護理師正在監測一名因深層靜脈栓塞接受持續性肝素（Heparin）滴注的患者。護理師應立即向醫師報告下列哪項實驗室結果？
A nurse is monitoring a client receiving a continuous heparin infusion for deep vein thrombosis. Which of the following laboratory results should the nurse report to the provider immediately?
- APlatelet count of 90,000/mm³✓ 正解血小板計數為 90,000/mm³
- BHemoglobin of 12.5 g/dL血紅素為 12.5 g/dL
- CaPTT of 65 secondsaPTT 為 65 秒
- DINR of 1.1INR 為 1.1
此題的核心概念是監測抗凝血療法中的嚴重併發症：肝素誘發之血小板低下症（HIT）。在使用肝素的病人中，若血小板計數在短時間內顯著下降（通常指低於 150,000/mm³ 或比基準值下降 50% 以上），必須高度懷疑 HIT，這是一種免疫反應，會導致血栓形成的風險反而增加。aPTT 65 秒通常在治療目標範圍內（基準值的 1.5-2.5 倍），不需立即報告。INR 是監測 Warfarin 的指標，對 Heparin 使用者而言 1.1 是正常的，因為 Heparin 不顯著改變 INR。血紅素 12.5 屬於正常範圍。護理安全原則要求護理師不僅監測藥物療效（aPTT），更要警覺致命性副作用。HIT 可能導致嚴重的肢體缺血或栓塞，因此血小板數值下降是臨床上的「紅燈」，必須停藥並改用其他抗凝血劑如 Argatroban。
The core concept of this question is monitoring a serious complication of anticoagulant therapy: heparin-induced thrombocytopenia (HIT). In clients receiving heparin, if the platelet count drops substantially in a short period (generally below 150,000/mm³ or a >50% drop from baseline), HIT must be strongly suspected. HIT is an immune response that paradoxically increases the risk of thrombus formation. An aPTT of 65 seconds is generally within the therapeutic range (1.5 to 2.5 times the baseline value) and does not require immediate reporting. INR is used to monitor warfarin; for clients on heparin, an INR of 1.1 is normal because heparin does not significantly change INR. Hemoglobin of 12.5 is within normal range. Nursing safety principles require the nurse not only to monitor drug efficacy (aPTT) but also to remain alert for life-threatening side effects. HIT can cause severe limb ischemia or embolism, so a decreased platelet count is a clinical 'red flag' that requires drug discontinuation and switching to another anticoagulant such as argatroban.
在美國 NCLEX 考試中，HIT 被視為極高頻考點，護理師必須能獨立識別血小板下降的趨勢。在台灣臨床環境，護理師同樣會監測 CBC，但對於 HIT 的警覺性有時會被 aPTT 的監測所掩蓋，且在通報醫師前，護理師通常會先確認病人是否有皮下出血點（petechiae）等物理表徵。