一位心衰竭病人被開立每日口服 furosemide 40 mg，給藥前護理師應優先檢查哪項檢驗值？
A client is prescribed furosemide 40 mg PO daily for heart failure. Which laboratory value should the nurse prioritize checking before administration?
- ASerum sodium血清鈉
- BSerum potassium✓ 正解血清鉀
- CSerum creatinine血清肌酸酐
- DBlood glucose血糖
Furosemide 是強效的環利尿劑（Loop diuretic），會抑制亨利氏環（Loop of Henle）對鈉、氯及鉀的再吸收，導致大量鉀離子隨尿液排出。低血鉀（Hypokalemia）是使用此藥最常見的電解質副作用。對於心衰竭病人，若同時併用毛地黃（Digoxin），低血鉀會顯著增加毛地黃毒性風險，進而引發致命性心律不整，因此監測鉀離子為給藥前的優先安全防護。
Furosemide is a potent loop diuretic that inhibits the reabsorption of sodium, chloride, and potassium in the loop of Henle, leading to significant urinary potassium loss. Hypokalemia is the most common electrolyte side effect of this medication. In a client with heart failure who is also receiving digoxin, hypokalemia significantly increases the risk of digoxin toxicity, which can in turn precipitate life-threatening dysrhythmias; therefore, checking the serum potassium level is the priority safety measure prior to administration.