Acute exacerbations and respiratory failure in chronic obstructive pulmonary disease

Preclinical Identification of Poorly Controlled COPD: Patients with a Single Moderate Exacerbation Matter Too

Background and Objectives: Chronic obstructive pulmonary disease (COPD) remains a critical global health challenge, characterized by high morbidity, mortality, and healthcare costs. Current guidelines may overlook patients who present with only one moderate exacerbation or with frequent short-acting beta-agonist (SABA) use. Building on findings from the Seleida study, this research refines the criteria for poor COPD control to include these patients, aiming to improve early identification of high-risk cases in primary care. Methods: A retrospectiveand multicenter study is conducted using data from 110 COPD patients in Spain. Poor control is redefined as having at least one moderate exacerbation or as using three or more SABA inhalers annually. Key predictors, such as SABA/short-acting muscarinic antagonist (SAMA) inhalers and antibiotic prescriptions, are identified using logistic regression and LASSO regularization to enhance predictive accuracy. Results: The model achieves a good predictive performance, with an AUC-ROC of 0.978, sensitivity of 92.86%, and specificity of 87.50%. Key predictors reliably identify high-risk patients, enabling timely interventions. This study demonstrates a statistically significant association between once-daily inhaler therapies and better COPD control compared to multiple daily doses, supported by chi-square analysis (p = 0.008) and binary logistic regression (p = 0.018). Nevertheless, the variable 'daily inhalation frequency' (1 vs. >1 inhalation/day) was excluded from the final model to prevent overfitting. Conclusions: By refining the criteria for COPD control to include patients with at least one moderate exacerbation or frequent SABA use, this model provides a practical tool for early risk stratification in primary care, particularly in resource-limited settings. Early identification of high-risk patients can reduce hospitalizations and healthcare costs, supporting a proactive approach to COPD management. Further validation in larger cohorts is essential to confirm its broader applicability.

Molecular breath profile of acute COPD exacerbations

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) show high variability in individual susceptibility and promote disease progression; thus, accurate diagnosis and treatment is essential. Unravelling the molecular metabolic changes during AECOPD in breath could promote understanding of AECOPD and its treatment. Our objective was to investigate the metabolic breath profiles during AECOPD for biomarker detection. We conducted real-time breath analysis in patients with COPD during AECOPD and during subsequent stable phase. Molecular breath patterns were compared between AECOPD and stable phase by dimension reduction techniques and paired t-tests. Pathway enrichment analyses were performed to investigate underlying metabolic pathways. Partial least-squares discriminant analysis and XGboost were utilised to build a prediction model to differentiate AECOPD from stable state. 35 patients (60% male) with a mean age of 65 (10.2) yr with AECOPD were included. AECOPD could be predicted with a high sensitivity of 82.5% (95% confidence interval of 68.8%-93.8%) and an excellent discriminative power (AUC = 0.86). Metabolic changes in the linoleate, tyrosine, and tryptophan pathways during AECOPD were predominant. Significant metabolic changes occur during COPD exacerbations, predominantly in the linoleate, tyrosine, and tryptophan pathways, which are all linked to inflammation. Real-time exhaled breath analysis enables a good prediction of AECOPD compared to stable state and thus could enhance precision of AECOPD diagnosis and efficacy in clinical practice.

Prognostic risk prediction model for patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD): a systematic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory condition and a leading cause of mortality, with acute exacerbations (AECOPD) significantly complicating its management and prognosis. Despite the development of various prognostic prediction models for patients with AECOPD, their performance and clinical applicability remain unclear, necessitating a systematic review to evaluate these models and provide guidance for their future improvement and clinical use.

METHOD

PubMed, Web of Science, CINAHL, Scopus, EMBASE, and Medline were searched for studies published from their inception until February 5, 2024. Data extraction and evaluation were conducted using the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS). The Prediction model Risk Of Bias Assessment Tool (PROBAST) was employed to assess the risk of bias and applicability of the models.

RESULTS

After deduplication and screening 5942 retrieved articles, 46 studies comprising 53 models were included. Of these, 17 (37.0%) studies developed from studies conducted in China. All models were based on cohort studies. Mortality was the predicted outcome in 27 (50.9%) models. Logistic regression was used in 41 (77.4%) models, while machine learning methods were employed in 9 (17.0%) models. The median (minimum, maximum) sample size for model development was 672 (106, 150,035). The median (minimum, maximum) number of predictors per model was 5 (2, 42). Frequently used predictors included age (n = 28), dyspnea severity scores (n = 12), and PaCO2 (n = 11). The pooled AUC was 0.80 for mortality prediction models and 0.84 for hospitalization-related outcomes. 52 models have a high overall risk of bias, and all models were judged to have low concern regarding applicability. Major sources of bias included insufficient sample sizes (83.0%), reliance on univariate analysis for predictor selection (73.6%), inappropriate internal and external validation methods (54.7%), inappropriate inclusion and exclusion criteria for study subjects (50.9%) and so on. The only model with low bias was the PEARL score.

CONCLUSION

Current prognostic risk prediction models for patients with AECOPD generally exhibit high bias. Future efforts should standardize model development and validation methods, and develop widely usable clinical models.

Impact of blood eosinophil count on clinical outcomes in hospitalized Syrian patients with COPD exacerbation

OBJECTIVE

In this multicenter retrospective study, we evaluated the prognostic role of blood eosinophil count on clinical outcomes in hospitalized patients with exacerbations of chronic obstructive pulmonary disease (COPD).

METHODS

We included patients aged 20 to 90 years with a COPD diagnosis. Patients were divided into groups with blood eosinophil count ≤300 or >300 cells/μL and then further classified into 1-99, 100-300, or >300 cells/μL. We compared sociodemographic features and clinical outcomes between groups and identified risk factors associated with mortality in hospitalized patients with COPD and blood eosinophil count ≤300 cells/μL.

RESULTS

In total, 217 patients were included (82% men, average age 64.3±10.3 years). Patients with eosinophil counts ≤300 cells/μL had significantly longer hospital stays, more admissions to the intensive care unit (22.2% vs. 4.3%), and more frequent mechanical ventilation (21.6% vs. 4.3%) than those with eosinophil counts >300 cells/μL. Mortality only occurred in the group with ≤300 cells/μL; patients with COPD who had eosinophil counts >300 cells/μL had significantly better survival rates (17.0% vs. 0%).

CONCLUSION

High blood eosinophil counts at admission were associated with improved short-term outcomes. Our findings reveal the importance of considering eosinophil counts in clinical decision-making to manage hospitalized patients with COPD.

Effect of pneumonia on the outcomes of acute exacerbation of chronic obstructive pulmonary disease: a systematic review and meta-analysis

BACKGROUND

To assess the effect of pneumonia on the risk of mortality and other clinical outcomes in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

METHODS

PubMed, EMBASE and Scopus were screened for observational cohort and case-control studies that reported outcomes in AECOPD patients with and without pneumonia. Pooled effect sizes were reported as relative risks (RR) or hazard ratio (HR) for categorical outcomes and as weighted mean difference (WMD) for continuous outcomes. The primary outcome was mortality. Secondary outcomes were risk of admission to intensive care unit (ICU), need for assisted ventilation and readmission as well as duration of stay at the hospital. The certainty of the evidence was assessed using the GRADE approach.

RESULTS

Thirteen studies were included. AECOPD patients with pneumonia had significantly higher risk of in-hospital mortality (RR 2.29, 95% CI: 1.40, 3.73), mortality at 1 month (RR 1.84, 95% CI: 1.09, 3.13), and 1 year or more of follow-up (HR 2.30, 95% CI: 1.15, 4.61) compared to AECOPD patients without pneumonia. Pneumonia was associated with significantly higher risk of admission to ICU (RR 2.79, 95% CI: 1.47, 5.28), need for assisted ventilation (RR 2.02, 95% CI: 1.52, 2.67), and longer hospital stay (in days) (WMD 3.31, 95% CI: 2.33, 4.29). The risk of readmission was comparable in the two groups of patients (RR 1.07, 95% CI: 0.97, 1.19). The overall quality of evidence for the outcomes was judged to be "Low".

CONCLUSION

Pneumonia during acute exacerbation of COPD may lead to increases in both short-term and long-term mortality as well as increased hospital stay, need for ventilatory support and admission to ICU. Our findings suggest the need for close monitoring, early intervention, and long-term follow-up, to improve the outcomes in AECOPD patients with concurrent pneumonia.

Development and Validation of Machine Learning-Based Models for Prediction of Intensive Care Unit Admission and In-Hospital Mortality in Patients with Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Background

This present work focused on predicting prognostic outcomes of inpatients developing acute exacerbation of chronic obstructive pulmonary disease (AECOPD), and enhancing patient monitoring and treatment by using objective clinical indicators.

Methods

The present retrospective study enrolled 322 AECOPD patients. Registry data downloaded based on the chronic obstructive pulmonary disease (COPD) Pay-for-Performance Program database from January 2012 to December 2018 were used to check whether the enrolled patients were eligible. Our primary and secondary outcomes were intensive care unit (ICU) admission and in-hospital mortality, respectively. The best feature subset was chosen by recursive feature elimination. Moreover, 7 machine learning (ML) models were trained for forecasting ICU admission among AECOPD patients, and the model with the most excellent performance was used.

Results

According to our findings, a random forest (RF) model showed superb discrimination performance, and the values of area under the receiver operating characteristic curve were 0.973 and 0.828 in training and test cohorts, separately. Additionally, according to decision curve analysis, the net benefit of the RF model was higher when differentiating patients with a high risk of ICU admission at a <0.55 threshold probability. Moreover, the ML-based prediction model was also constructed to predict in-hospital mortality, and it showed excellent calibration and discrimination capacities.

Conclusion

The ML model was highly accurate in assessing the ICU admission and in-hospital mortality risk for AECOPD cases. Maintenance of model interpretability helped effectively provide accurate and lucid risk prediction of different individuals.

Frequency of Asymptomatic Deep Vein Thrombosis in Hospitalized Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease (COPD)

INTRODUCTION

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are always associated with high mortality. Because of the presence of some concomitant risk factors such as immobilization and bronchial superinfection, patients who are admitted for acute exacerbations of COPD are generally considered to be at moderate risk for the development of venous thromboembolism. Thromboembolism is a cause of unexplained dyspnea, exacerbations, and mortality in COPD. This study aims to determine the frequency of asymptomatic deep vein thrombosis (DVT) in patients with acute exacerbations of COPD presented at a tertiary care hospital.

METHODS

This is a descriptive cross-sectional study conducted at the Department of Chest Medicine, Jinnah Postgraduate Medical Center (JPMC), Karachi. A duplex ultrasound study of both lower limbs was performed by a sonologist to assess asymptomatic DVT in patients with acute exacerbations of COPD.

RESULTS

The mean age of the sample was 59.64 ± 9.711 years. Out of 106 patients, 95 (90%) were male and 11 (10%) were female. Asymptomatic DVT was found in 16 (15%) patients with acute exacerbations of COPD. Male patients exhibited a higher incidence of DVT, with 12 cases versus four in females, a statistically significant finding (p=0.03). Additionally, DVT was significantly more prevalent among patients with restricted mobility, with all 16 cases occurring in this group (p=0.006). Age did not show a statistically significant difference in DVT occurrence between patients above and below 59 years.

CONCLUSIONS

Deep venous thrombosis is a common occurrence in COPD exacerbations. It is a risk factor for pulmonary embolism that carries a high mortality. All patients with COPD exacerbations may need to be assessed for thromboembolic events. COPD morbidity and mortality are continually rising despite efforts to recognize new phenotypes and treatments. The cause may be the association of unrecognized and untreated thromboembolism. Prompt diagnosis and treatment with anticoagulants in COPD patients may lead to a better prognosis.

Risk of Death and Cardiovascular Events Following an Exacerbation of COPD: The EXACOS-CV US Study

Purpose

This study estimated the magnitude and duration of risk of cardiovascular events and mortality following acute exacerbations of chronic obstructive pulmonary disease (AECOPD), and whether risks varied by number and severity of exacerbation in a commercially insured population in the United States.

Methods

This was a retrospective cohort study of newly diagnosed COPD patients ≥40 years old in the Healthcare Integrated Research Database from 2012 to 2019. Patients experiencing exacerbations comprised the "exacerbation cohort". Moderate exacerbations were outpatient visits with contemporaneous antibiotic or glucocorticoid administration; severe exacerbations were emergency department visits or hospitalizations for AECOPD. Follow-up started on the exacerbation date. Distribution of time between diagnosis and first exacerbation was used to assign index dates to the "unexposed" cohort. Cox proportional hazards models estimated risks of a cardiovascular event or death following an exacerbation adjusted for medical and prescription history and stratified by follow-up time, type of cardiovascular event, exacerbation severity, and rank of exacerbation (first, second, or third).

Results

Among 435,925 patients, 170,236 experienced ≥1 exacerbation. Risk of death was increased for 2 years following an exacerbation and was highest during the first 30 days (any exacerbation hazard ratio (HR)=1.79, 95% CI=1.58-2.04; moderate HR=1.22, 95% CI=1.04-1.43; severe HR=5.09, 95% CI=4.30-6.03). Risks of cardiovascular events were increased for 1 year following an AECOPD and highest in the first 30-days (any exacerbation HR=1.34, 95% CI=1.23-1.46; moderate HR=1.23 (95% CI 1.12-1.35); severe HR=1.93 (95% CI=1.67-2.22)). Each subsequent AECOPD was associated with incrementally higher rates of both death and cardiovascular events.

Conclusion

Risk of death and cardiovascular events was greatest in the first 30 days and rose with subsequent exacerbations. Risks were elevated for 1-2 years following moderate and severe exacerbations, highlighting a sustained increased cardiopulmonary risk associated with exacerbations.

Particulate Matter and Its Impact on Macrophages: Unraveling the Cellular Response for Environmental Health

Particulate matter (PM) imposes a significant impact to environmental health with deleterious effects on the human pulmonary and cardiovascular systems. Macrophages (Mφ), key immune cells in lung tissues, have a prominent role in responding to inhaled cells, accommodating inflammation, and influencing tissue repair processes. Elucidating the critical cellular responses of Mφ to PM exposure is essential to understand the mechanisms underlying PM-induced health effects. The present review aims to give a glimpse on literature about the PM interaction with Mφ, triggering the cellular events causing the inflammation, oxidative stress (OS) and tissue damage. The present paper reviews the different pathways involved in Mφ activation upon PM exposure, including phagocytosis, intracellular signaling cascades, and the release of pro-inflammatory mediators. Potential therapeutic strategies targeting Mφ-mediated responses to reduce PM-induced health effects are also discussed. Overall, unraveling the complex interplay between PM and Mφ sheds light on new avenues for environmental health research and promises to develop targeted interventions to reduce the burden of PM-related diseases on global health.

Asthma in Pregnancy: A Critical Review of Impact, Management, and Outcomes

Asthma is a common chronic respiratory condition that can significantly impact the health of pregnant women and their developing fetuses. This comprehensive review provides insights into the prevalence of asthma in pregnant women, the physiological changes during pregnancy, and the multifaceted impact of asthma on maternal and fetal health. It emphasizes the importance of proper asthma diagnosis, medication management, and the development of personalized asthma action plans during pregnancy. Lifestyle modifications, trigger avoidance, and stress reduction are essential to effective management. Healthcare providers are pivotal in educating, monitoring, and individualized care to ensure optimal asthma control. The review underscores the critical significance of managing asthma during pregnancy, as it improves maternal and fetal outcomes and potentially influences long-term health for both mother and child. Future directions in this field involve ongoing research, personalized treatment, early intervention, and precision medicine to enhance the understanding and care of asthma during pregnancy.

Phenotypes, Etiotypes, and Endotypes of Exacerbations of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease is a major health problem with a high prevalence, a rising incidence, and substantial morbidity and mortality. Its course is punctuated by acute episodes of increased respiratory symptoms, termed exacerbations of chronic obstructive pulmonary disease (ECOPD). ECOPD are important events in the natural history of the disease, as they are associated with lung function decline and prolonged negative effects on quality of life. The present-day therapy for ECOPD with short courses of antibiotics and steroids and escalation of bronchodilators has resulted in only modest improvements in outcomes. Recent data indicate that ECOPD are heterogeneous, raising the need to identify distinct etioendophenotypes, incorporating traits of the acute event and of patients who experience recurrent events, to develop novel and targeted therapies. These characterizations can provide a complete clinical picture, the severity of which will dictate acute pharmacological treatment, and may also indicate whether a change in maintenance therapy is needed to reduce the risk of future exacerbations. In this review we discuss the latest knowledge of ECOPD types on the basis of clinical presentation, etiology, natural history, frequency, severity, and biomarkers in an attempt to characterize these events.

Cigarette Smoke-Induced Respiratory Response: Insights into Cellular Processes and Biomarkers

Cigarette smoke (CS) poses a significant risk factor for respiratory, vascular, and organ diseases owing to its high content of harmful chemicals and reactive oxygen species (ROS). These substances are known to induce oxidative stress, inflammation, apoptosis, and senescence due to their exposure to environmental pollutants and the presence of oxidative enzymes. The lung is particularly susceptible to oxidative stress. Persistent oxidative stress caused by chronic exposure to CS can lead to respiratory diseases such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (PF), and lung cancer. Avoiding exposure to environmental pollutants, like cigarette smoke and air pollution, can help mitigate oxidative stress. A comprehensive understanding of oxidative stress and its impact on the lungs requires future research. This includes identifying strategies for preventing and treating lung diseases as well as investigating the underlying mechanisms behind oxidative stress. Thus, this review aims to investigate the cellular processes induced by CS, specifically inflammation, apoptosis, senescence, and their associated biomarkers. Furthermore, this review will delve into the alveolar response provoked by CS, emphasizing the roles of potential therapeutic target markers and strategies in inflammation and oxidative stress.

COPD Exacerbation: Why It Is Important to Avoid ICU Admission

Chronic obstructive pulmonary disease (COPD) is one of the major causes of morbidity and mortality worldwide. Hospitalization due to acute exacerbations of COPD (AECOPD) is a relevant health problem both for its impact on disease outcomes and on health system resources. Severe AECOPD causing acute respiratory failure (ARF) often requires admission to an intensive care unit (ICU) with endotracheal intubation and invasive mechanical ventilation. AECOPD also acts as comorbidity in critically ill patients; this condition is associated with poorer prognoses. The prevalence reported in the literature on ICU admission rates ranges from 2 to 19% for AECOPD requiring hospitalization, with an in-hospital mortality rate of 20-40% and a re-hospitalization rate for a new severe event being 18% of the AECOPD cases admitted to ICUs. The prevalence of AECOPD in ICUs is not properly known due to an underestimation of COPD diagnoses and COPD misclassifications in administrative data. Non-invasive ventilation in acute and chronic respiratory failure may prevent AECOPD, reducing ICU admissions and disease mortality, especially when associated with a life-threating episode of hypercapnic ARF. In this review, we report on up to date evidence from the literature, showing how improving the knowledge and management of AECOPD is still a current research issue and clinical need.

Levels of immunoglobulin isotypes in serum and respiratory samples of patients with chronic obstructive pulmonary disease: protocol for a systematic review and meta-analysis

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is an inflammatory respiratory disorder characterised by the progressive worsening of lung function. Acute exacerbation of COPD (AECOPD) is a leading contributor to patient morbidity, mortality and hospitalisations. The clinical significance of immunoglobulin (Ig) levels in COPD patients is not well established and is in need of further investigation.

METHODS AND ANALYSIS

We will conduct a systematic review to describe levels of different Ig isotypes (IgG, IgA and IgM) in various samples (serum, sputum and bronchoalveolar lavage) of patients with COPD. IgE levels in COPD patients have been researched and reviewed extensively and hence will be excluded from this review. IgD levels will also be excluded from the review as there is a paucity of data on IgD levels in COPD patients. The primary outcome of interest in this systematic review is assessing Ig isotype levels in patients with COPD. Secondary outcomes that will be assessed include the differences between Ig isotype levels in COPD patients compared with healthy controls, as well as the relationships between Ig isotype levels and key clinical variables, including COPD severity, incidence of AECOPD and AECOPD severity. Embase and Ovid MEDLINE will be used to search for non-randomised studies published from 1946 to October 2022 that report our prespecified primary and secondary outcomes. As per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol, retrieved studies will undergo a two-phase screening process conducted by two independent reviewers. Prespecified primary and secondary outcomes will be extracted from eligible studies, and descriptive statistics will be used to analyse extracted outcomes. The risk of bias will be assessed using the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool.

ETHICS AND DISSEMINATION

Ethics approval is not required as this is a protocol for a systematic review and meta-analysis. Findings will be disseminated through peer-reviewed publications and other formats including conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42020192220.

Clinical assessment of balance and functional impairments in people with stable chronic obstructive pulmonary disease: a systematic review and meta-analysis

The objective of this study was to compare the balance and functional capacity between stable chronic obstructive pulmonary disease (COPD) patients versus healthy controls using clinical tests. A comprehensive search of PubMed/MEDLINE, the Cochrane Central Register of Controlled Trials (CENTRAL), Embase and Web of Science was conducted from inception to 21 January 2022. Studies reporting the association between COPD status and balance or functional capacity using clinical tests were included. Two independent reviewers examined the titles and abstracts, extracted the data using a standardised form, and assessed the risk of bias of the included articles. A total of 27 studies with 2420 individuals with stable COPD were included. Overall, the risk of bias in the included studies was low to moderate. The meta-analysis showed a higher history of falls in individuals with COPD (odds ratio 1.59, 95% CI 1.25-2.02). Furthermore, an overall effect in favour of the healthy controls was observed in the Timed Up and Go (mean difference: 2.61 s, 95% CI 1.79-3.43), Berg Balance Scale (mean difference: -6.57 points, 95% CI -8.31 to -4.83), static balance tests (standardised mean difference: -1.36, 95% CI -2.10 to -0.62) and the 6-min walk test (mean difference: -148.21 m, 95% CI -219.37 to -77.39). In conclusion, individuals with stable COPD have worse balance and functional capacity compared to healthy controls. These results may guide clinicians to elaborate on therapeutic strategies focused on screening of balance and functional impairments. This is in addition to generating rehabilitation guidelines aimed at reducing the risk of falling in people with COPD.

Azithromycin Versus Beta-lactams in Hospitalized Patients with Acute Exacerbations of COPD

BACKGROUND

There is a lack of data comparing azithromycin to alternative antibiotic choices in managing COPD exacerbations, making appropriate antibiotic selection controversial.

OBJECTIVE

To compare treatment failure in hospitalized patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) receiving azithromycin or beta-lactams.

DESIGN

Retrospective, multicenter cohort study using logistic regression for multivariable analysis. Patients were included if they were at least 18 years old, admitted with AECOPD, and received at least two consecutive days of either a beta-lactam or azithromycin. Patients were excluded if they received concomitant azithromycin and beta-lactam antibiotics during the first 2 days, had a history of other severe underlying pulmonary diseases, pregnancy, COVID-19, alpha-1 antitrypsin deficiency, or received a corticosteroid for a diagnosis other than COPD.

PARTICIPANTS

Five hundred ninety-five patients were included, of which 428 (72%) received azithromycin and 167 patients (28%) received a beta-lactam.

MAIN MEASURES

The primary endpoint was treatment failure rate in patients receiving azithromycin versus beta-lactams, which was a composite endpoint defined as in-hospital mortality, admission to intensive care, initiation of invasive mechanical ventilation, initiation of a new antibiotic, steroid therapy escalation, or readmission due to AECOPD within 30 days.

KEY RESULTS

The composite primary outcome occurred in 84 patients (19.6%) in the azithromycin group and 54 (32.3%) in the beta-lactam group (p<0.01). The difference in the composite outcome was a result of higher rates of new antibiotics during admission (12.6% vs 4.2%; p<0.01) and higher readmission within 30 days (19.3% vs 12.4%; p=0.032). After controlling for potential confounders, beta-lactams continued to demonstrate a higher risk for treatment failure (OR, 2.30; 95% CI, 1.46-3.63). There was no difference in adverse effects between the groups.

CONCLUSION

Azithromycin was associated with less treatment failure in AECOPD which was driven by lower readmission rates and prescription of new antimicrobials.

Chronic moderate hypercapnia suppresses ventilatory responses to acute CO&lt;sub&gt;2&lt;/sub&gt; challenges

Chronic hypercapnia (CH) is a hallmark of chronic lung disease, and CH increases the risk for acute-on-chronic exacerbations leading to greater hypoxemia/hypercapnia and poor health outcomes. However, the role of hypercapnia per se (duration and severity) in determining an individual's ability to tolerate further hypercapnic exacerbations is unknown. Our primary objective herein was to test the hypothesis that mild-to-moderate CH (arterial [Formula: see text] ∼50-70 mmHg) increases susceptibility to pathophysiological responses to severe acute CO₂ challenges. Three groups (GR) of adult female goats were studied during 14 days of exposure to room air (<i>GR 1</i>; control) or 6% inspired CO₂ (<i>GR 2</i>; mild CH), or 7 days of 6% inspired CO₂ followed by 7 days of 8% inspired CO₂ (<i>GR 3</i>; moderate CH). Consistent with previous reports, there were no changes in physiological parameters in <i>GR 1</i> (RA control), but mild CH (<i>GR 2</i>) increased steady-state ventilation and transiently suppressed CO₂/[H⁺] chemosensitivity. Further increasing InCO₂ from 6% to 8% (<i>GR 3</i>) transiently increased ventilation and arterial [H⁺]. Similar to mild CH, moderate CH increased ventilation to levels greater than predicted. However, in contrast to mild CH, acute ventilatory chemosensitivity was suppressed throughout the duration of moderate CH, and the arterial - mixed expired CO₂ gradient became negative. These data suggest that moderate CH limits physiological responses to acute severe exacerbations and provide evidence of recruitment of extrapulmonary systems (i.e., gastric CO₂ elimination) during times of moderate-severe hypercapnia.<b>NEW &amp; NOTEWORTHY</b> Moderate levels of chronic hypercapnia (CH; ∼70 mmHg) in healthy adult female goats elicited similar steady-state physiological adaptations compared with mild CH (∼55 mmHg). However, unlike mild CH, moderate CH chronically suppressed acute CO₂/[H⁺] chemosensitivity and reversed the arterial to mixed expired CO₂ gradient. These findings suggest that moderate CH suppresses vital mechanisms of ventilatory control and recruits additional physiological systems (i.e., gastric CO₂ release) to help buffer excess CO₂.

Patients with Chronic Obstructive Pulmonary Disease and Evidence of Eosinophilic Inflammation Experience Exacerbations Despite Receiving Maximal Inhaled Maintenance Therapy

Background

Some patients with chronic obstructive pulmonary disease (COPD) experience frequent exacerbations despite maximal inhaled therapy (“triple therapy”), possibly leading to high health care resource utilization (HCRU).

Aim

Describe characteristics, future HCRU, and mortality of patients with COPD who experience frequent exacerbations despite triple therapy; characterize individuals who may be candidates for biologic therapies.

Methods

This descriptive observational study used primary care data of patients aged ≥40 years in the United Kingdom receiving maintenance therapy for COPD who had ≥1 year of data prior to index date and ≥1 year of follow-up data. We described these patients’ clinical and demographic characteristics, including blood eosinophil counts (BEC), pattern of exacerbations, hospitalizations, and corticosteroid exposure, as well as future exacerbations, hospitalizations, and death.

Results

Of 43,753 patients with maintenance-treated COPD, 6480 experienced exacerbations despite ≥3 months of triple therapy. Of these, 5669 had available BEC: 1287 (22.7%) had BEC ≥250 cells/µL and ≥3 exacerbations in the year prior to the index date; 471 (36.6%) received ≥4 acute courses of oral corticosteroids. Patients with a pattern of high disease burden continued to have high disease burden: 51.1% experienced ≥3 exacerbations and 2.6% experienced ≥3 hospitalizations. Patients who experienced exacerbations despite triple therapy had a significantly higher risk of COPD-related death than other maintenance-treated patients (5.8% vs 2.1%).

Conclusion

Nearly one-quarter of patients receiving triple therapy for COPD who experienced frequent exacerbations had elevated BEC and ≥3 exacerbations, suggesting a potential mechanism of persistent eosinophilic inflammation that could be a target for eosinophil-depleting biologic therapy.

Peripheral neuropathy: A neglected cause of disability in COPD - A narrative review

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory syndrome with systemic involvement leading to various cardiovascular, metabolic, and neurological comorbidities. It is well known that conditions associated with oxygen deprivation and metabolic disturbance are associated with polyneuropathy, but current data regarding the relationship between COPD and peripheral nervous system pathology is limited. This review summarizes the available data on the association between COPD and polyneuropathy, including possible pathophysiological mechanisms such as the role of hypoxia, proinflammatory state, and smoking in nerve damage; the role of cardiovascular and metabolic comorbidities, as well as the diagnostic methods and screening tools for identifying polyneuropathy. Furthermore, it outlines the available options for managing and preventing polyneuropathy in COPD patients. Overall, current data suggest that optimal screening strategies to diagnose polyneuropathy early should be implemented in COPD patients due to their relatively common association and the additional burden of polyneuropathy on quality of life.

Arterial Spin Labeling technique and clinical applications of the intracranial compartment in stroke and stroke mimics - A case-based review

Magnetic resonance imaging perfusion (MRP) techniques can improve the selection of acute ischemic stroke patients for treatment by estimating the salvageable area of decreased perfusion, that is, penumbra. Arterial spin labeling (ASL) is a noncontrast MRP technique that is used to assess cerebral blood flow without the use of intravenous gadolinium contrast. Thus, ASL is of particular interest in stroke imaging. This article will review clinical applications of ASL in stroke such as assessment of the core infarct and penumbra, localization of the vascular occlusion, and collateral status. Given the nonspecific symptoms that patients can present with, differentiating between stroke and a stroke mimic is a diagnostic dilemma. ASL not only helps in differentiating stroke from stroke mimic but also can be used to specify the exact mimic when used in conjunction with the symptomatology and structural imaging. In addition to a case-based overview of clinical applications of the ASL in stroke and stroke mimics in this article, the more commonly used ASL labeling techniques as well as emerging ASL techniques, future developments, and limitations will be reviewed.

Various Aspects of Non-Invasive Ventilation in COVID-19 Patients: A Narrative Review

Non-invasive ventilation (NIV) is primarily used to treat acute respiratory failure. However, it has broad applications to manage a range of other diseases successfully. The main advantage of NIV lies in its capability to provide the same physiological effects as invasive ventilation while avoiding the placement of an artificial airway and its associated life-threatening complications. The war on the COVID-19 pandemic is far from over. The present narrative review aimed at identifying various aspects of NIV usage, in COVID-19 and other patients, such as the onset time, mode, setting, positioning, sedation, and types of interface. A search for articles published from May 2020 to April 2021 was conducted using MEDLINE, PMC central, Scopus, Web of Science, Cochrane Library, and Embase databases. Of the initially identified 5,450 articles, 73 studies and 24 guidelines on the use of NIV were included. The search was limited to studies involving human cases and English language articles. Despite several reported benefits of NIV, the evidence on the use of NIV in COVID-19 patients does not yet fully support its routine use.

Elevated PaCO2 levels increase pulmonary artery pressure

Permissive hypercapnia is commonly used in mechanically ventilated patients to avoid lung injury but its effect on pulmonary artery pressure (PAP) is still unclear, particularly in combination with tidal volume (Vt). Therefore, an in vivo study was performed on adult rabbits ventilated with low (9 ml/Kg, LVt group) or high (15 ml/Kg, HVt group) tidal volume (Vt) and alterations in PAP were estimated. Both groups of animals initially were ventilated with FiO2 0.3 (Normocapnia-1) followed by inhalation of enriched CO2 gas mixture (FiCO2 0.10) to develop hypercapnia (Hypercapnia-1). After 30 min of hypercapnia, animals were re-ventilated with FiO2 0.3 to develop normocapnia (Normocapnia-2) again and then with FiCO2 0.10 to develop hypercapnia (Hypercapnia-2). Systolic, diastolic and mean PAP were assessed with a catheter in the pulmonary artery. In HP-1 and HP-2, PaCO2 increased (p < 0.0001) in both LVt and HVt animals compared to baseline values. pH decreased to ≈7.2 in HP-1 and ≈7.1 in HP -2. In normocapnia, the rise in Vt from 9 to 15 ml/Kg induced an increase in static compliance (Cstat), plateau airway pressure (Pplat) and PAP. Hypercapnia increased PAP in either LVt or HVt animals without significant effect on Cstat or Pplat. A two-way ANOVA revealed that there was not a statistically significant interaction between the effects of hypercapnia and tidal volume on mPAP (p = 0.76). In conclusion, increased Vt per se induced an increase in Cstat, Pplat and PAP in normocapnia. Hypercapnia increased PAP in rabbits ventilated with low or high Vt but this effect was not long-lasting.

Diagnostic value of pulmonary ultrasound in acute exacerbation of chronic obstructive pulmonary disease: A pilot study

BACKGROUND

To evaluate the value of the pulmonary ultrasound for the diagnosis of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in emergency departments (EDs).

MATERIALS AND METHODS

Between January 2018 and December 2019, patients admitted to the ED of Shanxi Provincial People's Hospital for suspected AECOPD were prospectively included in this study. Pulmonary ultrasound was performed using a linear transducer. The pulmonary ultrasound findings were evaluated for further discrimination for patients with AECOPD. Then, the diagnostic performance of pulmonary ultrasound was estimated and calculated. The clinical characteristics between groups with and without pneumonia were compared.

RESULTS

A total of 53 patients with AECOPD were included in the final analysis. For diagnosis of AECOPD due to pneumonia, ultrasound findings, such as consolidation, slightly rough pleural line, or irregular and interrupted pleural line had a sensitivity of 92.3% and a specificity of 86.7%. For diagnosis of AECOPD complicating pulmonary fibrosis, fringed pleural line had a sensitivity of 100% and a specificity of 97.5%. In addition, patients with pleural effusion (n=19) or pneumothorax (n=1) were correctly identified and wavy or bulging pleural lines were common in patients with AECOPD (58.5%, 31/53).

CONCLUSION

Ultrasound findings could offer further discrimination for AECOPD complications and other pathological conditions, such as pneumonia, pulmonary fibrosis, pleural effusion, and pneumothorax in EDs.

Predictors of Influenza PCR Positivity in Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Purpose

Influenza infection is an important cause of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Clinical features predicting influenza PCR positivity are unknown. We aim to identify predictors of influenza PCR positivity in AECOPD.

Patients and Methods

A retrospective study of AECOPD cases admitted between 1st January 2016 to 30 June 2017 with combined nasal/throat swabs sent for influenza PCR (Xpert Xpress Flu/RSV) within 24 hours of admission was performed. Clinical parameters and investigations within 24 hours of admission were retrieved from electronic medical records.

Results

Influenza PCR were sent for 925 AECOPD cases (mean age 75 years, 87.9% male). There were 90 PCR positive cases (68 Influenza A, 22 Influenza B). Influenza PCR positive cases had higher temperatures, higher heart rates, lower white cell and lower eosinophil counts. Age, gender, COPD severity, comorbidities and smoking status were similar in both groups. There were no differences in blood pressure, oxygen status, neutrophil or lymphocyte counts, C reactive protein, procalcitonin or chest X-ray consolidation between groups. Higher temperature, higher heart rate, white cell count in the lowest quartile (Q1 < 8.1 x10⁹/L) and non-eosinophilic exacerbations predicted influenza PCR positivity on univariate logistic regression and these factors remained significant after multivariate adjustment (temperature adjusted odds ratio [adj OR] 1.324 [1.009–1.737], p = 0.043; heart rate adj OR 1.017 [1.004–1.030], p = 0.011; white cell count Q1 adj OR 3.330 [1.690–6.562], p = 0.001; eosinophilic exacerbations adj OR 0.390 [0.202–0.756], p = 0.005).

Conclusion

Higher temperature, higher heart rate, low white cell count (especially when < 8.1 x10⁹/L) and non-eosinophilic exacerbations are independent predictors of influenza PCR positivity in AECOPD cases.

Novel pharmacological strategies to treat cognitive dysfunction in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and currently the 3rd largest cause of death in the world, with approximately 3.23 million deaths per year. Globally, the financial burden of COPD is approximately €82 billion per year and causes substantial morbidity and mortality. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities and viral and bacterial-induced acute exacerbations (AECOPD). Recent clinical studies have shown that cognitive dysfunction is present in up to 60% of people with COPD, with impairments in executive function, memory, and attention, impacting on important outcomes such as quality of life, hospitalisation and survival. The high prevalence of cognitive dysfunction in COPD may also help explain the insufficient adherence to therapeutic plans and strategies, thus worsening disease progression in people with COPD. However, the mechanisms underlying the impaired neuropathology and cognition in COPD remain largely unknown. In this review, we propose that the observed pulmonary oxidative burden and inflammatory response of people with COPD 'spills over' into the systemic circulation, resulting in damage to the brain and leading to cognitive dysfunction. As such, drugs targeting the lungs and comorbidities concurrently represent an exciting and unique therapeutic opportunity to treat COPD and cognitive impairments, which may lead to the production of novel targets to prevent and reverse the debilitating and life-threatening effects of cognitive dysfunction in COPD.

Prevention of acute exacerbation of chronic obstructive pulmonary disease after bronchoscopic lung volume reduction with endobronchial valves

INTRODUCTION

Bronchoscopic lung volume reduction (BLVR) with endobronchial valves (EBVs) has emerged as an important treatment method for patients with severe chronic obstructive pulmonary disease (COPD). Acute exacerbations of COPD (AECOPD) are a frequent complication following BLVR with EBV. However, there is no consensus on the prevention of AECOPD.

OBJECTIVES

Our study aims to compare the outcomes of different prophylactic measures on the occurrence of AECOPD after BLVR with EBV.

METHODS

We conducted a multicenter, retrospective study of patients who underwent BLVR with EBV at six different institutions. Emphasis was directed towards the specific practices aimed at preventing AECOPD: antibiotics, steroids, antibiotics plus steroids, or no prophylaxis. Subgroups were compared, and odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 170 patients were reviewed. The rate of AECOPD was 21.2% for the full cohort. Patients who received prophylaxis had a significantly lower rate of AECOPD compared with those who did not (16.7% vs. 46.2%; p = 0.001). The rate was lowest in patients who received antibiotics alone (9.2%). There was no significant difference in the rate of AECOPD between patients who received steroids alone or antibiotics plus steroids, compared with the other subgroups. The OR for AECOPD was 4.3 (95% CI: 1.8-10.4; p = 0.001) for patients not receiving prophylaxis and 3.9 (95% CI: 1.5-10.1; p = 0.004) for prophylaxis other than antibiotics alone.

CONCLUSIONS

Administration of antibiotics after BLVR with EBV was associated with a lower rate of AECOPD. This was not observed with the use of steroids or in combination with antibiotics.

COPD, Pulmonary Fibrosis and ILAs in Aging Smokers: The Paradox of Striking Different Responses to the Major Risk Factors

Aging and smoking are associated with the progressive development of three main pulmonary diseases: chronic obstructive pulmonary disease (COPD), interstitial lung abnormalities (ILAs), and idiopathic pulmonary fibrosis (IPF). All three manifest mainly after the age of 60 years, but with different natural histories and prevalence: COPD prevalence increases with age to >40%, ILA prevalence is 8%, and IPF, a rare disease, is 0.0005–0.002%. While COPD and ILAs may be associated with gradual progression and mortality, the natural history of IPF remains obscure, with a worse prognosis and life expectancy of 2–5 years from diagnosis. Acute exacerbations are significant events in both COPD and IPF, with a much worse prognosis in IPF. This perspective discusses the paradox of the striking pathological and pathophysiologic responses on the background of the same main risk factors, aging and smoking, suggesting two distinct pathophysiologic processes for COPD and ILAs on one side and IPF on the other side. Pathologically, COPD is characterized by small airways fibrosis and remodeling, with the destruction of the lung parenchyma. By contrast, IPF almost exclusively affects the lung parenchyma and interstitium. ILAs are a heterogenous group of diseases, a minority of which present with the alveolar and interstitial abnormalities of interstitial lung disease.

The traditional herbal formulation, Jianpiyifei II, reduces pulmonary inflammation induced by influenza A virus and cigarette smoke in mice

Chronic obstructive pulmonary disease (COPD) is a worldwide chronic inflammatory lung disease, and influenza A virus (IAV) infection is a common cause of acute exacerbations of COPD (AECOPD). Therefore, targeting viral infections represents a promising strategy to prevent the occurrence and development of inflammatory flare ups in AECOPD. Jianpiyifei II (JPYFII) is a traditional herbal medicine used in China to treat patients with COPD, and its clinical indications are not well understood. However, investigation of the anti-inflammatory effects and underlying mechanism using an animal model of smoking have been reported in a previous study by our group. In addition, some included herbs, such as Radix astragali and Radix aupleuri, were reported to exhibit antiviral effects. Therefore, the aim of the present study was to investigate whether JPYFII formulation relieved acute inflammation by clearing the IAV in a mouse model that was exposed to cigarette smoke experimentally. JPYFII formulation treatment during smoke exposure and IAV infection significantly reduced the number of cells observed in bronchoalveolar lavage fluid (BALF), expression of proinflammatory cytokines, chemokines, superoxide production, and viral load in IAV-infected and smoke-exposed mice. However, JPYFII formulation treatment during smoke exposure alone did not reduce the number of cells in BALF or the expression of Il-6, Tnf-a, and Il-1β. The results demonstrated that JPYFII formulation exerted an antiviral effect and reduced the exacerbation of lung inflammation in cigarette smoke (CS)-exposed mice infected with IAV. Our results suggested that JPYFII formulation could potentially be used to treat patients with AECOPD associated with IAV infection.

Role of extracellular vesicles in chronic lung disease

To explore the role of extracellular vesicles (EVs) in chronic lung diseases.

EVs are emerging as mediators of intercellular communication and possible diagnostic markers of disease. EVs harbour cargo molecules including RNA, lipids and proteins that they transfer to recipient cells. EVs are intercellular communicators within the lung microenvironment. Due to their disease-specific cargoes, EVs have the promise to be all-in-one complex multimodal biomarkers. EVs also have potential as drug carriers in chronic lung disease.

Descriptive discussion of key studies of EVs as contributors to disease pathology, as biomarkers and as potential therapies with a focus on chronic obstructive pulmonary disorder (COPD), cystic fibrosis (CF), asthma, idiopathic pulmonary fibrosis and lung cancer.

We provide a broad overview of the roles of EV in chronic respiratory disease. Recent advances in profiling EVs have shown their potential as biomarker candidates. Further studies have provided insight into their disease pathology, particularly in inflammatory processes across a spectrum of lung diseases. EVs are on the horizon as new modes of drug delivery and as therapies themselves in cell-based therapeutics.

EVs are relatively untapped sources of information in the clinic that can help further detail the full translational nature of chronic lung disorders.

The Role of Human Leukocyte Antigen-DR in Regulatory T Cells in Patients with Virus-Induced Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Background

This study assessed the role of different immune phenotypes of T cells in virus-induced acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Material/Methods

The study involved 103 participants, including individuals with virus-induced AECOPD (n=32), non-virus-induced AECOPD (n=31), and stable COPD (n=20) and individuals who were healthy smokers (n=20). The immune phenotypes of T cells in peripheral blood were evaluated via flow cytometry analysis, and the differences were analyzed.

Results

Patients with virus-induced AECOPD (virus group) had a higher COPD assessment test score on admission than those in the group with non-virus-induced AECOPD (nonvirus group; 25.6±3.8 vs 21.9±4.8, P=0.045). A lower CD4⁺ human leukocyte antigen-DR (HLA-DR)⁺ frequency was found in the peripheral blood of the virus group compared with the nonvirus group (2.2 vs 4.2, P=0.015), and the frequency of CD4⁺ CD25^high CD127^low HLA-DR⁺ in CD4⁺ in the virus group was lower than in the nonvirus group (1.1 vs 3.6, P=0.011). The CD3⁺, CD4⁺, CD8⁺, CD4⁺ central memory T cell, CD4⁺ effector memory T cell (Tem), CD4⁺ end-stage T cell, and CD8⁺ Tem levels in lymphocytes of peripheral blood were lower in exacerbation groups relative to those in the stable COPD and healthy smoking groups, but similar between exacerbation groups. Similar frequencies and levels of T cells between different stagings of COPD were also identified.

Conclusions

The expression of HLA-DR on the cell surface of CD4⁺ regulatory T cells (Tregs) was lower in the peripheral blood of patients with virus-induced AECOPD. The expression of HLA-DR in CD4⁺ Tregs suggested the effect of respiratory viruses on adaptive immunity of patients with AECOPD to some extent.

Buyuan decoction inhibits autophagy in a rat model of chronic obstructive pulmonary disease

Efforts have been made to find a better therapeutic approach with fewer side effects in treating chronic obstructive pulmonary disease (COPD). This study investigated the effect of Buyuan decoction (BYD) on autophagy in COPD rats. An experimental model with Sprague-Dawley rats was established by lipopolysaccharide (LPS) injection and cigarette smoke exposure. Rats were randomly allocated into blank control (normal control), experimental model, low-dose BYD (8.0 g/kg/day), medium-dose BYD (16.0 g/kg/day), high-dose BYD (32.0 g/kg/day) and 3-MA (methyladenine) groups (6 rats/group). Cell and tissue morphology were observed using hematoxylin and eosin staining. Autophagic vesicles were examined with a transmission electron microscope. Protein expression of LC3-II/I, BNIP-1, ATG7, p62, PI3K and p-PI3K in lung tissue was detected by Western blotting. Compared with the experimental model group, the inflammatory infiltrate in lung tissue was reduced, the nuclei of the pulmonary epithelial cells were restored to normal, and the expression of LC3, BNIP1, ATG7 and p-PI3K was significantly downregulated, while p62 expression was significantly upregulated after treatment with the BYD. The effect was most significant in the lowdose BYD group (P<0.05, all groups). These findings suggest that the BYD inhibits the occurrence of autophagy in the pathogenesis of COPD and that it can be a potential treatment.

Heart Failure is Highly Prevalent and Difficult to Diagnose in Severe Exacerbations of COPD Presenting to the Emergency Department

BACKGROUND

Some 20% of patients with stable Chronic Obstructive Pulmonary Disease (COPD) might have heart failure (HF). HF contribution to acute exacerbations of COPD (AECOPD) presenting to the emergency department (ED) is not well established.

AIMS

To assess (1) the HF incidence in patients presenting to the ED with AECOPD; (2) the concordance between ED and respiratory ward (RW) diagnosis; (3) the factors associated with risk of death after hospital discharge.

METHODS

Retrospective chart review of 119 COPD patients presenting to ED for acute exacerbation of respiratory symptoms and then admitted to RW where a final diagnosis of AECOPD, AECOPD and HF and AECOPD and OD (other diagnosis), was obtained. ED and RW diagnosis were then compared. Factors affecting survival at follow-up were investigated.

RESULTS

At RW, 40.3% of cases were diagnosed of AECOPD, 40.3% of AECOPD and HF and 19.4% of AECOPD and OD, with ED diagnosis coinciding with RW's in 67%, 23%, and 57% of cases respectively. At RW, 60% of patients in GOLD1 had HF, of which 43% were diagnosed at ED, while 40% in GOLD4 had HF that was never diagnosed at ED. Lack of inclusion in a COPD care program, HF, and early readmission for AECOPD were associated with mortality.

CONCLUSIONS

HF is highly prevalent and difficult to diagnose in patients in all GOLD stages presenting to the ED with severe AECOPD, and along with lack of inclusion in a COPD care program, confers a high risk for mortality.

Early readmission and mortality in acute exacerbation of chronic obstructive pulmonary disease with community-acquired pneumonia

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are important causes of hospital admission and mortality. Pneumonia is a major contributor to hospitalization for AECOPD and has a close relationship with poor outcomes. We performed a prospective cohort study to evaluate the prognosis of AECOPD patients with or without community-acquired pneumonia (CAP) who hospitalized from January 2012 to December 2015. We investigated mortality and readmission rates within 6 months after the first admission between two groups and analyzed the difference of survival rate according to readmission duration (≤30 vs. >30 days) or intensive care unit (ICU) treatment. Total 308 AECOPD patients (134 with CAP and 174 without CAP) were enrolled. The mean age was 72.3 ± 9.5 years old, and 235 patients (76.3%) were male. The 180-day mortality was higher in AECOPD with CAP than without CAP (24.6% vs. 13.2%; hazard ratio (HR): 1.982; 95% CI: 1.164–3.375; p = 0.012). However, readmission rate showed no significant difference between two groups (51.5% vs. 46.6%; HR: 1.172; 95% CI: 0.850–1.616; p = 0.333). It showed a significantly lower survival rate in AECOPD with CAP rather than without CAP when were readmitted within 30 days (HR: 1.738; 95% CI:1.063–3.017; p = 0.031). According to ICU treatment, survival rate was not significantly different between two groups. Multivariate analysis revealed the readmission within 30 days (p  <  0.001), serum hemoglobin concentration (p  =  0.010), and albumin level (p =  0.049) were significantly associated with 180-day mortality of AECOPD with CAP. AECOPD with CAP showed lower survival rate than AECOPD without CAP during 6 months. Early readmission within 30 days was significantly associated with an increased risk of mortality.

Serum β2-Microglobulin is Associated with Mortality in Hospitalized Patients with Exacerbated Chronic Obstructive Pulmonary Disease

Purpose

We hypothesized that increased level of serum β2-microglobulin (β2M) is an independent factor associated with higher mortality in hospitalized patients with exacerbated chronic obstructive pulmonary disease (COPD).

Patients and Methods

We retrospectively analyzed 488 hospitalized patients with exacerbated COPD as the first diagnosis at Beijing Chao-Yang hospital, P. R. China between December 31st, 2012 and December 28th, 2017. Concentrations of serum β2M and other clinical indexes were measured or collected on admission, and all patients were followed up to 90 days. The relationship between β2M and 30- and 90-day all-cause mortality was explored by Cox regression analysis adjusted for age, C-reactive protein values, N-terminal pro-brain natriuretic peptide/100, respiratory failure [RF, defined as partial arterial oxygen pressure (PaO₂) <60 mmHg on room air or PaO₂ over the fraction of inspired oxygen (PaO₂/FiO₂) < 300], eosinopenia, consolidation, and acidaemia.

Results

Median concentrations of β2M were significantly higher in non-survivals compared to survivals within 30 days (4.11 mg/L (IQR 3.10–6.60) vs 2.79mg/L (IQR 2.13–3.76), P < 0.001) and 90 days (3.79 mg/L (IQR 2.61–6.69) vs 2.79 mg/L (IQR 2.13–3.73), P < 0.001). Serum levels of β2M were correlated with 30-day and 90-day mortality in overall exacerbated COPD patients, with hazard ratios (HRs) of 1.09 (95% CI 1.04–1.14, P = 0.001) and 1.09 (95% CI 1.05–1.14, P < 0.001). In exacerbated COPD patients without RF and with RF, the HRs were 1.06 (95% CI 0.995–1.137, P = 0.069) and 1.14 (95% CI 1.02–1.27, P = 0.021) for 30-day mortality, 1.09 (95% CI 1.02–1.15, P = 0.010) and 1.14 (95% CI 1.03–1.26, P = 0.014) for 90-day mortality, respectively.

Conclusion

Our data showed that concentrations of serum β2M were associated with an increased risk of mortality, suggesting that β2M might be a valuable predictor of poor prognosis for hospitalized patients with exacerbated COPD.

The association of delta neutrophil index with the prognosis of acute exacerbation of chronic obstructive pulmonary disease

Background

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is associated with infective triggers including bacterial or viral in many cases, and pneumonia is a major contributor to hospitalization for AECOPD and has a close relationship with poor outcomes. Increased delta neutrophil index (DNI) can be useful in the detection of COPD patients with pneumonia.

Methods

A retrospective cohort study was performed to investigate the mortality rate of the patients who were re-admitted within 6 months after discharge from the hospital due to AECOPD with or without CAP. We analyzed the difference of cumulative survival rate according to serum DNI level and readmission duration.

Results

Finally, 140 AECOPD patients with community-acquired pneumonia (CAP) and 174 AECOPD patients without CAP were enrolled during 6 months, respectively. The mean age was 72.2 ± 9.4 year-old, and 240 patients (76.4%) were male. When comparing the cumulative survival rate according to readmission duration (≤ 30 vs >  30 days) and DNI level (< 3.5 vs ≥ 3.5%), AECOPD patients with readmission ≤30 days and DNI ≥ 3.5% showed the lowest cumulative survival rate compared to other groups (P <  0.001). Multivariate analysis revealed readmission duration ≤30 days (HR 7.879, 95% CI 4.554–13.632, P <  0.001); and serum DNI level (HR 1.086, 95% CI 1.043–1.131, P <  0.001) were significantly associated with the mortality of AECOPD patients during 6 months. The area under the curve for readmission (≤ 30 days) + DNI level (≥ 3.5%) was 0.753 (95% CI 0.676–0.830, P <  0.001) with a sensitivity of 73.7% and a specificity of 67.3%.

Conclusion

AECOPD patients who were readmitted ≤30 days and DNI ≥ 3.5% showed higher mortality. DNI level can be used as a predictor of prognosis in AECOPD patients who were readmitted after discharge.

Dual Carbon Dioxide Capture to Achieve Highly Efficient Ultra-Low Blood Flow Extracorporeal Carbon Dioxide Removal

Extracorporeal CO₂ removal is a highly promising support therapy for patients with hypercapnic respiratory failure but whose clinical implementation and patient benefit is hampered by high cost and highly specialized expertise required for safe use. Current approaches target removal of the gaseous CO₂ dissolved in blood which limits their ease of clinical use as high blood flow rates are required to achieve physiologically significant CO₂ clearance. Here, a novel hybrid approach in which a zero-bicarbonate dialysis is used to target removal of bicarbonate ion coupled to a gas exchange device to clear dissolved CO₂, achieves highly efficiently total CO₂ capture while maintaining systemic acid-base balance. In a porcine model of acute hypercapnic respiratory failure, a CO₂-reduction of 61.4 ± 14.4 mL/min was achieved at a blood flow rate of 248 mL/min using pediatric-scale priming volumes. The dialyzer accounted for 81% of total CO₂ capture with an efficiency of 33% with a minimal pH change across the entire circuit. This study demonstrates the feasibility of a novel hybrid CO₂ capture approach capable of achieving physiologically significant CO₂ removal at ultralow blood flow rates with low priming volumes while leveraging widely available dialysis platforms to enable clinical adoption.

A systematic review with meta-analysis of gastroesophageal reflux disease and exacerbations of chronic obstructive pulmonary disease

Background

Gastroesophageal reflux disease (GERD) was suggested to be associated with exacerbations of chronic obstructive pulmonary disease (COPD) in recent years. The aim of this study was to examine the association between GERD and COPD exacerbation through a meta-analysis.

Methods

Databases including EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials were searched with a systematic searching strategy for original articles, published until Jan 2019, without language restriction.

Results

A total of 13,245 patients from 10 observational articles were included in the meta-analysis. The meta-analysis indicated that GERD is associated with increased risk of COPD exacerbation (OR: 5.37; 95% CI 2.71–10.64). Patients with COPD and GERD had increased number of exacerbation (WMD: 0.48; 95% CI: 0.31 to 0.65).

Conclusions

The meta-analysis showed that there was a significant correlation between GERD and COPD exacerbation.

G-CSFR antagonism reduces neutrophilic inflammation during pneumococcal and influenza respiratory infections without compromising clearance

Excessive neutrophilic inflammation can contribute to the pathogenesis of pneumonia. Whilst anti-inflammatory therapies such as corticosteroids are used to treat excessive inflammation, they do not selectively target neutrophils and may compromise antimicrobial or antiviral defences. In this study, neutrophil trafficking was targeted with a granulocyte-colony stimulating factor receptor monoclonal antibody (G-CSFR mAb) during Streptococcus pneumoniae (serotype 19F) or influenza A virus (IAV, strain HKx31) lung infection in mice. Firstly, we demonstrated that neutrophils are indispensable for the clearance of S. pneumoniae from the airways using an anti-Ly6G monoclonal antibody (1A8 mAb), as the complete inhibition of neutrophil recruitment markedly compromised bacterial clearance. Secondly, we demonstrated that G-CSF transcript lung levels were significantly increased during pneumococcal infection. Prophylactic or therapeutic administration of G-CSFR mAb significantly reduced blood and airway neutrophil numbers by 30–60% without affecting bacterial clearance. Total protein levels in the bronchoalveolar lavage (BAL) fluid (marker for oedema) was also significantly reduced. G-CSF transcript levels were also increased during IAV lung infection. G-CSFR mAb treatment significantly reduced neutrophil trafficking into BAL compartment by 60% and reduced blood neutrophil numbers to control levels in IAV-infected mice. Peak lung viral levels at day 3 were not altered by G-CSFR therapy, however there was a significant reduction in the detection of IAV in the lungs at the day 7 post-infection phase. In summary, G-CSFR signalling contributes to neutrophil trafficking in response to two common respiratory pathogens. Blocking G-CSFR reduced neutrophil trafficking and oedema without compromising clearance of two pathogens that can cause pneumonia.

NR, Make BJ, Marchetti N, Martinez FJ, Maselli DJ, Mathews AM, McCormack MC, McDonald MLN, McEvoy CE, Moll M, Molye SS, Murray S, Nath H, Newell Jr. JD, Occhipinti M, Paoletti M, Parekh T, Pistolesi M, Pratte KA, Putcha N, Ragland M, Reinhardt JM, Rennard SI, Rosiello RA, Ross JC, Rossiter HB, Ruczinski I, San Jose Estepar R, Sciurba FC, Sieren JC, Singh H, Soler X, Steiner RM, Strand MJ, Stringer WW, Tal-Singer R, Thomashow B, Vegas Sánchez-Ferrero G, Walsh JW, Wan ES, Washko GR, Michael Wells J, Wendt CH, Westney G, Wilson A, Wise RA, Yen A, Young K, Yun J, Silverman EK, Crapo JD. COPDGene® 2019: Redefining the Diagnosis of Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) remains a major cause of morbidity and mortality. Present-day diagnostic criteria are largely based solely on spirometric criteria. Accumulating evidence has identified a substantial number of individuals without spirometric evidence of COPD who suffer from respiratory symptoms and/or increased morbidity and mortality. There is a clear need for an expanded definition of COPD that is linked to physiologic, structural (computed tomography [CT]) and clinical evidence of disease. Using data from the COPD Genetic Epidemiology study (COPDGene®), we hypothesized that an integrated approach that includes environmental exposure, clinical symptoms, chest CT imaging and spirometry better defines disease and captures the likelihood of progression of respiratory obstruction and mortality.

METHODS

Four key disease characteristics - environmental exposure (cigarette smoking), clinical symptoms (dyspnea and/or chronic bronchitis), chest CT imaging abnormalities (emphysema, gas trapping and/or airway wall thickening), and abnormal spirometry - were evaluated in a group of 8784 current and former smokers who were participants in COPDGene® Phase 1. Using these 4 disease characteristics, 8 categories of participants were identified and evaluated for odds of spirometric disease progression (FEV1 > 350 ml loss over 5 years), and the hazard ratio for all-cause mortality was examined.

RESULTS

Using smokers without symptoms, CT imaging abnormalities or airflow obstruction as the reference population, individuals were classified as Possible COPD, Probable COPD and Definite COPD. Current Global initiative for obstructive Lung Disease (GOLD) criteria would diagnose 4062 (46%) of the 8784 study participants with COPD. The proposed COPDGene® 2019 diagnostic criteria would add an additional 3144 participants. Under the new criteria, 82% of the 8784 study participants would be diagnosed with Possible, Probable or Definite COPD. These COPD groups showed increased risk of disease progression and mortality. Mortality increased in patients as the number of their COPD characteristics increased, with a maximum hazard ratio for all cause-mortality of 5.18 (95% confidence interval [CI]: 4.15-6.48) in those with all 4 disease characteristics.

CONCLUSIONS

A substantial portion of smokers with respiratory symptoms and imaging abnormalities do not manifest spirometric obstruction as defined by population normals. These individuals are at significant risk of death and spirometric disease progression. We propose to redefine the diagnosis of COPD through an integrated approach using environmental exposure, clinical symptoms, CT imaging and spirometric criteria. These expanded criteria offer the potential to stimulate both current and future interventions that could slow or halt disease progression in patients before disability or irreversible lung structural changes develop.

Benralizumab for the Prevention of COPD Exacerbations

BACKGROUND

The efficacy and safety of benralizumab, an interleukin-5 receptor alpha-directed cytolytic monoclonal antibody, for the prevention of exacerbations in patients with moderate to very severe chronic obstructive pulmonary disease (COPD) are not known.

METHODS

In the GALATHEA and TERRANOVA trials, we enrolled patients with COPD (at a ratio of approximately 2:1 on the basis of eosinophil count [≥220 per cubic millimeter vs. <220 per cubic millimeter]) who had frequent exacerbations despite receiving guideline-based inhaled treatment. Patients were randomly assigned to receive benralizumab (30 or 100 mg in GALATHEA; 10, 30, or 100 mg in TERRANOVA) every 8 weeks (every 4 weeks for the first three doses) or placebo. The primary end point was the treatment effect of benralizumab, measured as the annualized COPD exacerbation rate ratio (benralizumab vs. placebo) at week 56 in patients with baseline blood eosinophil counts of 220 per cubic millimeter or greater. Safety was also assessed.

RESULTS

In GALATHEA, the estimates of the annualized exacerbation rate were 1.19 per year (95% confidence interval [CI], 1.04 to 1.36) in the 30-mg benralizumab group, 1.03 per year (95% CI, 0.90 to 1.19) in the 100-mg benralizumab group, and 1.24 per year (95% CI, 1.08 to 1.42) in the placebo group; the rate ratio as compared with placebo was 0.96 for 30 mg of benralizumab (P = 0.65) and 0.83 for 100 mg of benralizumab (P = 0.05). In TERRANOVA, the estimates of the annualized exacerbation rate for 10 mg, 30 mg, and 100 mg of benralizumab and for placebo were 0.99 per year (95% CI, 0.87 to 1.13), 1.21 per year (95% CI, 1.08 to 1.37), 1.09 per year (95% CI, 0.96 to 1.23), and 1.17 per year (95% CI, 1.04 to 1.32), respectively; the corresponding rate ratios were 0.85 (P = 0.06), 1.04 (P = 0.66), and 0.93 (P = 0.40). At 56 weeks, none of the annualized COPD exacerbation rate ratios for any dose of benralizumab as compared with placebo reached significance in either trial. Types and frequencies of adverse events were similar with benralizumab and placebo.

CONCLUSIONS

Add-on benralizumab was not associated with a lower annualized rate of COPD exacerbations than placebo among patients with moderate to very severe COPD, a history of frequent moderate or severe exacerbations, and blood eosinophil counts of 220 per cubic millimeter or greater (Funded by AstraZeneca [GALATHEA and TERRANOVA] and Kyowa Hakko Kirin [GALATHEA]; GALATHEA and TERRANOVA ClinicalTrials.gov numbers, NCT02138916 and NCT02155660.).

FEV1 and total Cardiovascular mortality and morbidity over an 18 years follow-up Population-Based Prospective EPIC-NORFOLK Study

BACKGROUND

Our study aimed to determine the association between forced expiratory volume in one second (FEV1) and subsequent fatal and non-fatal events in a general population.

METHODS

The Norfolk (UK) based European Prospective Investigation into Cancer (EPIC-Norfolk) recruited 25,639 participants between 1993 and 1997. FEV1 measured by portable spirometry, was categorized into sex-specific quintiles. Mortality and morbidity from all causes, cardiovascular disease (CVD) and respiratory disease were collected from 1997 up to 2015. Cox proportional hazard regression analysis was used with adjustment for socio-economic factors, physical activity and co-morbidities.

RESULTS

Mean age of the population was 58.7 ± 9.3 years, mean FEV1 for men was 294± 74 cL/s and 214± 52 cL/s for women. The adjusted hazard ratios for all-cause mortality for participants in the highest fifth of the FEV1 category was 0.63 (0.52, 0.76) for men and 0.62 (0.51, 0.76) for women compared to the lowest quintile. Adjusted HRs for every 70 cL/s increase in FEV1 among men and women were 0.77 (p < 0.001) and 0.68 (p < 0.001) for total mortality, 0.85 (p<0.001) and 0.77 (p<0.001) for CVD and 0.52 (p <0.001) and 0.42 (p <0.001) for respiratory disease.

CONCLUSIONS

Participants with higher FEV1 levels had a lower risk of CVD and all-cause mortality. Measuring the FEV1 with a portable handheld spirometry measurement may be used as a surrogate marker for cardiovascular risk. Every effort should be made to identify those with poorer lung function even in the absence of cardiovascular disease as they are at greater risk of total and CV mortality.

New frontiers in the treatment of comorbid cardiovascular disease in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a disease characterised by persistent airflow limitation that is not fully reversible and is currently the fourth leading cause of death globally. It is now well established that cardiovascular-related comorbidities contribute to morbidity and mortality in COPD, with approximately 50% of deaths in COPD patients attributed to a cardiovascular event (e.g. myocardial infarction). Cardiovascular disease (CVD) and COPD share various risk factors including hypertension, sedentarism, smoking and poor diet but the underlying mechanisms have not been fully established. However, there is emerging and compelling experimental and clinical evidence to show that increased oxidative stress causes pulmonary inflammation and that the spill over of pro-inflammatory mediators from the lungs into the systemic circulation drives a persistent systemic inflammatory response that alters blood vessel structure, through vascular remodelling and arterial stiffness resulting in atherosclerosis. In addition, regulation of endothelial-derived vasoactive substances (e.g. nitric oxide (NO)), which control blood vessel tone are altered by oxidative damage of vascular endothelial cells, thus promoting vascular dysfunction, a key driver of CVD. In this review, the detrimental role of oxidative stress in COPD and comorbid CVD are discussed and we propose that targeting oxidant-dependent mechanisms represents a novel strategy in the treatment of COPD-associated CVD.

Adjuvant therapy efficacy of Chinese drugs pharmaceutics for COPD patients with respiratory failure: a meta-analysis

We performed a meta-analysis to evaluate the efficacy and safety of Western medicine combined with Tanreqing for patients with chronic obstructive pulmonary disease (COPD) and respiratory failure. We comprehensively searched several online databases from the times of their inception to November 2018. The trial quality was assessed using the bias risk tool recommended by the Cochrane library. Relative risks (RRs) and their 95% confidence intervals (CIs) for binary outcomes and weighted mean differences (MDs) with 95% CIs for continuous data were calculated. A fixed effect model indicated that integrated Tanreqing group experienced higher overall treatment effectiveness (RR = 1.23, 95% CI: 1.17–1.30, P=0.000). Pooled results from random effects models indicated the oxygen partial pressure of the test group was significantly higher than that of the control groups (MD = 9.55, 95% CI: 4.57–14.52, P<0.000). The carbon dioxide pressure of the test group was significantly lower than that of the control groups (MD = –6.06, 95% CI: –8.19 to –3.93, P=0.000). The lung function score of the test group was significantly higher than that of the control group (MD = 7.87, 95% CI: 4.45–11.29). Sensitivity analysis indicated that the data were statistically robust. Clinical effects of Western medicine combined with Tanreqing used to treat combined COPD/respiratory failure were better than those afforded by Western medicine; no serious adverse reactions were noted. However, publication bias was evident, and further trials with larger sample sizes are required.

Efficacy and safety of Xuebijing injection and its influence on immunomodulation in acute exacerbations of chronic obstructive pulmonary disease: study protocol for a randomized controlled trial

BACKGROUND

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is the leading cause of mortality in chronic obstructive pulmonary disease (COPD). Traditional Chinese medicine (TCM) has been widely used in Asia as an adjunct treatment for AECOPD to improve the patients' symptoms. Xuebijing (XBJ) injection is one of the major herbal medicines used in TCM. Previous small-sample clinical trials have proven its efficacy and safety in the treatment of AECOPD; however, the current data on XBJ as an adjunct therapy are insufficient. The present study will be a multi-center randomized clinical trial (RCT) to evaluate the efficacy and safety of XBJ injection in AECOPD and explore its influence on the immune function based on the altered levels of T cells.

METHODS

This study will be a prospective, randomized, placebo-controlled, blinded, multi-center trial. A total of 300 eligible patients will be randomly assigned to the treatment or placebo control group in a 1:1 ratio using a central randomization system. The treatment group will receive routine medication plus XBJ injection, and the control group will receive routine medication plus 0.9% NaCl injection. The patients will receive the corresponding treatment for 5 days starting within 24 h of enrollment. The primary outcome, the of rate endotracheal intubation, will be evaluated on day 28 after treatment. The secondary outcomes will include changes in immune and inflammatory indicators, respiratory support, mortality rate after 28 days, blood gas analysis, improvement in Acute physiology and chronic health evaluation (APACHE) II scores and clinical symptoms, and the length and cost of intensive care unit stay and hospitalization. The safety of the interventions will be assessed throughout the trial.

DISCUSSION

This is the first and largest randomized, controlled, blinded trial that evaluates the efficacy of XBJ injection as adjuvant therapy for AECOPD. The results of this trial will provide valuable clinical evidence for recommendations on the management of the disease and identify the underlying mechanisms.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02937974 . Registered on 13 October 2016. Chinese clinical trial registry, ChiCTR-IPR-17011667. Registered on 15 June 2017.

Acute exacerbations of chronic obstructive pulmonary disease (COPD) experiences among COPD patients with comorbid gastrooesophageal reflux disease

AIMS AND OBJECTIVES

To explore perceptions of experience exacerbations of chronic obstructive pulmonary disease among chronic obstructive pulmonary disease patients with comorbid gastrooesophageal reflux disease by focusing on unravelling how patients differentiate and react to symptoms of chronic obstructive pulmonary disease and gastrooesophageal reflux disease.

BACKGROUND

While gastrooesophageal reflux disease has been suggested to be a risk factor for chronic obstructive pulmonary disease exacerbations, no study has explored perceptions of the symptoms leading up to severe exacerbation of chronic obstructive pulmonary disease events among chronic obstructive pulmonary disease patients with comorbid gastrooesophageal reflux disease.

DESIGN

Qualitative design.

METHODS

The analysis was performed in accordance with principles of Grounded Theory methodology. Data were collected via semi-structured interviews from 12 chronic obstructive pulmonary disease patients with endoscopy-diagnosed gastrooesophageal reflux disease who had experienced a chronic obstructive pulmonary disease exacerbation with hospitalisation. Appraisal and analysis using consolidated criteria for reporting qualitative research (COREQ) checklist were undertaken.

RESULTS

The core category of this study was the ineffective management of exacerbation symptoms, which was associated with perceived symptoms pre-exacerbation which contained three overlapping categories of symptom presentation experienced, and chronic obstructive pulmonary disease-related coping strategies, high anxiety and a sense of helplessness in disease management.

CONCLUSIONS

Patients with severe chronic obstructive pulmonary disease with comorbid gastrooesophageal reflux disease presented with some distinctly different atypical symptoms yet used common respiratory symptom management strategies. Patients and practitioners alike need to be more aware of the possibility of other symptoms such as nonspecific symptoms being clues of exacerbation onset for a more effective intervention.

RELEVANCE TO CLINICAL PRACTICE

The medical community needs to educate patients to understand and manage not only chronic obstructive pulmonary disease but also gastrooesophageal reflux disease symptoms so that they are better able to identify the cause of their symptoms, treat them appropriately and seek out medical assistance when necessary.

Dynamic Characteristics of Sequential Acute Exacerbations and Risk Windows in AECOPD Rats Induced by Cigarette-Smoke and Exposure to Klebsiella pneumoniae

The risk-window (RW) of chronic obstructive pulmonary disease (COPD) is a period after an acute exacerbation (AE) but before the following stable phase, in which exacerbations are easy to relapse. We established a sequential COPD-AE-RW rat model by cigarette-smoke and bacterial exposures in the first 8 weeks, and was challenged with Klebsiella pneumonia to mimic an AE on Day 1 of week 9, and found that body temperature, white blood cell, neutrophils, serum amyloid A (SAA) and C-reactive protein (CRP) increased in AECOPD rats 24 h after challenge, and declined in 3-6 d, while lung function declined in 48 h, and recovered in 7-16 d. When sacrificed, pulmonary forced expiratory volume (FEV)100 and FEV300 decreased, while elevated bronchoalveolar lavage fluid (BALF) neutrophils and marked airway inflammation, remodeling and emphysema were observed. Sequential COPD-AE-RW rat model was established successfully and AE phase lasts for approximately 5-7 d, followed by a 10-d around risk-window.