03. COPD Exacerbations

Definition

GOLD definition: an acute event characterized by a worsening of respiratory symptoms that is beyond normal day-to-day variations and leads to a change in medications. In general, the respiratory symptoms should include one of the following: worsening dyspnea, increase in cough, and change in sputum volume or character.

Evaluation

Differential diagnosis:

  • CHF, PE, pneumonia, asthma, vasculitis such as EGPA, interstitial lung disease, asthma-COPD overlap syndrome, cardiac ischemia, pneumothorax, pleural effusion (can mimic or aggravate exacerbation).

Precipitants:

  • Viral or bacterial respiratory tract infections and air pollution are the most common etiologies.
  • Bacterial infection is implicated in 30-50% of all exacerbations.
  • Consider pulmonary embolism (PE) in patients with no clear cause – a meta-analysis identified PE in 16% of patients hospitalized for COPD exacerbation without other identifiable cause.
  • No precipitant is identified in 33% of cases.

Assessment of attack severity:

  • Respiratory rate, accessory muscle use, paradoxical chest wall movements, inability to speak in full sentences, deteriorating mental status.
  • With severe hyperinflation, hypotension from impaired cardiac filling can be seen.

Work up:

  • Check ECG, CXR, ABG to assess degree of acidemia and CO2 retention. 
  • Spirometry is NOT recommended (not accurate in acute exacerbation).
  • Further testing guided by DDx (e.g. BNP, D-dimer, CBC, respiratory viral panel).

Management

  • Oxygen therapy: via NC or face mask – target oxygen saturation = 88-92%. Watch for CO2 retention. Check ABG 30-60 minutes after initiating oxygen to assess for hypercapnea. Consider use of Venturi-mask to titrate FiO2 delivered.
  • Bronchodilators: nebulized therapy with albuterol 2.5 mg q1-4h (based on severity) and ipratropium 0.5 mg q4h initially, followed by albuterol/ipratropium nebulizers q4-6h + prn. Change to metered dose inhalers as patient improves (usually after the first 24 hours).
  • Steroids: the optimal initial steroid dose is controversial. 
    • GOLD guidelines recommend 40 mg prednisone PO q day x 5 days for the majority of COPD exacerbations based on studies showing 5 days of steroids are equivalent to traditional 2-week course and evidence that oral therapy is not inferior to IV treatment.
    • There is limited data on steroid use in ICU patients. For impending or acute respiratory failure or patients in whom there is concern about impaired absorption or no oral route available, consider methylprednisolone up to 1-2 mg/kg/day (typical dose might be methylprednisolone 60mg IV q6h). Recent studies suggest lower dose corticosteroid use (<240 mg/day) may be associated with shorter length of stay, shorter length of invasive ventilation, and lower risk of fungal infections. This can then be changed to prednisone 40mg daily as above.
  • Antibiotics: for mild to moderate exacerbations, five days of doxycycline 100 mg PO BID should be sufficient – longer courses are not superior to short courses. The greater and more purulent the sputum, the more likely it is antibiotics will be of benefit. In severe exacerbations and patients with risk factors for pseudomonas, consider sputum cultures and use of a respiratory fluoroquinolone (e.g. levofloxacin) as these are more often due to gram negative bacteria.
  • Not useful: chest PT, mucolytics, methylxanthines (theophylline), epinephrine.
  • Non-invasive positive pressure ventilation (e.g., BiPAP): strongly consider in acute respiratory acidosis or increased work of breathing. Likely has a benefit in patients with a pH <7.35. Contraindications are hemodynamic instability, respiratory arrest, patient unable to cooperate due to altered mental status, patient unable to protect airway, copious secretions. See Critial Care: Noninvasive Positive Pressure Ventilation.
    • Reassessment after 30-60 minutes is critical. Intubation should be considered if the ABG has not improved and/or there is clinical worsening.
  • Level of care: indications for ICU admission include changes in mental status, persistent or worsening hypoxemia (PaO2 <40) and/or severe/worsening respiratory acidosis (pH <7.25) despite supplemental oxygen, or need for noninvasive ventilation.

Discharge Planning

  • Home oxygen (patient qualifies by Medicare criteria if O2 sat ≤ 88% or PO2 ≤ 55 on room air) and smoking cessation are the only interventions that reduce long-term mortality.
  • Initiate therapy with long acting bronchodilators prior to hospital discharge. May start with monotherapy (LAMA or LABA) or dual therapy (LAMA + LABA).
  • Tiotropium has been found to provide better outcomes in exacerbations over Salmeterol. Decreases symptoms, hospitalizations resulting from exacerbation, and improves pulmonary rehabilitation outcomes.
  • Consider pneumococcal and influenza vaccination on discharge.
  • Consider referral for pulmonary rehabilitation as an outpatient.
  • Consider azithromycin prophylaxis in patients with recurrent COPD exacerbations without cardiovascular risk factors and normal QTc on EKG.
  • There is emerging data on endobronchial valves for recurrent COPD exacerbations, roflumimast for chronic bronchitis-type COPD with recurrent exacerbations, and lung-volume reduction surgery for bullous emphysema.

 

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