A 72-year-old man is brought to the emergency department for severe, worsening shortness o… — USMLE Step 2 CK

A 72-year-old man is brought to the emergency department for severe, worsening shortness of breath that began 6 hours ago. The patient has a history of essential hypertension, type 2 diabetes mellitus, and a 40-pack-year smoking history. He reports that his breathing became significantly worse shortly after he laid down to sleep. Current medications include metformin, lisinopril, and amlodipine. His temperature is 37.1°C (98.8°F), blood pressure is 172/96 mmHg, pulse is 112/min and regular, and respiratory rate is 28/min. Pulse oximetry shows an oxygen saturation of 88% on room air.

Physical examination reveals a patient in moderate respiratory distress, using accessory muscles of respiration. Jugular venous pulsation is visible 9 cm above the sternal angle. Chest auscultation reveals diffuse expiratory wheezes and bibasilar crackles extending halfway up the lung fields. Cardiac examination reveals a regular tachycardia with a prominent third heart sound (S3). Bilateral 2+ pitting edema is present in the lower extremities.

Arterial blood gas on room air reveals:
pH: $7.28$
$pCO_2$ : $56 \text{ mmHg}$
$pO_2$ : $54 \text{ mmHg}$
$HCO_3^-$ : $25 \text{ mEq/L}$

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

Intravenous furosemide and nitroglycerinAnswer
B
Inhaled albuterol and intravenous methylprednisolone
C
Intravenous levofloxacin and ceftriaxone
D
Intravenous sodium bicarbonate
E
Emergent computed tomography angiography of the chest

Answer

Intravenous furosemide and nitroglycerin

The correct intervention provides immediate preload and afterload reduction. This patient's presentation is classic for acute decompensated heart failure (ADHF) with cardiogenic pulmonary edema, characterized by severe orthopnea, elevated jugular venous pressure, an S3 gallop, bibasilar crackles, and bilateral pitting edema. The presence of wheezing in this context represents 'cardiac asthma' resulting from peribronchial edema, rather than a primary obstructive airway disease. Initial management of ADHF with concurrent hypertension requires aggressive diuresis (e.g., intravenous furosemide) and vasodilation (e.g., intravenous nitroglycerin). These agents work rapidly to decrease cardiac filling pressures, shift fluid out of the alveolar spaces, and alleviate respiratory distress.

Step-by-Step Solution

Evaluate the clinical presentation and vital signs.

The patient presents with acute severe dyspnea, orthopnea, hypertension, hypoxia, elevated jugular venous pressure, an S3 gallop, crackles, wheezing, and lower extremity edema.

Identifying these clinical signs is necessary to establish the primary etiology of the respiratory failure.

Differentiate between cardiogenic and pulmonary causes of dyspnea.

Despite the smoking history and wheezing, the presence of an S3 gallop, elevated jugular venous pressure, and peripheral edema strongly points to acute decompensated heart failure (ADHF) over a chronic obstructive pulmonary disease (COPD) exacerbation. The wheezing represents 'cardiac asthma'.

Accurate differentiation is critical, as the treatments for ADHF and COPD exacerbations are fundamentally different.

Analyze the arterial blood gas results.

The ABG shows a low pH (

7.28

), elevated

pCO_2

(

56 \text{ mmHg}

), and normal

HCO_3^-

(

25 \text{ mEq/L}

), indicating an acute uncompensated respiratory acidosis.

This confirms severe impairment of gas exchange and impending respiratory failure due to pulmonary edema, guiding the urgency of treatment.

Determine the most appropriate immediate medical intervention.

Administering intravenous loop diuretics (furosemide) and vasodilators (nitroglycerin) is indicated to rapidly reduce cardiac preload and afterload.

Immediate pharmacological reduction of cardiac filling pressures is the standard of care for hypertensive ADHF to resolve pulmonary edema and improve oxygenation.

Key Concept

Patients with acute decompensated heart failure can present with wheezing ('cardiac asthma'), but the presence of an S3 gallop, elevated jugular venous pressure, and fluid overload distinguishes it from a COPD exacerbation and requires immediate preload and afterload reduction.

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