when the hyperosmolar exposure was on the luminal side of the epithelium. Mucin secretion was induced within minutes of 3.69 g/dL of saline solution exposure, and this increased mucin secretion quickly peaked. The ratio of mucin to lysozyme secretion was approximately 2. This ratio appeared to be independent of the osmotic concentration of the stimulus and therefore of secretory rate.Conclusions: Mucus secretion is markedly stimulated in response to hyperosmolarity. This may be a protective response. These results also suggest that the therapeutic use of hyperosmolar aerosols should be evaluated with care when used for patients with mucus hypersecretion and impaired mucus clearance. [ABSTRACT FROM AUTHOR]