Correct Answer: A

Rationale: Shortness of breath and frothy sputum are indicative of pulmonary edema, a serious condition that requires immediate intervention to improve oxygenation. Administering oxygen is the priority action to support the client's respiratory function and prevent further deterioration. Oxygen therapy helps increase the oxygen levels in the blood, alleviate respiratory distress, and support vital organ function. Prompt intervention with oxygen can help stabilize the client while further assessments and treatments are initiated.

Correct Answer: B

Rationale: Removing the nitroglycerin patch at night is essential to prevent the development of tolerance. Tolerance can occur when the body gets used to a constant level of the medication, reducing its effectiveness. By removing the patch at night, the client has a drug-free period, which helps prevent tolerance and maintains the effectiveness of the nitroglycerin for angina relief.

Correct Answer: B

Rationale: Encouraging the client to cough and deep breathe frequently is essential post-operative care to prevent respiratory complications such as atelectasis and pneumonia after CABG surgery.

Correct Answer: B

Rationale: The correct answer is serum potassium. Monitoring serum potassium levels is crucial when a client is receiving digoxin (Lanoxin) because low potassium levels can increase the risk of digoxin toxicity. Digoxin and low potassium levels can lead to serious cardiac complications, such as arrhythmias. Therefore, close monitoring of serum potassium is essential to prevent adverse effects and ensure the safe administration of digoxin in clients with heart failure.

Correct Answer: A

Rationale: Taking digoxin at the same time each day is essential to maintain a consistent blood level of the medication. This consistency helps optimize the therapeutic effects of digoxin in managing chronic heart failure. Deviating from the scheduled time could lead to fluctuations in drug levels, affecting its effectiveness and potentially causing harm.