A client with acute pulmonary edema receives furosemide (Lasix). What assessment finding indicates that the intervention is working?

• A. Potassium level decreased from 4.5 to 3.5 mEq/L.
• B. Crackles auscultated in the bases.
• C. Lungs clear.
• D. Output 30 mL/hr.

Answer: (C)

In acute pulmonary edema, the goal of furosemide is to remove excess fluid from the lungs and improve gas exchange. The best sign that the intervention is working is that the lungs become clear on auscultation, indicating that interstitial and alveolar edema has resolved and breathing should improve. A drop in potassium is a common diuretic side effect and doesn’t reflect treatment success. Persistent crackles mean fluid is still present in the lungs, so they do not indicate improvement. While urine output shows diuresis, it doesn’t directly prove that pulmonary edema has resolved. Therefore, lungs clear provides the clearest indication that the diuretic is effectively reducing pulmonary edema.