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Difficulty: EasyCardiovascular System

Paramedics bring a 64-year-old woman to the emergency department due to acute respiratory distress that began 2 hours ago. She reports severe difficulty breathing and the sensation of smothering, which worsens significantly when she tries to lie flat on the stretcher. Her medical history includes long-standing hypertension, diet-controlled type 2 diabetes mellitus, and a 30-pack-year history of cigarette smoking. Upon arrival, her blood pressure is 182/104 mmHg, heart rate is 112/min, and respiratory rate is 26/min. Pulse oximetry shows an oxygen saturation of 88% on room air. Physical examination reveals an anxious patient sitting upright and utilizing accessory muscles of respiration. Jugular venous pressure is visibly elevated. Pulmonary auscultation reveals bilateral basilar crackles and prominent diffuse expiratory wheezing. Cardiac auscultation is notable for a regular tachycardia and an audible S3 gallop. In addition to providing supplemental oxygen, which of the following is the most appropriate initial pharmacological intervention for this patient?

  1. Intravenous bolus of a loop diureticAnswer
  2. B
    Inhaled short-acting bronchodilator therapy
  3. C
    Intravenous administration of a systemic glucocorticoid
  4. D
    Empiric therapy with broad-spectrum antibiotics
  5. E
    Continuous intravenous infusion of unfractionated heparin

Answer

Intravenous bolus of a loop diuretic
The correct answer is an intravenous bolus of a loop diuretic. This patient presents with classic signs of acute decompensated heart failure (ADHF) with pulmonary edema, indicated by severe dyspnea, orthopnea, elevated jugular venous pressure, basilar crackles, and an S3 gallop. The severe hypertension suggests an acute afterload elevation precipitating the failure. The prominent wheezing is due to peribronchial edema compressing the airways, a phenomenon referred to as 'cardiac asthma.' The presence of a smoking history combined with wheezing can tempt a misdiagnosis of a COPD exacerbation; however, COPD does not cause a third heart sound (S3) or elevated left-sided filling pressures resulting in rapid-onset orthopnea and bilateral pulmonary crackles. The immediate management of ADHF requires aggressive preload and afterload reduction. Intravenous loop diuretics are the cornerstone of initial therapy because they induce rapid venodilation (decreasing preload even before diuresis begins) and subsequent diuresis to clear the pulmonary edema.

Step-by-Step Solution

1
Analyze the patient's vital signs and physical examination findings.
The patient has severe hypertension, tachycardia, hypoxia, orthopnea, elevated jugular venous pressure, bilateral crackles, wheezing, and an S3 gallop.
Identifying these clinical signs is necessary to determine the primary etiology of the acute respiratory distress.
2
Synthesize the findings to formulate a primary diagnosis.
The combination of elevated filling pressures (JVP, S3 gallop) and pulmonary edema (crackles, orthopnea) strongly indicates acute decompensated heart failure (ADHF). The wheezing is due to peribronchial edema, known as cardiac asthma.
Distinguishing ADHF from a primary pulmonary process like a COPD exacerbation guides the immediate management strategy.
3
Select the most appropriate initial pharmacological therapy for the primary diagnosis.
Intravenous loop diuretics are indicated to provide rapid symptomatic relief by reducing intravascular volume and decreasing pulmonary venous pressure.
Loop diuretics are the standard initial pharmacologic therapy for volume overload in ADHF.

Key Concept

Patients with acute decompensated heart failure can present with prominent wheezing (cardiac asthma) due to peribronchial edema. The presence of an S3 gallop, elevated jugular venous pressure, and rapid-onset orthopnea help clinically differentiate this from a COPD exacerbation.
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Topics

Cardiovascular System

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