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Difficulty: MediumPulmonary and Critical Care

Paramedics transport a 69-year-old female to the acute care clinic due to a three-day history of escalating respiratory distress. The patient describes a persistent cough yielding frothy white sputum and states she has been sleeping in her recliner to avoid a choking sensation. She has a documented background of essential hypertension, hyperlipidemia, and a 45-pack-year smoking habit. She takes lisinopril and atorvastatin.

Upon initial triage, her core body temperature is 37.0°C (98.6°F), arterial blood pressure measures 168/96 mm Hg, heart rate is 115/min, and respiratory rate is 28/min. Oxygen saturation reads 86% while breathing ambient air.

Clinical assessment reveals elevated jugular venous pressure. Pulmonary auscultation identifies a markedly prolonged expiratory phase accompanied by diffuse, high-pitched wheezing throughout all lung fields; no localized crackles are evident. Cardiac auscultation reveals tachycardia with a distinct protodiastolic gallop (S3). Examination of the lower extremities shows bilateral pitting edema up to the mid-calf.

Arterial blood gas analysis on ambient air:
ParameterValueReference Range
pH7.467.35–7.45
PaCO231 mm Hg35–45 mm Hg
PaO254 mm Hg75–105 mm Hg
HCO3-21 mEq/L22–28 mEq/L

A bedside chest radiograph displays enlargement of the upper lobe pulmonary veins, indistinct vascular margins, and blunting of both costophrenic angles. No lobar opacities are present.

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

  1. A
    Inhaled albuterol and systemic glucocorticoids
  2. B
    Intravenous piperacillin-tazobactam
  3. Intravenous furosemideAnswer
  4. D
    Intravenous magnesium sulfate
  5. E
    Intravenous sodium bicarbonate

Answer

Intravenous furosemide
The correct answer is intravenous furosemide. The patient's clinical presentation—progressive dyspnea, orthopnea, frothy sputum, jugular venous distention, an S3 gallop, and bilateral lower extremity edema—is classic for acute decompensated heart failure (ADHF). The chest radiograph findings of prominent upper lobe vessels (cephalization) and bilateral pleural effusions further support this diagnosis. Although she has a significant smoking history and presents with diffuse wheezing, the wheezing in this context is known as 'cardiac asthma.' It results from peribronchial edema and external compression of the small airways by engorged pulmonary vessels, rather than the intrinsic bronchospasm seen in COPD or asthma exacerbations. The most appropriate initial pharmacologic intervention to rapidly relieve her symptoms and reduce pulmonary congestion is a loop diuretic, such as intravenous furosemide, which decreases intravascular volume and reduces ventricular preload.

Step-by-Step Solution

1
Analyze the patient's vital signs, physical examination, and radiographic findings.
The patient exhibits hypertension, tachycardia, hypoxia, jugular venous distention, an S3 gallop, bilateral edema, and radiographic evidence of cephalization and pleural effusions.
To establish the primary physiological mechanism causing the severe respiratory distress.
2
Evaluate the significance of wheezing in the context of the overall clinical picture.
The wheezing is identified as 'cardiac asthma' secondary to peribronchial edema, rather than a primary obstructive lung disease exacerbation.
To distinguish between acute decompensated heart failure and a COPD or asthma exacerbation, as the targeted treatments differ significantly.
3
Interpret the arterial blood gas (ABG) results.
The ABG demonstrates an elevated pH (7.46) and a low PaCO2 (31 mm Hg), indicating a primary acute respiratory alkalosis driven by hypoxia-induced hyperventilation.
To rule out primary metabolic or respiratory acidosis and ensure appropriate targeted therapy.
4
Determine the most appropriate initial pharmacologic therapy based on the established diagnosis.
Intravenous furosemide is selected as the primary intervention.
Loop diuretics rapidly reduce intravascular volume and ventricular preload, directly addressing the pulmonary congestion and relieving the respiratory distress in acute decompensated heart failure.

Key Concept

Acute decompensated heart failure can present with diffuse wheezing (cardiac asthma) due to peribronchial edema; it must be differentiated from COPD exacerbation using clinical signs of volume overload (jugular venous distention, S3 gallop, peripheral edema) to ensure appropriate treatment with loop diuretics.
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Topics

Pulmonary and Critical Care

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