Update in Chronic Obstructive Pulmonary Disease 2005

Impact of adherence to long-term oxygen therapy on patients with COPD and exertional hypoxemia followed for one year

Objective:

To determine the impact of adherence to long-term oxygen therapy (LTOT) on quality of life, dyspnea, and exercise capacity in patients with COPD and exertional hypoxemia followed for one year.

Methods:

Patients experiencing severe hypoxemia during a six-minute walk test (6MWT) performed while breathing room air but not at rest were included in the study. At baseline and after one year of follow-up, all patients were assessed for comorbidities, body composition, SpO₂, and dyspnea, as well as for anxiety and depression, having also undergone spirometry, arterial blood gas analysis, and the 6MWT with supplemental oxygen. The Saint George’s Respiratory Questionnaire (SGRQ) was used in order to assess quality of life, and the Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity (BODE) index was calculated. The frequency of exacerbations and the mortality rate were noted. Treatment nonadherence was defined as LTOT use for < 12 h per day or no LTOT use during exercise.

Results:

A total of 60 patients with COPD and exertional hypoxemia were included in the study. Of those, 10 died and 11 experienced severe hypoxemia during follow-up, 39 patients therefore being included in the final analysis. Of those, only 18 (46.1%) were adherent to LTOT, showing better SGRQ scores, higher SpO₂ values, and lower PaCO₂ values than did nonadherent patients. In all patients, SaO₂, the six-minute walk distance, and the BODE index worsened after one year. There were no differences between the proportions of adherence to LTOT at 3 and 12 months of follow-up.

Conclusions:

Quality of life appears to be lower in patients with COPD and exertional hypoxemia who do not adhere to LTOT than in those who do. In addition, LTOT appears to have a beneficial effect on COPD symptoms (as assessed by SGRQ scores). (Brazilian Registry of Clinical Trials - ReBEC; identification number RBR-9b4v63 [http://www.ensaiosclinicos.gov.br])

Concordance between Doppler and pulsed-wave Doppler tissue imaging in estimation of the degree of left ventricular dysfunction and correlating it to the degree of chronic obstructive pulmonary disease

Objective

As a consequence of leftward shift of the interventricular septum and of pericardial restraint, related to the degree of right ventricular dilation, alveolar hypoxia and related pulmonary vascular changes, left ventricular function is influenced by chronic obstructive pulmonary disease (COPD). The aim of this study was to assess the prevalence of echocardiographic abnormalities by conventional echocardiography and Doppler tissue imaging (DTI) in COPD patients according to the degree of disease severity.

Methods

We enrolled forty consecutive patients with COPD and twenty matched control. Twenty of the patients were suffering from mild form of COPD, twenty were suffering from severe form of COPD as decided by pulmonary function test and arterial blood gases and twenty apparently healthy non COPD control persons were subjected to echocardiographic assessment to left ventricular diastolic and systolic functions by conventional echocardiography and DTI at the mitral annulus.

Results

There were no significant statistical difference between the three groups as regards the age and the gender. There were significant statistical differences between the patients and the control as regards the diastolic functions of the left ventricle. E and A waves obtained by conventional Doppler and by DTI showed significant statistical difference between mild, severe forms of COPD and control subjects. The degree of diastolic dysfunction increased significantly with increase of the severity of COPD.

Conclusion

Left ventricular diastolic function is significantly affected in patients with COPD and the degree of affection is related to the severity of COPD.

Relationship between Dysphagia and Exacerbations in Chronic Obstructive Pulmonary Disease: A Literature Review

Introduction The literature presents studies correlating chronic obstructive pulmonary disease to dysphagia and suggesting that the aspiration laryngeal phenomenon related to changes in the pharyngeal phase contributes significantly to the exacerbation of symptoms of lung disease.

Objectives This study aimed to conduct a literature review to identify the relation between dysphagia and exacerbations of chronic obstructive pulmonary disease.

Data Synthesis We found 21 studies and included 19 in this review. The few studies that related to the subject agreed that the presence of dysphagia, due to lack of coordination between swallowing and breathing, may be one of the triggering factors of chronic obstructive pulmonary disease exacerbation.

Conclusions The review noted that there is a relationship between dysphagia and exacerbations of chronic obstructive pulmonary disease, identified by studies demonstrating that the difficulties associated with swallowing may lead to exacerbation of the disease. There was difficulty in comparing studies by their methodological differences. More research is needed to clarify the relationship between dysphagia and exacerbations of chronic obstructive pulmonary disease, making it possible to develop multiprofessional treatment strategies for these patients, catered to specific needs due to the systemic manifestations of the disease.

Association between left ventricular diastolic dysfunction and severity of chronic obstructive pulmonary disease

OBJECTIVES

The prevalence of electrocardiographic and echocardiographic abnormalities in chronic obstructive pulmonary disease according to disease severity has not yet been established. The aim of this study was to assess the prevalence of electrocardiographic and echocardiographic abnormalities in chronic obstructive pulmonary disease patients according to disease severity.

METHODS

The study included 25 mild/moderate chronic obstructive pulmonary disease patients and 25 severe/very severe chronic obstructive pulmonary disease patients. All participants underwent clinical evaluation, spirometry and electrocardiography/echocardiography.

RESULTS

Electrocardiography and echocardiography showed Q-wave alterations and segmental contractility in five (10%) patients. The most frequent echocardiographic finding was mild left diastolic dysfunction (88%), independent of chronic obstructive pulmonary disease stage. The proportion of right ventricular overload (p<0.05) and blockage of the anterosuperior division of the left bundle branch were higher in patients with greater obstruction. In an echocardiographic analysis, mild/moderate chronic obstructive pulmonary disease patients showed more abnormalities in segmental contractility (p<0.05), whereas severe/very severe chronic obstructive pulmonary disease patients showed a higher prevalence of right ventricular overload (p<0.05), increased right cardiac chamber (p<0.05) and higher values of E-wave deceleration time (p<0.05). Age, sex, systemic arterial hypertension, C-reactive protein and disease were included as independent variables in a multiple linear regression; only disease severity was predictive of the E-wave deceleration time [r²=0.26, p=0.01].

CONCLUSION

Chronic obstructive pulmonary disease patients have a high prevalence of left ventricular diastolic dysfunction, which is associated with disease severity. Because of this association, it is important to exclude decompensated heart failure during chronic obstructive pulmonary disease exacerbation.

Combination of budesonide/formoterol more effective than fluticasone/salmeterol in preventing exacerbations in chronic obstructive pulmonary disease: the PATHOS study

OBJECTIVES

Combinations of inhaled corticosteroids (ICSs) and long-acting β2 -agonists (LABAs) are recommended for patients with moderate and severe chronic obstructive pulmonary disease (COPD). However, it is not known whether different fixed combinations are equally effective. The aim of this study was to investigate exacerbation rates in primary care patients with COPD treated with budesonide/formoterol compared with fluticasone/salmeterol.

METHODS

Patients with physician-diagnosed COPD and a record of postdiagnosis treatment with a fixed combination of budesonide/formoterol or fluticasone/salmeterol were included. Data from primary care medical records were linked to those from Swedish national hospital, drug and cause of death registers. Pairwise (1 : 1) propensity score matching was carried out at the index date (first prescription) by prescribed fixed ICS/LABA combination. Exacerbations were defined as hospitalizations, emergency visits and collection of oral steroids or antibiotics for COPD. Yearly event rates were compared using Poisson regression.

RESULTS

Matching of 9893 patients (7155 budesonide/formoterol and 2738 fluticasone/salmeterol) yielded two cohorts of 2734 patients, comprising 19 170 patient-years. The exacerbation rates were 0.80 and 1.09 per patient-year in the budesonide/formoterol and fluticasone/salmeterol groups, respectively (difference of 26.6%; P < 0.0001); yearly rates for COPD-related hospitalizations were 0.15 and 0.21, respectively (difference of 29.1%; P < 0.0001). All other healthcare outcomes were also significantly reduced with budesonide/formoterol versus fluticasone/salmeterol.

CONCLUSIONS

Long-term treatment with fixed combination budesonide/formoterol was associated with fewer healthcare utilization-defined exacerbations than fluticasone/salmeterol in patients with moderate and severe COPD.

Relationship between frequency, length, and treatment outcome of exacerbations to baseline lung function and lung density in alpha-1 antitrypsin-deficient COPD

Background

Diary cards are useful for analyzing exacerbations in chronic obstructive pulmonary disease (COPD), although factors influencing the length and frequency of each episode are poorly understood. This study investigated factors that influence the features of exacerbations in patients with alpha-1 antitrypsin (AAT) deficiency (PiZ phenotype) and COPD.

Methods

Daily diary cards were collected over 2 years. Patients had emphysema visualized and quantified by computed tomography scan, and had at least one documented exacerbation in the previous year.

Results

The patients (n = 23) had a mean age of 52.5 years, forced expiratory volume in one second (FEV₁) of 1.2 L (38.4% predicted), corrected gas transfer (KCO) of 0.90 mmol/min/kPa/L (59.7% predicted), and 15th percentile lung density of 44.55 g/L. Two hundred and sixty-three exacerbations (164 treated) were identified. The frequency of treated exacerbations correlated negatively with KCO% predicted (r = −0.432; P = 0.022). Exacerbation length (determined for 17 of the patients for whom diary card data through the episode were available) correlated negatively with baseline 15th percentile lung density (r = −0.361; P = 0.003), and increased the longer treatment was delayed (r = 0.503; P < 0.001). Treatment delay was shorter with higher day 1 symptom score, lower baseline FEV₁, FEV₁/forced vital capacity, and lower 15th percentile lung density (r = −0.368, 0.272, 0.461, and 0.786; P = 0.004, 0.036, <0.001, and <0.001, respectively). Time to resolution of exacerbation after treatment initiation was not affected by treatment delay, but correlated negatively with KCO% predicted (r = −0.647; P = 0.007).

Conclusion

In alpha-1 antitrypsin deficiency, the frequency and length of resolution of exacerbation were related to baseline gas transfer. Treatment delay adversely affected exacerbation length, and lung density was the best independent predictor of delay in starting treatment.

Early origins of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide and a significant challenge for adult physicians. However, there is a misconception that COPD is a disease of only adult smokers. There is a growing body of evidence to support the hypothesis that chronic respiratory diseases such as COPD have their origins in early life. In particular, adverse maternal factors will interact with the environment in a susceptible host promoting altered lung growth and development antenatally and in early childhood. Subsequent lung injury and further gene-environment interactions may result in permanent lung injury manifest by airway obstruction predisposing to COPD. This review will discuss the currently available data regarding risk factors in early life and their role in determining the COPD phenotype.

Protective effects of bone marrow mononuclear cell therapy on lung and heart in an elastase-induced emphysema model

We hypothesized that bone marrow-derived mononuclear cell (BMDMC) therapy protects the lung and consequently the heart in experimental elastase-induced emphysema. Twenty-four female C57BL/6 mice were intratracheally instilled with saline (C group) or porcine pancreatic elastase (E group) once a week during 4 weeks. C and E groups were randomized into subgroups receiving saline (SAL) or male BMDMCs (2 × 10(6), CELL) intravenously 3h after the first saline or elastase instillation. Compared to E-SAL group, E-CELL mice showed, at 5 weeks: lower mean linear intercept, neutrophil infiltration, elastolysis, collagen fiber deposition in alveolar septa and pulmonary vessel wall, lung cell apoptosis, right ventricle wall thickness and area, higher endothelial growth factor and insulin-like growth factor mRNA expressions in lung tissue, and reduced platelet-derived growth factor, transforming growth factor-β, and caspase-3 expressions. In conclusion, BMDMC therapy was effective at modulating the inflammatory and remodeling processes in the present model of elastase-induced emphysema.

Function and mechanisms of TSLP/TSLPR complex in asthma and COPD

Thymic stromal lymphopoietin (TSLP) is a key pro-allergic cytokine that has recently been linked to chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). High levels of TSLP were detected in bronchial mucosa of asthma and COPD patients suggesting TSLP's biological role beyond a signature 'Th2-favoring' or 'pro-allergic cytokine'. Besides inflammatory cells, airway structural cells produce and are targets of TSLP suggesting a potential autocrine loop that may have a profound effect on local inflammatory response and airway remodelling. This review sums up diverse mechanisms that mediate TSLP/TSLP receptor-signalling network in chronic airway diseases.

Gender differences in predictors of health status in patients with COPD

OBJECTIVE

To evaluate the health status (HS) of COPD patients and to identify the main predictors of HS in these patients according to gender.

METHODS

The study included 90 COPD patients (60 males and 30 females; mean age = 64 +/- 9 years) with a wide range of airway obstruction disorders (mean FEV1 = 56 +/- 19% of predicted). The men were individually matched to the women by % of predicted FEV1 (ratio: 2:1). The patients were assessed regarding body composition; six-minute walk distance; perception of dyspnea using the Modified Medical Research Council Dyspnea Scale; Saint George's Respiratory Questionnaire (SGRQ); Charlson comorbidity index; and the multidimensional Body mass index, airway Obstruction, Dyspnea, and Exercise capacity (BODE) index. Multiple linear regression analysis was performed to identify the predictors of HS by gender.

RESULTS

Impairment of HS was greater among the women than among the men for SGRQ total score and for all SGRQ domains (total: 51 +/- 18% vs. 38 +/- 19%; p = 0.002; symptoms: 61 +/- 22% vs. 42 +/- 21%; p < 0.001; activity: 62 +/- 18% vs. 49 +/- 21%; p = 0.004; and impact: 41 +/- 19% vs. 27 +/- 18%; p = 0.001). The multiple linear regression showed that age and perception of dyspnea correlated with SGRQ total score for both genders (males, r(2) = 0.42; females, r(2) = 0.70; p < 0.05).

CONCLUSIONS

Our results showed an association between gender and HS in COPD patients. Age and dyspnea are determinants of HS in both genders.

Identification of distinct plasma biomarker signatures in patients with rapid and slow declining forms of COPD

Chronic obstructive pulmonary disease (COPD) is a prevalent pulmonary disease characterized by a progressive decline in lung function. The identification of biomarkers capable of predicting the rate of lung function decline or capable of giving an early read on drug efficacy in clinical trials would be very useful. The aim of this study was to identify plasma biomarkers capable of accurately distinguishing patients with COPD from healthy controls. Eighty-nine plasma markers in 40 COPD patients and 20 healthy smoker controls were analyzed. The COPD patients were divided into two subgroups, rapid and slow decliners based on their rate of lung function decline measured over 15 years. Univariate analysis revealed that 25 plasma markers were statistically different between rapid decliners and controls, 4 markers were different between slow decliners and controls, and 10 markers were different between rapid and slow decliners (p < 0.05). Multivariate analysis led to the identification of groups of plasma markers capable of distinguishing rapid decliners from controls (signature 1), slow decliners from controls (signature 2) and rapid from slow decliners (signature 3) with over 90% classification accuracy. Importantly, signature 1 was shown to be longitudinally stable using plasma samples taken a year later from a subset of patients. This study describes a novel set of plasma markers differentiating slow from rapid decline of lung function in COPD. If validated in distinct and larger cohorts, the signatures identified will have important implications in both disease diagnosis, as well as the clinical evaluation of new therapies.

Pulmonary disorders, including vocal cord dysfunction

The lung is a very complex immunologic organ and responds in a variety of ways to inhaled antigens, organic or inorganic materials, infectious or saprophytic agents, fumes, and irritants. There might be airways obstruction, restriction, neither, or both accompanied by inflammatory destruction of the pulmonary interstitium, alveoli, or bronchioles. This review focuses on diseases organized by their predominant immunologic responses, either innate or acquired. Pulmonary innate immune conditions include transfusion-related acute lung injury, World Trade Center cough, and acute respiratory distress syndrome. Adaptive immunity responses involve the systemic and mucosal immune systems, activated lymphocytes, cytokines, and antibodies that produce CD4(+) T(H)1 phenotypes, such as for tuberculosis or acute forms of hypersensitivity pneumonitis, and CD4(+) T(H)2 phenotypes, such as for asthma, Churg-Strauss syndrome, and allergic bronchopulmonary aspergillosis.

Exercise intolerance and systemic manifestations of pulmonary emphysema in a mouse model

Background

Systemic effects of chronic obstructive pulmonary disease (COPD) significantly contribute to severity and mortality of the disease. We aimed to develop a COPD/emphysema model exhibiting systemic manifestations of the disease.

Methods

Female NMRI mice were treated 5 times intratracheally with porcine pancreatic elastase (emphysema) or phosphate-buffered saline (control). Emphysema severity was quantified histologically by mean linear intercept, exercise tolerance by treadmill running distance, diaphragm dysfunction using isolated muscle strips, pulmonary hypertension by measuring right ventricular pressure, and neurohumoral activation by determining urinary norepinephrine concentration.

Results

Mean linear intercept was higher in emphysema (260.7 ± 26.8 μm) than in control lungs (24.7 ± 1.7 μm). Emphysema mice lost body weight, controls gained weight. Running distance was shorter in emphysema than in controls. Diaphragm muscle length was shorter in controls compared to emphysema. Fatigue tests of muscle strips revealed impaired relaxation in emphysema diaphragms. Maximum right ventricular pressure and norepinephrine were elevated in emphysema compared to controls. Linear correlations were observed between running distance changes and intercept, right ventricular weight, norepinephrine, and diaphragm length.

Conclusion

The elastase mouse model exhibited severe emphysema with consecutive exercise limitation, and neurohumoral activation. The model may deepen our understanding of systemic aspects of COPD.

Alpha-1 antitrypsin deficiency: pathogenesis, clinical presentation, diagnosis, and treatment

Alpha-1 antitrypsin deficiency is an inherited disease affecting the lung and liver. The typical pulmonary manifestation is chronic obstructive pulmonary disease and emphysema. Severe chronic obstructive pulmonary disease may occur in young adulthood, and terminal respiratory insufficiency causes premature death in many patients. In the liver, alpha-1 antitrypsin deficiency may manifest as benign neonatal hepatitis syndrome; a small percentage of adults develop liver fibrosis, with progression to cirrhosis and hepatocellular carcinoma. The alpha-1 antitrypsin molecule is a serine protease inhibitor that is predominantly produced in the liver. Its most important physiologic functions are the protection of pulmonary tissue from aggressive proteolytic enzymes and regulation of pulmonary immune processes. Diagnosis of alpha-1 antitrypsin deficiency can be established by measurement of the serum alpha-1 antitrypsin concentration or by genetic analysis. Treatment is similar to the usual treatment for patients with chronic obstructive pulmonary disease. A further option is substitution therapy with human alpha-1 antitrypsin. The targets of treatment are the prevention of the accelerated decline of pulmonary function, reduction of lung infections, and improvements in exercise capacity.

Efficacy of the FEV1/FEV6 ratio compared to the FEV1/FVC ratio for the diagnosis of airway obstruction in subjects aged 40 years or over

The present cross-sectional, population-based study was designed to evaluate the performance of the FEV1/FEV6 ratio for the detection of airway-obstructed subjects compared to the FEV1/FVC <0.70 fixed ratio test, as well as the lower limit of normality (LLN) for 1000 subjects (3)40 years of age in the metropolitan area of São Paulo, SP, Brazil. After the exclusion of 37 (3.7%) spirometries, a total of 963 pre-bronchodilator (BD) and 918 post-BD curves were constructed. The majority of the post-BD curves (93.1%) were of very good quality and achieved grade A (762 curves) or B (93 curves). The FEV1/FEV6 and FEV1/FVC ratios were highly correlated (r(2) = 0.92, P < 0.000). Two receiver operator characteristic curves were constructed in order to express the imbalance between the sensitivity and specificity of the FEV1/FEV6 ratio compared to two FEV1/FVC cut-off points for airway obstruction: equal to 70 (area under the curve = 0.98, P < 0.0001) and the LLN (area under the curve = 0.97, P < 0.0001), in the post-BD curves. According to an FEV1/FVC <0.70, the cut-off point for the FEV1/FEV6 ratio with the highest sum for sensitivity and specificity was 0.75. The FEV1/FEV6 ratio can be considered to be a good alternative to the FEV1/FVC ratio for the diagnosis of airway obstruction, both using a fixed cut-off point or below the LLN as reference. The FEV1/FEV6 ratio has the additional advantage of being an easier maneuver for the subjects and for the lung function technicians, providing a higher reproducibility than traditional spirometry maneuvers.

Constitutive and inducible thymic stromal lymphopoietin expression in human airway smooth muscle cells: role in chronic obstructive pulmonary disease

Thymic stromal lymphopoietin (TSLP) is a novel cytokine that triggers dendritic cell-mediated T helper (Th)-2 inflammatory responses. Previous studies have demonstrated that human airway smooth muscle cells (HASMC) play a critical role in initiating or perpetuating airway inflammation by producing chemokines and cytokines. In this study, we first evaluated the expression of TSLP in primary HASMC and investigated how proinflammatory cytokines (TNF-alpha and IL-1beta) and Th-2 cytokines (IL-4, IL-9) regulate TSLP production from HASMC. TSLP mRNA and protein were assessed by real-time RT-PCR, ELISA, and immunofluorescence from primary HASMC cultures. Primary HASMC express constitutive level of TSLP. Incubation of HASMC with IL-1 or TNF-alpha resulted in a significant increase of TSLP mRNA and protein release from HASMC. Furthermore, combination of IL-1beta and TNF-alpha has an additive effect on TSLP release by HASMC. Primary HASMC pretreated with inhibitors of p38 or p42/p44 ERK MAPK, but not phosphatidylinositol 3-kinase, showed a significant decrease in TSLP release on IL-1beta and TNF-alpha treatment. Furthermore, TSLP immunoreactivity was present in ASM bundle from chronic obstructive pulmonary disease (COPD) and to lesser degree in normal subjects. Taken together, our data provide the first evidence of IL-1beta- and TNF-alpha-induced TSLP expression in HASMC via (p38, p42/p44) MAPK signaling pathways. Our results raise the possibility that HASMC may play a role in COPD airway inflammation via TSLP-dependent pathway.

Accumulation of Dendritic Cells and Increased CCL20 Levels in the Airways of Patients with Chronic Obstructive Pulmonary Disease

RATIONALE

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation. It is unclear if dendritic cells (DC) participate in this inflammatory process.

OBJECTIVES

To evaluate the presence of DC in small airways of patients with COPD.

METHODS

We evaluated DC infiltration in small airways by immunohistochemistry in patients with COPD (stage I-IV), never-smokers, and smokers without COPD. Chemokine ligand 20 (CCL20, the most potent chemokine in attracting DC) was determined in total lung by RT-PCR and in induced sputum by enzyme-linked immunsorbent assay. Chemokine receptor 6 (CCR6, the receptor for CCL20) expression on human pulmonary DC was evaluated by RT-PCR and flow cytometry.

MEASUREMENTS AND MAIN RESULTS

There is a significant increase in DC number in the epithelium (p = 0.007) and adventitia (p = 0.009) of small airways of patients with COPD compared with never-smokers and smokers without COPD. DC number in epithelium and adventitia increases along with disease severity. CCL20 mRNA expression in total lung and CCL20 protein levels in induced sputum are significantly higher in patients with COPD compared with never-smokers (p = 0.034 for CCL20 mRNA and p = 0.0008 for CCL20 protein) and smokers without COPD (p = 0.016 for CCL20 mRNA and p = 0.001 for CCL20 protein). DC isolated from human lung express CCR6 both at mRNA and at protein level.

CONCLUSIONS

This is the first description of airway infiltration by DC in COPD. Moreover, interaction between CCL20 and CCR6 provides a possible mechanism for accumulation of DC in the lungs in COPD.

Impact of Salmeterol/Fluticasone Propionate versus Salmeterol on Exacerbations in Severe Chronic Obstructive Pulmonary Disease

RATIONALE

Exacerbations of chronic obstructive pulmonary disease (COPD) greatly contribute to declining health status and the progression of the disease, thereby incurring significant direct and indirect health care costs. The prevention of exacerbations, therefore, is an important treatment goal.

OBJECTIVES

To assess the impact of combination therapy with salmeterol/fluticasone propionate compared with salmeterol alone on moderate and severe exacerbations in patients with severe COPD and a history of repeated exacerbations.

METHODS

Randomized, double-blind, parallel-group study. After a 4-wk run-in period, 994 clinically stable patients were randomized to one of two treatment groups: 507 patients received the salmeterol/fluticasone combination 50/500 micro g twice daily and 487 received salmeterol 50 micro g twice daily for 44 wk.

MAIN RESULTS

The total number of exacerbations was 334 in the combination therapy and 464 in the salmeterol group (p < 0.0001). The annualized rate of moderate and severe exacerbations per patient was 0.92 in the combination therapy and 1.4 in the salmeterol group, corresponding to a 35% decrease. In addition, the mean time to first exacerbation in the combination therapy group was significantly longer compared with that of the salmeterol group (128 vs. 93 d, p < 0.0001). Other endpoints, including health-related quality of life, peak expiratory flow, and use of rescue medication, were significantly improved in the combination therapy group. Both treatments were well tolerated.

CONCLUSIONS

This study demonstrates that combination therapy with salmeterol/fluticasone compared with salmeterol monotherapy significantly reduces the frequency of moderate/severe exacerbations in patients with severe COPD.

Volume Reduction Surgery Impairs Immediate Postoperative Pulmonary Function in Canine Emphysema

RATIONALE

In severe pulmonary emphysema, lung volume reduction surgery (LVRS) improves pulmonary function over a 2-yr period in selected patients. However, the changes in lung function and maximal flow (Vmax) occurring immediately postoperatively are not clear and may contribute to the high morbidity observed. In the present study, we used a chronic canine model of upper lobe emphysema to address this question.

METHODS

Bilateral upper lobe emphysema was produced by the intrabronchial administration of papain. Measurements were made before and immediately after LVRS was performed. A vacuum-assisted surgical system (VALR Surgical System; Spiration, Redmond, WA) that deploys a compression sleeve over portions of the disease tissue was used to produce LVRS. Changes in Vmax were interpreted in terms of the wave-speed theory of flow limitation in which a pressure sensor was placed into the airway to determine the site of limitation and intrabronchial pressures.

RESULTS

In the emphysema group, total lung capacity postemphysema increased to approximately 20% above the preemphysema value, whereas Vmax was reduced as compared with a control group. After LVRS, tidal respiratory compliance and Vmax decreased, whereas lung elastic recoil and frictional resistance increased in both the emphysema and control groups as compared with presurgery.

CONCLUSION

The acute effect of LVRS leads to an impairment in lung mechanical properties. These changes could contribute to ventilatory complications, including the difficulty of weaning patients from mechanical ventilation and the mortality observed from this procedure.