A 71-year-old woman is evaluated in the surgical step-down unit for a sudden onset of shor… — USMLE Step 2 CK

A $71$ -year-old woman is evaluated in the surgical step-down unit for a sudden onset of shortness of breath and a nonproductive cough. She is currently on postoperative day $3$ following an uncomplicated right total knee arthroplasty. Her medical history is significant for coronary artery disease, heart failure with preserved ejection fraction, and a $40$ -pack-year smoking history with known chronic obstructive pulmonary disease. Her temperature is $37.4^\circ\text{C}$ ( $99.3^\circ\text{F}$ ), blood pressure is $168/96\text{ mmHg}$ , pulse is $108/\text{min}$ , and respirations are $26/\text{min}$ . Oxygen saturation is $89\%$ on room air. Physical examination reveals distended neck veins with a jugular venous pressure of $11\text{ cm H}_2\text{O}$ . Chest auscultation demonstrates a prolonged expiratory phase with diffuse bilateral wheezes and scattered bibasilar crackles. Cardiac examination reveals a regular tachycardia with a distinct S4 gallop and no murmurs. Her lower extremities show bilateral $2+$ pitting edema, which is unchanged from her preoperative baseline. Which of the following is the most appropriate next step in management?

Intravenous loop diuretic therapyAnswer
B
Inhaled short-acting bronchodilators and systemic glucocorticoids
C
Computed tomography angiography of the chest
D
Intravenous broad-spectrum antibiotic therapy
E
Arterial blood gas analysis to determine acid-base status

Answer

Intravenous loop diuretic therapy is the most appropriate next step to manage this patient's acute decompensated heart failure.

The correct answer is the administration of intravenous loop diuretics. This patient is experiencing acute decompensated heart failure (ADHF). In the postoperative period, third-spaced fluids mobilize back into the intravascular space, frequently precipitating volume overload in patients with underlying heart failure (such as her known HFpEF). Her presentation of elevated jugular venous pressure, bibasilar crackles, and an S4 gallop strongly points to left and right-sided volume overload. The diffuse wheezing she is experiencing is known as 'cardiac asthma,' which occurs when pulmonary venous congestion leads to peribronchial edema, narrowing the small airways. The most critical next step is rapid diuresis to decrease preload and resolve the pulmonary edema.

Step-by-Step Solution

Analyze the patient's vital signs and physical examination findings.

The patient has severe hypertension (

168/96\text{ mmHg}

), tachypnea, hypoxia, elevated JVP (

11\text{ cm H}_2\text{O}

), bilateral crackles, wheezing, and an S4 gallop.

Identifying the constellation of symptoms distinguishes between primary pulmonary and cardiovascular etiologies.

Differentiate the cause of wheezing in the context of her comorbidities.

Despite her COPD history, the presence of crackles, an S4 gallop (indicating a stiff, non-compliant left ventricle), and elevated JVP strongly suggests fluid overload (acute decompensated heart failure) leading to peribronchial edema, clinically presenting as 'cardiac asthma'.

Postoperative fluid mobilization frequently triggers acute decompensated heart failure in patients with a history of heart failure with preserved ejection fraction.

Determine the most urgent therapeutic intervention.

Administration of an intravenous loop diuretic (e.g., furosemide) to rapidly reduce intravascular volume and alleviate pulmonary congestion.

Immediate preload reduction is required to resolve the pulmonary edema and improve oxygenation.

Key Concept

Patients with acute decompensated heart failure can present with wheezing (cardiac asthma) due to peribronchial edema. Elevated jugular venous pressure, bibasilar crackles, and an S3 or S4 gallop help differentiate this from a primary COPD or asthma exacerbation, directing the immediate need for intravenous diuresis.

Estimated Time:1m 15s

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