A nurse is caring for a client who has an acute respiratory failure (ARF). The nurse should monitor the client for which of the following manifestations of this condition? (Select all that apply.)

Choice a) is incorrect because troponin is not an enzyme, but a protein. Enzymes are molecules that speed up chemical reactions in the body. Troponin does not have this function.

Choice b) is correct because troponin is a protein that binds to calcium and regulates the contraction of heart muscle fibers. When the heart muscle is injured, such as in a myocardial infarction, troponin leaks into the bloodstream and can be detected by a blood test. The higher the level of troponin, the more severe the damage to the heart.

Choice c) is incorrect because troponin does not help transport oxygen throughout the body. That function is performed by hemoglobin, which is a protein found in red blood cells.

Choice d) is incorrect because troponin is not a lipid, but a protein. Lipids are fats that are used for energy storage and cell membrane formation. Troponin does not have these roles.

Choice a) is incorrect because morphine sulfate is an appropriate prescription for a client who has acute heart failure following MI. Morphine sulfate is an opioid analgesic that can relieve pain, anxiety, and dyspnea. Morphine sulfate can also reduce the preload and afterload of the heart, which can improve the cardiac output and oxygenation.

Choice b) is incorrect because laboratory testing of serum potassium is an appropriate prescription for a client who has acute heart failure following MI. Serum potassium is an electrolyte that is important for the normal function of the cardiac cells and muscles. Serum potassium can be altered by various factors, such as renal function, acid-base balance, medications, or dietary intake. Serum potassium can affect the cardiac rhythm and contractility, which can influence the outcome of the client.

Choice c) is correct because 0.9% normal saline IV at 50 mL/hr continuous is a prescription that requires clarification for a client who has acute heart failure following MI. 0.9% normal saline is an isotonic solution that can maintain the fluid balance and blood pressure in the body. However, 0.9% normal saline can also cause fluid overload and worsen the heart failure symptoms, such as edema, crackles, and dyspnea. The nurse should clarify with the provider if this prescription is appropriate for the client's condition and if there are any parameters or limits for the fluid administration.

Choice d) is incorrect because bumetanide 1 mg IV bolus every 12 hr is an appropriate prescription for a client who has acute heart failure following MI. Bumetanide is a loop diuretic that can increase the urine output and reduce the fluid volume and pressure in the body. Bumetanide can also decrease the preload and afterload of the heart, which can improve the cardiac output and oxygenation.