一位心臟衰竭病人被開立 furosemide。護理師應監測哪種電解質不平衡？

Furosemide 是一種強效的袢利尿劑（loop diuretic），主要作用於亨利氏環（loop of Henle）的粗上升支。它透過抑制鈉-鉀-氯共轉運體（Na+-K+-2Cl- cotransporter）來減少電解質的再吸收，從而增加鈉、氯和水從腎臟的排泄。然而，在作用的過程中，也會導致鉀離子的大量流失，因此被稱為「排鉀利尿劑」（potassium-wasting diuretic）。 心臟衰竭病人常因水腫和體液過量而使用 furosemide，以減輕心臟負擔。但由於其排鉀作用，病人極易發生低血鉀（hypokalemia）。低血鉀會引起多種併發症，包括心律不整（特別是在服用毛地黃的病人中）、肌肉無力、疲勞，甚至麻痺性腸阻塞。因此，護理師在照護服用 furosemide 的病人時，必須密切監測血清鉀離子濃度，並評估其臨床症狀，必要時給予鉀離子補充，以確保病人安全。

Furosemide is a potent loop diuretic that acts on the thick ascending limb of the loop of Henle. It inhibits the Na+-K+-2Cl- cotransporter, decreasing reabsorption of these electrolytes and thereby increasing renal excretion of sodium, chloride, and water. However, this mechanism also causes substantial potassium loss, which is why furosemide is known as a potassium-wasting diuretic. Clients with heart failure often receive furosemide for edema and fluid overload to reduce cardiac workload. Because of its potassium-wasting effect, clients are highly susceptible to hypokalemia. Hypokalemia can lead to numerous complications, including arrhythmias (especially in clients on digoxin), muscle weakness, fatigue, and even paralytic ileus. Therefore, when caring for clients receiving furosemide, the nurse must closely monitor serum potassium concentration, assess clinical symptoms, and provide potassium supplementation when necessary to ensure safety.

Furosemide 在台灣和美國皆是治療心臟衰竭和水腫的常用藥物，其排鉀作用及其導致低血鉀的風險在兩地的臨床實務中均是護理師必須掌握的核心知識。監測血清電解質（尤其是鉀）和心電圖，以及必要時給予口服或靜脈鉀離子補充的護理措施，在台灣和美國的臨床指南中是高度一致的。