Long-acting b2-agonists can produce the same level of bronchodilation as anticholinergic drugs in patients with COPD, but due to their lipophilicity, the action persists for 12 h after inhalation. Comparative studies between salmeterol and formoterol demonstrate an equivalent potency of salmeterol 50 mcg and formoterol 24 or 12 mcg when administered respectively by a metered dose inhaler or a turbuhaler. One must consider the inhaler in order to establish the equivalent potency between these two agents. Patients with COPD and associated cardiac diseases can use the long-acting b2-agonists safely. In this particular high-risk group of patients, salmeterol, a partial agonist, is considered safer than formoterol. A reassessment of the bronchodilator therapy in COPD might be considered. Tiotropium bromide is a new anticholinergic drug, the action of which prolongs for more than 1-3 days. It is the most promising new bronchodilator for COPD patients.

Keywords: COPD, long-acting b2-agonists, bronchodilators

Chronic obstructive pulmonary disease is progressive and is characterized by abnormal inflammation of the lungs in response to inhalation of noxious particles or toxic gases, especially cigarette smoke. Although this infirmity primarily affects the lungs, diverse extrapulmonary manifestations have been described. The likely mechanisms involved in the local and systemic inflammation seen in this disease include an increase in the number of inflammatory cells (resulting in abnormal production of inflammatory cytokines) and an imbalance between the formation of reactive oxygen species and antioxidant capacity (leading to oxidative stress). Weakened physical condition secondary to airflow limitation can also lead to the development of altered muscle function. Chronic obstructive pulmonary disease presents diverse systemic effects including nutritional depletion and musculoskeletal dysfunction (causing a reduction in exercise tolerance), as well as other effects related to the comorbidities generally observed in these patients. These manifestations have been correlated with survival and overall health status in chronic obstructive pulmonary disease patients. In view of these facts, the aim of this review was to discuss findings in the literature related to the systemic manifestations of chronic obstructive pulmonary disease, emphasizing the role played by systemic inflammation and evaluating various therapeutic strategies.

Keywords: Pulmonary disease, chronic obstructive/complications; Nutritional status; Exercise tolerance;

Introduction: A great emphasis has been placed on health-related quality of life of COPD patients and specific questionnaires have been developed in order to measure it. Interventions directed to improve symptoms and decrease morbi-mortality may be evaluated by such questionnaires. Objective: This study describes the language and cultural adaptation of a new (and short) disease-specific health status questionnaire developed for chronic obstructive pulmonary diseases: the Airways Questionnaire 20 (AQ20). This questionnaire has only 20 simple items, and is one of the shortest ones ever described in the literature. Methods: In order to validate this questionnaire in Brazil, an initial translation from English to Portuguese has been made. The cultural adaptation was taken into consideration and then a back translation to English was undertaken, in order to obtain a final Portuguese version. Correlations were made with FEV1, SpO2, BMI and another disease specific health status questionnaire, the Saint George Respiratory Questionnaire (SGRQ), previously validated in Brazil. To test the reproducibility of AQ20, the interclass correlation ratio was done. Results: The interclass correlation ratio for the total score was a = 0.90 (intraobserver variability) and a = 0.93 (interobserver variability). The correlation with total SGRQ score was 0.76, with p < 0.001. Conclusion: It can be concluded that the Brazilian Portuguese version of AQ20 is reproducible, with good correlation with SGRQ total score, which makes it a valid questionnaire to measure health status in obstructive patients in Brazil.

Objective: To quantify elastic fibers (EFs) and smooth muscle (SM) cells, as well as CD4+ and CD8+ T lymphocytes, in stable chronic obstructive pulmonary disease (COPD). Methods: Surgical specimens were obtained from 15 COPD patients, 18 smokers without airflow limitation, and 14 nonsmokers. Histological and immunohistochemical methods were employed in order to quantify EFs, SM cells, CD4+ T cells, and CD8+ T cells. Results: There was no significant difference in EF numbers among the three groups (p > 0.05). The number of EFs per unit area of lung tissue (mm2) and the percentage of EFs in the lung tissue were similar among the three groups. The numbers of SM cells were found to be higher in the COPD patients than in the smokers (p = 0.003) or in the nonsmokers (p = 0.009). There was a tendency toward an increase in CD8+ T-cell counts in the COPD patients. In specimens collected from the COPD patients, CD4+ T-cell counts were lower than in those collected from the smokers (p = 0.015) or from the nonsmokers (p = 0.003). There was a weak correlation between CD4+ T-cell count and the ratio of forced expiratory volume in one second to forced vital capacity (r2 = 0.003). Conclusions: The EF counts were similar among the three groups. Hypertrophy/hyperplasia of airway wall SM cells was found in the COPD patients and in the smokers, indicating that airway remodeling occurs in smokers. The CD4/CD8 ratio was lower in the COPD patients.

Keywords: Pulmonary disease, chronic obstructive; CD4 Lymphocyte Count; Elastic tissue; Muscle, smooth.

Chronic obstructive pulmonary disease is a prevalent condition and is currently the forth leading cause of mortality in the US. The prevalence of respiratory disturbance during sleep, or overlap syndrome as it was commonly known in the past, is still undetermined as conflicting reports have been published. Because of the adverse effects of sleep-related respiratory impairment in patients with underlying pulmonary disease, this condition deserves further investigation. In this report, we will briefly discuss the mechanisms involved in generating respiratory disturbance during sleep in Chronic Obstructive Pulmonary Disease and will guide the reader into distinguishing those patients who would benefit from a more detailed sleep evaluation, discussing management issues and treatment options.

Keywords: Key words: COPD. Sleep disorder breathing. Sleep apnea. Hypoxemia. Hypoventilation

We report the case of a patient with chronic obstructive pulmonary disease and bronchiectasis, chronically using corticosteroids, who acquired pulmonary nocardiosis, which presented as multiple cavitated nodules. The principal symptoms were fever, dyspnea and productive cough with purulent sputum. Chest X-ray and computed tomography of the chest revealed nodules, some of which were cavitated, in both lungs. Sputum smear microscopy and culture revealed the presence of Nocardia spp. The patient was treated with imipenem and cilastatin, which produced an excellent clinical response.

Keywords: Pulmonary disease, chronic obstructive; Nocardia infections; Bronchiectasis.

Pulmonary thromboembolism and exacerbation of chronic obstructive pulmonary disease are common conditions. Chronic obstructive pulmonary disease is a clinical risk factor for pulmonary thromboembolism. The presentation of acute pulmonary thromboembolism and acute exacerbation of chronic obstructive pulmonary disease often mimic each other so closely that they cannot be distinguished clinically. The structural abnormalities of the lungs in chronic obstructive pulmonary disease make also difficult to interpret the results of noninvasive tests like ventilation-perfusion lung scans. Therefore, diagnosing acute pulmonary thromboembolism in patients with underlying chronic obstructive pulmonary disease is a challenging task. In order to update knowledge of the subject and offer suggestions regarding conduct, we evaluated various studies addressing this theme, including case reports and case series. In addition, we reviewed diagnostic approaches to acute pulmonary thromboembolism, and we reflect upon that topic. The clinical probability of pulmonary thromboembolism concomitant to chronic obstructive pulmonary disease is typically intermediate, as is positivity on the ventilation-perfusion lung scan. Diagnostic algorithms should take that into consideration.

Keywords: Pulmonary disease, chronic obstructive/complications; Pulmonary embolism/diagnosis; Pulmonary embolism/epidemiology; Ventilation-perfusion ratio

Introduction: The term quality of life has gained increasing importance in the scientific context. This study describes the adaptation of a disease-specific questionnaire developed by Paul Jones et al. in 1991, the St. George's Respiratory Questionnaire (SGRQ), to the Brazilian language and culture. This questionnaire evaluates the quality of life in patients with chronic obstructive pulmonary disease (COPD) and contains three domains (symptoms, activity, and impacts) divided in 76 items. The questionnaire is self-administrated, but it may be read to illiterate persons. Goal: To verify if the St. George's Respiratory Questionnaire is a valid tool to measure quality of life in patients with chronic obstructive pulmonary disease in Brazil. Methods: In order to validate the questionnaire in Brazil, it was initially translated into Portuguese and afterwards a back-translation into English, that was compared to the original version. A final Portuguese version was then written. This final version was, then, answered by 30 clinically stable COPD patients, according to the spirometry and oximetry values. Patients answered the questionnaire twice, within a 15 day interval. The length of time the patients took to answer the questionnaire and their doubts were noted. Wilcoxon test was used for the calculation of r probability between every single question between the two days; interclass correlation ratio was calculated to test the trustworthiness and reliability of the questionnaire. Results: Among the 30 participant patients, 10 were female and 20 were male. Mean age was 65.9 years. Most of the patients were found to be in stage 2 (56.7 %) of COPD, according to the American Thoracic Society classification. The interclass correlation ratio for the total score of the questionnaire was a = 0.79 and Wilcoxon p = 0.2110 (not statistically significant). The mean answering time for the two days of interview was, respectively, 11 minutes and 50 seconds and 10 minutes and 31 seconds. As concerns the doubts about the questions, the patients reported difficulties in answering Sections 4 and 5, each one of these questions written in a negative form. Conclusion: It can be concluded that the Brazilian version of the St. George's Respiratory Questionnaire is a valid and reliable tool to measure quality of life in patients with COPD in Brazil.

Keywords: obstructive lung diseases, questionnaire, quality of life, reproducibility of results, evolution studies

Depression is the most prevalent psychiatric disorder among hospitalized patients. Chronic obstructive pulmonary disease (COPD) is the most common pulmonary disease, responsible for a high incidence of hospitalization. The purpose of this study is to determine the prevalence of major depression in patients hospitalized due to COPD and correlate such depression with PaCO2, PaO2, respiratory infection, degree of functional airflow obstruction, and steroid therapy. Depression was diagnosed according to DSM IV criteria for major depressive disorders, and assessed by the Beck Depression Inventory. The interview, spirometry, and arterial blood gas analysis were performed between the third and the tenth day of hospitalization. The authors made a prospective study of 51 patients, 34 male and 17 female, with a mean age of 61 ± 11 years. Respiratory infection was the most frequent cause of hospital admission. Major depression was present in 26.9% (n = 11) of the patients, and proportionally higher in females (8 vs 3, p = 0.003). PaCO2 was higher in depressive patients than in non-depressive ones (60.1 ± 18.0 vs 45.8 ± 10.0 mmHg, p = 0.004). Other variables did not display significant differences. The authors conclude that major depression is highly prevalent among patients with COPD, specially in hypercapnic individuals and women.

Keywords: Chronic obstructive pulmonary disease. Steroid. Hypercapnia. Hypoxemia. Depression.

Objective: To determine cell profiles, as well as to identify CD4+ and CD8+ lymphocyte subgroups, in induced sputum (IS) and peripheral venous blood (PVB) of patients with chronic obstructive pulmonary disease (COPD). Methods: Total cell counts and counts of individual cell types, including CD4+ and CD8+ T lymphocytes, were determined in the IS and PVB of 85 subjects (38 with COPD without exacerbation, 29 smokers without obstruction and 18 nonsmokers). Mann-Whitney and Spearman non-parametric tests were used in the statistical analysis, and values of p < 0.05 were considered statistically significant. Results: Comparing the IS of subjects with COPD to that of nonsmokers, neutrophil, eosinophil and CD8+ T lymphocyte counts were higher (respectively p = 0.005, p < 0.05 and p < 0.05), whereas the percentage of macrophages was lower (p = 0.003). There were weak linear correlations (r2 < 0.1) between each cell type in IS and forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio. Eosinophil and CD8+ T lymphocyte counts were also higher in PVB (p = 0.04 and p = 0.02). Conclusions: In patients with stable COPD, CD8+ T lymphocyte counts were higher in PVB, whereas total leukocyte counts were similar to those of the other two groups analyzed, suggesting systemic inflammatory involvement. The CD8+ T lymphocyte count in blood can be a useful marker of systemic inflammation and can help identify smokers who already present a COPD inflammatory pattern.

Keywords: Sputum; T-lymphocytes; Neutrophils; Macrophages; Eosinophils; Pulmonary disease, chronic obstructive.

Objective: To correlate the postbronchodilator (post-BD) inspiratory capacity (IC), % of predicted, with other markers of severity and prognostic factors in chronic obstructive pulmonary disease (COPD). Methods: Eighty stable patients with COPD performed forced vital capacity and slow vital capacity maneuvers, as well as the 6-min walk test, prior to and after receiving albuterol spray (400 μg). Patients were divided into four groups, based on post-BD forced expiratory volume in one second. Several variables were tested to establish correlations with the post-BD distance walked, using univariate and multivariate analysis. Post-BD IC was found to correlated with Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging and with the Body mass index, airway Obstruction, Dyspnea, and Exercise capacity (BODE) index. Results: Multivariate regression analysis revealed that the distance walked, % predicted, correlated significantly with the IC post-BD, % predicted (p = 0.001), long-term oxygen use (p = 0.014), and number of medications used in the treatment (p = 0.044). IC ≤ 70% was observed in 56% patients in GOLD stages 3 or 4 vs. 20% in GOLD 1 or 2 (p < 0.001). IC ≤ 70% was observed in (60%) patients with BODE score 3 or 4 vs. (33%) BODE score 1 or 2 (p = 0.02). Conclusion: Post-BD IC% predicted is the best functional predictor of distance walked and is significantly associated with GOLD staging and BODE index. Therefore, We propose that the inspiratory capacity should be added to the routine evaluation of the COPD patients.

Keywords: Pulmonary disease, chronic obstructive; Walking; Respiratory function tests; Inspiratory capacity.

Objective: To evaluate, using pulmonary function tests, the effectiveness of formoterol as a bronchodilator at 30 min after its administration in patients with poorly reversible COPD. Methods: A prospective study including 40 COPD patients not responding to the short-acting bronchodilator used in the spirometric test-variation of less than 200 mL and less than 7% of predicted in forced expiratory volume in one second (FEV1). All patients were classified as having stage II, III, or IV COPD (Brazilian Thoracic Society/Global Initiative for Chronic Obstructive Lung Disease) and presented FEV1 ≤ 70% of predicted value. The patients were randomized into two groups of 20, with similar clinical characteristics, receiving, via a dry powder inhaler, either formoterol or a placebo. The pulmonary function testing (plethysmography) was repeated at 30 min after formoterol or placebo administration. Results: In the formoterol group, the mean values obtained for FEV1, inspiratory capacity, and forced vital capacity were significantly greater than those obtained in the placebo group (p = 0.00065, p = 0.05, and p = 0.017, respectively), whereas that obtained for airway resistance was significantly lower (p = 0.010). Less pronounced differences were observed for residual volume, vital capacity and specific airway conductance, which were lower, higher and higher, respectively, in the formoterol group. Conclusions: In COPD patients not responding to the short-acting bronchodilator used in the spirometric test, formoterol promoted significant improvement in lung function at 30 min after of administration. Further studies are required to confirm whether formoterol can also be used as a medication for immediate relief of symptoms in COPD.

Keywords: Chronic obstructive pulmonary disease; Respiratory function tests; Bronchodilator agents.

Background: The six minutes walk test has been increasingly utilized to assess the effectiveness of different clinical and surgical treatment options in pulmonary diseases. However lack of standardization for their performance may influence measurements and jeopardize assessment of the functional capacity of patients with cardiopulmonary disease. Objective: To determine the possible effects of learning on the distance covered during the six minute walk test for bearers of chronic obstructive pulmonary disease. Method: A retrospective analysis of 35 medical records of COPD patients referred to the Pulmonary Rehabilitation Program of the University Hospital of Brasília was carried out. On alternate days these patients had performed two six minutes walk tests, spirometry and arterial blood gas analysis. Clinical and functional diagnosis was based upon the history of exposure to risk factors, mucus production, dyspnea and spirometric dysfunction after use of bronchodilators. The Student test was used for the comparison of results that were different. Results: The distances covered in the second six-minute walk test (515 ± 82 meters) were greater than those covered in the first six-minute walk test (480 ± 85 metros), with statistically significant differences (p<0.05). However measurements of the muscular effort and perception of dyspnea (Borg scale), peripheral blood oxygen saturation (SpO2), respiratory and heart rates did not disclose any statistically significant differences between the two tests (p<0.05). Conclusion: The present study suggests that in order to standardize the six minutes walk test, the procedure should be performed at least twice to better assess the functional capacity of patients, bearers of chronic obstructive pulmonary disease.

Keywords: Walking. Effectiveness. Lung diseases, obstrutive.

Objective: To compare the efficacy, safety, and tolerability of azithromycin and amoxicillin in the treatment of patients with infectious exacerbation of chronic obstructive pulmonary disease. Methods: This study was conducted at six medical centers across Brazil and included 109 patients from 33 to 82 years of age. Of those, 102 were randomized to receive either azithromycin (500 mg/day for three days, n = 49) or amoxicillin (500 mg every eight hours for ten days, n = 53). The patients were evaluated at the study outset, on day ten, and at one month. Based on the clinical evaluation of the signs and symptoms present on day ten and at one month, the outcomes were classified as cure, improvement, or treatment failure. The microbiological evaluation was made through the culture of sputum samples that were considered appropriate samples only after leukocyte counts and Gram staining. Secondary efficacy evaluations were made in order to analyze symptoms (cough, dyspnea, and expectoration) and pulmonary function. Results: There were no differences between the groups treated with azithromycin or amoxicillin in terms of the percentages of cases in which the outcomes were classified as cure or improvement: 85% vs. 78% (p = 0.368) on day ten; and 83% vs. 78% (p = 0.571) at one month. Similarly, there were no significant differences between the two groups in the secondary efficacy variables or the incidence of adverse effects. Conclusion: Azithromycin and amoxicillin present similar efficacy and tolerability in the treatment of acute exacerbation of chronic obstructive pulmonary disease.

Keywords: Amoxicillin/therapeutic use; Azithromycin/therapeutic use; Bronchitis, chronic/drug therapy;

Objective: To evaluate the presence and severity of symptoms of anxiety and depression in individuals with asthma or chronic obstructive pulmonary disease. Methods: In order to evaluate symptoms of anxiety and depression, specific instruments of quantification (the State-Trait Anxiety Inventory and the Beck Depression Inventory, respectively) were administered to patients at an outpatient clinic for the treatment of asthma and chronic obstructive pulmonary disease. The population comprised 189 randomly and prospectively selected patients that were divided into three study groups (each with a different therapeutic objective): 40 patients with controlled asthma, 100 patients with uncontrolled asthma, and 49 patients with chronic obstructive pulmonary disease. Included among the variables studied, as part of the methodology, were symptoms of anxiety and depression. The data obtained were compared taking into consideration demographic and functional aspects, as well as the severity of the symptoms of anxiety and depression. Results: Among the asthma patients, the prevalence of moderate or severe anxiety was significantly higher than that observed among those with chronic obstructive pulmonary disease (p <  0.001). The uncontrolled asthma group presented significantly higher rates of depressive symptoms than did the controlled asthma group (p < 0.05). Conclusion: The frequency of symptoms of anxiety and depression is greater among asthma patients than among patients with chronic obstructive pulmonary disease, which can make clinical control difficult.

Keywords: Anxiety; Depression; Asthma; Pulmonary disease; Chronic obstructive

Objective: To study the effects of nocturnal hypoxemia in patients with chronic obstructive pulmonary disease without obstructive sleep apnea syndrome. Methods: We studied 21 patients-10 desaturators and 11 nondesaturators-submitted to arterial blood gas analysis, polysomnography, spirometry, cardiopulmonary exercise testing (cycle ergometer), and hand-grip dynamometry, as well as measurements of maximal inspiratory pressure, maximal expiratory pressure, and C-reactive protein (CRP) levels. Patients with arterial oxygen tension > 60 mmHg were included; those with an apnea-hypopnea index > 5 events/hour of sleep were excluded. Maximal oxygen uptake, maximal power, systolic blood pressure, diastolic blood pressure (DBP), and maximal heart rate were measured during exercise in order to detect hemodynamic alterations. Patients presenting CRP levels above 3 mg/L were considered CRP-positive. Results: Minimal peripheral oxygen saturation during sleep was significantly higher among nondesaturators (p = 0.03). More desaturators presented CRP > 3 mg/L (p < 0.05). No differences were observed in terms of any variables, However, mean peripheral oxygen saturation during sleep correlated with DBP and maximal inspiratory pressure (p < 0.001 and p = 0.001, respectively). Conclusions: Although nocturnal hypoxemia does not reduce exercise capacity or hand-grip strength in patients with mild/moderate COPD, its effect on maximal exercise DBP seems to depend on the degree of hypoxemia. In addition, there is a positive relationship between maximal inspiratory pressure and mean peripheral oxygen saturation during sleep, as well as evidence of pronounced inflammatory activation in patients with nocturnal hypoxemia.

Keywords: Pulmonary disease, chronic obstructive; Exercise test; Anoxia; Respiratory function tests.

Chronic obstructive pulmonary disease (COPD) is a public health problem. Tobacco smoking is the major cause, but not the only one. Air pollution, exposure to chemical compounds, environmental smoke exposure, and environmental tobacco smoke are among other contributing causes; viral and bacterial infection are risk factors too. Gender and weight loss are associated to the severity of the disease. Co-morbidity is frequent. Objective: To characterize a population of COPD outpatients followed at a tertiary medical service. Methods: Questionnaires were applied to patients with COPD. The data included gender, age, weight, body mass index (BMI), oxygen delivery users, and FEV1, exposure to tobacco smoke, exposure to wood smoke, tuberculosis antecedent and co-morbid diseases. Results: Of the 70 patients enrolled in the study, 70% (49) were male with an average age of 64 ± 10 years, an average weight of 63 ± 16 kg and an average BMI of 22 ± 5 kg/m2. 45,7% were oxygen dependent and the FEV1 average was 35 ± 14%. Nine (12.8%) patients never smoked, while 78.8% had quit tobacco smoking, (38 ± 11 pack/years was the average). Nine (12.8%) smoked straw cigarettes. Eighteen (25.7%) had environmental exposure to wood smoke. Eleven (15.7%) patients had tuberculosis, 5.7% complained of asthma symptoms, 2.8% had bronchiectasis, 11.4% diabetes mellitus, 51.4% hypertension, and 20% Cor pulmonale. Conclusion: Other possible COPD etiologies must be investigated. Determinants for the pulmonary injury could be environmental smoke exposure associated to former infections. Men with low BMI are typically representative of this severe patient population. Hypertension and Cor Pulmonale are frequent co-morbidity factors.

Chronic obstructive pulmonary disease is an inflammatory disease. Together with oxidant stimuli, which directly affect lung structures, macrophages, neutrophils and CD8+ lymphocytes actively participate in the pathogenesis of the disease and promote biochemical reactions that result in progressive alteration of the upper airways and irreversible lung remodeling. The release of substances promoted by inflammatory cell recruitment and by oxidative stress lead to a temporary imbalance in the pulmonary defense mechanisms. Understanding the long-term maintenance of this imbalance is key to understanding the current physiopathology of the disease. The present study explores the cellular and molecular alterations seen in chronic obstructive pulmonary disease.

Keywords: Pulmonary disease, chronic obstructive/physiopathology; Lung/metabolism; Inflammation; Oxydants; Antioxidants; Oxidative stress

Chronic obstructive pulmonary disease is currently considered a systemic disease, presenting structural and metabolic alterations that can lead to skeletal muscle dysfunction. This negatively affects the performance of respiratory and peripheral muscles, functional capacity, health-related quality of life and even survival. The decision to prescribe ergogenic aids for patients with chronic obstructive pulmonary disease is based on the fact that these drugs can avert or minimize catabolism and stimulate protein synthesis, thereby reducing the loss of muscle mass and increasing exercise tolerance. This review summarizes the available data regarding the use of anabolic steroids, creatine, L-carnitine, branched-chain amino acids and growth hormones in patients with chronic obstructive pulmonary disease. The advantage of using these ergogenic aids appears to lie in increasing lean muscle mass and inducing bioenergetic modifications. Within this context, most of the data collected deals with anabolic steroids. However, to date, the clinical benefits in terms of increased exercise tolerance and muscle strength, as well as in terms of the effect on morbidity and mortality, have not been consistently demonstrated. Dietary supplementation with substances of ergogenic potential might prove to be a valid adjuvant therapy for treating patients with advanced chronic obstructive pulmonary disease, especially those presenting loss of muscle mass or peripheral muscle weakness.

Keywords: Lung diseases, obstructive; Respiratory muscle; Dietary supplements; Anabolic agents/therapeutic use; Exercício; Energy metabolism

Objective: Pulmonary rehabilitation (PR) improves exercise capacity in most but not all COPD patients. The factors associated with treatment success and the role of chest wall mechanics remain unclear. We investigated the impact of PR on exercise performance in COPD with severe hyperinflation. Methods: We evaluated 22 COPD patients (age, 66 ± 7 years; FEV1 = 37.1 ± 11.8% of predicted) who underwent eight weeks of aerobic exercise and strength training. Before and after PR, each patient also performed a six-minute walk test and an incremental cycle ergometer test. During the latter, we measured chest wall volumes (total and compartmental, by optoelectronic plethysmography) and determined maximal workloads. Results: We observed significant differences between the pre- and post-PR means for six-minute walk distance (305 ± 78 vs. 330 ± 96 m, p < 0.001) and maximal workload (33 ± 21 vs. 39 ± 20 W; p = 0.02). At equivalent workload settings, PR led to lower oxygen consumption, carbon dioxide production (VCO2), and minute ventilation. The inspiratory (operating) rib cage volume decreased significantly after PR. There were 6 patients in whom PR did not increase the maximal workload. After PR, those patients showed no significant decrease in VCO2 during exercise, had higher end-expiratory chest wall volumes with a more rapid shallow breathing pattern, and continued to experience symptomatic leg fatigue. Conclusions: In severe COPD, PR appears to improve oxygen consumption and reduce VCO2, with a commensurate decrease in respiratory drive, changes reflected in the operating chest wall volumes. Patients with severe post-exercise hyperinflation and leg fatigue might be unable to improve their maximal performance despite completing a PR program.

Keywords: Pulmonary disease, chronic obstructive/rehabilitation; Exercise therapy; Respiratory therapy.