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Difficulty: MediumGeneral Internal Medicine

A 72-year-old retired mechanic presents to the emergency department with a 3-day history of progressively worsening shortness of breath. He reports needing to sleep propped up on three pillows and has developed a new nocturnal cough producing frothy white sputum. His medical history includes severe chronic obstructive pulmonary disease (COPD), a myocardial infarction three years ago, and chronic fatigue. His only home medications are a tiotropium inhaler and aspirin.

Vital signs show a temperature of 37.0°C (98.6°F), blood pressure of 160/90 mm Hg, heart rate of 110/min, and respiratory rate of 26/min. Pulse oximetry is 88% on room air.

Physical examination reveals an anxious man using accessory muscles of respiration. Jugular venous pressure is measured at 10 cm H2OH_2O. Chest auscultation reveals diffuse bilateral expiratory wheezes and fine bibasilar crackles. An S3 gallop is heard at the cardiac apex. The lower extremities show bilateral 2+ pitting edema.

Initial laboratory studies show:
Leukocyte count: 8,500/mm3mm^3
Brain natriuretic peptide (BNP): 920 pg/mL (normal < 100)
Thyroid-stimulating hormone (TSH): 1.5 μU/mL\mu U/mL (normal: 0.5-5.0)
Free T4: 0.6 ng/dL (normal: 0.9-1.7)

Arterial blood gas on room air:
pH: 7.28
PaCO2PaCO_2: 58 mm Hg
PaO2PaO_2: 54 mm Hg
HCO3−HCO_3^-: 26 mEq/L

Which of the following is the most appropriate next step in the management of this patient?

  1. A
    Administration of oral prednisone and nebulized tiotropium
  2. B
    Initiation of intravenous meropenem therapy
  3. Intravenous administration of bumetanideAnswer
  4. D
    Intravenous infusion of sodium bicarbonate
  5. E
    Initiation of oral levothyroxine therapy

Answer

Intravenous administration of bumetanide
The correct intervention is the intravenous administration of a loop diuretic, such as bumetanide. The patient's clinical presentation is classic for acute decompensated heart failure (ADHF) with cardiogenic pulmonary edema. While he has a history of COPD, the combination of orthopnea, elevated jugular venous pressure, an S3 gallop, bibasilar crackles, and an elevated BNP level strongly confirms ADHF. The diffuse wheezing is a manifestation of peribronchial edema, often termed 'cardiac asthma.' Initial management of ADHF requires supplemental oxygen and rapid preload reduction using intravenous loop diuretics.

Step-by-Step Solution

1
Evaluate the primary cause of acute respiratory distress based on physical exam and laboratory findings.
Findings of orthopnea, elevated jugular venous pressure, an S3 gallop, bibasilar crackles, and an elevated brain natriuretic peptide (BNP) indicate acute decompensated heart failure (ADHF) with pulmonary edema.
Differentiating between ADHF and a COPD exacerbation is a critical first step, as both can present with dyspnea, hypoxia, and wheezing ('cardiac asthma').
2
Analyze the arterial blood gas results.
An acute, uncompensated respiratory acidosis is present, which is consistent with poor gas exchange secondary to severe pulmonary edema.
Understanding the primary acid-base disturbance ensures the clinician avoids treating secondary physiological compensations inappropriately.
3
Select the most appropriate initial pharmacological intervention.
Intravenous loop diuretics (such as bumetanide or torsemide) are indicated alongside supplemental oxygen.
Loop diuretics rapidly reduce intravascular volume and right-sided preload, effectively relieving pulmonary congestion and improving oxygenation.

Key Concept

Differentiating acute decompensated heart failure (cardiac asthma) from a COPD exacerbation, and initiating appropriate acute management with intravenous loop diuretics.
Estimated Time:1m 30s
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Topics

General Internal Medicine

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