護理師正在照護一位因深部靜脈栓塞（DVT）接受連續靜脈注射肝素（Heparin）的病人。護理師應監測哪項檢驗值以調整藥物劑量？
A nurse is caring for a client receiving a continuous intravenous heparin infusion for a deep vein thrombosis (DVT). Which laboratory value should the nurse monitor to adjust the dosage?
- APlatelet count血小板計數
- BActivated partial thromboplastin time (aPTT)✓ 正解活化部分凝血活酶時間 (aPTT)
- CProthrombin time (PT)凝血酶原時間 (PT)
- DInternational Normalized Ratio (INR)國際標準化比值 (INR)
肝素（Unfractionated Heparin）的藥理監測核心是 aPTT。Heparin 透過與 Antithrombin III 結合，抑制凝血因子 IIa 與 Xa，達到抗凝血效果。靜脈輸注肝素時，其半衰期短，需要頻繁監測 aPTT 以確保數值落在治療區間（通常是基準值的 1.5 到 2.5 倍）。若 aPTT 太短，則有血栓擴大的風險；若太長，則有自發性出血的危險。PT 與 INR（選項 C、D）主要用於監測口服抗凝血劑 Warfarin，這與 Heparin 的機轉不同。雖然監測血小板（A）對發現肝素誘發之血小板低下症（HIT）很重要，但它並非用來『調整劑量』的依據。
The pharmacologic monitoring of heparin (unfractionated heparin) centers on aPTT. Heparin binds to antithrombin III, inhibiting clotting factors IIa and Xa, producing anticoagulation. During intravenous heparin infusion, its half-life is short, requiring frequent aPTT monitoring to ensure the value falls within the therapeutic range (typically 1.5 to 2.5 times the baseline). If the aPTT is too short, the risk of thrombus extension increases; if too long, spontaneous bleeding may occur. PT and INR (options C and D) are primarily used to monitor oral warfarin, whose mechanism differs from heparin. Although monitoring platelets (A) is important for detecting heparin-induced thrombocytopenia (HIT), it is not the basis for 'adjusting the dose.'
美國臨床多採用「Heparin Protocol / Nomogram」，護理師可根據 aPTT 結果（或現在逐漸流行的 Anti-Xa 數值）直接在電腦系統中自行調整輸注速率，不需每次詢問醫師。台灣則多由醫師根據報告下達劑量更動醫囑，護理師的自主調整權限相對較小。