Diagnosis and Management of Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Table of Contents

 

As more and more patients present to the ED with symptoms that suggest an acute exacerbation of COPD –worsening dyspnea, cough and sputum production  – emergency clinicians can improve patient comfort and possibly mitigate morbidity and mortality with the right testing and treatment interventions:

COPD is a clinical diagnosis, but some tests can exclude comorbid conditions

When to give antibiotics and when to culture

The SpO₂ range to aim for

ECG findings typical of COPD

The role of ultrasound

Oxygen, bronchodilators, corticosteroids, and antibiotics: which ones, and how much?

Reviewing noninvasive ventilation and intubation options

1. Abstract
2. Case Presentations
3. Introduction
4. Selected Abbreviations
5. Critical Appraisal of the Literature
6. Definition
7. Epidemiology, Etiology, and Pathophysiology
   1. Epidemiology of COPD
   2. Etiology of Acute Exacerbation of COPD
   3. Pathophysiology of COPD
8. Differential Diagnosis
9. Prehospital Care
10. Emergency Department Evaluation
    1. History
    2. Physical Examination
11. Diagnostic Studies
    1. Laboratory Testing and Arterial Blood Gas Sampling
    2. Chest Imaging
    3. Electrocardiogram
    4. Serum Cardiac Biomarkers
    5. Microbiologic Evaluation
    6. Point-of-Care Ultrasound
    7. Other Tests
12. Treatment
    1. Supplemental Oxygen
    2. Bronchodilators
    3. Corticosteroids
    4. Antibiotics
    5. Magnesium Sulfate
    6. Methylxanthines
    7. Noninvasive Positive-Pressure Ventilation
    8. Mechanical Ventilation
    9. High-Flow Nasal Cannula
13. Controversies and Cutting Edge
    1. Biomarkers
    2. Heliox
    3. Capnography
14. Disposition
    1. Outpatient Versus Inpatient Care
    2. Management for Patients Going Home
15. Summary
16. Risk Management Pitfalls in Managing Acute Exacerbation of COPD
17. Time- and Cost-Effective Strategies
18. Case Conclusions
19. Clinical Pathways
    1. Clinical Pathway For Diagnostic Evaluation of Acute Exacerbation of COPD
    2. Clinical Pathway For Management of Acute Exacerbation of COPD
20. Tables and Figures
    1. Table 1. Model of Symptom Risk Evaluation of COPD
    2. Table 2. Differential Diagnosis of Acute Exacerbation of COPD
    3. Table 3. Summary of Diagnostic Testing in Patients With Acute Exacerbation of COPD
    4. Table 4. Arrhythmias Related to COPD
    5. Table 5. Electrocardiogram Abnormalities Related to COPD
    6. Table 6. Antibiotics to Consider for the Treatment of Acute Exacerbation of COPD
    7. Table 7. Exclusion Criteria for Noninvasive Positive-Pressure Ventilation and Indications for Intubation
    8. Table 8. Ventilator Setting Recommendations Post Intubation
    9. Table 9. Factors Associated With Risk of Death From COPD Exacerbation
    10. Table 10. Indications for Hospital Admission
    11. Figure 1. Saber-Sheath Trachea on Computed Tomography
    12. Figure 2. Electrocardiogram of Multifocal Atrial Tachycardia
    13. Figure 3. Electrocardiogram of Right Ventricular Hypertrophy
    14. Figure 4. End-Tidal Capnography Tracings
21. References

Abstract

Acute exacerbation of chronic obstructive pulmonary disease (COPD) is a clinical diagnosis that is based on changes in dyspnea, cough, and/or sputum production in a COPD patient; however, patients presenting with an acute exacerbation may be undiagnosed or have a variety of comorbid conditions that can complicate diagnosis. This issue presents strategies and algorithms for the early use of evidence-based interventions, including appropriate use of antibiotics, bronchodilators, and corticosteroids, along with noninvasive ventilation with capnography, to minimize morbidity and mortality associated with this disease.

Case Presentation

It is change of shift, and you receive sign-out on a 67-year-old gentleman with a history of COPD presenting with 5 days of worsening productive cough, wheezing, and increased albuterol use despite outpatient treatment with prednisone and doxycycline. His oxygen saturation was 86% on arrival, and the nurse placed him on oxygen therapy at 6 L/min via nasal cannula shortly before you arrived. You find the patient sitting on the edge of his bed, tachypneic, with increased work of breathing and audible wheezing on auscultation. He is alert and acknowledges your presence but does not speak. You wonder why he continues to be hypoxic and if there is any other intervention that is indicated . . .

Your next patient is a 57-year-old woman with a history of smoking 2 packs of cigarettes per day. Her husband called 911 because she was having increased difficulty with breathing and productive cough for the previous week. She has no documented pulmonary history. Upon arrival, EMS noted that she could not speak in full sentences, her oxygen saturation was 81% on room air, and she had diffuse end-expiratory wheezing on auscultation. IV access was obtained. She was given continuous albuterol nebulization without relief and started on supplemental oxygen. The chest x-ray does not demonstrate a focal infiltrate; however, her lungs appear hyperinflated, with flattened diaphragms and a small cardiac silhouette. You wonder if she has COPD with an acute exacerbation and whether prednisone and antibiotics are indicated . . .

Introduction

Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. From a financial perspective, COPD exacted a net $36 billion toll in 2010 in the United States, and its costs are expected to continue to rise.¹ Despite decreasing tobacco use nationally, emergency department (ED) visits for COPD-related problems continue to climb, with over 1.7 million in 2011 alone. Moreover, about one-fifth of COPD patients presenting to the ED required hospitalization.²

COPD is characterized by a persistent airflow limitation, after administration of bronchodilators, that can be identified on spirometry as a ratio of forced expired volume in 1 second (FEV₁) to forced vital capacity (FVC) that is < 70%. Although COPD is a treatable disease, the airflow limitation is not fully reversible. Previous definitions of COPD have included the terms emphysema and chronic bronchitis; however, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines do not, and they clarify the distinction: Emphysema is a pathological term that refers to the destruction of alveoli, which can be present but is not inherent in patients with COPD. Chronic bronchitis is an independent clinical entity characterized by cough and sputum production for at least 3 months in each of 2 consecutive years and can occur without the development of airflow limitation. Guidelines define acute exacerbation of COPD (AECOPD) as an event characterized by a worsening of the patient’s respiratory symptoms (dyspnea, cough, and/or sputum production) that is beyond normal day-to-day variations, and that leads to a change in medication.^3,4

Patients with COPD often have comorbid conditions that may have either resulted from COPD, (eg, pulmonary hypertension or malnutrition) or are simply associated with it (eg, anxiety, cardiovascular disease, sleep apnea, and venous thromboembolism).⁵ Because of the myriad presenting features of COPD and/or these comorbidities, diagnostic challenges exist when these patients present to the ED in extremis. This issue of Emergency Medicine Practice reviews the most recent evidence-based recommendations for the diagnosis and management of AECOPD, with a focus on tailoring management to the underlying pathophysiology of the disease state.

Selected Abbreviations

Critical Appraisal of the Literature

A literature search was performed in PubMed, with the search terms COPD, chronic obstructive pulmonary disease, and acute COPD exacerbation. The search was limited to articles published within the last 10 years, and studies relating specifically to acute COPD exacerbation (as opposed to stable COPD) were reviewed. In addition, references were appraised for additional relevant articles. A total of 127 articles have been included in this review.

The Cochrane Library was searched for systematic reviews using the key term acute COPD exacerbation, which identified 25 articles. In addition, guidelines from the GOLD, American Thoracic Society (ATS), European Respiratory Society (ERS), American College of Chest Physicians (ACCP), and National Institute for Health and Care Excellence (NICE) were reviewed.

COPD is a composite of heterogenous etiologies that contribute to variations in the presentation in patient populations. For example, it has been increasingly recognized that exposures to substances other than cigarette smoke contribute to the pathophysiology of disease. The asthma-COPD overlap syndrome is a newly identified condition, with varied acceptance in the community, but it illustrates that a history of asthma does not exclude coexisting COPD. Cohorts included in studies are similarly diverse, making the generalizability of results challenging. Clinically, the varied presentation of COPD makes detecting previously undiagnosed patients more difficult; however, these patients may well be the ones seeking care in the ED.

The current state of the literature remains limited mainly by the retrospective observational nature of most studies. There are few randomized controlled trials to direct management of acute COPD exacerbations. Furthermore, existing studies have wide-ranging outcome measures, such as pulmonary function, symptom scores, rate of exacerbation, and short-term mortality. In the absence of high-quality data, some interventions should be directed by prior individual patient response.

Risk Management Pitfalls in Managing Acute Exacerbation of COPD

1. “But the patient said he has asthma.”

Not all wheezing is asthma, and not all patient-reported histories of asthma are actually asthma. Ensure that the patient’s risk factors and history align with the diagnosis.

2. “I know she has COPD, but I doubt that’s what’s causing her respiratory distress.”

Inadequately assessing triggers for AECOPD may lead you down an expensive and ultimately fruitless diagnostic path. A good history can increase efficiency, decrease costs, and most importantly, improve clinical outcomes.

3. “This COPD patient’s respiratory and hemodynamic statuses are simply not improving, despite doing everything by the book. What’s going on?”

Largely due to the high systemic inflammatory state in individuals with COPD, patients presenting with an AECOPD have a surprisingly high incidence of pulmonary embolism. Be vigilant to ensure that the patient does not have a pulmonary embolism when he fails to respond as expected to the standard interventions for an AECOPD.

4. “COPD is not possible - I don’t hear any wheezing.”

Although wheezing is often considered a hallmark of COPD, a lack of wheezing can actually signify a loss of effective airflow and can indicate imminent clinical deterioration.

5. “His COPD exacerbation wasn’t that bad - I didn’t need to actually measure anything.”

Much of the physical examination is inherently subjective, which may cause an underappreciation of the severity of a patient’s AECOPD. A focused diagnostic assessment can identity poor prognostic markers.

6. “We need to keep the oxygen saturation as high as possible to make sure that oxygenation remains stable.”

Not only is there no benefit to maintaining an oxygen saturation in the high 90s in a patient with COPD, it may actually be harmful. Recent guidelines agree on an arterial saturation target of 88% to 92%.

7. “She looks really sick; let’s intubate to assist her breathing now.”

Many patients can avoid endotracheal intubation with early implementation of NIPPV with bilevel positive airway pressure. Taking into account the absolute contraindications for NIPPV, consider a trial to assist breathing.

8. “We need to provide high tidal volumes on the ventilator to blow down the CO₂!”

Despite a desire to increase minute ventilation to remove CO₂ in a COPD patient, excessive tidal volumes on the ventilator may actually injure the lungs.

9. “I don’t need to give any oral or IV corticosteroids because the patient is already on inhaled ones.”

Although some systemic absorption of inhaled steroids can occur, it is insufficient to suppress the inflammatory process in the airways during an AECOPD. Therefore, oral or IV steroids are necessary for these circumstances.

10. “There’s no need to tell the patient to stop smoking because it’s so obvious and, plus, there’s nothing I can do to change that.”

Smoking cessation can normalize the natural rate of decline in a person’s lung function, even in a long-term smoker, and brief clinician advice about the need to stop smoking

Tables and Figures

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study is included in bold type following the reference, where available. In addition, the most informative references cited in this paper, as determined by the authors, are noted by an asterisk (*) next to the number of the reference.

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