This week’s edition of the Step 1 Question of the Week is about cardiology. See if you can answer the question and then watch the video to learn the correct answer as well as the rationales for each option.
A 62-year-old man admitted for bacterial pneumonia is intubated for airway protection due to altered mental status. Temperature is 38.8°C (101.8°F), pulse is 133/min, and blood pressure is 82/40 mm Hg. He has a tidal volume of 450 mL and a fraction of inspired oxygen of 40%. Lung fields are clear to auscultation, and there is a 2/6 apical systolic murmur. Blood pressure is not improved after 3 L of normal saline. Intravenous administration of norepinephrine is started.
Norepinephrine administration in this patient would be expected to produce which of the following physiological responses?
A. Decrease in diastolic filling pressure of the heart
B. Decrease in heart rate
C. Decrease in platelet aggregation
D. Decrease in pupillary dilator tone
E. Decrease in systemic vascular resistance
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