Acute exacerbation of COPD

Background

• Worsening respiratory symptoms, including dyspnea, cough, sputum production, or change in sputum

Classification

• Mild: treated with short-acting bronchodilators only
• Moderate: also requiring antibiotics or oral corticosteroids
• Severe: requires emergency room visit or hospital admission
  • No respiratory failure: RR 20-30, no use of accessory muscles, no mental status changes, hypoxemia improves with ≤35% FiO₂ by Venturi mask, and no increase in PaCO₂
  • Non-life-threatening acute respiratory failure: RR >30, using accessory muscles, no mental status changes, hypoxemia improves with ≤30% FiO₂ by Venturi mask, hypercarbia with PaCO₂ 50-60 mmHg
  • Life-threatening acute respiratory failure: RR>30, using accessory muscles, mental status changes, hypoxemia requiring FiO₂ >40%, hypercarbia >60 mmHg or pH ≤7.25

Etiology

• Infections (bacterial or viral)
  • Rhinovirus is the most common cause overall
• Air pollution and ambient temperature
• Pulmonary embolism
• Congestive heart failure

Clinical Manifestations

• Dyspnea, cough
• Increase sputum production, sometimes purulent

Complications and Prognosis

• 11% in-hospital mortality
• 23-33% 6-month or 1-year mortality
• 50% 2-year mortality
• Symptoms usually last 7 to 10 days, but up to 20% are still not back to baseline by 8 weeks

Differential Diagnosis

• Pneumonia
• Pneumothorax
• Pleural effusion
• Pulmonary embolism
• Acute coronary syndrome
• Acute heart failure
• Atrial fibrillation or atrial flutter

Investigations

• CXR to rule out pneumonia, pneumothorax, pleural effusion
• ECG and troponins to rule out ACS
• D-dimer or US Doppers to rule out PE
• CBC
• ABG in severe exacerbation
• Sputum cultures to help guide later therapy
• Spirometry at some point during their hospitalization, if it's the first presentation

Management

Severe Exacerbations

• Assess patient, get ABG and chest x-ray
• Start supplemental oxygen, get serial ABG/VBGs/SpO_2Puffers
  • Increase dose and frequency of short-acting bronchodilators
  • Use both short-acting β-2-agonists (salbutamol) and anticholinergics (ipratropium)
  • Add long-acting bronchodilators (e.g. tiotropium) when patient is more stable
  • Consider spacers or nebulizers when needed (though no difference between the two)
• Steroids: prednisone 40mg for 5 days, or equivalent
• Antibiotics: if purulent/sputum change
• Non-invasive ventilation
  • Decreases mortality and prevents intubation
  • Indicated if any of the following:
    • Respiratory acidosis (pH ≤7.35 and pCO₂ ≥45 mmHg)
    • Severe dyspnea with increased work of breathing or concern for fatigue
    • Resistant hypoxia despite supplemental oxygen
• Invasive ventilation is indicated if:
  • Failure of or inability to tolerate non-invasive ventilation
  • Respiratory or cardiac arrest
  • Decreased level of consciousness or psychomotor agitation not controlled by sedation
  • Massive aspiration or persistent vomiting
  • Inability to control respiratory secretions
  • Severe hemodynamic instability despite appropriate management
  • Severe arrhythmias
  • Life-threatening hypoxemia
• Routine:
  • Monitor fluid balance
  • DVT prophylaxis
  • Treat comorbidities including heart failure, arrhythmias, and pulmonary embolism
  • Vitamin D replacement if deficient

Further Reading

• Global Initiative for Chronic Obstructive Lung Disease (GOLD) Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease.