Internal Medicine · Year 3 · from Internal Medicine
Case 1: COPD Exacerbation
Patient Presentation
A 67-year-old man with a 50-pack-year smoking history and known COPD (GOLD Stage III) presents with 3 days of worsening shortness of breath, increased sputum production, and change in sputum color from white to yellow-green. He has been using his rescue inhaler every 2 hours with minimal relief. His home medications include tiotropium, fluticasone-salmeterol, and albuterol PRN.
Vital Signs
- Blood Pressure: 148/88 mmHg
- Heart Rate: 104 bpm
- Respiratory Rate: 26/min
- Oxygen Saturation: 86% on room air
- Temperature: 37.9°C
Physical Examination
- General: Moderate respiratory distress, using accessory muscles, speaking in phrases
- HEENT: Pursed lip breathing
- Cardiovascular: Tachycardic, distant heart sounds
- Pulmonary: Decreased breath sounds bilaterally, diffuse expiratory wheezes, prolonged expiratory phase, barrel chest
- Extremities: No edema, no cyanosis
Initial Workup
- ABG (room air): pH 7.32, PaCO2 58 mmHg, PaO2 52 mmHg, HCO3 28 mEq/L
- CBC: WBC 13,200/μL with 78% neutrophils
- BMP: Normal
- Chest X-ray: Hyperinflation, flattened diaphragms, no infiltrates
- Procalcitonin: 0.18 ng/mL
Clinical Image
Figure 1: Chest X-ray demonstrating hyperinflation with flattened hemidiaphragms and increased AP diameter characteristic of COPD.
Image Source: Educational illustration for teaching purposes.
Questions
- What is the Anthonisen classification of this COPD exacerbation?
- A) Type I (all three cardinal symptoms)
- B) Type II (two of three cardinal symptoms)
- C) Type III (one cardinal symptom)
- D) Not classifiable
- What do the ABG results indicate?
- A) Uncompensated respiratory acidosis
- B) Compensated respiratory acidosis (acute on chronic hypercapnic respiratory failure)
- C) Metabolic acidosis
- D) Respiratory alkalosis
- What is the target oxygen saturation in this patient?
- A) 95-100%
- B) 88-92%
- C) 80-85%
- D) >97%
- Outline the management of acute COPD exacerbation.
- When is non-invasive positive pressure ventilation (NIPPV) indicated?
Answers
- A) Type I (all three cardinal symptoms) - The Anthonisen criteria include: (1) increased dyspnea, (2) increased sputum volume, (3) increased sputum purulence. Type I has all three; this patient meets all criteria.
- B) Compensated respiratory acidosis (acute on chronic hypercapnic respiratory failure) - The elevated HCO3 (28) indicates metabolic compensation for chronic hypercapnia. The acute acidemia (pH 7.32) suggests acute-on-chronic respiratory failure with superimposed acute hypercapnia.
- B) 88-92% - In COPD patients with chronic hypercapnia, the target SpO2 is 88-92%. Higher oxygen levels can suppress hypoxic ventilatory drive and worsen hypercapnia and respiratory acidosis.
- Management of acute COPD exacerbation:
- Bronchodilators: SABA (albuterol) ± SAMA (ipratropium) via nebulizer
- Corticosteroids: Prednisone 40 mg daily for 5 days (or IV methylprednisolone)
- Antibiotics: If purulent sputum or requiring ventilation (azithromycin, doxycycline, or fluoroquinolone)
- Oxygen: Target SpO2 88-92% via controlled oxygen (Venturi mask)
- NIPPV: If respiratory acidosis persists (pH <7.35, PaCO2 >45) despite initial treatment
- VTE prophylaxis: Pharmacologic prophylaxis unless contraindicated
- Indications for NIPPV in COPD exacerbation:
- Respiratory acidosis (pH <7.35, PaCO2 >45 mmHg)
- Severe dyspnea with accessory muscle use
- Persistent hypoxemia despite supplemental oxygen
- Contraindications include: decreased consciousness (unable to protect airway), hemodynamic instability, facial trauma, copious secretions, recent GI surgery