Loop diuretics have been considered the cornerstone of CPE treatment for many years. Furosemide is used most commonly. Loop diuretics are presumed to decrease preload through 2 mechanisms: diuresis and direct vasoactivity (venodilation).
In most patients, diuresis does not occur for at least 20-90 minutes; therefore, the effect is delayed. Loop diuretics affect the ascending loop of Henle; therefore, the diminished renal perfusion in CPE may delay the onset of effects of loop diuretics.
Many patients with CPE do not have fluid overload. Continued use of diuretics in these patients after their acute symptoms have resolved may be associated with adverse outcomes, including electrolyte derangements, hypotension, and worsening renal function (GFR) as a result of tubuloglomerular feedback.
The presumption that these medications have a direct vasoactive (venodilating) effect has been questioned. Some studies demonstrated initial adverse hemodynamic consequences (eg, elevations of PCWP, LV filling pressure, heart rate, and systemic vascular resistance) after the administration of IV furosemide, perhaps due to direct neurohormonal stimulation.
Premedication with drugs that decrease preload (eg, NTG) and afterload (eg, angiotensin-converting enzyme [ACE] inhibitors) before the administration of loop diuretics can prevent potential adverse hemodynamic changes.
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Radiograph shows acute pulmonary edema in a patient who was admitted with acute anterior myocardial infarction. Findings are vascular redistribution, indistinct hila, and alveolar infiltrates.
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Radiograph shows acute pulmonary edema in a patient known to have ischemic cardiomyopathy. Findings are Kerley B lines (1mm thick and 1cm long) in the lower lobes and Kerley A lines in the upper lobes.
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Radiograph demonstrates cardiomegaly, bilateral pleural effusions, and alveolar opacities in a patient with pulmonary edema.
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Radiograph shows interstitial pulmonary edema, cardiomegaly, and left pleural effusion presenting at an earlier stage of pulmonary edema.
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Lateral chest radiograph shows prominent interstitial edema and pleural effusions.
