Physiologic Similarities and Differences Between COPD and Asthma

Prevalence and clinical features of most frequent phenotypes in the Italian COPD population: the CLIMA Study

Background

Chronic obstructive pulmonary disease (COPD) is a complex, progressive respiratory condition characterized by heterogeneous clinical presentations (phenotypes). The aim of this study was to assess the prevalence of the main COPD phenotypes and match of each phenotype to the most fitting clinical and lung function profile.

Methods

the CLIMA (Clinical Phenotypes in Actual Clinical Practice) study was an observational, cross-sectional investigation involving twenty-four sites evenly distributed throughout Italy. Patients were tentatively grouped based on their history and claimed prevailing symptoms at recruitment: chronic cough (CB, suggesting chronic bronchitis); dyspnoea (possible emphysema components, E); recurrent wheezing (presuming asthma components, A). Variables collected were: anagraphics; smoking habit; history of asthma; claim of >1 exacerbations in the previous year; blood eosinophil count; total blood IgE and alpha¹ anti-trypsin (α¹-AT) levels; complete lung function, and the chest X-ray report. mMRC, CAT, BCS, EQ5d-5L were also used. The association between variables and phenotypes were checked by Chi-square test and multinomial logistic regression.

Results

The CB phenotype was prevalent (48.3%), followed by the E and the A phenotypes (38.8% and 12.8%, respectively). When dyspnoea was the prevailing symptom, the probability of belonging to the COPD-E phenotype was 3.40 times higher. Recurrent wheezing was mostly related to the COPD-A phenotype. Lung function proved more preserved in the COPD-CB phenotype. Smoke; n. exacerbations/year; VR, and BODE index were positively correlated with the COPD-E phenotype, while SpO₂, FEV₁/FVC, FEV₁/VC, and FEV₁ reversibility were negatively correlated. Lower DLco values were highly probative for the COPD-E phenotype (p<0.001). Conversely, smoke, wheezing, plasma eosinophils, FEV₁ reversibility, and DLco were positively correlated with the COPD-A phenotype. The probability of belonging to the COPD-A phenotype raised by 2.71 times for any increase of one unit in % plasma eosinophils (p<0.001). Also multiparametrical scores contributed to discriminate the three phenotypes.

Conclusion

The recognition of the main phenotypes of COPD can be effectively pursued by means of a few clinical and instrumental parameters, easy to obtain also in current daily practice. The phenotypical approach is crucial in the management of COPD as it allows to individualize the therapeutic strategy and to obtain more effective clinical outcomes.

Small airway remodeling in a sheep model of bleomycin-induced pulmonary fibrosis

BACKGROUND

Although IPF is described traditionally as a disease affecting lung parenchyma, there is renewed interest in the alterations in the structure and function of the small airways in both IPF patients, and animal models of pulmonary fibrosis. Small airway remodeling may contribute to the pathophysiology of pulmonary fibrosis. Given the dearth of knowledge of small airway changes in pulmonary fibrosis, this study aims to assess the structural remodeling, as well as functional changes associated with bleomycin-injured small airways in a sheep model of pulmonary fibrosis.

MATERIALS AND METHODS

Two separate lung segments in ten sheep received two challenges of either 3 IU bleomycin, or saline (control), two weeks apart. The animals were euthanized seven weeks after the final bleomycin injury. Airflow resistance in the infused segments was measured with a wedged-bronchoscope procedure. This parameter was measured at baseline before bleomycin/saline-infusion, and at 2-, 4-, and 7-weeks after the final bleomycin-infusion. Inflammation and fibrosis in the airways were assessed by semi-quantitative morphological parameters. The density of blood vessels in the small airway walls was assessed in lung tissue sections immuno-stained with antibodies against collagen type IV.

RESULTS

There were a number of changes in the distal airways of bleomycin-infused lung segments. Bleomycin exposure significantly elevated airway resistance in these lung segments when compared to saline-infused control lung segments. In the peribronchial and peribronchiolar regions of the small airways, there were significantly increased levels of inflammation, fibrosis, airway wall area, and collagen deposition in bleomycin-infused airways when compared to saline-infused airways. Bronchial blood vessel density was not significantly different between bleomycin-and saline-infused lung segments.

CONCLUSIONS

In summary, our results indicate that the distal airways are involved in the pathology induced by bleomycin in this sheep model. This suggests that the sheep model may be useful for studying small airway remodeling in pulmonary fibrosis.

Pulmonary rehabilitation for obstructive lung disease

Pulmonary rehabilitation (PR) is a highly effective, established therapy to improve exercise intolerance, impaired quality of life and limb muscle weakness associated with a range of chronic respiratory diseases. The evidence base for PR is largest in the area of chronic obstructive pulmonary disease (COPD), yet its role in other obstructive lung diseases such as asthma is less well defined. Despite several features being common across both COPD and asthma, factors such as younger age or employment may affect the potential applicability of traditional PR models for patients with asthma. This review examines the current evidence regarding PR for the obstructive lung diseases of COPD and asthma. It offers appraisal of some of the strengths and weaknesses of existing literature, identifies areas in need of future research and details some of the issues facing clinicians responsible for the clinical management and rehabilitation of patients with these diseases.

Transfer coefficients better reflect emphysematous changes than carbon monoxide diffusing capacity in obstructive lung diseases

The overlap between asthma and chronic obstructive pulmonary disease (COPD) has attracted the interest of pulmonary physicians; thus, measurement of carbon monoxide diffusion capacity (DLco) and/or transfer coefficients (Kco, DLco/V_A) may become valuable in clinical settings. How these parameters behave in chronic obstructive lung diseases is poorly understood. We predicted that Kco might more accurately reflect emphysematous changes in the lungs than DLco. We examined DLco and Kco in nonsmokers and smokers with asthma and investigated their relationships with forced expiratory volume in 1 s (%FEV₁) by group. We then selected nonsmokers (As-NS) and smokers with asthma (As-Sm) in both groups and those with COPD while controlling for the degree of airflow limitation across groups. Emphysema volumes [%lung attenuation volume (%LAV)] and percentage of cross-sectional area of small pulmonary vessels <5 mm² (%CSA_<5) were measured by computed tomography. In As-NS, %Kco was significantly higher when FEV₁% was reduced, but such a correlation was not seen in As-Sm. %Kco successfully differentiated among the three groups when airflow limitation levels were matched. However, %DLc, was significantly reduced only in patients with COPD. Both %LAV and %CSA_<5 were better correlated with %Kco than with %DLco. There was discordance between %DL_CO and %Kco in As-Sm, which was not seen in As-NS. Overall, %Kco better reflects emphysematous changes in obstructive lung diseases than %DLco. NEW & NOTEWORTHY Despite differing behaviors of %Kco and %DLco in several diseases, the characteristics of these parameters have not been fully examined in smokers with asthma. Here, we demonstrated that %Kco is a more sensitive parameter of pathophysiology, better reflecting emphysematous changes in chronic obstructive lung diseases overall, compared with %DLco. Thus, more precise interpretations of %DLco and %Kco may provide clues for understanding the pathophysiology of obstructive lung diseases.

House Dust Endotoxin Association with Chronic Bronchitis and Emphysema

BACKGROUND

Endotoxin has been reported to be associated with chronic bronchitis or emphysema (CBE) at high occupational exposures. However, whether levels found in domestic environments have similar effects is unknown.

OBJECTIVES

We aimed to study the association between house dust endotoxin and CBE in a sample representative of the U.S. population.

METHODS

We analyzed data from 3,393 participants ≥20 y old from the National Health and Nutrition Examination Survey (NHANES) 2005-2006. House dust from bedding and from bedroom floors was analyzed for endotoxin content. NHANES participants received questionnaires and underwent examination as well as extensive laboratory testing. Logistic regression was used to examine the association of endotoxin levels with CBE diagnosis and symptoms, adjusting for covariates. The survey design and weights were applied so that estimates were nationally representative and so that statistical inferences were made appropriately.

RESULTS

The median endotoxin concentration in house dust was 14.61 EU/mg dust, and CBE was reported by 8.2% of participants. In the adjusted analysis, one unit (EU/mg) increase in log₁₀-transformed endotoxin concentrations was associated with a 27% increase in the odds of CBE diagnosis [OR=1.27 (95% CI: 1.00, 1.61)] and a 78% increase in the odds of chronic bronchitis symptoms (defined as cough and phlegm for ≥3 mo in a year for ≥2 y) [OR=1.78 (95% CI: 1.01, 3.12)]. Sensitization to inhalant allergens (p=0.001) modified the relationship between endotoxin and CBE diagnosis, with stronger associations observed in sensitized participants [OR=2.46 (95% CI: 1.72, 3.50) for a unit increase in log₁₀-endotoxin].

CONCLUSIONS

In a population-based sample of U.S. adults, endotoxin levels in homes were associated with a self-reported history of CBE diagnosis and chronic bronchitis symptoms, with stronger associations among people sensitized to inhalant allergens. https://doi.org/10.1289/EHP2452.

Blood biomarkers as predictors of long-term mortality in COPD

BACKGROUND

Blood biomarkers are easily accessible and might reflect chronic obstructive pulmonary disease (COPD) activity.

AIM

The aim of this study was to determine whether a panel of blood biomarkers [C-reactive protein (CRP), neutrophils, eosinophils, albumin and vitamin D] could predict mortality in COPD.

METHODS

We analyzed data from 431 COPD participants to the 2007-2010 National Health and Nutrition Examination Surveys who were followed for a median time of 36 months. COPD was defined as post-bronchodilator forced expiratory volume in 1 second (FEV1) and forced vital capacity ratio <0.70. Weibull survival analysis adjusted for covariates was performed to calculate the risk of mortality associated with the biomarkers, and C-statistics was used to assess their added predictive value.

RESULTS

During follow-up, 38 of the 431 participants died. Participants with high CRP, eosinophil count <2%, hypoalbuminemia and hypovitaminosis D had worse baseline FEV1 and subsequently higher mortality compared to controls. In adjusted analysis, increasing CRP [hazard ratio (HR): 4.45, 95% CI: 1.91-10.37] and neutrophil count (HR: 1.07, 95% CI: 1.03-1.11) as well as decreasing eosinophil count (HR: 7.03, 95% CI: 2.05-24.01) were associated with an increased risk of mortality. The addition of CRP with eosinophil and/or neutrophil count significantly improved a base model for the prediction of mortality which included age, gender, race/ethnicity, body mass index, smoking, poverty income ratio, asthma, diabetes, hypertension and history of stroke or myocardial infarction.

CONCLUSION

High CRP and neutrophils as well as low eosinophils are predictive of poor COPD prognosis. They also add significant value to prediction models of mortality in COPD.

The Ultrasonic Directional Tidal Breathing Pattern Sensor: Equitable Design Realization Based on Phase Information

Pulmonary ailments are conventionally diagnosed by spirometry. The complex forceful breathing maneuver as well as the extreme cost of spirometry renders it unsuitable in many situations. This work is aimed to facilitate an emerging direction of tidal breathing-based pulmonary evaluation by designing a novel, equitable, precise and portable device for acquisition and analysis of directional tidal breathing patterns, in real time. The proposed system primarily uses an in-house designed blow pipe, 40-kHz air-coupled ultrasound transreceivers, and a radio frequency (RF) phase-gain integrated circuit (IC). Moreover, in order to achieve high sensitivity in a cost-effective design philosophy, we have exploited the phase measurement technique, instead of selecting the contemporary time-of-flight (TOF) measurement; since application of the TOF principle in tidal breathing assessments requires sub-micro to nanosecond time resolution. This approach, which depends on accurate phase measurement, contributed to enhanced sensitivity using a simple electronics design. The developed system has been calibrated using a standard 3-L calibration syringe. The parameters of this system are validated against a standard spirometer, with maximum percentage error below 16%. Further, the extracted respiratory parameters related to tidal breathing have been found to be comparable with relevant prior works. The error in detecting respiration rate only is 3.9% compared to manual evaluation. These encouraging insights reveal the definite potential of our tidal breathing pattern (TBP) prototype for measuring tidal breathing parameters in order to extend the reach of affordable healthcare in rural regions and developing areas.

Fibrocyte measurement in peripheral blood correlates with number of cultured mature fibrocytes in vitro and is a potential biomarker for interstitial lung disease in Rheumatoid Arthritis

Background

Interstitial lung disease (ILD) can be a severe extra-articular disease manifestation in Rheumatoid Arthritis (RA). A potential role of fibrocytes in RA associated ILD (RA-ILD) has not previously been described. We present a modified faster method for measuring circulating fibrocytes, without intracellular staining. The results are compared to the traditional culture method, where the number of monocytes that differentiate into mature fibrocytes in vitro are counted. The results are following compared to disease activity in patients with severe asthma, ILD, RA (without diagnosed ILD) and RA with verified ILD (RA-ILD).

Method

CD45⁺ CD34⁺ CD11b⁺ (7-AAD⁻ CD3⁻ CD19⁻ CD294⁻) cells were isolated by cell sorting and stained for pro-collagen type 1. Thirty-nine patients (10 RA, 9 ILD and 10 with severe asthma, 10 with RA-ILD) and 10 healthy controls (HC) were included. Current medication, disease activity, pulmonary function test and radiographic data were collected. Circulating fibrocytes were quantified by flow cytometry. Peripheral blood mononuclear cells were isolated and cultured for 5 days and the numbers of mature fibrocytes were counted.

Results

90.2% (mean, SD = 1.5%) of the sorted cells were pro-collagen type 1 positive and thereby fulfilled the criteria for being circulating fibrocytes. The ILD and RA-ILD groups had increased levels of circulating fibrocytes compared to HC (p < 0.05). Levels of circulating fibrocytes correlated overall to number of monocytes that subsequently in vitro differentiated to mature fibrocytes (r = 0.81, p < 0.001). RA patients with pathologically reduced diffusion capacity for carbon monoxide adjusted for hemoglobin (DLCO_c) in both the RA and in the combined RA + RA-ILD group, had significantly higher levels of both circulating and number of cultured mature fibrocytes (both p < 0.05). In both groups, the level of circulating fibrocytes and number of mature fibrocytes in culture also correlated to a reduction in DLCO_c (r = −0.61 an r = −0.58 both p < 0.05).

Conclusions

We presented a fast and valid method for measuring circulating fibrocytes using flow cytometry on lysed peripheral blood. Further, we showed for the first time, that the level of circulating fibrocytes correlated with the number of peripheral blood mononuclear cells, that differentiated into mature fibrocytes in vitro. Reduced DLCO_c was correlated with high levels of circulating and mature fibrocytes in RA, which have not been reported previously. In such, this study suggests that fibrocytes may exhibit an important role in the pathogenesis of RA-ILD, which requires further clarification in future studies.

Trial registration

ClinicalTrials.gov:NCT02711657, registered 13/3–2016, retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0623-9) contains supplementary material, which is available to authorized users.

Asthma and COPD: Similarities and Differences in the Pathophysiology, Diagnosis and Therapy

Asthma and chronic obstructive pulmonary disease (COPD) are two of the most common chronic lung diseases worldwide. Distinguishing between these different pulmonary diseases can be difficult in practice because of symptomatic similarities. A definitive diagnosis is essential for correct treatment. This review article presents the different symptoms of these two chronic inflammatory lung diseases following a selective search of the PubMed database for relevant literature published between 1996 and 2012. While cough occurs in both diseases, asthmatics often have a dry cough mainly at night, which is often associated with allergies. In contrast, COPD is usually caused by years of smoking. Paroxysmal dyspnea, which occurs in asthma, is characterized by shortness of breath, while in COPD it occurs during physical exertion in early stages and at rest in later stages of the disease. Asthma often begins in childhood or adolescence, whereas COPD occurs mainly in smokers in later life. It is possible to live with asthma into old age, whereas the life expectancy of patients with COPD is significantly limited. Currently, there is no general curative treatment for either disorder.

MyD88 in lung resident cells governs airway inflammatory and pulmonary function responses to organic dust treatment

Inhalation of organic dusts within agriculture environments contributes to the development and/or severity of airway diseases, including asthma and chronic bronchitis. MyD88 KO (knockout) mice are nearly completely protected against the inflammatory and bronchoconstriction effects induced by acute organic dust extract (ODE) treatments. However, the contribution of MyD88 in lung epithelial cell responses remains unclear. In the present study, we first addressed whether ODE-induced changes in epithelial cell responses were MyD88-dependent by quantitating ciliary beat frequency and cell migration following wounding by electric cell-substrate impedance sensing. We demonstrate that the normative ciliary beat slowing response to ODE is delayed in MyD88 KO tracheal epithelial cells as compared to wild type (WT) control. Similarly, the normative ODE-induced slowing of cell migration in response to wound repair was aberrant in MyD88 KO cells. Next, we created MyD88 bone marrow chimera mice to investigate the relative contribution of MyD88-dependent signaling in lung resident (predominately epithelial cells) versus hematopoietic cells. Importantly, we demonstrate that ODE-induced airway hyperresponsiveness is MyD88-dependent in lung resident cells, whereas MyD88 action in hematopoietic cells is mainly responsible for ODE-induced TNF-α release. MyD88 signaling in lung resident and hematopoietic cells are necessary for ODE-induced IL-6 and neutrophil chemoattractant (CXCL1 and CXCL2) release and neutrophil influx. Collectively, these findings underscore an important role for MyD88 in lung resident cells for regulating ciliary motility, wound repair and inflammatory responses to ODE, and moreover, show that airway hyperresponsiveness appears uncoupled from airway inflammatory consequences to organic dust challenge in terms of MyD88 involvement.

New scoring system for the differentiation of chronic obstructive pulmonary disease and asthma

BACKGROUND AND OBJECTIVE

It remains difficult to differentiate between chronic obstructive pulmonary disease (COPD) and asthma in clinical practice, especially in a primary care setting. The purpose of this study was to develop a new scoring system for differentiating between COPD and asthma, and to evaluate its effectiveness.

METHODS

First, to identify important variables differentiating COPD from asthma, the data of 197 patients with COPD and 138 patients with asthma were assessed retrospectively. Secondly, a scoring system that was based on these variables was then developed, and its performance was internally validated using a bootstrapping-based method. Thirdly, the scoring system was externally validated using prospectively collected data from patients with COPD (n = 104) or asthma (n = 96).

RESULTS

The final scoring system was composed of the four variables: age of onset of breathlessness (<40 years, 0 points; 40-60 years, 2 points; >60 years, 4 points), continuous breathlessness (no, 0 points; yes, 1 point), diurnal variation of breathlessness (yes, 0 points; no, 1 point) and emphysematous change in chest X-ray (no, 0 points; yes, 1 point). The patients were classified by their total score into three categories: 0-2 points, probable asthma; 3-4 points, difficult-to-differentiate; 5-7 points, probable COPD. The new scoring system performed well in the external validation dataset (area under the curve, 0.86; 95% confidence interval: 0.813-0.911; P < 0.001).

CONCLUSIONS

The new scoring system that was developed in this study may be a useful tool for differentiating between COPD and asthma in primary care.

Functional phenotype and its correlation with therapeutic response and inflammatory type of bronchoalveolar lavage fluid in feline lower airway disease

Background

Currently, functional assessment to monitor therapeutic response in feline lower airway disease (FLAD) has limited application.

Objectives

To evaluate if expiratory indices derived from pseudo‐tidal breathing flow‐volume loop (pTBFVL) representing lower airway obstruction would decrease after clinical improvement and to investigate the correlation between functional phenotype and inflammatory cell type in bronchoalveolar lavage (BAL) fluid.

Animals

Nineteen client‐owned cats with FLAD.

Methods

Prospective observational study. Functional assessment with pTBFVL indices (eg, peak to mid‐expiratory flow; PEF/EF50) and conventional barometric whole body plethysmography (BWBP) parameters (eg, enhanced pause) was carried out before receiving treatment. BAL was performed to analyze inflammatory cell types. Signs were assessed by scoring. The cats were treated with glucocorticoids daily and functional testing was repeated.

Results

Loop indices PEF/EF50 and PEF/EF25 were significantly decreased after treatment (P < .001). Conventional BWBP parameters were not significantly different before and after treatment. Cats with PEF/EF50 > 1.51 before treatment had a significantly higher granulocyte (eosinophil plus neutrophil) percentage in BAL fluid (P = .014). Granulocyte percentage in BAL fluid was strongly correlated with PEF/EF25 (P = .001, r_s = 0.74) and moderately correlated with PEF/EF50 (P = .022, r_s = 0.57), whereas eosinophil or neutrophil percentage alone had no significant correlation with functional parameters.

Conclusions and Clinical Importance

Functional parameters including PEF/EF50 and PEF/EF25 can be used for monitoring therapeutic response. The presence of airflow limitation during mid‐ to late expiration is affected by the overall extent of granulocyte infiltration.

The independent and combined effects of lifetime smoke exposures and asthma as they relate to COPD

Chronic obstructive pulmonary disease (COPD) is part of a worldwide tobacco-related disease epidemic, and is associated with progressive airflow obstruction and varying degrees of emphysema and/or hyperinflation. Greater focus has been placed recently on the potential for early life factors to influence the development of COPD, based on the premise that delayed lung growth during childhood and adolescence might predispose to lung disease in later life. For most people, the adverse effects on lung function of adult and early childhood factors are additive, which provides no additional incentive for current smokers to quit. However, if there is a (synergistic) interaction between active smoking and asthma, smoking cessation is likely to have a greater lung function benefit for the smoker who is also asthmatic, especially if quitting occurs at an early age. This article critically evaluates the evidence for the independent associations of lifetime asthma, smoking and smoke exposures with airflow obstruction, plus their interaction when multiple factors are present.

Early lung development: lifelong effect on respiratory health and disease

Interest in the contribution of changes in lung development during early life to subsequent respiratory morbidity is increasing. Most evidence of an association between adverse intrauterine factors and structural effects on the developing lung is from animal studies. Such evidence has been augmented by epidemiological studies showing associations between insults to the developing lung during prenatal and early postnatal life and adult respiratory morbidity or reduced lung function, and by physiological studies that have elucidated mechanisms underlying these associations. The true effect of early insults on subsequent respiratory morbidity can be understood only if the many prenatal and postnatal factors that can affect lung development are taken into account. Adverse factors affecting lung development during fetal life and early childhood reduce the attainment of maximum lung function and accelerate lung function decline in adulthood, initiating or worsening morbidity in susceptible individuals. In this Review, we focus on factors that adversely affect lung development in utero and during the first 5 years after birth, thereby predisposing individuals to reduced lung function and increased respiratory morbidity throughout life. We focus particularly on asthma and COPD.

Pulmonary hyperinflation and left ventricular mass: the Multi-Ethnic Study of Atherosclerosis COPD Study

BACKGROUND

Left ventricular (LV) mass is an important predictor of heart failure and cardiovascular mortality, yet determinants of LV mass are incompletely understood. Pulmonary hyperinflation in chronic obstructive pulmonary disease (COPD) may contribute to changes in intrathoracic pressure that increase LV wall stress. We therefore hypothesized that residual lung volume in COPD would be associated with greater LV mass.

METHODS AND RESULTS

The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study recruited smokers 50 to 79 years of age who were free of clinical cardiovascular disease. LV mass was measured by cardiac magnetic resonance. Pulmonary function testing was performed according to guidelines. Regression models were used to adjust for age, sex, body size, blood pressure, and other cardiac risk factors. Among 119 MESA COPD Study participants, the mean age was 69±6 years, 55% were male, and 65% had COPD, mostly of mild or moderate severity. Mean LV mass was 128±34 g. Residual lung volume was independently associated with greater LV mass (7.2 g per 1-SD increase in residual volume; 95% confidence interval, 2.2-12; P=0.004) and was similar in magnitude to that of systolic blood pressure (7.6 g per 1-SD increase in systolic blood pressure; 95% confidence interval, 4.3-11; P<0.001). Similar results were observed for the ratio of LV mass to end-diastolic volume (P=0.02) and with hyperinflation measured as residual volume to total lung capacity ratio (P=0.009).

CONCLUSIONS

Pulmonary hyperinflation, as measured by residual lung volume or residual lung volume to total lung capacity ratio, is associated with greater LV mass.

High hospital burden in overlap syndrome of asthma and COPD

BACKGROUND

Overlap syndrome of asthma and chronic obstructive pulmonary disease (COPD) is a common condition, which is not well understood. This study describes the characteristics and hospital impact of patients suffering from this condition.

METHODS

The data are comprised of the hospital discharge registry data maintained by National Institute for Health and Welfare [Terveyden ja hyvinvoinnin laitos (THL)] between 1972 and 2009 covering the entire Finnish population (5.35 million inhabitants in 2009). In THL, treatment periods for patients with the primary or secondary diagnosis of asthma or COPD were selected. From that data, patients over 34 years and their treatment periods starting and ending 2000-2009 with a principal or secondary diagnosis of asthma [International Classification of Diseases (ICD) 10: J45-J46] or COPD (ICD 10: J41-J44) were picked up. There were 105 122 such patients who had 343 420 treatment periods altogether.

RESULTS

Patients with asthma were younger than patients with COPD and overlap syndrome, while COPD and overlap syndrome patients' age distribution was very similar. Patients with both asthma and COPD had 30.4% of all treatment periods, even though the percentage of all patients in this group was only 16.1%. These patients had an increased number of hospitalisation episodes across all age groups. Average number of treatment periods during 2000-2009 was 2.1 in asthma, 3.4 in COPD and 6.0 in overlap syndrome. Hospital impact of the same period in asthma was 939 900 days in COPD 1 517 308 and 1 000 724 days in overlap syndrome.

CONCLUSION

Overlap syndrome of asthma and COPD is a common condition with high hospital impact for patients with this condition.

The role of circulating serotonin in the development of chronic obstructive pulmonary disease

Background

Cigarette smoking is a major risk factor in the development of age-related chronic obstructive pulmonary disease (COPD). The serotonin transporter (SERT) gene polymorphism has been reported to be associated with COPD, and the degree of cigarette smoking has been shown to be a significant mediator in this relationship. The interrelation between circulating serotonin (5-hydroxytyptamine, 5-HT), cigarette smoking and COPD is however largely unknown. The current study aimed at investigating the mediation effects of plasma 5-HT on cigarette smoking-induced COPD and the relation between plasma 5-HT levels and age.

Methods

The association between plasma 5-HT, age and COPD was analyzed in a total of 62 COPD patients (ever-smokers) and 117 control subjects (healthy non-smokers and ever-smokers). Plasma 5-HT levels were measured by enzyme-linked immuno assay (EIA).

Results

The elevated plasma 5-HT levels were significantly associated with increased odds for COPD (OR = 1.221, 95% CI = 1.123 to 1.319, p<0.0001). The effect remained significant after being adjusted for age and pack-years smoked (OR = 1.271, 95% CI = 1.134 to 1.408, p = 0.0003). Furthermore, plasma 5-HT was found to mediate the relation between pack-years smoked and COPD. A positive correlation (r = 0.303, p = 0.017) was found between plasma 5-HT levels and age in COPD, but not in the control subjects (r = −0.149, p = 0.108).

Conclusion

Our results suggest that cigarette smoke-induced COPD is partially mediated by the plasma levels of 5-HT, and that these become elevated with increased age in COPD. The elevated plasma 5-HT levels in COPD might contribute to the pathogenesis of this disease.

Airway resistance at maximum inhalation as a marker of asthma and airway hyperresponsiveness

Background

Asthmatics exhibit reduced airway dilation at maximal inspiration, likely due to structural differences in airway walls and/or functional differences in airway smooth muscle, factors that may also increase airway responsiveness to bronchoconstricting stimuli. The goal of this study was to test the hypothesis that the minimal airway resistance achievable during a maximal inspiration (R_min) is abnormally elevated in subjects with airway hyperresponsiveness.

Methods

The R_min was measured in 34 nonasthmatic and 35 asthmatic subjects using forced oscillations at 8 Hz. R_min and spirometric indices were measured before and after bronchodilation (albuterol) and bronchoconstriction (methacholine). A preliminary study of 84 healthy subjects first established height dependence of baseline R_min values.

Results

Asthmatics had a higher baseline R_min % predicted than nonasthmatic subjects (134 ± 33 vs. 109 ± 19 % predicted, p = 0.0004). Sensitivity-specificity analysis using receiver operating characteristic curves indicated that baseline R_min was able to identify subjects with airway hyperresponsiveness (PC₂₀ < 16 mg/mL) better than most spirometric indices (Area under curve = 0.85, 0.78, and 0.87 for R_min % predicted, FEV₁ % predicted, and FEF_25-75 % predicted, respectively). Also, 80% of the subjects with baseline R_min < 100% predicted did not have airway hyperresponsiveness while 100% of subjects with R_min > 145% predicted had hyperresponsive airways, regardless of clinical classification as asthmatic or nonasthmatic.

Conclusions

These findings suggest that baseline R_min, a measurement that is easier to perform than spirometry, performs as well as or better than standard spirometric indices in distinguishing subjects with airway hyperresponsiveness from those without hyperresponsive airways. The relationship of baseline R_min to asthma and airway hyperresponsiveness likely reflects a causal relation between conditions that stiffen airway walls and hyperresponsiveness. In conjunction with symptom history, R_min could provide a clinically useful tool for assessing asthma and monitoring response to treatment.

Comparison of airway remodelling assessed by computed tomography in asthma and COPD

BACKGROUND

Few studies have directly compared airway remodelling assessed by computed tomography (CT) between asthma and chronic obstructive pulmonary disease (COPD). The present study was conducted to determine whether there are any differences between the two diseases with similar levels of airflow limitation under clinically stable conditions.

METHODS

Subjects included older male asthmatic patients (n = 19) showing FEV(1)/FVC <70% with smoking history less than 5-pack/year. Age- and sex-matched COPD patients (n = 28) who demonstrated similar airflow limitation as asthmatic patients and age-matched healthy non-smokers (n = 13) were recruited. Using proprietary software, eight airways were selected in the right lung, and wall area percent (WA%) and airway luminal area (Ai) were measured at the mid-portion of the 3rd to 6th generation of each airway. For comparison, the average of eight measurements per generation was recorded.

RESULTS

FEV(1)% predicted and FEV(1)/FVC was similar between asthma and COPD (82.3 ± 3.3% vs. 77.6 ± 1.8% and 57.7 ± 1.6% vs. 57.9 ± 1.4%). At any generation, WA% was larger and Ai was smaller in asthma, both followed by COPD and then controls. Significant differences were observed between asthma and controls in WA% of the 3rd to 5th generation and Ai of any generation, while no differences were seen between COPD and controls. There were significant differences in Ai of any generation between asthma and COPD.

CONCLUSIONS

Airway remodelling assessed by CT is more prominent in asthma compared with age- and sex-matched COPD subjects in the 3rd- to 6th generation airways when airflow limitations were similar under stable clinical conditions.

Increased adverse events after percutaneous coronary intervention in patients with COPD: insights from the National Heart, Lung, and Blood Institute dynamic registry

BACKGROUND

Previous studies have demonstrated that patients with COPD are at higher risk for death after percutaneous coronary intervention (PCI), but other clinical outcomes and possible associations with adverse events have not been described.

METHODS

Using waves 1 through 5 (1999-2006) of the National Heart, Lung, and Blood Institute Dynamic Registry, patients with COPD (n = 860) and without COPD (n = 10,048) were compared. Baseline demographics, angiographic characteristics, and in-hospital and 1-year adverse events were compared.

RESULTS

Patients with COPD were older (mean age 66.8 vs 63.2 years, P < .001), more likely to be women, and more likely to have a history of diabetes, prior myocardial infarction, peripheral arterial disease, renal disease, and smoking. Patients with COPD also had a lower mean ejection fraction (49.1% vs 53.0%, P < .001) and a greater mean number of significant lesions (3.2 vs 3.0, P = .006). Rates of in-hospital death (2.2% vs 1.1%, P = .003) and major entry site complications (6.6% vs 4.2%, P < .001) were higher in pulmonary patients. At discharge, pulmonary patients were significantly less likely to be prescribed aspirin (92.4% vs 95.3%, P < .001), β-blockers (55.7% vs 76.2%, P < .001), and statins (60.0% vs 66.8%, P < .001). After adjustment, patients with COPD had significantly increased risk of death (hazard ratio [HR] = 1.30, 95% CI = 1.01-1.67) and repeat revascularization (HR = 1.22, 95% CI = 1.02-1.46) at 1 year, compared with patients without COPD.

CONCLUSIONS

COPD is associated with higher mortality rates and repeat revascularization within 1 year after PCI. These higher rates of adverse outcomes may be associated with lower rates of guideline-recommended class 1 medications prescribed at discharge.

Imaging of lung function using hyperpolarized helium-3 magnetic resonance imaging: Review of current and emerging translational methods and applications

During the past several years there has been extensive development and application of hyperpolarized helium-3 (HP (3)He) magnetic resonance imaging (MRI) in clinical respiratory indications such as asthma, chronic obstructive pulmonary disease, cystic fibrosis, radiation-induced lung injury, and transplantation. This review focuses on the state-of-the-art of HP (3)He MRI and its application to clinical pulmonary research. This is not an overview of the physics of the method, as this topic has been covered previously. We focus here on the potential of this imaging method and its challenges in demonstrating new types of information that has the potential to influence clinical research and decision making in pulmonary medicine. Particular attention is given to functional imaging approaches related to ventilation and diffusion-weighted imaging with applications in chronic obstructive pulmonary disease, cystic fibrosis, asthma, and radiation-induced lung injury. The strengths and challenges of the application of (3)He MRI in these indications are discussed along with a comparison to established and emerging imaging techniques.

Management of asthma: new approaches to establishing control

PURPOSE

The high burden of asthma indicates suboptimal control of this chronic condition. This review describes approaches for establishing asthma control based on an understanding of potential issues in the achievement and maintenance of asthma control, recent changes in asthma management guidelines that facilitate attainment of treatment goals, and the importance of the healthcare provider-patient partnership to emphasize treatment based on asthma control.

DATA SOURCES

Review of the published literature, asthma management guidelines, and patient asthma education resources.

CONCLUSIONS

Asthma control is best achieved by patient-oriented versus disease-oriented management strategies that incorporate a combination of pharmacologic and nonpharmacologic treatment modalities. Tools that assess and monitor asthma may facilitate the achievement and maintenance of asthma control. Key components of an optimal management strategy include solid partnerships between healthcare providers and patients, comprehensive patient and caregiver education, personalized written asthma action plans, patient-reported evaluation of symptom control, appropriate drug therapy, strategies for improving compliance with asthma medication regimens, and a treatment algorithm that outlines the facets of asthma management.

IMPLICATIONS FOR PRACTICE

Information presented in this article will guide nurse practitioners in helping patients with asthma achieve and maintain long-term disease control.

Diagnosing asthma in general practice with portable exhaled nitric oxide measurement--results of a prospective diagnostic study: FENO < or = 16 ppb better than FENO < or =12 ppb to rule out mild and moderate to severe asthma [added]

BACKGROUND

To evaluate the sensitivity, specificity and predictive values of fractional exhaled nitric oxide (FENO) for the diagnosis of asthma in general practice.

METHODS

Prospective diagnostic study with 160 patients attending 10 general practices for the first time with complaints suspicious of obstructive airway disease (OAD). Patients were referred to a lung function laboratory for diagnostic investigation. The index test was FENO measured with a portable FENO analyser based on electrochemical sensor. The reference standard was the Tiffeneau ratio (FEV1/VC) as received by spirometric manoeuvre and/or results of bronchial provocation. Bronchial provocation with methacholine was performed to determine bronchial hyper-responsiveness (BHR) in the event of inconclusive spirometric results.

RESULTS

88 (55%) were female; their average age was 43.9 years. 75 (46.9%) patients had asthma, 25 (15.6%) had COPD, 8 (5.0%) had an overlap of COPD and asthma, and 52 (32.5%) had no OAD. At a cut-off level of 46 parts per billion (ppb) (n = 30; 18.8%), sensitivity was 32% (95%CI 23-43%), specificity 93% (95%CI 85-97%), positive predictive value (PPV) 80% (95%CI 63-91%), negative predictive value (NPV) 61% (95%CI 52-69%) when compared with a 20% fall in FEV1 from the baseline value (PC20) after inhaling methacholine concentration

CONCLUSION

Asthma could be ruled in with FENO > 46 ppb. Mild and moderate to severe asthma could be ruled out with FENO Collapse

Key Words Collapse

MESH Headings

• Adult
• Aged
• Asthma/diagnosis
• Asthma/metabolism
• Asthma/physiopathology
• Breath Tests/instrumentation
• Bronchial Hyperreactivity
• Bronchial Provocation Tests
• Bronchoconstrictor Agents
• Electrochemical Techniques/instrumentation
• Equipment Design
• Exhalation
• Family Practice
• Female
• Forced Expiratory Volume
• Germany
• Humans
• Lung/physiopathology
• Male
• Methacholine Chloride
• Middle Aged
• Netherlands
• Nitric Oxide/analysis
• Predictive Value of Tests
• Prospective Studies
• Sensitivity and Specificity
• Severity of Illness Index
• Vital Capacity
• Young Adult

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Grants Collapse

Affiliation(s)

Antonius Schneider Department of General Practice and Health Services Research, University Hospital, University of Heidelberg, Heidelberg, Germany
Lisa Tilemann Department of General Practice and Health Services Research, University Hospital, University of Heidelberg, Heidelberg, Germany
Tjard Schermer Department of Primary Care Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
Lena Gindner Department of General Practice and Health Services Research, University Hospital, University of Heidelberg, Heidelberg, Germany
Gunter Laux Department of General Practice and Health Services Research, University Hospital, University of Heidelberg, Heidelberg, Germany
Joachim Szecsenyi Department of General Practice and Health Services Research, University Hospital, University of Heidelberg, Heidelberg, Germany
Franz Joachim Meyer Department of Cardiology, Pulmonology and Angiology, Medical Centre, University of Heidelberg, Heidelberg, Germany

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Asthma overview

This article presents our current understanding of the biological heterogeneity of asthma and reviews some of the key features of the latest proposed recommendations of the National Asthma Education and Prevention Program Guidelines. The diagnosis of asthma is based on such clinical features as variable airflow obstruction that is partially if not fully reversible and airway hyperresponsiveness that predisposes to episodic bronchospasm following exposure to a variety of triggers. The underlying inflammation and airway biology of asthma is heterogeneous and is part of the explanation for the variable response to therapy. New biologics that help to characterize patients according to their underlying biology will aid in making better choices for treatment. New asthma guidelines emphasize the importance of regular monitoring.

Physiological associations of computerized tomography lung density: a factor analysis

Background

Objective quantification of emphysema using computerized tomography (CT) density measurements is rapidly gaining wide acceptance as an in vivo measurement tool. However, some studies have suggested that abnormal lung function in the absence of emphysema can affect lung density, and the role of such measurements in identifying and monitoring the progression of emphysema is not clear.

Objective

To clarify the relationship between lung density measurements and pulmonary function.

Methods

CT measurements of the proportion of lung occupied by low density tissue (as percentage of lung area below predetermined Hounsfield unit [HU] thresholds) were obtained in a large random population (n = 739) and the association with detailed pulmonary function tests studied using factor analysis.

Results

Density measurements showed a greater association with measures of hyperinflation and airflow obstruction than measures of gas transfer (correlation coefficient, high resolution scan, − 950 HU threshold vs FEV₁/FVC, RV, and DLCO/VA of − 0.39, 0.22, and − 0.15 respectively). The strongest lung density factor coefficients of 0.51 (standard resolution scan, − 950 HU threshold) and 0.46 (high resolution scan, − 910 HU threshold) were seen with factors predominantly consisting of measures of airflow obstruction and hyperinflation. Most variation in lung density was not accounted for by lung function measurements (communality 0.21–0.34).

Conclusion

Lung density measurements associate most strongly with measures of airway disease that are not specific to emphysema.

Physiologic similarities and differences between asthma and chronic obstructive pulmonary disease

PURPOSE OF REVIEW

This review examines the physiologic mechanisms responsible for persistent maximum expiratory airflow limitation in nonsmoking patients with acute and chronic moderate to severe persistent asthma in comparison to chronic obstructive pulmonary disease.

RECENT FINDINGS

The phenomenon of acute but reversible loss of lung elastic recoil during acute asthma is reviewed, although no plausible pathophysiologic explanation has been offered. Nonsmoking adults with stable asthma and persistent maximum expiratory airflow limitation, despite optimal polytherapy, were shown to have unsuspected and unexplained marked loss of lung elastic recoil in the absence of lung computed tomography scored emphysema. This condition resulted in up to 50% reduction in maximum expiratory airflow. Furthermore, these patients remain at high risk for adverse clinical events, including near-fatal asthma. In chronic obstructive pulmonary disease, reduction in maximum expiratory airflow is related to variable extent of loss of lung elastic recoil secondary to emphysema and concurrent intrinsic airway obstruction or obliteration of small airways. There is also an unexplained loss of lung elastic recoil in primary intrinsic small airways disease in the absence of emphysema.

SUMMARY

Nonsmoking patients with moderate-severe persistent asthma and patients with smoking-related chronic obstructive pulmonary disease share similar physiologic mechanisms of expiratory airflow limitation, but probably caused by different anatomic abnormalities.

Impact of chronic obstructive pulmonary disease on post-myocardial infarction outcomes

Although chronic obstructive pulmonary disease (COPD) is common in patients with myocardial infarction (MI), its association with long-term mortality after MI is controversial and little is known about its influence on patients' health status (symptoms, function, and quality of life). We prospectively enrolled 2,481 patients presenting with MI at 19 United States centers to examine the relations between COPD and patients' long-term mortality, rehospitalization rates, and health status after MI. Patients were administered the disease-specific Seattle Angina Questionnaire and the generic Short Form 12 at baseline and 1 year later. COPD was common (15.6% of patients) and was associated with a substantially greater risk of 1-year mortality (15.8% vs 5.7%, p <0.001) and rehospitalization (48.7% vs 38.6%, p <0.001). After extensive adjustment for baseline differences, patients with COPD had a twofold greater 1-year mortality rate (hazard ratio 2.00, 95% confidence interval [CI] 1.44 to 2.79) and higher rehospitalization rates (hazard ratio 1.22, 95% CI 1.01 to 1.48). Similarly, adjusted 1-year health status was worse in patients with COPD, with lower 1-year Seattle Angina Questionnaire quality-of-life score (-2.53 points, 95% CI -0.25 to -4.81) and Short Form 12 physical component score (-1.83 points, 95% CI -0.43 to -3.24). In addition, COPD was associated with a trend toward a greater prevalence of angina at 1 year (risk ratio 1.12, 95% CI 0.89 to 1.41). In conclusion, patients with COPD have greater mortality, higher rehospitalization rates, and poorer health status 1 year after a MI. Although additional research is needed, clinicians should recognize that patients with COPD are at high risk for poor outcomes after MI.

Cystic Fibrosis in Adults

The aim of this cross-sectional retrospective study was to describe clinical and functional characteristics and the microbiological profile of an adult population with cystic fibrosis. The study was performed at the Pulmonary Diseases Service of the Hospital of the Medical School of the State University of Campinas. The charts of 54 adults (27 males, 27 females) with cystic fibrosis were reviewed. Demographic, clinical, and microbiological data were collected. Clinical and functional characteristics of patients with chronic Pseudomonas infection were compared with those without it. The mean age of the patients was 41.8 years and the mean sweat chloride concentration was 106.4 mEq/L. Forty-nine percent had chronic respiratory symptoms only after 18 years of age, and 85% reported chronic production of purulent sputum. Six percent had diarrhea or fat in stools, and no patient suffered from diabetes mellitus. Pseudomonas was present in 48%, and 73% of them had the mucoid strain. Others agents found were Staphylococcus aureus (28%), Hemophylus sp. (34%), Aspergillus sp. (22%), Stenotrophomonas maltophilia (9%), Acinetobacter sp. (7%), and Burkholderia cepacia (2%). Nontuberculous mycobacteria were found in sputum from 9 patients (11%); 34 patients (67%) had obstructive ventilatory defect; and 47% had obstruction and restriction. Concerning the groups with and without Pseudomonas colonization, only the values of sweat chloride were significantly higher in chronic colonized patients. Less severe phenotypes of cystic fibrosis may be found among patients previously diagnosed as having bronchiectasis. Chronic colonization with Pseudomonas aeruginosa in this study was not associated with worse clinical status but colonized patients did show significantly higher levels of chloride in sweat.

Study of physiological responses to acute carbon monoxide exposure with a human patient simulator

Human patient simulators are widely used to train health professionals and students in a clinical setting, but they also can be used to enhance physiology education in a laboratory setting. Our course incorporates the human patient simulator for experiential learning in which undergraduate university juniors and seniors are instructed to design, conduct, and present (orally and in written form) their project testing physiological adaptation to an extreme environment. This article is a student report on the physiological response to acute carbon monoxide exposure in a simulated healthy adult male and a coal miner and represents how 1) human patient simulators can be used in a nonclinical way for experiential hypothesis testing; 2) students can transition from traditional textbook learning to practical application of their knowledge; and 3) student-initiated group investigation drives critical thought. While the course instructors remain available for consultation throughout the project, the relatively unstructured framework of the assignment drives the students to create an experiment independently, troubleshoot problems, and interpret the results. The only stipulation of the project is that the students must generate an experiment that is physiologically realistic and that requires them to search out and incorporate appropriate data from primary scientific literature. In this context, the human patient simulator is a viable educational tool for teaching integrative physiology in a laboratory environment by bridging textual information with experiential investigation.

Effect of fluticasone propionate/salmeterol on lung hyperinflation and exercise endurance in COPD

STUDY OBJECTIVE

To examine the effect of fluticasone propionate, 250 microg/salmeterol, 50 microg combination (FSC 250/50) twice daily on lung hyperinflation and associated measures of exercise performance in patients with COPD.

DESIGN

This was a randomized, double-blind, parallel-group study.

PATIENTS

Eligible patients were > or = 40 years old with a diagnosis of COPD, prealbuterol FEV(1) < 70% of predicted, FEV1/FVC ratio > or = 0.70, and functional residual capacity (FRC) > or = 120% of predicted normal.

INTERVENTIONS

Patients were randomized to FSC 250/50; salmeterol, 50 microg; or placebo twice daily for 8 weeks. Predose and postdose spirometry, plethysmography, and constant-load cycle cardiopulmonary exercise test evaluations were compared. The primary comparison was FSC 250/50 with placebo. The salmeterol group was included for exploratory comparisons with FSC 250/50.

RESULTS

A total of 185 patients (mean baseline FEV1 of 41% predicted) were enrolled. At rest, FSC 250/50 significantly reduced postdose FRC and increased inspiratory capacity (IC) compared with placebo (differences of - 0.35 +/- 0.12 L and 0.33 +/- 0.06 L [mean +/- SE], respectively, at week 8; p > or = 0.003) and increased exercise endurance time (difference, 132 +/- 45 s; p = 0.004). At a standardized time during exercise (isotime), FSC 250/50 increased postdose IC by 0.20 +/- 0.05 L over placebo with associated improvements in tidal volume and minute ventilation (p < 0.05 vs placebo at week 8). Improvement in exercise time was significantly correlated with the increase in IC (r = 0.45, p < 0.001) but not FEV1 (r = 0.23, p = 0.08). Predose comparisons of FSC 250/50 with salmeterol and placebo favored FSC 250/50.

CONCLUSION

We conclude that FSC 250/50 decreases lung hyperinflation at rest and during exercise with an associated increase in exercise endurance time when compared with placebo.

Bronchodilator effect of infused B-type natriuretic peptide in asthma

STUDY OBJECTIVE

To determine the bronchodilator effect of recombinant human B-type natriuretic peptide (BNP; nesiritide) on patients with asthma.

DESIGN

A prospective, open-label study.

SETTING

Outpatient setting.

PATIENTS

Eight adult patients with asthma confirmed by > 12% and > 200 mL increase in FEV1 after bronchodilator inhalation.

INTERVENTIONS

An IV nesiritide bolus, 2 microg/kg, followed by continuous infusion for a total of 3 h at escalating doses of 0.01, 0.02, and 0.03 microg/kg/min for 1 h each as tolerated.

MEASUREMENTS

Spirometry and forced oscillation technique (FOT) measurements were both obtained at baseline and every 30 min during the infusion. Two doses of albuterol, 90 microg, inhalation via metered-dose inhaler were then administered at the end of nesiritide infusion, followed by repeat spirometry and FOT measurements after 30 min. Primary end points were FEV1 and FVC changes after the nesiritide infusion for 3 h. Wilcoxon signed-ranks tests were used to compare the effects of nesiritide and albuterol.

RESULTS

Baseline measurements (mean +/- SD) were as follows: FEV1, 1.89 +/- 0.87 L; FVC, 3.02 +/- 0.99 L; respiratory resistance at 5 Hz (Rrs5), 10.3 +/- 3.85 cm H2O . s/L; and mean respiratory resistance at 5 to 20 Hz, 7.56 +/- 1.92 cm H2O/L/s. Mean baseline serum BNP level was 27 +/- 27 pg/mL. After 180 min of nesiritide infusion, the following measurements showed significant changes: FEV1 increased to 2.41 +/- 0.78 L (mean increase, 520 mL), p = 0.012; FVC increased to 3.65 +/- 1.05 L (mean increase, 630 mL), p = 0.017; and Rrs5 decreased to 8.24 +/- 4.02 cm H2O/L/s, p = 0.017. After albuterol, there were no further significant changes in these measurements.

CONCLUSION

IV nesiritide is an effective bronchodilator in patients with asthma.

12-year change in prevalence of respiratory symptoms in elderly Chinese living in Hong Kong

Respiratory diseases may cause considerable disability in the elderly because of their limited respiratory reserve related to aging. This study aimed to assess the time trend of respiratory symptoms and common chronic respiratory diseases in the elderly Chinese living in Hong Kong. Two questionnaire surveys were conducted in 1991-1992 and 2003-2004. Subjects aged > or = 70 years were invited to complete a respiratory questionnaire. A total of 2032 (999 male) and 1524 (698 male) subjects completed the questionnaire surveys in 1991 and 2003, respectively. The response rates were 60% in 1991 and 78% in 2003. The prevalence of most respiratory symptoms increased over time after adjusting the data for age, sex, social status and smoking habits. Comparing the symptoms between 1991 and 2003, wheeze over the past 12 months increased from 7.5 to 12.1% (adjusted OR 2.00, 95% CI 1.54-2.61) and morning chest tightness from 4.2 to 8.8% (adjusted OR 2.48, 95% CI 1.79-3.43). The prevalence of self-reported physician-diagnosed emphysema increased over time (2.4-3.1%, adjusted OR 1.78, 95% CI 1.12-2.86), but there was no change for asthma (5.1% in 1991 and 5.8% in 2003) or chronic bronchitis (6.7% in 1991 and 7.7% in 2003). The prevalence of respiratory symptoms has increased over the past 12 years and this may be related to environmental factors especially increasing air pollution in Hong Kong.

The Rationale for Pharmacologic Therapy in Stable Chronic Obstructive Pulmonary Disease

The structural changes in airways and alveoli that characterize chronic obstructive pulmonary disease (COPD) result from an abnormal and persistent inflammatory reaction to inhaled noxious particles or gases, notably tobacco smoke. This remodeling of the lung leads to irreversible airflow obstruction. However, COPD should be viewed by clinicians as a treatable condition, since most patients with COPD have an additional reversible component related to increased bronchomotor tone. The use of bronchodilators, especially anticholinergics and beta2-agonists, results in a reduction in airway smooth muscle tone and airflow resistance; this translates into marked improvement in significant clinical outcomes such as dyspnea, quality of life, and exercise capacity. An increasing amount of evidence supports the idea that long-acting agents have more significant impact in these parameters than the short-acting preparations.