A patient on furosemide reports muscle weakness and dizziness.
Which laboratory value should the nurse check?

Choice A rationale

Beta-blockers are used in heart failure to reduce myocardial oxygen demand and improve left ventricular ejection fraction. However, they are not the primary choice for immediate reduction of preload and pulmonary congestion, which are more effectively addressed by medications that directly reduce fluid volume.

Choice B rationale

Diuretics, such as loop diuretics like furosemide, are commonly used in heart failure to reduce preload by increasing sodium and water excretion from the body. This reduction in intravascular volume decreases venous return to the heart, thereby lowering pulmonary congestion and relieving symptoms like dyspnea and edema.

Choice C rationale

ACE inhibitors (angiotensin-converting enzyme inhibitors) are foundational for long-term heart failure management. They reduce afterload and slow disease progression by inhibiting the renin-angiotensin-aldosterone system. While they have some effect on fluid balance, they are not as effective as diuretics for rapid preload reduction and symptom relief.

Choice D rationale

Calcium channel blockers are generally not recommended for systolic heart failure. While some can reduce afterload, most may have negative inotropic effects, which could worsen heart failure symptoms by weakening the heart's pumping action. Their use is limited in specific types of heart failure.

Choice A rationale

While blood glucose levels are important for patients with heart failure who also have a history of diabetes, they are not a primary and direct monitoring parameter for the heart failure condition itself. Heart failure monitoring focuses on parameters that reflect the cardiac output, fluid balance, and workload on the heart.

Choice B rationale

Respiratory rate is a vital sign that is monitored in patients with heart failure. An elevated respiratory rate can be a sign of worsening heart failure, such as pulmonary edema. However, it is one of several vital signs and is typically monitored alongside other more direct indicators of cardiac function, such as blood pressure and heart rate.

Choice C rationale

Blood pressure and heart rate are two of the most critical vital signs to monitor in a patient with heart failure. Blood pressure reflects the workload on the heart, with hypotension potentially indicating cardiogenic shock and hypertension increasing cardiac afterload. Heart rate is a direct measure of cardiac function; a fast rate (tachycardia) can be a compensatory mechanism or a sign of poor cardiac output.

Choice D rationale

Liver function tests are not typically a primary monitoring parameter for heart failure itself. While severe chronic heart failure can lead to liver congestion and elevated liver enzymes, they are not the main or initial parameters used for routine monitoring of the condition's progression or stability. Routine monitoring focuses on cardiac output and fluid status.