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.

Correct Answer: A

Rationale: Enalapril, an ACE inhibitor, can lead to hypotension, particularly following the initial dose or dosage escalation. This effect is due to the medication's mechanism of action in dilating blood vessels, which can result in lowered blood pressure. Monitoring for hypotension is crucial to prevent complications such as dizziness, lightheadedness, or fainting in clients taking enalapril.

Correct Answer: C

Rationale: Hypokalemia increases the risk of digoxin toxicity as low potassium levels enhance the effects of digoxin on the heart, leading to toxicity and potential adverse effects.

Correct Answer: C

Rationale: When a client is receiving furosemide, which is a loop diuretic, it can lead to potassium loss. Therefore, monitoring the serum potassium levels is crucial to prevent life-threatening complications such as cardiac arrhythmias.

Correct Answer: D

Rationale: Rotating the application site every 24 hours is essential to prevent skin irritation and ensure consistent absorption of the medication. This practice helps to maintain the effectiveness of the nitroglycerin patch and reduce the risk of local skin reactions.