Subinternship Medicine · Year 4 · from Subinternship Medicine

Case 2: Acute Hypoxic Respiratory Failure from COPD Exacerbation

Clinical Presentation

Patient Demographics: 68-year-old male

Chief Complaint: "I can't breathe"

Clinical Context: You are called to evaluate Mr. Davis, who was admitted 2 days ago for a COPD exacerbation. He had been improving on steroids and bronchodilators but now is in acute respiratory distress.

History of Present Illness: Mr. Davis is a 68-year-old male with severe COPD (FEV1 32% predicted), oxygen-dependent at baseline (2L NC), and heart failure with reduced ejection fraction (EF 35%) who presented 2 days ago with increased dyspnea and productive cough. He was started on prednisone, nebulizers, and azithromycin. He was improving until 30 minutes ago when he developed acute worsening of dyspnea while getting up to use the bathroom.

Past Medical History:

  • COPD (GOLD Stage IV)
  • Heart failure with reduced EF (ischemic cardiomyopathy)
  • Coronary artery disease, s/p stents
  • Type 2 diabetes mellitus
  • Former smoker (60 pack-years, quit 2 years ago)

Current Medications:

  • Prednisone 40 mg daily
  • Albuterol/ipratropium nebulizers Q4H
  • Azithromycin 250 mg daily
  • Carvedilol 12.5 mg BID
  • Lisinopril 20 mg daily
  • Furosemide 40 mg daily
  • Metformin 1000 mg BID

Physical Examination:

  • Vital Signs: Temperature 37.1C, HR 108 bpm, BP 152/88 mmHg, RR 32/min, SpO2 82% on 2L NC
  • General: Severe respiratory distress, tripod positioning, using accessory muscles
  • Lungs: Diffuse expiratory wheezes, prolonged expiratory phase, diminished breath sounds at bases
  • Cardiovascular: Tachycardic, JVP elevated to 12 cm
  • Extremities: 1+ pitting edema bilaterally (new)

Immediate Assessment and Intervention

ABCDE Primary Survey:

  • Airway: Patent, patient speaking in short phrases
  • Breathing: Severe distress, SpO2 82% on 2L - immediately increase oxygen
  • Circulation: Elevated JVP and new edema suggest fluid overload
  • Disability: Alert, anxious, GCS 15
  • Exposure: No concerning findings

Immediate Actions:

  1. High-flow oxygen via non-rebreather mask (SpO2 improves to 89%)
  2. Continuous pulse oximetry and cardiac monitoring
  3. Stat nebulizer treatment (albuterol 2.5 mg + ipratropium 0.5 mg)
  4. Call respiratory therapy for BiPAP setup
  5. Stat portable chest X-ray
  6. Stat ABG, BNP, troponin
  7. Notify senior resident

Workup Results

Arterial Blood Gas (on 15L non-rebreather):

  • pH 7.28
  • pCO2 62 mmHg
  • pO2 58 mmHg
  • HCO3 28 mEq/L

Interpretation: Acute on chronic hypercapnic respiratory failure with hypoxemia

Additional Labs:

  • BNP 1,840 pg/mL (elevated from admission 620)
  • Troponin I 0.08 ng/mL (mildly elevated)
  • WBC 11,200/uL

Chest X-ray: Bilateral interstitial edema, cardiomegaly, small bilateral pleural effusions (new compared to admission)

Diagnosis

Primary Diagnosis: Acute hypoxic and hypercapnic respiratory failure

  • Contributing factors: COPD exacerbation + acute decompensated heart failure

Differential for acute worsening:

  1. Flash pulmonary edema (most likely given exam and X-ray)
  2. Pulmonary embolism (possible given immobility)
  3. Pneumonia superinfection
  4. Mucus plugging

Treatment Plan

Immediate Management:

  1. BiPAP initiated (IPAP 12, EPAP 5, FiO2 50%)
  2. IV furosemide 80 mg (double home dose)
  3. Continue nebulizers
  4. Hold beta-blocker (carvedilol) temporarily
  5. Consider CT-PA to rule out PE if not improving

Response to Treatment (30 minutes):

  • SpO2 improved to 94% on BiPAP
  • RR decreased to 24/min
  • Patient reports feeling "better"
  • Repeat ABG: pH 7.32, pCO2 54, pO2 72

Escalation Considerations:

  • Discussed with attending: Patient stable on BiPAP, monitor closely
  • ICU transfer if: Unable to wean BiPAP, worsening acidosis, altered mental status, need for intubation

Clinical Image

Image Description: Chest radiograph demonstrating cardiomegaly with bilateral pulmonary vascular congestion and interstitial edema, consistent with acute decompensated heart failure superimposed on COPD.

Image Source: Wikimedia Commons - "Congestive heart failure x-ray"

  • URL: https://commons.wikimedia.org/wiki/File:Congestive_heart_failure_x-ray.png
  • License: Public Domain

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