病人正在靜脈輸注氯化鉀 20 mEq (溶於 100 mL 生理食鹽水)，輸注時間為 1 小時。輸注過程中護理師最應密切監測哪項指標？

核心概念：靜脈輸注氯化鉀（Potassium Chloride）的安全性。 為何正確答案對： B. 氯化鉀（Potassium Chloride）是強刺激性藥物，靜脈輸注時，若滲漏至血管外組織，會引起嚴重的組織發炎、疼痛，甚至組織壞死。因此，在輸注過程中，密切監測注射部位的狀況，包括是否有紅腫、疼痛、硬結或藥液滲出，是確保病人安全的首要任務。這是護理人員在執行靜脈注射時的直接職責。 為何其他選項錯： C. 血壓和心率（Blood pressure and heart rate）雖然是重要生命徵象，尤其鉀離子異常會影響心臟，但相對而言，注射部位的局部反應是藥物輸注本身最直接的風險，且護理人員能直接觀察與干預。 C. 呼吸速率和呼吸費力程度（Respiratory rate and effort）雖然嚴重高血鉀也可能影響呼吸，但其影響不如對心臟傳導系統直接，且不如注射部位的局部風險來得即時。 D. 尿量（Urine output volume）是監測腎臟排泄功能的指標，對於預防全身性高血鉀很重要，但在輸注「氯化鉀」這個動作本身，注射部位的安全性是護理人員最直接需要關注的局部風險。

Core concept: safety of intravenous potassium chloride infusion. Why the correct answer is correct: B. Potassium chloride is a strongly irritating drug. If the IV solution extravasates into perivascular tissue, it can cause severe tissue inflammation, pain, and even tissue necrosis. Therefore, during the infusion, closely monitoring the injection site for redness, swelling, pain, induration, or leakage is the nurse's foremost priority for client safety. This is the nurse's direct responsibility when administering IV therapy. Why the other options are incorrect: A. Blood pressure and heart rate are important vital signs, and potassium abnormalities do affect the heart; however, the local reaction at the injection site is the most direct risk of the infusion itself, and one the nurse can directly observe and intervene upon. C. Respiratory rate and effort may be affected in severe hyperkalemia, but the impact is less direct than that on cardiac conduction and is less immediate than the local risk at the infusion site. D. Urine output volume reflects renal excretory function and is important for preventing systemic hyperkalemia, but during the act of infusing potassium chloride itself, safety at the injection site is the most direct local risk the nurse must address.