A 72-year-old patient with a history of ischemic cardiomyopathy is admitted to the medical unit with acute exacerbation. The patient presents with severe dyspnea, orthopnea, and frothy pink sputum. Vital signs: BP 170/100 mmHg, HR 105 bpm, RR 30/min, O2 sat 85% on room air. The patient is started on oxygen therapy and IV furosemide. After 4 hours of treatment, which nursing intervention should be the priority?

After 4 hours of diuretic therapy, assessing urine output and weight is priority to evaluate fluid removal effectiveness in heart failure. Other options like increasing oxygen or administering morphine may be needed but depend on this assessment first.

Clinical Context and Initial Assessment
This patient presents with a classic picture of acute decompensated heart failure (ADHF) with pulmonary edema, evidenced by severe dyspnea, orthopnea, and frothy pink sputum. The vital signs—BP 170/100 mmHg, HR 105 bpm, RR 30/min, and O2 sat 85%—reflect a state of sympathetic overdrive and significant respiratory compromise. The immediate therapeutic goals are to reduce preload and afterload while improving gas exchange. The initiation of oxygen therapy and IV furosemide, a loop diuretic, directly targets these goals by reducing intravascular volume and, consequently, pulmonary congestion.

Why Option 4 is the Priority Nursing Intervention
After 4 hours of treatment, the priority is to evaluate the effectiveness of the primary therapy, which is diuresis. The core pathophysiological problem in this ADHF scenario is fluid volume excess leading to pulmonary edema. The nursing intervention of assessing urine output and daily weight provides the most direct, objective data on whether the IV furosemide is achieving its intended effect of removing excess fluid. This aligns directly with the principles of fluid management nursing interventions, which have been shown to improve clinical outcomes by focusing on objective measures of fluid balance ^[1]. A positive response would be indicated by a significant increase in urine output and a corresponding decrease in daily weight, signaling mobilization of the pulmonary edema.

Analysis of Incorrect Options
- Option 1 (Increase oxygen flow rate): While the patient’s O2 sat of 85% is critically low, simply increasing the oxygen flow rate is a reactive, supportive measure that does not address the underlying cause of the hypoxia: fluid-filled alveoli. The primary mechanism to improve oxygenation in this context is effective diuresis to clear the alveolar fluid. Furthermore, the effectiveness of the current oxygen delivery device and flow rate should be assessed, but it is secondary to evaluating the definitive therapy.
- Option 2 (Administer PRN morphine): Morphine can be an adjunctive therapy in ADHF for its anxiolytic and venodilatory effects, which can reduce dyspnea and preload. However, its use is not without risk and is no longer a first-line recommendation in many guidelines. Prioritizing a PRN medication for symptom relief over evaluating the objective response to the primary, disease-modifying treatment (diuretic) is not sound clinical judgment 4 hours into therapy.
- Option 3 (Encourage deep breathing exercises): Deep breathing exercises are a beneficial intervention for many respiratory conditions, but they are physiologically insufficient for a patient with acute pulmonary edema. The work of breathing is driven by fluid in the alveolar space, which must be removed pharmacologically. Encouraging this activity before confirming the diuretic is working would be premature and potentially exhausting for a patient in severe distress.

Pathophysiological and Clinical Rationale
The connection between the heart and kidneys, known as the cardiorenal axis, is central to this case. The patient’s ischemic cardiomyopathy leads to reduced cardiac output, which in turn causes renal hypoperfusion and activation of the renin-angiotensin-aldosterone system (RAAS), promoting sodium and water retention. This creates a vicious cycle of worsening congestion and further cardiac strain, a phenomenon described as cardiorenal syndrome (CRS) [3, 4]. IV furosemide works by breaking this cycle at the renal level, blocking sodium and chloride reabsorption in the loop of Henle to force diuresis. The priority nursing assessment directly monitors the efficacy of this critical intervention. Failure to produce adequate urine output after 4 hours could indicate diuretic resistance, a common and serious complication in CRS that is associated with poor outcomes and may require escalation of therapy . Therefore, this assessment is not merely a task but a critical clinical judgment point to determine if the treatment plan is working or if the patient is deteriorating.