Correct Answer: B

Rationale: Nitroglycerin is a rapid-acting medication used to relieve angina pain by dilating blood vessels. The correct administration is to take one tablet every 5 minutes as needed, up to three doses. If chest pain persists after three doses, the client should seek emergency medical attention as it can indicate a more serious cardiac issue.

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: 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: A

Rationale: Encouraging the client to cough and deep breathe every 1 to 2 hours is crucial post-CABG surgery to prevent respiratory complications, such as atelectasis and pneumonia. These actions help to expand lung volume, clear secretions, and prevent the collapse of alveoli.

Correct Answer: C

Rationale: The correct instruction for the client before a stress test is to wear loose, comfortable clothing, and walking shoes. This is crucial as the stress test involves physical exercise, and the client should be prepared for the activity involved. Beta-blockers may need to be adjusted or held before the test as per healthcare provider's instructions. Fasting before the test is not typically required, and avoiding physical activity for 24 hours beforehand is not necessary and may interfere with the accuracy of the test results.