Lung Mechanics and Dyspnea during Exacerbations of Chronic Obstructive Pulmonary Disease

Admission prevention in COPD: non-pharmacological management

Exacerbations of chronic obstructive pulmonary disease (COPD) are one of the commonest causes of hospital admission in Europe, Australasia, and North America. These adverse events have a large effect on the health status of the patients and impose a heavy burden on healthcare systems. While we acknowledge the contribution of pharmacotherapies to exacerbation prevention, our interpretation of the data is that exacerbations continue to be a major burden to individuals and healthcare systems, therefore, there remains great scope for other therapies to influence exacerbation frequency and preservation of quality of life. In this review, the benefits and limitations of pulmonary rehabilitation, non-invasive ventilation, smoking cessation, and long-term oxygen therapy are discussed. In addition, supported discharge, advanced care coordination, and telehealth programs to improve clinical outcome are reviewed as future directions for the management of COPD.

Changes in oscillatory impedance and nitrogen washout with combination fluticasone/salmeterol therapy in COPD

INTRODUCTION

Combination inhaled corticosteroid/long-acting bronchodilator (ICS/LABA) therapy reduces the exacerbation rate and improves spirometry and quality of life in COPD. We hypothesized that ICS/LABA therapy also improves small airway function measured by FOT.

METHODS

14 subjects with COPD were commenced on combination fluticasone propionate/salmeterol therapy for 3 months. At baseline, subjects completed the St George Respiratory Questionnaire (SGRQ) and underwent standard pulmonary function tests as well as forced oscillation technique (FOT) and single and multiple breath nitrogen washouts. All tests were repeated at the completion of 3 months of therapy.

RESULTS

Subjects were of mean (SD) age 65.9 years (8.4), BMI 30.0 (5.6), pack years 51.4 (21.1), post-bronchodilator FEV1% predicted 62.7 (20). At baseline, mean SGRQ total was 39.0 (17.7) and FRC% predicted 125.4 (31.3). From FOT, Rrs-total was 5.69 (1.29) cmH2O/L/s, Xrs-total -3.48 (2.16) cmH2O/L/s, EFL Index 3.51 (2.45) cmH2O/L/s. After 3 months of therapy, there were significant improvements in SGRQ score (-13.81, p < 0.0001) despite no change in FEV1 (+40 mL, p = 0.14). From FOT, total resistance (-0.63 cmH2O/L/s, p = 0.0004), reactance (+1.2 cmH2O/L/s, p = 0.013), and expiratory flow limitation (-1.21 cmH2O/L/s, p = 0.02) also improved. There were no significant changes in ventilation heterogeneity indices.

CONCLUSION

Combination therapy is associated with improvements in small airways function in COPD, despite an absence of change in FEV1. FOT may be a clinically useful marker of small airway function in COPD that is responsive to treatment.

Day-to-day measurement of patient-reported outcomes in exacerbations of chronic obstructive pulmonary disease

Background

Exacerbations of chronic obstructive pulmonary disease (COPD) are a major burden to patients and to society. Little is known about the possible role of day-to-day patient-reported outcomes during an exacerbation. This study aims to describe the day-to-day course of patient-reported health status during exacerbations of COPD and to assess its value in predicting clinical outcomes.

Methods

Data from two randomized controlled COPD exacerbation trials (n = 210 and n = 45 patients) were used to describe both the feasibility of daily collection of and the day-to-day course of patient-reported outcomes during outpatient treatment or admission to hospital. In addition to clinical parameters, the BORG dyspnea score, the Clinical COPD Questionnaire (CCQ), and the St George’s Respiratory Questionnaire were used in Cox regression models to predict treatment failure, time to next exacerbation, and mortality in the hospital study.

Results

All patient-reported outcomes showed a distinct pattern of improvement. In the multivariate models, absence of improvement in CCQ symptom score and impaired lung function were independent predictors of treatment failure. Health status and gender predicted time to next exacerbation. Five-year mortality was predicted by age, forced expiratory flow in one second % predicted, smoking status, and CCQ score. In outpatient management of exacerbations, health status was found to be less impaired than in hospitalized patients, while the rate and pattern of recovery was remarkably similar.

Conclusion

Daily health status measurements were found to predict treatment failure, which could help decision-making for patients hospitalized due to an exacerbation of COPD.

No room to breathe: the importance of lung hyperinflation in COPD

Patients with chronic obstructive pulmonary disease (COPD) are progressively limited in their ability to undertake normal everyday activities by a combination of exertional dyspnoea and peripheral muscle weakness. COPD is characterised by expiratory flow limitation, resulting in air trapping and lung hyperinflation. Hyperinflation increases acutely under conditions such as exercise or exacerbations, with an accompanying sharp increase in the intensity of dyspnoea to distressing and intolerable levels. Air trapping, causing increased lung hyperinflation, can be present even in milder COPD during everyday activities. The resulting activity-related dyspnoea leads to a vicious spiral of activity avoidance, physical deconditioning, and reduced quality of life, and has implications for the early development of comorbidities such as cardiovascular disease. Various strategies exist to reduce hyperinflation, notably long-acting bronchodilator treatment (via reduction in flow limitation and improved lung emptying) and an exercise programme (via decreased respiratory rate, reducing ventilatory demand), or their combination. Optimal bronchodilation can reduce exertional dyspnoea and increase a patient's ability to exercise, and improves the chance of successful outcome of a pulmonary rehabilitation programme. There should be a lower threshold for initiating treatments appropriate to the stage of the disease, such as long-acting bronchodilators and an exercise programme for patients with mild-to-moderate disease who experience persistent dyspnoea.

Dynamic hyperinflation correlates with exertional oxygen desaturation in patients with chronic obstructive pulmonary disease

BACKGROUND

Dynamic hyperinflation (DH) causes exercise limitation and exertional dyspnea in patients with chronic obstructive pulmonary disease (COPD). Exertional desaturation (ED) also occurs commonly in COPD but neither routine physiologic parameters nor imaging predict ED accurately. In this study we evaluated the relationship between DH and ED during 6-min walk testing (6MWT).

METHODS

We measured ED and DH in patients with stable COPD. SpO2 was measured by continuous pulse oximetry during 6MWT. ED was defined as a decline in SpO2 (ΔSpO2) ≥4 %. DH was determined by measuring inspiratory capacity (IC) before and after the 6MWT using a handheld spirometer. DH was defined as ΔIC >0.0 L. We correlated DH and ED with clinical and pulmonary physiologic variables by regression analysis, χ (2), and receiver operator curve (ROC) analysis.

RESULTS

Thirty males [age = 65 ± 9.4 years, FEV1 % predicted = 48 ± 14 %, and DLCO % predicted = 50 ± 21 % (mean ± SD)] were studied. ΔSpO2 correlated with ΔIC (r = 0.49, p = 0.005) and age (r = 0.39, p = 0.03) by univariate analysis; however, only ΔIC correlated on multivariate regression analysis (p = 0.01). ΔSpO2 did not correlate with FEV1, FVC, FEF25-75, RV, DLCO % predicted, BMI, smoking, BORG score, or distance covered in 6MWT. DH strongly correlated with ED (p = 0.001). On ROC analysis, DH had an area under the curve of 0.92 for the presence of ED (sensitivity = 90 %; specificity = 77 %, p < 0.001).

CONCLUSION

Routine pulmonary function test results and clinical variables did not correlate with ED in patients with stable COPD. Dynamic hyperinflation strongly correlates with exertional desaturation and could be a reason for this desaturation.

Day-to-day variability of oscillatory impedance and spirometry in asthma and COPD

Variability in airway function may be a marker of disease activity in COPD and asthma. The aim was to determine the effects of repeatability and airway obstruction on day-to-day variability in respiratory system resistance (Rrs) and reactance (Xrs) measured by forced oscillation technique (FOT). Three groups of 10 subjects; normals, stable asthmatic and stable COPD subjects underwent daily FOT recordings for 7 days. Mean total and inspiratory Rrs and Xrs, and expiratory flow limitation (EFL) Index (inspiratory - expiratory Xrs), were calculated. The ICC's were high for all parameters in all groups. Repeatability, in terms of absolute units, correlated with airway obstruction and was therefore lowest in COPD. Day-to-day variability was due mostly to repeatability, with a small contribution from the mean value for some parameters. FOT measures are highly repeatable in health, stable asthma and COPD in relation to the wide range of measures between subjects. For home monitoring in asthma and COPD, either the coefficient of variation or individualized SDs could be used to define day-to-day variability.

[Prevention of COPD exacerbation: a fundamental challenge]

INTRODUCTION

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are a cause of suffering for patients and a burden for healthcare systems and society. Their prevention represents individual and collective challenge. The present article is based on the work of a group of experts who met on 5th and 6th May 2011 and seeks to highlight the importance of AECOPD.

STATE OF THE ART

In the absence of easily quantifiable criteria, the definition of AECOPD varies in the literature, making identification difficult and affecting interpretation of study results. Exacerbations increase mortality and risk of cardiovascular disease. They also increase the risk of developing further exacerbations, accelerate the decline in lung function and contribute to reduction in muscle mass. By limiting physical activity and affecting mental state (anxiety, depression), AECOPD are disabling and impair quality of life. They increase work absenteeism and are responsible for about 60% of the global cost of COPD.

PERSPECTIVES

Earlier identification with simple criteria, possibly associated to patient phenotyping, could be helpful in preventing hospitalization.

CONCLUSIONS

Given their immediate and delayed impact, AECOPD should not be trivialized or neglected. Their prevention is a fundamental issue.

Health status assessment in routine clinical practice: the chronic obstructive pulmonary disease assessment test score in outpatients

BACKGROUND

The chronic obstructive pulmonary disease (COPD) assessment test (CAT) is a simple, self-completion questionnaire developed to measure health status in patients with COPD, which is potentially suitable for routine clinical use.

OBJECTIVES

The purpose of this study was to establish the determinants of the CAT score in routine clinical practice.

METHODS

Patients attending the clinic completed the CAT score before being seen. Clinical data, including, where available, plethysmographic lung volumes, transfer factor and arterial blood gas analysis, were recorded on a pro forma in the clinic.

RESULTS

In 224 patients (36% female), mean forced expiratory volume in 1 s (FEV₁) was 40.1% (17.9) of predicted (%pred); CAT score was associated with exacerbation frequency [0-1/year 20.1 (7.6); 2-4/year 23.5 (7.8); >4/year 28.5 (7.3), p < 0.0001; 41/40/19% in each category] and with Medical Research Council (MRC) dyspnoea score (r² = 0.26, p < 0.0001) rising approximately 4 points with each grade. FEV(1) %pred had only a weak influence. Using stepwise regression, CAT score = 2.48 + 4.12 [MRC (1-5) dyspnoea score] + 0.08 (FEV(1) %pred) + 1.06 (exacerbation rate/year)] (r² = 0.36, p < 0.0001). The CAT score was higher in patients (n = 54) with daily sputum production [25.9 (7.5) vs. 22.2 (8.2); p = 0.004]. Detailed lung function (plethysmography and gas transfer) was available in 151 patients but had little influence on the CAT score.

CONCLUSION

The CAT score is associated with clinically important variables in patients with COPD and enables health status measurement to be performed in routine clinical practice.

Inspiratory capacity as a preoperative assessment of patients undergoing thoracic surgery

Although inspiratory capacity (IC) is strongly associated with the disease severity of chronic obstructive pulmonary disease, there was no appropriate equation to compute predicted values for IC. Furthermore, whether assessment of IC can identify the risk of prolonged postoperative stay (PPS) in patients undergoing thoracic surgery also remains unclear. To evaluate whether %IC predicted, for which the new equation to compute the predicted values for IC was utilized, could be applied to identify the risk of PPS, we retrospectively analysed the cases of 412 patients who underwent thoracic surgery in Nagoya University Hospital. The multivariate analysis demonstrated that %IC predicted < 85% was one of the most critical risk predictors for PPS (odds ratio, 1.65; 95% confidence intervals, 1.03-2.648) and, in particular, was independent of percentage predicted forced expiratory volume in 1 s (%FEV1) < 80%. A combined assessment of ICFEV1 Low, defined as %IC predicted <85% or %FEV1 <80%, was able to identify more than double the number of patients with PPS, compared with %FEV1 <80% alone (65.9 vs. 28.5%, respectively). This is the first study to demonstrate the significance of %IC predicted in screening for the risk for PPS in patients undergoing thoracic surgery.

Dynamic hyperinflation and auto-positive end-expiratory pressure: lessons learned over 30 years

Auto-positive end-expiratory pressure (auto-PEEP; AP) and dynamic hyperinflation (DH) may affect hemodynamics, predispose to barotrauma, increase work of breathing, cause dyspnea, disrupt patient-ventilator synchrony, confuse monitoring of hemodynamics and respiratory system mechanics, and interfere with the effectiveness of pressure-regulated ventilation. Although basic knowledge regarding the clinical physiology and management of AP during mechanical ventilation has evolved impressively over the 30 years since DH and AP were first brought to clinical attention, novel and clinically relevant characteristics of this complex phenomenon continue to be described. This discussion reviews some of the more important aspects of AP that bear on the care of the ventilated patient with critical illness.

Management of patients during and after exacerbations of chronic obstructive pulmonary disease: the role of primary care physicians

Current treatments have failed to stem the continuing rise in health care resource use and fatalities associated with exacerbations of chronic obstructive pulmonary disease (COPD). Reduction of severity and prevention of new exacerbations are therefore important in disease management, especially for patients with frequent exacerbations. Acute exacerbation treatment includes short-acting bronchodilators, systemic corticosteroids, and antibiotics if bacterial infections are present. Oxygen and/or ventilatory support may be necessary for life-threatening conditions. Rising health care costs have provided added impetus to find novel therapeutic approaches in the primary care setting to prevent and rapidly treat exacerbations before hospitalization is required. Proactive interventions may include risk reduction measures (eg, smoking cessation and vaccinations) to reduce triggers and supplemental pulmonary rehabilitation to prevent or delay exacerbation recurrence. Long-term treatment strategies should include individualized management, addressing coexisting nonpulmonary conditions, and the use of maintenance pharmacotherapies, eg, long-acting bronchodilators as monotherapy or in combination with inhaled corticosteroids to reduce exacerbations. Self-management plans that help patients recognize their symptoms and promptly access treatments have the potential to prevent exacerbations from reaching the stage that requires hospitalization.

Neuromodulatory effect of endogenous opioids on the intensity and unpleasantness of breathlessness during resistive load breathing in COPD

BACKGROUND

Endogenous opioids are naturally occurring peptides released by the brain in response to noxious stimuli. Although these naturally occurring peptides modulate pain, it is unknown whether endogenous opioids affect the perception of breathlessness associated with a specific respiratory challenge. The hypothesis is that intravenous administration of naloxone, used to block opioid signaling and inhibit neural pathways, will increase ratings of breathlessness during resistive load breathing (RLB) in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Fourteen patients with COPD (age, 64 ± 9 years) inspired through resistances during practice sessions to identify an individualized target load that caused ratings of intensity and/or unpleasantness of breathlessness ≥ 50 mm on a 100 mm visual analog scale. At two intervention visits, serum beta-endorphins were measured, naloxone (10 mg/25 ml) or normal saline (25 ml) was administered intravenously, and patients rated the two dimensions of breathlessness each minute during RLB.

RESULTS

Patient ratings of intensity (p = 0.0004) and unpleasantness (p = 0.024) of breathlessness were higher with naloxone compared with normal saline. Eleven patients (79%) reported that it was easier to breathe during RLB with normal saline (p = 0.025). RLB led to significant increases in serum beta-endorphin immunoreactivity and decreases in inspiratory capacity. There were no significant differences in physiological responses between interventions.

CONCLUSIONS

Endogenous opioids modulate the intensity and the unpleasantness of breathlessness in patients with COPD. Differences in breathlessness ratings between interventions were clinically relevant based on the patients' global assessment.

Budesonide and formoterol in a single pressurized metered-dose inhaler for treatment of COPD

Budesonide/formoterol in two dosage strengths (80/4.5 µg and 160/4.5 µg), each administered as two inhalations twice daily, was previously developed as a fixed-dose inhaled corticosteroid/long-acting β-agonist combination in a pressurized metered-dose inhaler for use in asthma. More recent double-blind, randomized controlled trials of 6 and 12 months duration (referred to, respectively, as SHINE and SUN) have demonstrated the efficacy and safety of the higher-dose formulation in patients with severe and very severe chronic obstructive pulmonary disease. Specifically, budesonide/formoterol 160/4.5 µg (two inhalations twice daily) has demonstrated additive benefits over one or the other of its monocomponents with respect to improvements in morning predose and 1-h postdose lung function, as well as greater improvements in respiratory symptoms, health status and rescue medication use, and greater reductions in exacerbations of chronic obstructive pulmonary disease than placebo. It also has a satisfactory safety profile and has not been shown to increase the risk of pneumonia.

Impact of tiotropium on the course of moderate-to-very severe chronic obstructive pulmonary disease: the UPLIFT trial

The Understanding Potential Long-term Improvements in Function with Tiotropium (UPLIFT) trial was a global 4-year randomized placebo-controlled clinical trial that evaluated the long-term impact of tiotropium bromide 18 microg once daily on the accelerated age-related decline in pre- and post-bronchodilator forced expiratory volume in 1 s (FEV(1); co-primary end points). Secondary end points included lung function at serial clinic visits, health-related quality of life, exacerbations, exacerbation-related hospitalizations, mortality, safety and tolerability. The study was carried out in 5992 patients (75% male, mean age 65 years, 30% current smokers) with moderate-to-very severe chronic obstructive pulmonary disease who were permitted to receive prescribed treatment with long-acting beta(2)-agonists and/or inhaled corticosteroids in addition to the study drug. While the results failed to show an effect of tiotropium on the primary end points (rate of decline in pre- and post-bronchodilator FEV(1)), they did show improvements in lung function and health-related quality of life that were maintained throughout the study and a reduction in the risk of exacerbations and related hospitalizations. Tiotropium also reduced all-cause mortality in patients on treatment over the 4-year trial period and reduced lower respiratory and cardiovascular morbidity, including respiratory failure and myocardial infarction. Adverse events were consistent with the drug's known anticholinergic pharmacology.

Inspiratory capacity and forced expiratory volume in the first second in exacerbation of chronic obstructive pulmonary disease

OBJECT

Periodic exacerbations of symptoms are the major cause of morbidity, mortality and health care costs in patients with chronic obstructive pulmonary disease (COPD). Dyspnea is the major factor affecting the comfort of patients in the exacerbation of COPD. In this study, we aimed to compare the value of forced expiratory volume in the first second (FEV(1)) and inspiratory capacity (IC) measured before and after treatment in exacerbations and in the improvement in dyspnea.

METHODS

Eighty-seven patients (male/female, 80/7; mean age, 63 +/- 7) with COPD exacerbation were included in this study. All subjects underwent spirometric tests on the first day and at the end of treatment. The subjects were asked to quantify the sensation of dyspnea that was described to them as a nonspecific discomfort associated with the act of breathing. The patients quantified dyspnea by pointing to a score on a large Borg scale from 0 to 10 arbitrary units. In the beginning and at the end of treatment, forced vital capacity (FVC), FEV(1), forced expiratory flow rate between 25% and 75% of FVC (FEF25-75), peak expiratory flow rate (PEF), IC and Borg score (BS) values were compared.

RESULTS

After treatment of COPD exacerbations, FEV(1), FEF25-75, PEF and IC significantly increased, and the BS significantly decreased compared to the initial values. The increase in IC was more significantly correlated with the improvement in BS compared with FEV(1). Admission and discharge day BS was negatively correlated with FEV(1), FEF25-75 and IC.

CONCLUSION

We have shown a more dramatic improvement in IC compared with FEV(1) in patients treated as a result of acute exacerbation of COPD. These data suggest that IC may be more useful than FEV(1) during acute exacerbation of COPD. Moreover, IC better reflects the severity of dyspnea in these patients.

Preventing and managing exacerbations in COPD--critical appraisal of the role of tiotropium

The course of COPD is punctuated by acute exacerbations that are associated with an increase in the morbidity and mortality related to this chronic disease and may contribute to its rate of progression. Therefore, preventing and treating exacerbations are major goals of COPD management. The role of tiotropium in the prevention of exacerbations has been investigated in several placebo-controlled randomized clinical trials varying in duration from 3 months to 4 years in patients with moderate to very severe COPD. In all of these trials, tiotropium has uniformly reduced the proportion of patients experiencing at least one exacerbation and delayed the time to the first exacerbation compared with placebo. In the longer trials (> or =6 months' duration) tiotropium has also reduced the exposure-adjusted incidence rate of exacerbations. In trials of at least 1 year in duration, tiotropium either significantly reduced the risk of hospitalization for an exacerbation and/or the proportion of patients with an exacerbation-related hospitalization. In a meta-analysis that included 15 trials of tiotropium vs either placebo (n = 13) and/or a long-acting beta-agonist (LABA; n = 4), tiotropium significantly reduced the odds of experiencing an exacerbation compared to placebo as well as a LABA. The potential additive benefits of tiotropium to those of a LABA and/or inhaled corticosteroid in reducing exacerbations require further investigation. The mechanism whereby tiotropium reduces exacerbations is not due to an anti-inflammatory effect but more likely relates to its property of causing a sustained increase in airway patency and reduction in hyperinflation, thereby counteracting the tendency for respiratory insults to worsen airflow obstruction and hyperinflation. For the management of acute exacerbations, an increase in short-acting inhaled bronchodilators is recommended as needed, while the potential role of long-acting bronchodilators, such as tiotropium, in conjunction with short-acting agents, is unclear and warrants further study.

Dyspnea and Activity Limitation in COPD: Mechanical Factors

Dyspnea and activity limitation are the primary symptoms of chronic obstructive pulmonary disease and progress relentlessly as the disease advances. In COPD, dyspnea is multifactorial but abnormal dynamic ventilatory mechanics are believed to be important. Dynamic lung hyperinflation occurs during exercise in the majority of flow-limited patients with chronic obstructive pulmonary disease and may have serious sensory and mechanical consequences. This proposition is supported by several studies, which have shown a close correlation between indices of dynamic lung hyperinflation and measures of both exertional dyspnea and exercise performance. The strength of this association has been further confirmed by studies that have therapeutically manipulated this dependent variable. Relief of exertional dyspnea and improved exercise endurance following bronchodilator therapy correlate well with reduced lung hyperinflation. The mechanisms by which dynamic lung hyperinflation give rise to exertional dyspnea and exercise intolerance are complex. However, recent mechanistic studies suggest that dynamic lung hyperinflation-induced volume restriction and consequent neuromechanical uncoupling of the respiratory system are key mechanisms. This review examines, in some detail, the derangements of ventilatory mechanics that are peculiar to chronic obstructive pulmonary disease and attempts to provide a mechanistic rationale for the attendant respiratory discomfort and activity limitation.

The efficacy and safety of cilomilast in COPD

The aim of this review is to present the clinical data on the efficacy and safety of cilomilast in patients with chronic obstructive pulmonary disease (COPD). Over 6000 COPD patients received cilomilast during an extensive clinical development programme performed by GlaxoSmithKline (GSK).Five phase III randomized, double-blind, placebo-controlled, parallel-group pivotal studies were conducted in poorly reversible patients (<15% or <200 mL improvement over baseline in forced expiratory volume in 1 second (FEV(1)) after salbutamol). Patients were randomized to receive oral cilomilast 15 mg (n = 2088) or placebo (n = 1408) twice daily for 24 weeks. The co-primary efficacy variables were changes from baseline in trough (predose) FEV(1) and in total score of the St George's Respiratory Questionnaire (SGRQ).Additional studies were performed to investigate the anti-inflammatory actions of cilomilast by measuring inflammatory cells and mediators in biopsies and induced sputum; to assess the long-term effects of cilomilast; to assess the cardiac safety of cilomilast; and to assess the efficacy of cilomilast on hyperinflation. Results from one of the phase III and from one supportive study have been previously published.In the phase III pivotal studies, when averaged over 24 weeks, the mean change from baseline in FEV(1) in the cilomilast group showed improvement compared with placebo in all studies (range 24-44 mL treatment difference). When averaged over 24 weeks, there was a similar improvement in the mean total SGRQ score in both treatment groups with a decrease ranging from -1.8 to -4.2 units in the cilomilast group and 0.4 to -4.9 units in the placebo group. Only one study, however, showed both a statistically and clinically meaningful difference between the two treatment groups (treatment difference -4.1 units; p < 0.001). Although cilomilast was shown to reduce COPD exacerbations in some of these studies, there was no effect on the incidence of COPD exacerbations in a study specifically powered to detect a difference compared with placebo.No significant change was found in the primary endpoints of the anti-inflammatory studies, although some anti-inflammatory activity was detected, including a reduction in tissue CD8+ T lymphocytes and CD68+ macrophages in airway biopsies. In addition, studies did not demonstrate a consistent significant effect of cilomilast on hyperinflation.In all studies, adverse events associated with the gastrointestinal body system were reported more frequently in the cilomilast group than the placebo group and predominantly occurred within the first 2 weeks of initiating cilomilast therapy.During the cilomilast development programme a number of different endpoints were investigated to characterize the efficacy and safety of this second-generation phosphodiesterase 4 inhibitor. Safety assessments throughout the late-phase programme did not reveal any evidence of serious safety concerns with the use of cilomilast. Previous studies in phase II and early phase III had shown improvements in efficacy endpoints and some evidence of an anti-inflammatory mechanism of action. However, subsequent phase III studies failed to definitively confirm the earlier programme results, which led to termination of the development of cilomilast.

[Dynamic lung hyperinflation and its clinical implication in COPD]

Static lung hyperinflation is defined as the elevation of end- expiratory lung volume above its predicted value, with no increase in end-expiratory alveolar pressure, which remains equal to atmospheric pressure. Dynamic hyperinflation is the transient increase of this volume above the relaxation volume. In patients with COPD, dynamic hyperinflation is mainly determined by the mechanical properties of the respiratory system. Its measurement relies on plethysmography and, during exercise, inspiratory capacity. During exercise, dynamic hyperinflation attenuates expiratory flow limitation but increases the inspiratory loading and induces functional weakness of the diaphragm. It also has haemodynamic consequences and results in more rapid, shallow breathing and progressive reduction in dynamic lung compliance. These events explain exercise intolerance. Several approaches may help combat dynamic hyperinflation and its deleterious clinical effects: bronchodilators, hyperoxia, helium-oxygen mixtures, lung volume reduction surgery...

Lung function changes following methacholine inhalation in COPD

BACKGROUND

The non-specific bronchial hyper-responsiveness reported in mild to moderate COPD is usually attributed to reduced airway calibre accentuating the effect of airway smooth muscle shortening. We hypothesized that in more severe COPD the fall in forced expiratory volume in 1 second (FEV(1)) seen during methacholine challenge would result from an increase in residual volume and decrease in vital capacity rather than an increase in airways resistance.

METHODS

Twenty-five subjects with moderate to severe COPD and 10 asthmatic subjects had spirometry and oscillatory mechanics measured before methacholine challenge and at a 20% fall from baseline post challenge (PC(20)FEV(1)).

RESULTS

In the COPD subjects median PC(20) was 0.35mg/mL. Comparing baseline to PC(20) there were significant falls in forced vital capacity (FVC) (2.91 vs. 2.2L; p<0.001), slow vital capacity (3.22 vs. 2.58L; p<0.001) and IC (2.21 vs. 1.75L; p<0.001) without change in FEV(1)/FVC ratio (0.52 vs. 0.52; not significant) or in total lung capacity where this was measured. Total respiratory system resistance (R(5)) was unchanged (0.66 vs. 0.68; not significant) but total respiratory system reactance decreased significantly (-0.33 vs. -0.44; p<0.001). In contrast, the asthmatics became more obstructed and showed a proportionally smaller fall in lung volume with increase in R(5) (0.43 vs. 0.64; p<0.01).

CONCLUSIONS

In moderate to severe COPD the fall in FEV(1) with methacholine is mainly due to increases in residual volume, which may represent airway closure and new-onset expiratory flow limitation.

Targeting the COPD exacerbation

Exacerbations of COPD have a profound detrimental effect on the patient and impose a significant burden on healthcare resource utilization. Prevention and treatment of exacerbations are major objectives of the clinical management of COPD. For this approach to be successful, clinicians must combine both pharmacologic approaches and non-pharmacologic strategies aimed at improving the patient's disease management. Non-pharmacologic approaches include those that can be incorporated into the office setting as well as intervention strategies that are integrated into the lifelong management of COPD. These strategies include developing a partnership with the patient and their social supports, encouraging and facilitating smoking cessation, immunizations, proper use of supplemental oxygen, and most importantly, giving the patient the tools to manage their illness appropriately. Moreover there is clear evidence of an irrevocable decline in pulmonary function after each exacerbation, usually resulting in reduced physical activity and impaired skeletal muscle function. Not surprisingly, pulmonary rehabilitation after such events has been shown to prevent relapse, improve survival and enhance patients' overall function after acute exacerbations.

Mechanisms of dyspnea in chronic lung disease

PURPOSE OF REVIEW

To discuss three emerging areas of research triggering new hypotheses for mechanisms of dyspnea.

RECENT FINDINGS

There has been an emphasis on the importance of lung volumes in evaluating symptoms and lung function in patients with chronic obstructive pulmonary disease. Dyspnea intensity seems to more closely correlate with measures of hyperinflation than airflow limitation, highlighting the importance of neuromechanical dissociation in the development of dyspnea. Inhaled furosemide has demonstrated a beneficial effect in laboratory-induced dyspnea, and the sensation of air hunger has been ameliorated by this therapy, possibly via activation of pulmonary stretch receptors. There appear to be distinct affective and sensory components of dyspnea, and the affective dimension may be modifiable, although this has not been fully studied.

SUMMARY

Dyspnea in chronic obstructive pulmonary disease is clearly related to hyperinflation, and lung volumes are valuable for characterizing disease. It remains unclear whether a limitation in tidal volume due to dynamic hyperinflation is the key factor in exertional dyspnea in this disease. Research of inhaled furosemide demonstrates the importance of afferent sensory input in modifying dyspnea, and deserves further study. The contributions of the affective and sensory components of dyspnea remain unclear, but should be studied further.

The volumetric response to bronchodilators in stable chronic obstructive pulmonary disease

A significant proportion of patients with COPD show post-bronchodilator improvement in lung volume even though this response is rarely considered when classifying subjects as having reversible or irreversible airway disease. We studied 266 patients with a clinical and physiological diagnosis of COPD who underwent pulmonary function testing and had their spirometric response to 5 mg salbutamol assessed. After the bronchodilator 125 (47%) patients increased their forced vital capacity by more than the known variability of the test while 60 (23%) showed only a volume response without improvement in expiratory flow. These 'volume responders' had greater degrees of airflow obstruction-lower FEV(1) (p < 0.001) and FEV(1)/FVC (p < 0.05)-and a higher residual volume at rest (p = 0.005) with similar degrees of emphysema measured by K(CO). Subjects with evidence of greater dynamic airway collapse, assessed by the ratio of early to mid expiratory flow, were less likely to have a flow response but more likely to have a volume response after salbutamol (p < 0.005). This would be compatible with volume response being commoner in patients who exhibit tidal expiratory flow limitation. We suggest that post-bronchodilator absolute change in FVC provides important additional physiological information when interpreting bronchodilator reversibility testing.

Inflammatory response in acute viral exacerbations of COPD

BACKGROUND

Respiratory viruses are important triggers of acute exacerbations of COPD (AE-COPD). However, the inflammatory response in virus-positive exacerbations is still not fully understood.

METHODS

We investigated CRP, IL-6, IL-8, IL-10, IFN-gamma, blood and sputum cells in patients with acute exacerbation (n = 36) and in stable disease (n = 20) and correlated these parameters to virus detection in respiratory secretions.

RESULTS

Similar to other studies we found a significant increase in systemic CRP and absolute numbers of blood leukocytes in AE-COPD patients. Sputum IL-6 levels and sputum eosinophils tended to be higher during exacerbation. In patients with detection of respiratory viruses in nasal lavage, local IL-6 production in sputum was significantly increased; FEV(1) was significantly decreased and both parameters were inversely correlated to each other.

CONCLUSION

This study supports previous findings of both, increased local and systemic inflammation in acute exacerbation of COPD. In virus-associated exacerbations, IL-6 is significantly increased and negatively correlated to FEV1 indicating a relation between virus-induced inflammation and airway obstruction. However, regarding our finding and previous data, it is becoming increasingly clear that the mediators investigated so far do not permit identifying the etiology of AE-COPD. Hence, further studies are needed to better define the inflammatory response in AE-COPD in general and in viral exacerbations in particular.

The airway response to deep inspirations decreases with COPD severity and is associated with airway distensibility assessed by computed tomography

In patients with mild chronic obstructive pulmonary disease (COPD), the effect of deep inspirations (DIs) to reverse methacholine-induced bronchoconstriction is largely attenuated. In this study, we tested the hypothesis that the effectiveness of DI is reduced with increasing disease severity and that this is associated with a reduction in the ability of DI to distend the airways. Fifteen subjects [Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I-II: n = 7; GOLD stage III-IV: n = 8] underwent methacholine bronchoprovocation in the absence of DI, followed by DI. The effectiveness of DI was assessed by their ability to improve inspiratory vital capacity and forced expiratory volume in 1 s (FEV(1)). To evaluate airway distensibility, two sets of high-resolution computed tomography scans [at residual volume (RV) and at total lung capacity] were obtained before the challenge. In addition, mean parenchymal density was calculated on the high-resolution computed tomography scans. We found a strong correlation between the response to DI and baseline FEV(1) %predicted (r(2) = 0.70, P < 0.0001) or baseline FEV(1)/forced vital capacity (r(2) = 0.57, P = 0.001). RV %predicted and functional residual capacity %predicted correlated inversely (r(2) = 0.33, P = 0.02 and r(2) = 0.32, P = 0.03, respectively), and parenchymal density at RV correlated directly (r(2) = 0.30, P = 0.03), with the response to DI. Finally, the effect of DI correlated to the change in large airway area from RV to total lung capacity (r(2) = 0.44, P = 0.01). We conclude that loss of the effects of DI is strongly associated with COPD severity and speculate that the reduction in the effectiveness of DI is due to the failure to expand the lungs because of the hyperinflated state and/or the parenchymal damage that prevents distension of the airways with lung inflation.

Hyperinflation and its management in COPD

Chronic obstructive pulmonary disease (COPD) is characterized by poorly reversible airflow limitation. The pathological hallmarks of COPD are inflammation of the peripheral airways and destruction of lung parenchyma or emphysema. The functional consequences of these abnormalities are expiratory airflow limitation and dynamic hyperinflation, which then increase the elastic load of the respiratory system and decrease the performance of the respiratory muscles. These pathophysiologic features contribute significantly to the development of dyspnea, exercise intolerance and ventilatory failure. Several treatments may palliate flow limitation, including interventions that modify the respiratory pattern (deeper, slower) such as pursed lip breathing, exercise training, oxygen, and some drugs. Other therapies are aimed at its amelioration, such as bronchodilators, lung volume reduction surgery or breathing mixtures of helium and oxygen. Finally some interventions, such as inspiratory pressure support, alleviate the threshold load associated to flow limitation. The degree of flow limitation can be assessed by certain spirometry indexes, such as vital capacity and inspiratory capacity, or by other more complexes indexes such as residual volume/total lung capacity or functional residual capacity/total lung capacity. Two of the best methods to measure flow limitation are to superimpose a flow–volume loop of a tidal breath within a maximum flow–volume curve, or to use negative expiratory pressure technique. Likely this method is more accurate and can be used during spontaneous breathing. A definitive definition of dynamic hyperinflation is lacking in the literature, but serial measurements of inspiratory capacity during exercise will document the trend of end-expiratory lung volume and allow establishing relationships with other measurements such as dyspnea, respiratory pattern, exercise tolerance, and gas exchange.

Role of macrolide therapy in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of death and disability worldwide. The Global Burden of Disease study has concluded that COPD will become the third leading cause of death worldwide by 2020, and will increase its ranking of disability-adjusted life years lost from 12th to 5th. Acute exacerbations of COPD (AECOPD) are associated with impaired quality of life and pulmonary function. More frequent or severe AECOPDs have been associated with especially markedly impaired quality of life and a greater longitudinal loss of pulmonary function. COPD and AECOPDs are characterized by an augmented inflammatory response. Macrolide antibiotics are macrocyclical lactones that provide adequate coverage for the most frequently identified pathogens in AECOPD and have been generally included in published guidelines for AECOPD management. In addition, they exert broad-ranging, immunomodulatory effects both in vitro and in vivo, as well as diverse actions that suppress microbial virulence factors. Macrolide antibiotics have been used to successfully treat a number of chronic, inflammatory lung disorders including diffuse panbronchiolitis, asthma, noncystic fibrosis associated bronchiectasis, and cystic fibrosis. Data in COPD patients have been limited and contradictory but the majority hint to a potential clinical and biological effect. Additional, prospective, controlled data are required to define any potential treatment effect, the nature of this effect, and the role of bronchiectasis, baseline colonization, and other cormorbidities.

Pathogen-directed therapy in acute exacerbations of chronic obstructive pulmonary disease

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are important events in the natural history of this chronic lung disorder. These events can be caused by a large number of infectious and noninfectious agents and are associated with an increased local and systemic inflammatory response. Their frequency and severity have been linked to progressive deterioration in lung function and health status. Infectious pathogens ranging from viral to atypical and typical bacteria have been implicated in the majority of episodes. Most therapeutic regimens to date have emphasized broad, nonspecific approaches to bronchoconstriction and pulmonary inflammation. Increasingly, therapy that targets specific etiologic pathogens has been advocated. These include clinical and laboratory-based methods to identify bacterial infections. Further additional investigation has suggested specific pathogens within this broad class. As specific antiviral therapies become available, better diagnostic approaches to identify specific pathogens will be required. Furthermore, prophylactic therapy for at-risk individuals during high-risk times may become a standard therapeutic approach. As such, the future will likely include aggressive diagnostic algorithms based on the combination of clinical syndromes and rapid laboratory modalities to identify specific causative bacteria or viruses.

What have we learned from large drug treatment trials in COPD?

Although the development of effective treatments for patients with chronic obstructive pulmonary disease (COPD) has not been seen as a high priority, the past decade has seen a substantial increase in the number of clinical studies examining different treatments for this disease. Large studies are needed to adequately assess the effectiveness of treatment because of the chronic nature of the disease and the intermittent occurrence of some key outcomes such as exacerbations. Data from randomised controlled trials show that treatment improves exercise performance by increasing lung volume rather than changing expiratory flow. Although assessment of lung function remains the cornerstone of drug assessment, improvements in health status, the number of exacerbations and admissions to hospital are now recognised as important treatment outcomes. Randomised controlled trial data provide the best evidence for treatment efficacy, but results of these studies can be affected by differences in inclusion criteria and patient dropout during the study. Bronchodilator reversibility testing does not reliably define subgroups that will respond to a particular treatment. Carefully done and adequately powered clinical trials continue to inform, not only our views about treatment, but also our understanding of COPD and how it is best assessed and managed. Ensuring that these expensive studies are done objectively to the highest standard is an important goal for the next decade.

Canadian Thoracic Society recommendations for management of chronic obstructive pulmonary disease - 2007 update

Chronic obstructive pulmonary disease (COPD) is a major respiratory illness in Canada that is both preventable and treatable. Our understanding of the pathophysiology of this complex condition continues to grow and our ability to offer effective treatment to those who suffer from it has improved considerably. The purpose of the present educational initiative of the Canadian Thoracic Society (CTS) is to provide up to date information on new developments in the field so that patients with this condition will receive optimal care that is firmly based on scientific evidence. Since the previous CTS management recommendations were published in 2003, a wealth of new scientific information has become available. The implications of this new knowledge with respect to optimal clinical care have been carefully considered by the CTS Panel and the conclusions are presented in the current document. Highlights of this update include new epidemiological information on mortality and prevalence of COPD, which charts its emergence as a major health problem for women; a new section on common comorbidities in COPD; an increased emphasis on the meaningful benefits of combined pharmacological and nonpharmacological therapies; and a new discussion on the prevention of acute exacerbations. A revised stratification system for severity of airway obstruction is proposed, together with other suggestions on how best to clinically evaluate individual patients with this complex disease. The results of the largest randomized clinical trial ever undertaken in COPD have recently been published, enabling the Panel to make evidence-based recommendations on the role of modern pharmacotherapy. The Panel hopes that these new practice guidelines, which reflect a rigorous analysis of the recent literature, will assist caregivers in the diagnosis and management of this common condition.

The Biology of a Chronic Obstructive Pulmonary Disease Exacerbation

Much of the morbidity and mortality in chronic obstructive pulmonary disease relates to symptomatic deteriorations in respiratory health termed exacerbations. Exacerbations also are associated with changes in lung function and both airway and systemic inflammation. The most common causes of exacerbation are micro-organisms: respiratory viruses such as rhinovirus, and various bacterial species. This article reviews and discusses current understanding of the biology of exacerbations, considering the definition, epidemiology, etiology, and the nature and evolution of the changes in symptoms, lung function, and inflammation that characterize these important events.

COPD exacerbations: defining their cause and prevention

Exacerbations of chronic obstructive pulmonary disease (COPD) are episodes of worsening of symptoms, leading to substantial morbidity and mortality. COPD exacerbations are associated with increased airway and systemic inflammation and physiological changes, especially the development of hyperinflation. They are triggered mainly by respiratory viruses and bacteria, which infect the lower airway and increase airway inflammation. Some patients are particularly susceptible to exacerbations, and show worse health status and faster disease progression than those who have infrequent exacerbations. Several pharmacological interventions are effective for the reduction of exacerbation frequency and severity in COPD such as inhaled steroids, long-acting bronchodilators, and their combinations. Non-pharmacological therapies such as pulmonary rehabilitation, self-management, and home ventilatory support are becoming increasingly important, but still need to be studied in controlled trials. The future of exacerbation prevention is in assessment of optimum combinations of pharmacological and non-pharmacological therapies that will result in improvement of health status, and reduction of hospital admission and mortality associated with COPD.

Gas exchange response to short-acting beta2-agonists in chronic obstructive pulmonary disease severe exacerbations

RATIONALE

Short-acting beta(2)-agonists are one of the mainstays of bronchodilator strategy for exacerbations of chronic obstructive pulmonary disease (COPD). The assessment of pulmonary gas exchange after salbutamol in COPD severe exacerbations remains unknown.

OBJECTIVES

We investigated whether the effects of nebulized salbutamol during COPD severe exacerbations are associated with further deterioration of pulmonary gas exchange.

METHODS

We examined patients with severe COPD when hospitalized for exacerbation (n = 9), and while in stable convalescence.

MEASUREMENTS AND MAIN RESULTS

We assessed spirometry, arterial blood gases, systemic hemodynamics, and V/Q relationships 30 and 90 minutes after administration of 5.0 mg salbutamol. At exacerbation, compared with baseline, 30 minutes after salbutamol administration, cardiac output (Q) increased (from 6.5 +/- [SEM] 0.4 to 7.3 +/- 0.5 L . min(-1)) (p < 0.03) alone, without inducing changes in gas exchange indices. When in convalescence, compared with baseline, 30 minutes after salbutamol, there was an increase in Q (from 5.7 +/- 0.5 to 7.0 +/- 0.6 L . min(-1)) and Vo(2) (from 211 +/- 12 to 232 +/- 11 ml . min(-1)) (p < 0.002 each), whereas Pa(O(2)) decreased (from 71 +/- 4 to 63 +/- 3 mm Hg) and alveolar-arterial Po(2) difference increased due to increased perfusion of low-V/Q-ratio regions (from 4.5 +/- 2.6 to 9.6 +/- 4.1% of Q) (p < 0.05); Sa(O(2)) (93 +/- 2%) and Pa(CO(2)) (43 +/- 2 mm Hg) remained unchanged. This deleterious gas exchange response persisted at 90 minutes.

CONCLUSIONS

At exacerbation, salbutamol does not aggravate pulmonary gas exchange abnormalities. When in convalescence, however, baseline lung function improvement was associated with a detrimental gas exchange response to salbutamol, resulting in further V/Q imbalance and small decreases in Pa(O(2)) compounded by small increases in Q and Vo(2).

The clinical importance of dynamic lung hyperinflation in COPD

Lung hyperinflation commonly accompanies expiratory flow-limitation in patients with Chronic Obstructive Pulmonary Disease (COPD) and contributes importantly to dyspnea and activity limitation. It is not surprising, therefore, that lung hyperinflation has become an important therapeutic target in symptomatic COPD patients. There is increasing evidence that acute dynamic increases in lung hyperinflation, under conditions of worsening expiratory flow-limitation and increased ventilatory demand (or both) can seriously stress cardiopulmonary reserves, particularly in patients with more advanced disease. Our understanding of the physiological mechanisms of dynamic lung hyperinflation during both physical activity and exacerbations in COPD continues to grow, together with an appreciation of its serious negative mechanical and sensory consequences. In this review, we will discuss the basic pathophysiology of COPD during rest, exercise and exacerbation so as to better understand how this can be pharmacologically manipulated for the patient's benefit. Finally, we will review current concepts of the mechanisms of symptom relief and improved exercise endurance following pharmacological lung volume reduction.

Évolution de la capacité inspiratoire au cours de la BPCO décompensée

INTRODUCTION

Inspiratory Capacity (IC), which reflects dynamic pulmonary hyperinflation, correlates with outcome in moderate exacerbation of COPD. Whether this is also true in COPD with acute respiratory failure (ARF) has not been studied.

METHODS

A prospective multicenter assessment of IC measurement feasibility, reliability, time-course and relationship to outcome in COPD with ARF was conducted. Dyspnea (visual analogue scale) and IC were repeatedly measured. Outcome was classified as not favourable (death or intubation or non invasive ventilation increased or patient referred to ICU from respiratory ward) or favourable (none of the above criteria).

RESULTS

Fifty patients were included and 48 analysed. IC measurement was possible in all but one patient and its coefficient of variation was 9+/-8%. Between inclusion into the study and discharge, IC increased from 39.9+/-15.5 to 50.2+/-14.5% pred (p<0.001) and dyspnea declined from 48+/-23 to 33+/-22 mm (p<0.001). Inclusion IC was not different on average between patients with or without favourable outcome.

CONCLUSION

In COPD patients with ARF, IC measurement at bedside was feasible and reproducible. IC was low at entry and increased over time from inclusion to discharge tending to correlate with patient outcome.

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.

Systemic Cytokines, Clinical and Physiological Changes in Patients Hospitalized for Exacerbation of COPD

BACKGROUND

Systemic inflammation in patients with COPD may worsen during exacerbations, but there is limited information relating levels of systemic inflammatory markers with symptoms and physiologic changes during an exacerbation

METHODS

We measured dyspnea using the visual analog scale, pulmonary function tests, hemograms, and plasma levels for interleukin (IL)-6, IL-8, leukotriene B(4) (LTB4), tumor necrosis factor-alpha, and secretory leukocyte protease inhibitor (SLPI) in 20 patients on admission to a hospital for exacerbation of COPD (ECOPD), 48 h later (interim), and 8 weeks after hospital discharge (recovery).

RESULTS

Dyspnea was present in all patients. Inspiratory capacity improved faster than FEV(1). Compared to recovery, there was a significant increase in the mean (+/- SD) hospital admission plasma levels of IL-6 (6.38 +/- 0.72 to 2.80 +/- 0.79 pg/mL; p = 0.0001), IL-8 (8.18 +/- 0.85 to 3.72 +/- 0.85 pg/mL; p = 0.002), and LTB4 (8,675 +/- 1,652 to 2,534 +/- 1,813 pg/mL; p = 0.003), and the percentages of segmented neutrophils (79 to 69%; p < 0.02) and band forms (7.3 to 1.0%; p < 0.01) in peripheral blood, with no changes in TNF-alpha and SLPI. There were significant correlations between changes in IL-6 (r = 0.61; p = 0.01) and IL-8 (r = 0.56; p = 0.04) with changes in dyspnea and levels of IL-6 (r = -0.51; p = 0.04) and TNF-alpha (r = -0.71; p < 0.02) with changes in FEV(1.)

CONCLUSIONS

Hospitalized patients with ECOPDs experience significant changes in systemic cytokine levels that correlate with symptoms and lung function. An ECOPD represents not only a worsening of airflow obstruction but also increased systemic demand in a host with limited ventilatory reserve.

Measurement of physiological recovery from exacerbation of chronic obstructive pulmonary disease using within-breath forced oscillometry

BACKGROUND

Within-breath reactance from forced oscillometry estimates resistance via its inspiratory component (X(rs,insp)) and flow limitation via its expiratory component (X(rs,exp)).

AIM

To assess whether reactance can detect recovery from an exacerbation of chronic obstructive pulmonary disease (COPD).

METHOD

39 subjects with a COPD exacerbation were assessed on three occasions over 6 weeks using post-bronchodilator forced oscillometry, arterial blood gases, spirometry including inspiratory capacity, symptoms and health-related quality of life (HRQOL).

RESULTS

Significant improvements were seen in all spirometric variables except the ratio of forced expiratory volume in 1 s (FEV(1)) to vital capacity, ranging in mean (SEM) size from 11.0 (2.2)% predicted for peak expiratory flow to 12.1 (2.3)% predicted for vital capacity at 6 weeks. There was an associated increase in arterial partial pressure of oxygen (PaO(2)). There were significant mean (SEM) increases in both X(rs,insp) and X(rs,exp) (27.4 (6.7)% and 37.1 (10.0)%, respectively) but no change in oscillometry resistance (R(rs)) values. Symptom scales and HRQOL scores improved. For most variables, the largest improvement occurred within the first week with spirometry having the best signal-to-noise ratio. Changes in symptoms and HRQOL correlated best with changes in FEV(1), PaO(2) and X(rs,insp).

CONCLUSIONS

The physiological changes seen following an exacerbation of COPD comprised both an improvement in operating lung volumes and a reduction in airway resistance. Given the ease with which forced oscillometry can be performed in these subjects, measurements of X(rs,insp) and X(rs,exp) could be useful for tracking recovery.

COPD exacerbations.5: management

A review of the most relevant evidence based therapeutic options currently available for the management of exacerbations of COPD.

Novel insights into the aetiology and pathophysiology of increased airway inflammation during COPD exacerbations

Airway inflammation increases during acute exacerbations of COPD. Extrinsic factors, such as airway infections, increased air pollution, and intrinsic factors, such as increased oxidative stress and altered immunity may contribute to this increase. The evidence for this and the potential mechanisms by which various aetiological agents increase inflammation during COPD exacerbations is reviewed. The pathophysiologic consequences of increased airway inflammation during COPD exacerbations are also discussed. This review aims to establish a cause and effect relationship between etiological factors of increased airway inflammation and COPD exacerbations based on recently published data. Although it can be speculated that reducing inflammation may prevent and/or treat COPD exacerbations, the existing anti-inflammatory treatments are modestly effective.

COPD exacerbations . 3: Pathophysiology

Exacerbations of chronic obstructive pulmonary disease (COPD) are associated with increased morbidity and mortality. The effective management of COPD exacerbations awaits a better understanding of the underlying pathophysiological mechanisms that shape its clinical expression. The clinical presentation of exacerbations of COPD is highly variable and ranges from episodic symptomatic deterioration that is poorly responsive to usual treatment, to devastating life threatening events. This underscores the heterogeneous physiological mechanisms of this complex disease, as well as the variation in response to the provoking stimulus. The derangements in ventilatory mechanics, muscle function, and gas exchange that characterise severe COPD exacerbations with respiratory failure are now well understood. Critical expiratory flow limitation and the consequent dynamic lung hyperinflation appear to be the proximate deleterious events. Similar basic mechanisms probably explain the clinical manifestations of less severe exacerbations of COPD, but this needs further scientific validation. In this review we summarise what we have learned about the natural history of COPD exacerbations from clinical studies that have incorporated physiological measurements. We discuss the pathophysiology of clinically stable COPD and examine the impact of acutely increased expiratory flow limitation on the compromised respiratory system. Finally, we review the chain of physiological events that leads to acute ventilatory insufficiency in severe exacerbations.