一位高血壓病史並開立 beta-blocker 的病人，下列評估最重要？
Which assessment is most important for a client with a history of hypertension who is prescribed a beta-blocker?
- ASerum potassium血清鉀
- BRespiratory rate呼吸速率
- CBlood glucose血糖
- DApical pulse✓ 正解心尖脈搏
Beta-blocker（如 Metoprolol）的主要藥理機轉是競爭性阻斷心臟的 Beta-1 受體，進而降低心率與心肌收縮力。由於其直接影響傳導系統並可能導致心搏過緩（Bradycardia），服藥前的臨床評估重點在於確認心率是否在安全範圍內。若心率過低，持續給藥可能導致心輸出量不足，引發嚴重的低血壓或心臟停滯。
The primary pharmacologic mechanism of beta-blockers (such as metoprolol) is competitive blockade of cardiac beta-1 receptors, which decreases heart rate and myocardial contractility. Because these drugs directly affect the conduction system and may cause bradycardia, the key pre-administration clinical assessment is confirming that the heart rate is within a safe range. If the heart rate is too low, continued administration may lead to inadequate cardiac output, resulting in severe hypotension or cardiac arrest.
在美國臨床實務中，護理師對於給藥前心率下限的判斷（通常為 60 bpm）具備高度自主權，若評估發現心率低於標準，護理師有義務暫停給藥並立即通知醫師，這是 NCLEX 常考的護理判斷。