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Difficulty: MediumPulmonary and Critical Care

A 7474-year-old man presents to the emergency department with a 22-day history of worsening shortness of breath and a nonproductive cough. He has a past medical history of hypertension, ischemic cardiomyopathy, and chronic obstructive pulmonary disease (COPD). His daily medications include lisinopril, metoprolol, low-dose aspirin, and a tiotropium inhaler. He has a 4040-pack-year smoking history but quit 55 years ago. He reports waking up several times last night gasping for air. His temperature is 37.0∘C(98.6∘F)37.0^\circ\text{C} (98.6^\circ\text{F}), blood pressure is 158/92 mmHg158/92 \text{ mmHg}, pulse is 112/min112/\text{min}, and respiratory rate is 26/min26/\text{min}. Pulse oximetry on room air is 88%88\%. Physical examination shows jugular venous distention 8 cm8 \text{ cm} above the sternal angle. Lung auscultation reveals diffuse expiratory wheezes bilaterally; no crackles are heard. Cardiac auscultation demonstrates a regular tachycardia with a prominent S3S_3 gallop. There is 2+2+ pitting edema in the bilateral lower extremities. A bedside portable chest radiograph shows prominent perihilar vasculature and indistinct vascular margins without focal opacities. Arterial blood gas analysis on room air shows:

pH: 7.477.47
PaCO2\text{PaCO}_2: 30 mmHg30 \text{ mmHg}
PaO2\text{PaO}_2: 58 mmHg58 \text{ mmHg}
HCO3−\text{HCO}_3^-: 22 mEq/L22 \text{ mEq/L}

Which of the following is the most appropriate initial therapy for this patient?

  1. Intravenous furosemideAnswer
  2. B
    Inhaled albuterol
  3. C
    Intravenous methylprednisolone
  4. D
    Intravenous levofloxacin
  5. E
    Intravenous sodium bicarbonate

Answer

Intravenous furosemide
The patient is presenting with acute decompensated heart failure (ADHF). Despite his history of COPD and the presence of wheezing, the clinical findings of paroxysmal nocturnal dyspnea (waking up gasping), jugular venous distention, an S3S_3 gallop, and lower extremity edema strongly point to left ventricular failure causing pulmonary edema. The wheezing is due to peribronchial edema, a condition often termed 'cardiac asthma.' The chest radiograph showing prominent perihilar vasculature further supports ADHF. The arterial blood gas demonstrates an acute respiratory alkalosis driven by hypoxia-induced hyperventilation. The most appropriate initial therapy is a loop diuretic, such as intravenous furosemide, which reduces preload and quickly relieves pulmonary congestion.

Step-by-Step Solution

1
Analyze the patient's history and symptoms.
The patient has a history of ischemic cardiomyopathy and COPD. He presents with acute orthopnea, paroxysmal nocturnal dyspnea, and a nonproductive cough.
Identifies risk factors and classic symptoms that differentiate between volume overload and primary airway disease.
2
Interpret the physical examination and diagnostic findings.
Findings include hypoxia, elevated jugular venous pressure, an S3 gallop, bilateral edema, and prominent perihilar vasculature. The ABG reveals an acute respiratory alkalosis.
These findings strongly point to cardiogenic pulmonary edema (cardiac asthma) rather than a COPD exacerbation or bacterial pneumonia.
3
Determine the appropriate initial management.
Administer an intravenous loop diuretic (e.g., furosemide).
Loop diuretics rapidly reduce cardiac preload and relieve pulmonary congestion in acute decompensated heart failure.

Key Concept

Differentiating acute decompensated heart failure (cardiac asthma) from COPD exacerbation and managing it with preload reduction.
Estimated Time:1m 30s
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Topics

Pulmonary and Critical Care

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