護理師正在監測一名血鉀濃度為 2.8 mEq/L 的病人。下列哪項評估結果最需要向醫療提供者報告？
The nurse is monitoring a client with a potassium level of 2.8 mEq/L. Which assessment finding is most important to report to the healthcare provider?
- AFatigue and lethargy疲倦和嗜睡
- BIrregular heart rhythm✓ 正解心律不整
- CMuscle weakness in lower extremities下肢肌肉無力
- DDecreased bowel sounds腸鳴音減弱
核心概念：低血鉀（Hypokalemia）的臨床表現及其對心臟的影響。 為何正確答案對： C. 血鉀濃度低於 3.5 mEq/L 即為低血鉀。鉀離子在心臟細胞膜電位的維持中扮演關鍵角色，低血鉀會導致心肌細胞去極化困難，影響心臟電傳導系統，增加心律不整的風險，特別是可能引發致命性的心室頻脈（Ventricular Tachycardia）或心室纖維顫動（Ventricular Fibrillation）。因此，觀察到不規則心律（Irregular heart rhythm）是低血鉀病人最重要且最危急的評估結果，必須立即向醫療提供者報告。 為何其他選項錯： A. 腸道平滑肌功能受鉀離子影響，低血鉀可能導致腸蠕動減慢（Decreased bowel sounds），但這不如心律不整來得緊急。 B. 肌肉無力（Muscle weakness）是低血鉀的常見症狀，但通常影響四肢近端肌肉，並非立即危及生命。 D. 疲倦與嗜睡（Fatigue and lethargy）也是低血鉀的可能症狀，但其嚴重度不及心律不整。 臨床思路（Priority/Safety）：心臟功能對維持生命至關重要。低血鉀對心臟電生理的影響是直接且潛在致命的，因此任何與心律異常相關的發現都應被視為最高優先處理事項。
Core concept: clinical manifestations of hypokalemia and its effect on the heart. Why the correct answer is right: C. A serum potassium level below 3.5 mEq/L is considered hypokalemia. Potassium plays a key role in maintaining the cardiac cell membrane potential, and hypokalemia causes difficulty in cardiac myocyte depolarization, affecting the cardiac electrical conduction system and increasing the risk of arrhythmias, particularly potentially fatal ventricular tachycardia or ventricular fibrillation. Therefore, the observation of an irregular heart rhythm is the most important and critical assessment finding in a client with hypokalemia and must be reported to the healthcare provider immediately. Why the other options are incorrect: A. Gastrointestinal smooth muscle function is affected by potassium, and hypokalemia can cause decreased bowel motility (decreased bowel sounds), but this is less urgent than cardiac arrhythmias. B. Muscle weakness is a common symptom of hypokalemia but typically affects proximal limb muscles and is not immediately life-threatening. D. Fatigue and lethargy may also be symptoms of hypokalemia, but their severity does not compare to cardiac arrhythmias. Clinical reasoning (priority/safety): Cardiac function is essential to maintaining life. The effect of hypokalemia on cardiac electrophysiology is direct and potentially fatal, so any finding related to cardiac rhythm abnormalities should be regarded as the highest priority.