Question

A 31-year-old G1P0 woman at 38 weeks gestation presents for an urgent evaluation due to severe, worsening shortness of breath over the past week. She reports that her breathing is particularly difficult at night, requiring her to sleep in a recliner chair. She also notes a persistent, dry cough and significant swelling in her legs. She has no significant past medical history, and her pregnancy has been uncomplicated thus far. Her blood pressure is 112/74 mm Hg, pulse is 116/min, and respirations are 24/min. Pulse oximetry shows 92% on ambient air. Physical examination reveals prominent jugular venous distension while sitting at a 45-degree angle. Cardiac auscultation demonstrates a regular tachycardia with a low-pitched, early diastolic sound at the cardiac apex. Lung auscultation reveals crackles in bilateral lung bases. There is 2+ pitting edema in both lower extremities extending to the knees. Which of the following is the most appropriate next step in evaluation?