A rapid response is called for a 74-year-old man who develops acute shortness of breath an… — USMLE Step 2 CK

A rapid response is called for a $74$ -year-old man who develops acute shortness of breath and agitation $48$ hours after undergoing a right femoral-popliteal bypass. His past medical history is significant for type 2 diabetes mellitus, hypertension, hyperlipidemia, and a $40$ -pack-year smoking history. The operative report notes a brief $15$ -minute episode of hypotension that resolved with intravenous fluid administration. He currently denies any chest pain. His temperature is $37.8^\circ\text{C}$ ( $100.0^\circ\text{F}$ ), pulse is $116$ /min, blood pressure is $100/60$ mmHg, respirations are $26$ /min, and oxygen saturation is $91\%$ on room air. Physical examination reveals jugular venous distention. Pulmonary auscultation demonstrates fine bibasilar crackles. Cardiac auscultation reveals a regular, rapid rhythm with an $S_4$ gallop. The surgical incisions are intact, and distal pulses are palpable. Which of the following is the most appropriate next step in management?

A
Initiate empiric intravenous broad-spectrum antibiotics
B
Administer an intravenous bolus of isotonic crystalloid
Obtain an electrocardiogram and measure cardiac biomarkersAnswer
D
Order computed tomography angiography of the chest
E
Administer nebulized albuterol and intravenous methylprednisolone

Answer

The most appropriate next step is to obtain an electrocardiogram and measure cardiac biomarkers.

This patient is presenting with acute dyspnea, tachycardia, hypoxia, and signs of left heart failure (bibasilar crackles, elevated jugular venous pressure, S4 gallop) on postoperative day 2 following high-risk vascular surgery. Given his history of diabetes mellitus and intraoperative hypotension, he is at very high risk for a perioperative myocardial infarction (PMI). PMIs frequently lack typical chest pain (silent ischemia) and instead present with secondary complications such as acute heart failure, altered mental status (agitation), or arrhythmias, typically peaking within the first 2-3 days after surgery. An electrocardiogram and cardiac biomarkers (troponins) are the most appropriate immediate steps to diagnose myocardial ischemia and guide further management.

Step-by-Step Solution

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

The patient has hypoxia, tachycardia, jugular venous distention, bibasilar crackles, and an S4 gallop.

These findings are the classic constellation of acute decompensated left heart failure causing cardiogenic pulmonary edema.

Correlate the clinical presentation with the patient's surgical timeline and risk factors.

The patient is on postoperative day 2 following high-risk vascular surgery and has a history of diabetes, placing him at immense risk for a perioperative myocardial infarction (PMI).

PMIs frequently peak within the first 48-72 hours postoperatively. Diabetic and elderly patients often do not experience classic chest pain (silent ischemia), presenting instead with acute heart failure or altered mental status.

Determine the most appropriate immediate intervention.

An electrocardiogram and cardiac biomarkers must be ordered immediately.

Diagnostic confirmation of myocardial ischemia is required before initiating targeted treatments (such as diuresis, antiplatelets, or anticoagulation) in the setting of acute postoperative heart failure.

Key Concept

Perioperative myocardial infarction often presents silently (without chest pain) as acute decompensated heart failure, altered mental status, or hypotension within the first 2-3 days after high-risk surgery, necessitating immediate evaluation with an ECG and cardiac biomarkers.

Estimated Time:1m 15s

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