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Difficulty: HardCardiovascular System

An ambulance transports a 70-year-old man to the emergency department for severe dyspnea and a persistent cough that have progressively worsened over the last 72 hours. He notes waking up multiple times at night feeling as though he is suffocating, and he has developed new-onset swelling in his lower legs. His past medical history includes a 45-pack-year smoking habit and chronic obstructive pulmonary disease (COPD), which is managed with a daily tiotropium inhaler. He also has poorly controlled hypertension and has not seen a physician in over five years. He denies having a fever, and his cough yields only a small amount of clear, frothy sputum.

Upon arrival, his temperature is 37.2∘C37.2^\circ\text{C}, blood pressure is 172/98 mm Hg172/98\text{ mm Hg}, heart rate is 112/min112\text{/min}, and respiratory rate is 26/min26\text{/min}. Pulse oximetry on room air indicates an oxygen saturation of 88%88\%.

Physical examination shows a patient in moderate respiratory distress using accessory muscles of respiration. The jugular venous pulse is distended and visible 10 cm10\text{ cm} above the sternal angle. Auscultation of the lungs reveals a prolonged expiratory phase with widespread, diffuse expiratory wheezing; no crackles are heard. Cardiac auscultation demonstrates tachycardia with a regular rhythm. A distinct, low-frequency extra heart sound is heard in diastole just after the second heart sound, localized to the fifth intercostal space at the midclavicular line. Pitting edema (2+) is present bilaterally extending to the mid-calves.

Arterial blood gas analysis obtained on room air demonstrates:
- pH: 7.307.30
- PaCO 2_2: 54 mm Hg54\text{ mm Hg}
- PaO 2_2: 55 mm Hg55\text{ mm Hg}

A chest radiograph displays hyperinflation of the lungs, enlarged central pulmonary arteries, and prominent peribronchial cuffing without focal infiltrates or pleural effusions.

Which of the following is the most appropriate initial pharmacologic intervention for this patient's acute presentation?

  1. Intravenous furosemideAnswer
  2. B
    Inhaled ipratropium and intravenous methylprednisolone
  3. C
    Intravenous levofloxacin
  4. D
    Intravenous sodium bicarbonate
  5. E
    Intravenous magnesium sulfate

Answer

Intravenous furosemide
This patient is presenting with acute decompensated heart failure (ADHF) characterized by volume overload (elevated JVP, peripheral edema) and pulmonary edema. Although he has a history of COPD and presents with wheezing, the presence of a left-sided third heart sound (S3 gallop) at the cardiac apex is highly specific for left ventricular systolic dysfunction with elevated filling pressures. Furthermore, his chest radiograph shows peribronchial cuffing, a classic sign of interstitial pulmonary edema. The wheezing in this context is termed 'cardiac asthma' and results from bronchospasm triggered by peribronchial edema compressing small airways. The most appropriate initial pharmacotherapy to reduce intravascular volume and alleviate pulmonary congestion is an intravenous loop diuretic such as furosemide.

Step-by-Step Solution

1
Analyze the patient's history and presenting symptoms.
The patient has progressive dyspnea, orthopnea, and lower extremity swelling with a background of COPD and hypertension.
Establishing the symptom timeline helps differentiate between primary pulmonary and cardiac etiologies, specifically highlighting volume overload.
2
Interpret the physical examination findings.
The patient exhibits elevated JVP, bilateral lower extremity edema, diffuse wheezing, and most importantly, a third heart sound (S3 gallop) at the cardiac apex.
An apical S3 gallop is a hallmark of left ventricular volume overload and elevated end-diastolic pressure, distinguishing this presentation from isolated cor pulmonale or a primary COPD exacerbation.
3
Evaluate the diagnostic data.
Chest radiography shows peribronchial cuffing, indicating interstitial edema, while the ABG demonstrates respiratory acidosis.
Integrating the imaging and ABG confirms cardiogenic pulmonary edema leading to impaired gas exchange and resultant hypercapnia.
4
Determine the most appropriate initial management.
Select an intravenous loop diuretic.
The primary pathology is fluid overload due to left heart failure; diuresis rapidly decreases pulmonary capillary hydrostatic pressure and improves respiratory mechanics.

Key Concept

Acute decompensated heart failure can present with severe wheezing (cardiac asthma) due to peribronchial edema. It must be differentiated from a COPD exacerbation by identifying signs of left-sided volume overload, such as an apical S3 gallop, elevated jugular venous pressure, and peribronchial cuffing.
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Topics

Cardiovascular System

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