The role of infection in COPD

Molecular Accounting and Profiling of Human Respiratory Microbial Communities: Toward Precision Medicine by Targeting the Respiratory Microbiome for Disease Diagnosis and Treatment

The wide diversity of microbiota at the genera and species levels across sites and individuals is related to various causes and the observed differences between individuals. Efforts are underway to further understand and characterize the human-associated microbiota and its microbiome. Using 16S rDNA as a genetic marker for bacterial identification improved the detection and profiling of qualitative and quantitative changes within a bacterial population. In this light, this review provides a comprehensive overview of the basic concepts and clinical applications of the respiratory microbiome, alongside an in-depth explanation of the molecular targets and the potential relationship between the respiratory microbiome and respiratory disease pathogenesis. The paucity of robust evidence supporting the correlation between the respiratory microbiome and disease pathogenesis is currently the main challenge for not considering the microbiome as a novel druggable target for therapeutic intervention. Therefore, further studies are needed, especially prospective studies, to identify other drivers of microbiome diversity and to better understand the changes in the lung microbiome along with the potential association with disease and medications. Thus, finding a therapeutic target and unfolding its clinical significance would be crucial.

Mediastinitis in open heart surgery: a systematic review and meta-analysis of risk factors

Objective. We aimed to summarize the evidence from observational studies examining the risk factors of the incidence of mediastinitis in open heart surgery. Design. The study was a systematic review and meta-analysis of cohorts and case-control studies. Material and methods. We searched the literature and 74 studies with at least one risk factor were identified. Both fixed and random effects models were used. Heterogeneity between studies was examined by subgroup and meta-regression analysis. Publication bias or small study effects were evaluated and corrected by limit meta-analysis. Results. When correcting for small study effect, presence of obesity as estimated from 43 studies had Odds Ratio OR = 2.26. (95% CI: 2.17-2.36). This risk was increasing with decreasing latitude of study place. Presence of diabetes mellitus from 63 studies carried an OR = 1.90 (95% CI: 1.59-2.27). Presence of Chronic Obstructive Pulmonary Disease (COPD) from 30 studies had an OR = 2.59 (95% CI: 2.22-2.85). Presence of bilateral intramammary graft (BIMA) from 23 studies carried an OR = 2.54 (95% CI: 2.07-3.13). This risk was increasing with increasing frequency of female patients in the study population. Conclusion. Evidence from this study showed the robustness of the risk factors in the pathogenesis of mediastinitis. Preventive measures can be implemented for reducing obesity, especially in lower latitude countries. Furthermore, it is mandatory to monitor perioperative hyperglycemias with continuous insulin infusion. Use of skeletonized BIMA carries higher risk of mediastinitis especially in female patients without evidence of beneficial effect on survival for the time being.

Haemophilus influenzae uses the surface protein E to acquire human plasminogen and to evade innate immunity

Pathogenic microbes acquire the human plasma protein plasminogen to their surface. In this article, we characterize binding of this important coagulation regulator to the respiratory pathogen nontypeable Haemophilus influenzae and identify the Haemophilus surface protein E (PE) as a new plasminogen-binding protein. Plasminogen binds dose dependently to intact bacteria and to purified PE. The plasminogen-PE interaction is mediated by lysine residues and is also affected by ionic strength. The H. influenzae PE knockout strain (nontypeable H. influenzae 3655Δpe) bound plasminogen with ∼65% lower intensity as compared with the wild-type, PE-expressing strain. In addition, PE expressed ectopically on the surface of Escherichia coli also bound plasminogen. Plasminogen, either attached to intact H. influenzae or bound to PE, was accessible for urokinase plasminogen activator. The converted active plasmin cleaved the synthetic substrate S-2251, and the natural substrates fibrinogen and C3b. Using synthetic peptides that cover the complete sequence of the PE protein, the major plasminogen-binding region was localized to a linear 28-aa-long N-terminal peptide, which represents aa 41-68. PE binds plasminogen and also vitronectin, and the two human plasma proteins compete for PE binding. Thus, PE is a major plasminogen-binding protein of the Gram-negative bacterium H. influenzae, and when converted to plasmin, PE-bound plasmin aids in immune evasion and contributes to bacterial virulence.

Antibiotic resistance in sputum isolates of Streptococcus pneumoniae in chronic obstructive pulmonary disease is related to antibiotic exposure

Streptococcus pneumoniae (S. pneumoniae) is recovered from sputum of patients with chronic obstructive pulmonary disease (COPD) during stable disease and exacerbations. In patients with community acquired pneumonia, antibiotic exposure in the prior 3-6 months is associated with recovery of antibiotic resistant isolates of S. pneumoniae. Whether the same relationship is seen in COPD is not known. From April 1994 to June 2004, 127 adults with COPD were enrolled in a prospective longitudinal study. Sputum isolates of S. pneumoniae were characterized with susceptibility testing and pulsed-field gel electrophoresis (PFGE). The relationship between antibiotic use in the previous 3 and 6 months with either new acquisition of a resistant pneumococcal isolate or development of resistance (4-fold increase in MIC) in a pre-existing colonizing pneumococcal strain was determined. A total of 194 pneumococcal isolates were recovered from 38 patients. Among 71 newly acquired and 4 resistance-emergent strains analyzed further, rates of resistance to penicillin (MIC ≥2), erythromycin (MIC ≥1), tetracycline (MIC ≥8) and trimethoprim/sulfamethoxazole (MIC ≥4) were 8%, 24%, 17% and 16% respectively. Flouroquinolone resistance was not seen. Among strains isolated from patients exposed to a macrolide within 6 months, 53.6% displayed erythromycin resistance vs. 14% of strains without such exposure (p = 0.00085). Similar associations were not seen for other antibiotics. Macrolide use in the previous 6 months is associated with macrolide resistance in sputum isolates of S. pneumoniae. Recent antibiotic exposure may help in determining appropriate antibiotic treatment in these patients.

Pseudomonas aeruginosa in adults with chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Pseudomonas aeruginosa is isolated in sputum cultures from adults with chronic obstructive pulmonary disease (COPD) but the significance of the organism in this clinical setting is not well known. The purpose of this review is to critically review the literature in an effort to understand the role of P. aeruginosa in the course and pathogenesis of COPD.

RECENT FINDINGS

When examined longitudinally, two distinct patterns of carriage of P. aeruginosa are observed in adults with COPD: short-term colonization followed by clearance and long-term persistence. Acquisition of P. aeruginosa is associated with the occurrence of an exacerbation, indicating that the organism causes exacerbations. Exacerbations caused by P. aeruginosa are more likely to be seen in patients with more advanced COPD, those who have received recent antibiotic therapy and those who require mechanical ventilation for an exacerbation. A subset of adults with COPD becomes chronically colonized with P. aeruginosa, but whether such patients benefit from antimicrobial therapy is not yet known.

SUMMARY

P. aeruginosa has several different manifestations in the setting of COPD. The organism is a colonizer that is cleared quickly, causes acute exacerbations and also may cause chronic infection in a subset of adults with COPD.

Infections

This chapter reviews the epidemiological evidence implicating infectious pathogens as triggers and will discuss the mechanisms of interaction between the host–pathogen response and preexisting airway pathology that result in an exacerbation. Asthma is a multifaceted syndrome involving atopy, bronchial hyperreactivity, and IgE and non-IgE-mediated acute and chronic immune responses. The asthmatic airway is characterized by an infiltrate of eosinophils and of T-lymphocytes expressing the type 2 cytokines IL-4, IL-5, and IL-13. Trigger factors associated with acute exacerbations of asthma include exposure to environmental allergens, especially animals, molds, pollens and mites, cold, exercise, and drugs. The frequency of exacerbations is a major factor in the quality of life of patients with COPD. The typical clinical features of an exacerbation include increased dyspnea, wheezing, cough, sputum production, and worsened gas exchange. Although noninfectious causes of exacerbations such as allergy, air pollution, or inhaled irritants including cigarette smoke may be important, acute airway infections are the major precipitants. The infection and consequent host inflammatory response result in increased airway obstruction. The success of vaccination to prevent respiratory virus infections has been limited by significant variation within the major virus types causing disease. Currently much of the treatment of infective exacerbations of asthma and COPD is symptomatic, consisting of increased bronchodilators, either short-acting β 2—agonists in inhaled or intravenous form or anticholinergics or theophyllines, or supportive in the form of oxygen and in severe cases noninvasive or invasive ventilatory measures.

Pseudomonas aeruginosa in chronic obstructive pulmonary disease

RATIONALE

Pseudomonas aeruginosa is isolated from adults with chronic obstructive pulmonary disease (COPD) in cross-sectional studies. However, patterns of carriage and the role of P. aeruginosa in COPD are unknown.

OBJECTIVES

To elucidate carriage patterns, phenotypes of strains, clinical manifestations, and the antibody response to P. aeruginosa in COPD.

METHODS

A prospective study of adults with COPD was conducted. Isolates of P. aeruginosa were subjected to genotypic and phenotypic analysis. Sputum samples were studied for P. aeruginosa DNA, and immune responses were assayed.

MEASUREMENTS AND MAIN RESULTS

We analyzed longitudinal clinical data, sputum cultures, pulsed-field gel electrophoresis of bacterial DNA, polymerase chain reaction of sputum, and immunoblot assays of serum. Fifty-seven episodes of acquisition of strains of P. aeruginosa were observed in 39 of 126 patients over 10 years. Acquisition of a new strain was associated with exacerbation. Thirty-one episodes of carriage were followed by clearance of the strain; 16 were of short (<1 mo) duration. Thirteen strains demonstrated persistence, and 13 strains were of indeterminate duration. Six strains were mucoid and were more likely to persist than nonmucoid strains (P = 0.005). Antibody responses developed in 53.8% of persistent carriage and in only 9.7% of short-term carriage episodes (P = 0.003). Antibiotics did not account for clearance.

CONCLUSIONS

Two distinct patterns of carriage by P. aeruginosa were observed: (1) short-term colonization followed by clearance and (2) long-term persistence. Mucoid strains showed persistence. Acquisition of P. aeruginosa is associated with the occurrence of an exacerbation. Serum antibody responses do not mediate clearance of P. aeruginosa.

Vaccine development for non-typeable Haemophilus influenzae and Moraxella catarrhalis: progress and challenges

An urgent need exists for vaccines to prevent infections caused by nontypeable Haemophilus influenzae and Moraxella catarrhalis. These bacteria cause otitis media in children, a clinical problem associated with enormous morbidity and cost. H. influenzae and M. catarrhalis also cause lower respiratory tract infections in adults with chronic lung disease. Infections in this clinical setting are associated with disability and death. Recent progress in identifying potential vaccine antigens in both bacteria raises great promise in developing effective vaccines. This paper reviews the key issues in vaccine development for H. influenzae and M. catarrhalis, including areas where progress has been stalled, and proposes areas that deserve investigation in the next 5 years.

The role of quinolones in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a disease state characterized by the presence of airflow obstruction due to chronic bronchitis and/or emphysema. The airflow obstruction is generally progressive. In the past asthma was often confused with chronic obstructive pulmonary disease but as the cellular inflammatory mechanisms are quite different to chronic bronchitis and emphysema it is prudent to separate this condition of airway hyper-responsiveness. Exacerbation of chronic obstructive pulmonary disease is a considerable burden on health service resources in terms of morbidity and mortality. Approximately one half of exacerbations can be attributed to bacterial pathogens, the major pathogens being Haemophilus influenzae, Streptococcus pnemoniae and Moraxella catarrhalis. Resistance to common first-line treatment antibiotics such as the beta-lactams can be variable. Newer fluoroquinolones such as grepafloxacin, levofloxacin, sparfloxacin, clinafloxacin, moxifloxacin, gatifloxacin and gemifloxacin are characterized by improved activity against Gram positive bacteria as well as their Gram negative properties. However, more randomized controlled trials need to be accomplished before the true role of quinolones in exacerbation of chronic obstructive pulmonary disease is clearly ascertained.

Interaction with C4b-binding protein contributes to nontypeable Haemophilus influenzae serum resistance

Complement evasion by various mechanisms is important for microbial virulence and survival in the host. One strategy used by some pathogenic bacteria is to bind the complement inhibitor of the classical pathway, C4b-binding protein (C4BP). In this study, we have identified a novel interaction between nontypeable Haemophilus influenzae (NTHi) and C4BP, whereas the majority of the typeable H. influenzae (a-f) tested showed no binding. One of the clinical isolates, NTHi 506, displayed a particularly high binding of C4BP and was used for detailed analysis of the interaction. Importantly, a low C4BP-binding isolate (NTHi 69) showed an increased deposition of C3b followed by reduced survival as compared with NTHi 506 when exposed to normal human serum. The main isoform of C4BP contains seven identical alpha-chains and one beta-chain linked together with disulfide bridges. Each alpha-chain is composed of eight complement control protein (CCP) modules and we have found that the NTHi 506 strain did not interact with rC4BP lacking CCP2 or CCP7 showing that these two CCPs are important for the binding. Importantly, C4BP bound to the surface of H. influenzae retained its cofactor activity as determined by analysis of C3b and C4b degradation. Taken together, NTHi interferes with the classical complement activation pathway by binding to C4BP.

Factors associated with hospital admission among emergency department patients with chronic obstructive pulmonary disease exacerbation

OBJECTIVES To determine the patient factors associated with hospital admission among adults who present to the emergency department (ED) with acute exacerbations of chronic obstructive pulmonary disease (COPD) and to determine whether admissions were concordant with recommendations in the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines.

METHODS

The authors performed a prospective multicenter cohort study involving 29 EDs in the United States and Canada. By using a standard protocol, consecutive ED patients with COPD exacerbation were interviewed, and their charts were reviewed. Predictors of admission were determined by multivariate logistic regression.

RESULTS

Of 384 patients, 233 (61%; 95% confidence interval = 56% to 66%) were admitted. Multivariate analysis showed that a higher likelihood of admission was associated with older age, female gender, more pack-years of smoking, recent use of inhaled corticosteroid, self-reported activity limitation in the past 24 hours, higher respiratory rate at ED presentation, and a concomitant diagnosis of pneumonia. Patients who reported the ED as their usual site for problem COPD care, or who had mixed COPD and asthma, were less likely to be admitted. The authors confirmed five of the seven testable indications for hospital admission in the GOLD guidelines.

CONCLUSIONS

Several patient factors were independently associated with hospital admission among ED patients with COPD exacerbations. Overall, concordance with admission recommendations in the GOLD guidelines was high. The authors also identified a few novel predictors of admission (female gender, ED as the usual site for problem COPD care, mixed diagnosis of COPD and asthma, recent use of inhaled corticosteroid) that require replication in future studies.

Bronchitis

Bronchitis is characterized by bronchial inflammation that results in …

Antigenic specificity of the mucosal antibody response to Moraxella catarrhalis in chronic obstructive pulmonary disease

Moraxella catarrhalis is an important human mucosal pathogen causing otitis media in children and lower respiratory tract infection in adults with chronic obstructive pulmonary disease (COPD). Little is known about the mucosal antibody response to M. catarrhalis in adults with COPD. In this study, 10 pairs of well-characterized sputum supernatant samples from adults with COPD who had acquired and subsequently cleared M. catarrhalis from their respiratory tracts were studied in detail in an effort to begin to elucidate potentially protective immune responses. Flow cytometry analysis was used to study the distribution of immunoglobulin isotypes in paired preacquisition and postclearance sputum samples. The results showed that immunoglobulin A (IgA) is the predominant M. catarrhalis-specific immunoglobulin isotype and that the sputum IgA contains a secretory component, indicating that it is locally produced at the mucosal site. Most patients made new sputum IgA responses to the adhesins UspA1 and Hag, along with the surface protein UspA2. A smaller proportion of patients made new sputum IgA responses to the iron-regulated proteins TbpB and CopB and to lipooligosaccharide. These results have important implications in understanding the mucosal immune response to M. catarrhalis in the setting of COPD and in elucidating the elements of a protective immune response.

Identification of surface antigens of Moraxella catarrhalis as targets of human serum antibody responses in chronic obstructive pulmonary disease

Moraxella catarrhalis is an important respiratory tract pathogen, causing otitis media in children and lower respiratory tract infections in adults with chronic obstructive pulmonary disease (COPD). Adults with COPD make antibody responses to M. catarrhalis following infection, but little is known about the identity of the antigens to which these antibodies are directed. In this study, 12 serum samples obtained from adults with COPD who had cleared M. catarrhalis from the respiratory tract following infection and who had developed new serum immunoglobulin G (IgG) to their infecting strain were subjected to a series of assays to identify the antigens to which potentially protective antibodies were directed. Sera were adsorbed with intact bacterial cells, and antibodies were eluted from the surfaces of the bacteria. Analysis by flow cytometry established that adsorption and elution effectively detected antibodies specifically directed to surface-exposed epitopes. Immunoblot assays of adsorbed and eluted serum fractions were performed with purified outer membranes and purified lipooligosaccharide of homologous infecting strains and with a series of mutants deficient in expression of individual outer membrane proteins (OMPs). While heterogeneity in antibody responses among individuals was observed, five major OMPs, UspA1, UspA2, Hag, TbpB, and OMP CD, were identified as targets of antibodies to surface epitopes in the majority of adults with COPD who cleared the organism. These results have important implications in understanding human immune responses to M. catarrhalis and in elucidating the elements of a protective immune response.

Impaired systemic cell-mediated immunity and increased susceptibility to acute respiratory tract infections in patients with COPD

Although it has been reported that chronic obstructive pulmonary disease (COPD) is frequently associated with systemic immune disturbances, negative impact of these disturbances on the increased prevalence of acute respiratory tract infections (aRTIs) has remained unclear. We evaluated circulating levels of interferon-gamma (IFN-gamma), soluble interleukin-2 receptor (sIL-2R), neopterin, and soluble intercellular adhesion molecule-1 (sICAM-1) in 35 clinically stable patients with COPD and in 22 age-matched healthy controls, since these molecules are considered to reflect the in vivo status of systemic cell-mediated immunity (CMI). We found that circulating levels of sIL-2R (1.52+/-1.25 vs. 0.97+/-0.48 ng/ml; P<0.05), neopterin (7.23+/-4.24 vs. 4.95+/-1.52 nmol/l; P<0.05), and sICAM-1 (665+/-302 vs. 328+/-164 ng/ml; P<0.0001), but not IFN-gamma (7.55+/-4.72 vs. 6.65+/-1.13 pg/ml; P=NS) were significantly higher in patients with COPD than in the controls. Importantly, follow-up study for 12 months demonstrated that patients in subgroup with relatively higher circulating levels of sIL-2R (2.20+/-1.44 ng/ml, n=18) had significantly higher risk of developing aRTIs (P=0.0204) than those in subgroup with relatively lower circulating levels of sIL-2R (0.80+/-0.23 ng/ml, n=17). These results may suggest that impaired systemic CMI observed in COPD patients is associated with the increased susceptibility to aRTIs in these patients.

Moraxella catarrhalis in chronic obstructive pulmonary disease: burden of disease and immune response

RATIONALE

Moraxella catarrhalis is frequently present in the sputum of adults with chronic obstructive pulmonary disease (COPD). Little is known about the role of M. catarrhalis in this common disease.

OBJECTIVE

To elucidate the burden of disease, the dynamics of carriage, and immune responses to M. catarrhalis in COPD.

METHODS

Prospective cohort study of 104 adults with COPD in an outpatient clinic at the Buffalo Veterans Affairs Medical Center.

MEASUREMENTS

Clinical information, sputum cultures, molecular typing of isolates, and immunoassays to measure antibodies to M. catarrhalis.

MAIN RESULTS

Over 81 months, 104 patients made 3,009 clinic visits, 560 during exacerbations. Molecular typing identified 120 episodes of acquisition and clearance of M. catarrhalis in 50 patients; 57 (47.5%) of the acquisitions were associated with clinical exacerbations. No instances of simultaneous acquisition of a new strain of another pathogen were observed. The duration of carriage of M. catarrhalis was shorter with exacerbations compared with asymptomatic colonization (median, 31.0 vs. 40.4 days; p = 0.01). Reacquisition of the same strain was rare. The intensity of the serum IgG response was greater after exacerbations than asymptomatic colonization (p = 0.009). Asymptomatic colonization was associated with a greater frequency of a sputum IgA response than exacerbation (p = 0.009).

CONCLUSIONS

M. catarrhalis likely causes approximately 10% of exacerbations of COPD, accounting for approximately 2 to 4 million episodes annually. The organism is cleared efficiently after a short duration of carriage. Patients develop strain-specific protection after clearance of M. catarrhalis from the respiratory tract.

[ANTEAB: a study of early antibiotic therapy in intensive care management of acute exacerbations of chronic obstructive lung disease]

INTRODUCTION

Intensive Care Unit (ICU) admission for acute exacerbation of chronic obstructive lung disease (COLD) is a major cause of morbidity and mortality in such patients. Although bacterial and/or viral infections are considered as the major precipitating factor, the antibiotic strategy in this setting is unclear. The potential benefit of routine antibiotic therapy in the absence of evidence of overt infection remains controversial, and has not been adequately studied in patients admitted to the ICU. To assess the benefit (or lack thereof) of routine early systemic antibiotic therapy in patients with COLD admitted to the ICU.

METHODS

This is a multicenter, randomized, double-blind controlled trial, comparing amoxicillin-clavulanic acid administered for 7 days to a placebo. Patients included are those with documented or suspected COLD, exclusive of other bronchial or lung disease, and admitted for acute exacerbation, in the absence of overt sepsis or broncho-pneumonia, and having no other organ failure. Patients recently hospitalized, having received antibiotics for > 24 h, or on long-term steroids will not be included. Co-interventions (bronchodilators, steroids) are controlled for. Patients will be administered the antibiotic or placebo within 24 hours of admission.

EXPECTED RESULTS

A 20% reduction of the duration of clinical symptoms of exacerbation is expected. To this end, 520 patients are planned to be included in 15 centers in a 2-year period. Secondary end-points are the incidence of documented infection (lower respiratory tract or other sites), antibiotic use, the proportion of patients having infection with resistant bacteria, the incidence of endotracheal intubation, the duration of stay and mortality in the ICU and the hospital.

Factors Associated With Outcomes of Acute Exacerbations of Chronic Obstructive Pulmonary Disease

The purpose of this article is to provide a general review of the current literature on the factors associated with the outcomes of hospitalizations, survival and health-related quality of life in acute exacerbations of chronic obstructive pulmonary disease (AECOPD), highlighting the limitations and the complexities in interpretation of the results of current studies. There is no consensus definition for AECOPD; onsets may be difficult to define and the determination of duration elusive. The prevalence of acute exacerbations of COPD (AECOPD) in the community appears to be underestimated as exacerbations are underreported by patients and their doctors. Hospitalization for COPD is due mainly to severe AECOPDs which drive the cost of care. There are few longitudinal epidemiological studies on factors associated with hospitalizations for AECOPD. The results of current studies do not allow clear differentiation between associations that are predictors of event, the consequences of the event, or indicators of severity. Strategies to reduce severe exacerbations of COPD include pharmacological treatment, vaccinations, pulmonary rehabilitation, and home care programs. The optimal strategy for the reduction of hospitalization in COPD remains unclear. Long-term interventional studies are needed to provide clearer information for the prevention of exacerbations and hospitalizations in COPD.

Antimicrobials in acute exacerbations of chronic obstructive pulmonary disease - An analysis of the time to next exacerbation before and after the implementation of standing orders

OBJECTIVE

To compare the mean time to next exacerbation in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) before and after the implementation of standing orders.

SETTING

Tertiary care hospital, Halifax, Nova Scotia, Canada.

POPULATION STUDIED

The records of 150 patients were analyzed, 76 were in the preimplementation group, 74 in the postimplementation group.

INTERVENTION

The management and outcomes of patients admitted with an acute exacerbation of COPD before and after the implementation of standing orders were compared.

DESIGN

A retrospective chart review.

MAIN RESULTS

THERE WAS NO DIFFERENCE IN THE MEAN TIME TO NEXT EXACERBATION BETWEEN TREATMENT GROUPS (PREIMPLEMENTATION GROUP: 310 days, postimplementation group: 289 days, P=0.53). Antibiotics were used in 90% of the cases (preimplementation group: 87%, postimplementation group: 93%). The postimplementation group had a 20% increase in the use of first-line agents over the preimplementation group. Overall, first-line agents represented only 37% of the antibiotic courses.

CONCLUSIONS

The implementation of standing orders encouraged the use of first-line agents but did not influence subsequent symptom resolution, length of hospital stay, or the infection-free interval in patients with acute exacerbations of COPD.

Emergency department management of acute exacerbations of chronic obstructive pulmonary disease in the elderly: the Multicenter Airway Research Collaboration

OBJECTIVES

To determine adherence of emergency department (ED) management of acute exacerbation of chronic obstructive pulmonary disease (COPD) to current treatment guidelines.

DESIGN

A prospective cohort study, as part of the Multicenter Airway Research Collaboration.

SETTING

The study was performed at 29 EDs in 15 U.S. states and three Canadian provinces.

PARTICIPANTS

ED patients, aged 55 and older, who presented with COPD exacerbation and underwent a structured interview in the ED and another by telephone 2 weeks later.

MEASUREMENTS

Adherence of ED management of COPD exacerbation to that recommended in current treatment guidelines.

RESULTS

The cohort consisted of 397 subjects, of whom 224 (56%) reported only COPD and 173 (44%) reported asthma and COPD. The average age was 70. Most (80%) patients had used rescue medications in the 6 hours before seeking emergency care. Only 31% were evaluated using spirometry and 48% using arterial blood gas measurement. ED treatment included inhaled short-acting beta-agonists for 91% of patients, inhaled anticholinergics for 77%, methylxanthines for 0.3%, systemic corticosteroids for 62%, and antibiotics for 28%. More than half the patients required hospitalization. At 2-week follow-up, 43% of patients reported a relapse event or ongoing exacerbation. Overall, adherence to national and international guidelines was low.

CONCLUSION

Important differences exist between guideline recommendations and actual ED management of COPD exacerbations in older adults. Outcomes after ED treatment are poor and may be related to these shortcomings in quality of care. Better adherence to guideline recommendations when caring for elderly patients with COPD exacerbations may lead to improved clinical outcomes and better resource usage.

Impaired pulmonary inflammatory responses are a prominent feature of streptococcal pneumonia in mice with experimental emphysema

Little is known about why patients with chronic obstructive pulmonary disease are susceptible to bacterial infections. Using an animal model of pulmonary emphysema, we investigated the inflammatory responses to bacterial infection. After intratracheal infection with Streptococcus pneumoniae (10(3)-10(7) cfu/mouse), the control mice did not die. However, the mice with emphysema died in a dose-dependent manner. Bronchoalveolar lavage fluid, examined 24 hours after infection showed that the numbers of total cells and neutrophils, in addition to murine tumor necrosis factor-alpha and macrophage inflammatory protein-2 concentrations, were significantly less in the mice with emphysema compared with the control mice. Histopathologic findings revealed that the alveoli were filled with inflammatory cells and exudate in the control mice but not in the mice with emphysema. Seventy-two hours after infection, serum cytokine levels were significantly higher in the mice with emphysema, and significant numbers of S. pneumoniae were detected in both the whole lung tissues and the blood of mice with emphysema. These findings suggest that the inflammatory response in mice with emphysema was impaired at the site of bacterial infection despite the bacteremia, which accelerated severe systemic inflammatory responses. Accordingly, intra-alveolar but not systemic immune responses to bacterial infection were impaired in the presence of experimental emphysema.

Prevalence and clinical significance of fever in acute exacerbations of chronic obstructive pulmonary disease

Fever is an important, although not always present, sign in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). The objective of this study was to determine the prevalence of fever and its clinical significance in these episodes. Two hundred seventeen AECOPD hospitalizations were included in a prospective study and were categorized as febrile (FH) or afebrile (AFH), using as a cutoff a rectal temperature measurement of 37.8 degrees C during hospitalization. Eighty-six hospitalizations (39.6%) were identified as AFH. The patients in this group had significantly more severe airway obstruction and hypoxemia, a higher rate of chronic obstructive pulmonary disease (COPD) complications, a higher rate of type 3 exacerbation, a shorter length of hospitalization and a higher rate of readmissions than patients in the FH group. The results of this study show that more than one-third of AECOPD hospitalizations are attributable to afebrile episodes. These episodes are characterized by lower rates of bronchitis manifestations in patients with more severe disease. Although the length of hospitalization for these episodes is shorter, the readmission rate is higher.

Genes of non-typeable Haemophilus influenzae expressed during interaction with human epithelial cell lines

Non-typeable Haemophilus influenzae may infect the lower respiratory airways of chronic obstructive pulmonary disease patients. We characterized genes of non-typeable H. influenzae expressed during interaction with two human respiratory tract-derived epithelial cell lines. A library of 8000 clones was constructed in H. influenzae Rd (rec1) by cloning chromosomal fragments upstream of a promoterless cat gene. Exposure of this library to NCI-H292 epithelial cell layers in the presence of chloramphenicol (Cam) resulted in survival of bacteria expressing cat. A total of 52 clones were selected that were resistant to Cam in the presence of epithelial cells of cell line NCI-H292. These did not (n = 42) or hardly grow (n = 10) on sBHI plates containing Cam and were sensitive to Cam in cell culture medium alone. All clones, moreover, survived Cam in the presence of Hep2 epithelial cell layers. Sequence analysis showed that four clones contained sequences without homology to Rd or any other sequence, and therefore contained promoters and parts of open reading frames (ORFs) of novel genes. The other 48 clones were homologous to Rd, and characterization was based upon this genome. Six different functional classes were distinguished: (i) metabolic processes; (ii) stress response; (iii) gene expression; (iv) cell envelope biosynthesis; (v) DNA-related processes and cell division; and (vi) ORFs encoding proteins of unknown function. The contribution of identified genes to non-typeable H. influenzae adaptation to the epithelial cell environment is discussed.

Urinary desmosine excretion in acute exacerbations of COPD: a preliminary report

Desmosine (DES) is an elastin-derived, cross-link amino acid, which is not metabolized; hence, its urinary levels reflect elastin breakdown. We hypothesized that elastin degradation should increase as a result of increased lung inflammation during an acute exacerbation of COPD and should decrease after recovery. To test this hypothesis we measured DES in three urine samples from nine COPD subjects during the first 5 days of an acute exacerbation and at 2 months after recovery. We also measured forced expiratory volume in 1 sec (FEV1) to monitor the effects ofthe exacerbation on ventilatory function. The mean (SD) FEV1 was 45 (15)% predicted during the exacerbation and 57.8 (16)% predicted 2 months later (P=0.00001). The mean (SD) DES excretion was 25.3 (9) microg g(-1) creatinine at day 1;23.5 (9) at day 3 and 24 (9) at day 5 of the exacerbation. The mean (SD) urinary DES excretion 60 days after discharge was 20.9 (7) microg g(-1) creatinine (P=0.049) in comparison with the mean of the three acute-phase values. The size of the increase in desmosine excretion during exacerbation is small, 3.2 microg g(-1) creatinine or 16% of the recovery desmosine value. We conclude that there is a small but statistically significant increase in lung elastin breakdown in the body during an acute exacerbation of COPD.

Infections

Infection, in particular by respiratory viruses, plays an important role in triggering exacerbations and has also been implicated in the etiology of asthma and chronic obstructive pulmonary disease (COPD). This chapter reviews the epidemiological evidence that implicates infectious pathogens as triggers. The chapter also discusses the mechanisms of interaction between the host-pathogen response and preexisting airway pathology resulting in an exacerbation. Much of the treatment of infective exacerbations for both asthma and COPD is symptomatic, consisting of bronchodilators or supportive in the form of oxygen, and in severe cases it includes noninvasive or invasive ventilatory measures. The current therapy for virus-induced exacerbations of asthma and COPD relies on increased treatment of preexisting disease. Antibiotics are indicated for bacterial infections. The effective use of antiviral agents, particularly for influenza viruses, requires viral diagnosis, commencement of treatment early in the course of an exacerbation, or the targeting of high-risk groups for prophylaxis. Alternative strategies for drug development involve the identification of key factors common to exacerbations induced by a range of different viruses. Increased knowledge of the host–virus interaction can help in designing treatments that can increase virus clearance and minimize immunopathology.

Protein D expression promotes the adherence and internalization of non-typeable Haemophilus influenzae into human monocytic cells

Protein D, having a glycerol-3-phosphodiester phosphodiesterase activity, is found at the surface of all Haemophilus influenzae strains and is a possible virulence factor. In the present study, the involvement of protein D in the entry of NTHi into human monocytic cells is reported. Primary monocytes and the monocytic cell lines U-937 and THP-1 were infected with NTHi strain 772 and the mutant 772 Delta hpd 1 (lacking the gene for protein D). NTHi 772 adhered to and entered monocytic cells up to four-fold more efficiently compared to 772 Delta hpd 1. When an Escherichia coli transformant expressing protein D was incubated with monocytic cells, the number of intracellular bacteria increased 1.6-fold compared to protein D-deficient controls. Any correlation between internalization and phosphorylcholine expression was not detected. In conclusion, our data suggest that surface-expressed protein D promotes the adherence of NTHi to human monocytes leading to a higher number of internalized bacteria.

Conservation of outer membrane protein E among strains of Moraxella catarrhalis

Outer membrane protein E (OMP E) is a 50-kDa protein of Moraxella catarrhalis which has several features that suggest that the protein may be an effective vaccine antigen. To assess the conservation of OMP E among strains of M. catarrhalis, 22 isolates were studied with eight monoclonal antibodies which recognize epitopes on different regions of the protein. Eighteen of 22 strains were reactive with all eight antibodies. The sequences of ompE from 16 strains of M. catarrhalis were determined, including the 4 strains which were nonreactive with selected monoclonal antibodies. Analysis of sequences indicate a high degree of conservation among strains, with sequence differences clustered in limited regions of the gene. To assess the stability of ompE during colonization of the human respiratory tract, the sequences of ompE of isolates collected from patients colonized with the same strain for 3 to 9 months were determined. The sequences remained unchanged. These results indicate that OMP E is highly conserved among strains of M. catarrhalis, and preliminary studies indicate that the gene which encodes OMP E remains stable during colonization of the human respiratory tract.

Role of antimicrobial therapy in acute exacerbations of chronic obstructive pulmonary disease

OBJECTIVE

To define the role of antimicrobial therapy in the treatment of acute bronchitic exacerbations of chronic obstructive pulmonary disease (COPD) through review of placebo-controlled clinical trials. Specificalty, to determine the benefit of antimicrobial therapy on patient outcome.

DATA SOURCES

Placebo-controlled dinical trials identified by MEDLINE search (1957-December 1999).

STUDY SELECTION AND DATA EXTRACTION

All placebo-controlled clinical trials that included COPD patients with no evidence of pneumonia or underlying asthma were included in the evaluation.

DATA SYNTHESIS

The role of antimicrobial agents in the treatment of acute exacerbations of COPD is controversial. Patients with COPD are often chronically colonized with bacteria, and many exacerbations are due to nonbacterial causes. Four placebo-controlled clinical trials and a meta-analysis have demonstrated significant improvements in outcome for patients treated with an antibiotic versus placebo. In contrast, six studies failed to demonstrate statistical differences, possibly due to the small sample size and the subjectivity of outcome measures. Overall, the data suggest that the benefit of antimicrobial therapy in acute exacerbations of COPD may be related to exacerbation severity.

CONCLUSIONS

Antimicrobial agents may have a beneficial effect in the treatment of acute exacerbations of COPD in certain patients. Pending further research in this area, we recommend antimicrobial therapy only for COPD patients with acute bronchitic exacerbations characterized by increased dyspnea, sputum volume, and purulence.

Bacterial infection in chronic obstructive pulmonary disease in 2000: a state-of-the-art review

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. The precise role of bacterial infection in the course and pathogenesis of COPD has been a source of controversy for decades. Chronic bacterial colonization of the lower airways contributes to airway inflammation; more research is needed to test the hypothesis that this bacterial colonization accelerates the progressive decline in lung function seen in COPD (the vicious circle hypothesis). The course of COPD is characterized by intermittent exacerbations of the disease. Studies of samples obtained by bronchoscopy with the protected specimen brush, analysis of the human immune response with appropriate immunoassays, and antibiotic trials reveal that approximately half of exacerbations are caused by bacteria. Nontypeable Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae are the most common causes of exacerbations, while Chlamydia pneumoniae causes a small proportion. The role of Haemophilus parainfluenzae and gram-negative bacilli remains to be established. Recent progress in studies of the molecular mechanisms of pathogenesis of infection in the human respiratory tract and in vaccine development guided by such studies promises to lead to novel ways to treat and prevent bacterial infections in COPD.

Management of Chronic Obstructive Pulmonary Disease: A Review

Chronic obstructive pulmonary disease (COPD) affects about 14 million persons in the United States and is the only common cause of death that is increasing in incidence. Chronic management of this disorder includes nonpharmacologic interventions such as smoking cessation, immunization, nutritional support, and pulmonary rehabilitation. The pharmacotherapy of COPD is based on regular administration of bronchodilators, when symptoms are persistent. Long-acting bronchodilators have been shown to improve quality of life in patients with COPD. Ipratropium remains the anticholinergic of choice, but more specific agents with a longer duration of action should become available. Four recent large clinical trials on the use of inhaled corticosteroids (ICS) have been published. The results demonstrate that ICS do not alter the decline in lung function in patients with COPD. Patients with more severe COPD and frequent exacerbations may have a better quality of life and a reduced rate of exacerbations with ICS. Management of acute exacerbations involves three major pharmacologic treatment modalities: antibiotics, short-acting bronchodilators, and systemic steroids. Recent data shows the benefits of systemic corticosteroids in the management of acute exacerbations.

Airway inflammation in nonobstructive and obstructive chronic bronchitis with chronic haemophilus influenzae airway infection. Comparison with noninfected patients with chronic obstructive pulmonary disease

Nonencapsulated Haemophilus influenzae often causes chronic infections of the lower respiratory tract in both nonobstructive and obstructive chronic bronchitis. We assessed airway inflammation in clinically stable, chronically H. influenzae-infected patients with nonobstructive (CB-HI, n = 10) and in patients with obstructive chronic bronchitis (COPD-HI, n = 10) by analyses of the sol phase of spontaneously expectorated sputum (SSP). As compared with the CB-HI group, the COPD-HI group had significantly higher (p < 0.05) levels of myeloperoxidase (MPO) and tumor necrosis factor (TNF)-alpha in their SSP, whereas the degree of plasma protein leakage (SSP-to-serum ratio of plasma proteins) and the levels of interleukin (IL)-8, secretory IgA, and lactoferrin were similar in the two groups. These findings point to differences in pathophysiology in CB-HI and COPD-HI. The high level of TNF-alpha in the SSP of COPD-HI patients is in accord with the proposed role of TNF-alpha in the development of airway obstruction in COPD patients. In apparent contradiction, low levels of TNF-alpha were found in the SSP of noninfected but otherwise similar COPD patients (n = 9). This finding, however, does not exclude an exaggerated TNF-alpha response to infection or another stimulus in the airways of COPD patients. The SSP levels of MPO and IL-8, and the degree of plasma protein leakage in the COPD-HI group, were retrospectively compared with and found significantly higher than those of noninfected COPD patients, suggesting a more marked inflammatory response in COPD-HI. Whether this reflects a direct cause-and-effect relationship should be addressed in a future long-term prospective study involving repeated measurements in the same patients.

Basis for nebulized antibiotics: droplet characterization and in vitro antimicrobial activity versus Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa

The aims of this study were to (1) quantify the particle size characteristics of several antibiotics considered suitable for aerosol therapy after aerosolization with the PARI IS/2 nebulizer (Pari GmbH, Sarnberg, Germany) and (2) determine the degree to which in vitro antimicrobial activity of these antibiotics is maintained after nebulization. The aerosolized drugs were tobramycin sulfate, streptomycin, and imipenem, with saline solution as the control. Mean mass aerodynamic diameter of the nebulized drugs was 3.25 microns for tobramycin, 2.26 microns for imipenem, and 2.38 microns for streptomycin. In vitro tests showed that tobramycin and imipenem were unaltered in their bacteriostatic activity against strains of Escherichia coli (American Type Culture Collection [ATCC] 25922) and Staphylococcus aureus (ATCC 29213) as well as against Pseudomonas aeruginosa (ATCC 27853) with minimal inhibitory concentration (MIC) values less than 0.3 microgram/mL. Nebulized streptomycin showed significantly higher MIC values against P. aeruginosa (ATCC 27853). These results suggest that tobramycin and imipenem may be prescribed as an aerosol generated by jet nebulization (PARI IS/2) to treat S. aureus, E. coli, and P. aeruginosa infections without any risk of altering the drugs minimum bacteriostatic activity by the nebulization process. Aerosolization of streptomycin with this nebulizer may not be as effective against P. aeruginosa because it seems to alter the bacteriostatic activity.

Relation of FEV(1) to clinical outcomes during exacerbations of chronic obstructive pulmonary disease. Department of Veterans Affairs Cooperative Study Group

FEV(1) is an objective measure of airflow obstruction used in clinical practice and in therapeutic trials. The precise relationship of FEV(1) to clinical outcomes is generally uncertain. As part of a randomized trial to assess systemic corticosteroid efficacy, we obtained serial FEV(1) measurements in patients hospitalized for exacerbations of chronic obstructive pulmonary disease (COPD). Over the first 14 Study Days at least one FEV(1) value was obtained in 261 subjects. Sixty-four of these subjects experienced treatment failure, defined as death, intubation, readmission for COPD, or intensification of drug therapy, by Study Day 30. After adjustment, both FEV(1) at entry into the study (odds ratio [OR] for a 100-ml increase, 0.87; 95% confidence interval [CI], 0.79 to 0.96) and change in FEV(1) over the first two Study Days (OR for a 100 ml increase, 0.80; 95% CI, 0.69 to 0.92) predicted treatment failure. We identified no baseline characteristic that was significantly related to FEV(1) at entry into the study. Assignment to the systemic corticosteroid treatment arm was associated with a significantly larger FEV(1) at Study Day two (p = 0.01). We conclude that FEV(1) measurements at admission and over the first several days of hospitalization are highly predictive of clinical outcomes during exacerbations of COPD.

Upregulation of gelatinases A and B, collagenases 1 and 2, and increased parenchymal cell death in COPD

BACKGROUND

A central feature in the pathogenesis of COPD is the inflammation coexisting with an abnormal protease/antiprotease balance. However, the possible role of different serine and metalloproteinases remains controversial.

PATIENTS AND MEASUREMENTS

We examined the expression of gelatinases A and B (matrix metalloproteinase [MMP]-2 and MMP-9); collagenases 1, 2, and 3 (MMP-1, MMP-8, and MMP-13); as well as the presence of apoptosis in lung tissues of 10 COPD patients and 5 control subjects. In addition, gelatinase-A and gelatinase-B activities were assessed in BAL obtained from eight COPD patients, and from six healthy nonsmokers and six healthy smoker control subjects.

SETTING

Tertiary referral center and university laboratories of biochemistry, and lung cell kinetics.

RESULTS

Immunohistochemical analysis of COPD lungs showed a markedly increased expression of collagenases 1 and 2, and gelatinases A and B, while collagenase 3 was not found. Neutrophils exhibited a positive signal for collagenase 2 and gelatinase B, whereas collagenase 1 and gelatinase A were revealed mainly in macrophages and epithelial cells. BAL gelatin zymography showed a moderate increase of progelatinase-A activity and intense bands corresponding to progelatinase B. In situ end labeling of fragmented DNA displayed foci of positive endothelial cells, although some alveolar epithelial, interstitial, and inflammatory cells also revealed intranuclear staining.

CONCLUSION

These findings suggest that there is an upregulation of collagenase 1 and 2 and gelatinases A and B, and an increase in endothelial and epithelial cell death, which may contribute to the pathogenesis of COPD through the remodeling of airways and alveolar structures.

Acid phosphatase activity as a measure of Haemophilus influenzae adherence to mucin

Haemophilus influenzae is an important respiratory tract pathogen. Toward understanding the progression of H. influenzae from commensal to pathogen, we need to understand the steps of colonization and infection, processes which must involve overcoming the normal host mucociliary clearance mechanism. A reliable method for the screening and quantitation of mucin-H. influenzae binding to allow for the assessment of the physiological variables significant to H. influenzae-mucin interactions in the normal and diseased conditions, will provide insight on how to intervene to prevent, inhibit, or treat infection. The current methods for enumeration of mucin-bound H. influenzae are labor intensive and rely on viable organisms. In this report, we present a new detection method, which reduces the number of variables, processing steps, and time involved, providing an economical, rapid, and reliable means to screen for and quantitate mucin-bound H. influenzae. Organisms are applied to mucin-coated microtiter wells for a set time; nonadherent organisms are removed with gentle rinses; wells are incubated with the phosphomonoesterase substrate p-nitrophenyl phosphate; and the absorbance, reflecting phosphatase activity of the mucin-bound organisms, is read at 410 nm in a microtiter plate reader against enzymatic activity calibration curves. All nonencapsulated and encapsulated H. influenzae tested exhibited significant acid phosphate activity within 20 min, which provided linear relationships with the numbers of organisms present. H. influenzae mucin binding characteristics obtained by this method were generally comparable to published data, and ranged from 10(3) to 10(6) organisms per well, depending on both strain of organism and type of mucin employed. This convenient, rapid and economical mucin adherence assay, will enable more extensive and comprehensive studies of the interactions of H. influenzae adhesins and specific ligands on mucin macromolecules, as well as the nonspecific means by which mucins function in preventing bacterial infection.

Analysis of antigenic structure and human immune response to outer membrane protein CD of Moraxella catarrhalis

Moraxella catarrhalis is an important cause of otitis media in children and lower respiratory tract infections in adults with chronic obstructive pulmonary disease (COPD). Outer membrane protein CD (OMP CD) is a 45-kDa protein which is a potential vaccine antigen to prevent infections caused by M. catarrhalis. Eight monoclonal antibodies were used to study the antigenic structure of the OMP CD molecule by assaying recombinant peptides corresponding to the sequence of the protein. This approach identified two surface-exposed epitopes, including one near the amino terminus (amino acids 25 to 44) and one in the central region of the molecule (amino acids 261 to 331). Assays with serum and sputum supernatants of adults with COPD revealed variable levels of antibodies to OMP CD among individuals. To determine which portions of the OMP CD molecule were recognized by human antibodies, three human serum samples were studied with six recombinant peptides which span the sequence of OMP CD. All three sera contained immunoglobulin G antibodies which recognized exclusively the peptide corresponding to amino acids 203 to 260 by immunoblot assay. Adsorption experiments with whole bacteria established that some of the human antibodies are directed at surface-exposed epitopes on OMP CD. We conclude that OMP CD is a highly conserved molecule which contains at least two separate epitopes which are exposed on the bacterial surface. While individual adults with COPD show variability in the immune response to OMP CD, a specific region of the OMP CD molecule (amino acids 203 to 260) is important as a target of the human immune response.

The role of antimicrobial therapy in acute exacerbations of chronic bronchitis

Acute exacerbations of chronic bronchitis (AECB) result in increased morbidity and mortality. The role of bacteria in AECB, the importance of antimicrobial therapy, and the choice of antimicrobial agents have been debated for decades. Fortunately, within the past few years, a number of studies and one consensus statement have been reported that have increased the understanding of the role of bacteria in AECB and suggest approaches in selecting antimicrobial therapy. This article will review these studies and present an empiric approach in treating AECB based upon the patient's presenting findings, related risk factors, and potential antimicrobial resistance patterns that may be encountered.

[Alpha 1-protease inhibitor deficiency. Diagnosis, follow-up and therapy options]

DEFINITION

Alpha-1 antitrypsin (alpha-1 proteinase inhibitor) deficiency is characterized by a marked reduction of alpha-1 antitrypsin, the major antiprotease in man.

PREVALENCE

Alpha-1 antitrypsin deficiency is one of the most common hereditary diseases in Caucasians of European descent. Alpha-1 antitrypsin deficiency is the underlying disorder in approximately 2% of all patients with chronic obstructive pulmonary disease and lung emphysema.

CLINICAL MANIFESTATIONS

Young adults by the age of 30 to 45 years have a high risk for the development of lung emphysema with cough, sputum expectoration and respiratory insufficiency. There is a moderate risk of liver disease.

DIAGNOSTIC PROCEDURES AND TREATMENT

The diagnosis is obtained by measurement of alpha-1 antitrypsin serum levels. Recognition of the disorder is important to prevent deterioration of the pulmonary function by early initiation of preventive measures and treatment. Therapeutic options are physiotherapy, antiobstructive medication and antibiotics. The most direct approach is the intravenous augmentation therapy with purified alpha-1 antitrypsin.

Chronic obstructive pulmonary disease

Acute exacerbations of underlying COPD are a common cause of respiratory deterioration. Developments have been made in preventive measures, but admission to hospital for acute exacerbations can be expected to remain common. Several expert consensus guidelines have been published to define the appropriate management of COPD patients. These consensus guidelines generally agree, but all acknowledge a lack of large well-controlled clinical studies, especially studies focusing on the management of acute exacerbations. Consequently, many potential controversies exist about the details of managing patients with acute exacerbations. Although studies of many fundamental aspects of management are still needed, the results of controlled clinical trials are sufficient to emphasise the importance of a careful clinical assessment, supplemental oxygen, inhaled bronchodilators to partially improve airway obstruction, corticosteroids to decrease the likelihood of treatment failures and to speed recovery, antibiotics, especially in severe patients, and non-invasive positive-pressure ventilation for treatment of acute ventilatory failure in selected patients.

Medication use in home care patients with COPD

Chronic obstructive pulmonary disease (COPD) is the fourth-leading cause of death in the United States. Although many other diseases have seen a gradual decline in their associated mortality, COPD rates have increased nearly 33% from 1979 to 1991. The disease is defined as a slowly progressive obstruction of airflow that is predominantly irreversible. COPD usually begins in the fifth decade of life as an increased cough. Dyspnea on exertion is frequently observed in the sixth or seventh decade.