Key Clinical Questions
What conditions mimic an acute exacerbation of chronic obstructive pulmonary disease (COPD) and require different diagnostic and treatment modalities?
What inpatient therapeutic modalities reduce mortality or length of stay for patients with exacerbation of COPD?
What are the indications for noninvasive ventilation for patients with an acute exacerbation of COPD?
Explain the therapeutic interventions that you would consider and discuss with a patient at the time of discharge following an acute exacerbation of COPD?
DEFINITION AND BACKGROUND
Chronic obstructive pulmonary disease (COPD) is a group of clinical and pathological pulmonary disorders that are preventable and treatable and are characterized by airflow limitation that is not fully reversible. The most common phenotypes of COPD are emphysema and chronic bronchitis. Emphysema is generally defined as irreversible enlargement of the airways and loss of elastic recoil. Clinically, emphysema presents with dyspnea along with clinical findings of an expanded chest, decreased breath sounds, radiographic lucency, and flattening of the diaphragms. Chronic bronchitis is defined by the finding of cough and sputum production on most days of at least 3 months per year for two consecutive years. Pathologically, the hallmarks of chronic bronchitis are large airway inflammation and the hypertrophy and hyperplasia of the mucous-secreting goblet cells. COPD is diagnosed after demonstrating airflow limitation by spirometry (at a time free of exacerbation) that is not fully reversible in patients who exhibit cough, sputum production, dyspnea or other appropriate risk factors. The severity of COPD is classified by the degree of limitation in the forced expiratory volume in 1 second (FEV1) as well as by the frequency of exacerbations (0-1 vs ≥ 2 per year) and patient reported symptoms using validated questionnaires (Tables 232-1 and 232-2).
TABLE 232-1GOLD Spirometry Criteria for Chronic Obstructive Pulmonary Disease Severity ||Download (.pdf) TABLE 232-1 GOLD Spirometry Criteria for Chronic Obstructive Pulmonary Disease Severity
|GOLD Stage ||Severity ||Spirometry |
|I ||Mild ||FEV1/FVC < 0.7 and FEV1 80% predicted |
|II ||Moderate ||FEV1/FVC < 0.7 and 50% FEV1 < 80% predicted |
|III ||Severe ||FEV1/FVC < 0.7 and 30% FEV1 < 50% predicted |
|IV ||Very severe || |
FEV1/FVC < 0.7 and FEV1 < 30% predicted
FEV1 < 50% predicted with respiratory failure or signs of right heart failure
TABLE 232-2GOLD Grading Criteria for Chronic Obstructive Pulmonary Disease ||Download (.pdf) TABLE 232-2 GOLD Grading Criteria for Chronic Obstructive Pulmonary Disease
|Grade ||Spirometry ||Yearly Exacerbation Rate ||Symptom Score |
|A ||Stage 1 or 2 ||≤1 exacerbation not leading to a hospitalization ||CAT <10 or mMRC 0-1 |
|B ||Stage 1 or 2 ||≤1 exacerbation not leading to a hospitalization ||CAT ≥10 or ...|