Many definitions for acute exacerbations of COPD have been proposed and include many of the same components. Episodes may be diagnosed in people with a history of COPD who experience any of the following: worsening respiratory symptoms and physiologic status;[10] or worsening of degree of cough, level of dyspnea, and/or the volume and character of sputum,[62] particularly if these changes are acute in onset, sustained over time, beyond the normal day-to-day variation, or lead to a change in the patient's baseline medication regimens.[1][171][172][173]

Clinical evaluation

Most patients presenting with a potential acute exacerbation are stable enough that they may be evaluated and managed in the outpatient setting. Clinical evaluation should include determination of the following: vital signs (including SaO2 via pulse oximetry), mental status, severity of the level of dyspnea and airflow obstruction, history of symptoms associated with the patient's chief complaints, and the ability to continue to provide self-care at home. The risk of exacerbations should also be assessed: people with severe or very severe airflow obstruction, those with a history of two or more exacerbations in the preceding year, or those with history of hospitalization due to exacerbation in the previous year are considered at high risk of subsequent exacerbations.[1] Patients should be questioned regarding changes in their baseline level of dyspnea, cough, wheeze, and sputum production; character of the sputum; presence of fever; any other focal complaints (e.g., chest pain, signs/symptoms of an upper respiratory tract infection, palpitations, lightheadedness, or leg swelling); as well as their understanding and adherence with their current medical regimen for COPD, including the use of supplemental oxygen and any change in their requirement for rescue inhaler use. On examination, auscultation may reveal wheeze, and it is important to observe patients for signs of respiratory failure (e.g., tachypnea, accessory muscle use, chest retractions, paradoxical movements of the abdomen, and/or cyanosis) and/or signs of cor pulmonale, hemodynamic instability, or worsened mental status.

Laboratory evaluation and imaging

Diagnostic tests are typically reserved for those with moderate to severe exacerbations. Features of this include but are not limited to unstable vital signs, severe symptoms, low SaO2 on pulse oximetry, evidence of ventilatory failure, or mental status change (e.g., confusion, lethargy, coma). Diagnostic testing should also be considered if the diagnosis of an episode is uncertain.

Diagnostic tests for people with moderate to severe exacerbations may include:

  • Pulse oximetry

  • Chest radiograph

  • ECG

  • ABG

  • CBC with platelets

  • Electrolytes

  • Creatinine

  • BUN levels

  • Sputum analysis.

In severe disease, a sputum Gram stain and culture should be obtained, and, if hospitalization is being considered and where feasible, tests for respiratory viruses should be conducted, to prevent healthcare-associated transmission of the pathogen (e.g., influenza, respiratory syncytial virus, and parainfluenza virus).

Emerging investigation

Procalcitonin is emerging as a promising biomarker for the diagnosis of bacterial infections as it tends to be higher in severe bacterial infections and low in viral infections. The Food and Drug Administration has approved procalcitonin as a test for guiding antibiotic therapy in patients with acute respiratory tract infections. A Cochrane review of the use of procalcitonin to guide initiation and duration of antibiotic treatment in people with acute respiratory tract infections found it lowered the risk of mortality, and lead to lower antibiotic consumption, and lower risk for antibiotic-related side effects in all patients including those with acute exacerbation of COPD.[174]Further research is required to establish its use in clinical practice.

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