🧪 实验室检查值 · 第4课，共5课 · 7 min
治疗药物浓度与凝血检查
Therapeutic Drug Levels and the Clotting Tests
💉 Digoxin 0.5到2.0。Lithium 0.6到1.2。Phenytoin 10到20。这些数字看起来毫无规律，直到你注意到考试会给你一个浓度和一个症状，并期望你在医务人员之前说出“中毒”。
💉 Digoxin 0.5 to 2.0. Lithium 0.6 to 1.2. Phenytoin 10 to 20. The numbers look random until you notice the exam gives you a level and a symptom and expects you to say 'toxic' before the provider does.
💡 核心要点
谷浓度在给药前，峰浓度在给药后。Digoxin低于2，lithium低于1.2，phenytoin低于20。大多数适应证使用warfarin时INR为2到3，使用heparin时aPTT为对照值的1.5到2.5倍。
Trough before the dose, peak after. Digoxin under 2, lithium under 1.2, phenytoin under 20. INR 2 to 3 on warfarin for most indications, aPTT 1.5 to 2.5 times control on heparin.
🧠 为什么重要
DIGOXIN 0.5到2.0 ng/mL（中毒表现：恶心、心动过缓、视觉光晕）。LITHIUM 0.6到1.2 mEq/L（高于1.5时中毒：粗大震颤、呕吐、共济失调）。PHENYTOIN 10到20 mcg/mL（中毒表现：眼球震颤、共济失调、言语含糊；长期使用会出现牙龈增生）。CARBAMAZEPINE 4到12 mcg/mL。VALPROIC ACID 50到100 mcg/mL（影响肝脏和血小板）。THEOPHYLLINE约为10到20 mcg/mL，较新的目标为5到15（中毒表现：心动过速、癫痫发作）。VANCOMYCIN通过谷浓度监测，在下一剂给药前抽取，或按药房指导采用AUC指导给药；GENTAMICIN需要同时检测峰浓度和谷浓度：峰浓度确认剂量足够高以有效，谷浓度确认药物正在清除，以免损伤肾脏和耳朵。TROUGH在一剂给药前立即抽取；PEAK在给药后抽取，约在IV输液结束后30分钟。COAGULATION：PT正常约为11到13.5秒，INR正常为0.8到1.2，大多数适应证使用warfarin时INR目标为2到3（某些机械瓣膜要求更高）；aPTT正常约为30到40秒，使用heparin时为对照值的1.5到2.5倍；FIBRINOGEN在弥散性血管内凝血时下降，D-DIMER升高，其表现是各个部位出血并伴有凝血。凝血检查应从未用heparin冲管的管路抽取。
DIGOXIN 0.5 to 2.0 ng/mL (toxicity: nausea, bradycardia, visual halos). LITHIUM 0.6 to 1.2 mEq/L (toxicity above 1.5: coarse tremor, vomiting, ataxia). PHENYTOIN 10 to 20 mcg/mL (toxicity: nystagmus, ataxia, slurred speech; gingival hyperplasia with long use). CARBAMAZEPINE 4 to 12 mcg/mL. VALPROIC ACID 50 to 100 mcg/mL (liver and platelets). THEOPHYLLINE about 10 to 20 mcg/mL, with newer targets of 5 to 15 (toxicity: tachycardia, seizures). VANCOMYCIN is monitored with trough levels, drawn just before the next dose, or AUC-guided dosing, per pharmacy; GENTAMICIN needs both peak and trough levels: the peak confirms the dose is high enough to be effective, and the trough confirms the drug is clearing so it does not damage the kidneys and ears. A TROUGH is drawn immediately before a dose; a PEAK is drawn after it, about 30 minutes after an IV infusion ends. COAGULATION: PT about 11 to 13.5 seconds and INR 0.8 to 1.2 normally, with an INR goal of 2 to 3 on warfarin for most indications (higher for some mechanical valves); aPTT about 30 to 40 seconds normally, 1.5 to 2.5 times control on heparin; FIBRINOGEN falls and D-DIMER rises in disseminated intravascular coagulation, which presents with bleeding from every site plus clotting. Draw coagulation studies from a line that has not been flushed with heparin.
🏥 真实场景
👁️ 一名因癫痫发作服用phenytoin的患者报告头晕，护士注意到他向侧方看时眼睛来回抽动。检测结果为28。暂停该剂量并通知医务人员。眼球震颤是考试最爱考的phenytoin中毒征象，从门口就能看见。
👁️ A client on phenytoin for seizures reports dizziness and the nurse notices the eyes jerking back and forth when he looks to the side. The level comes back at 28. The dose is held and the provider is called. Nystagmus is the exam's favorite phenytoin toxicity sign, and it is visible from the doorway.
📌 要点总结
- Digoxin 0.5–2.0，lithium 0.6–1.2，phenytoin 10–20，theophylline 10–20Digoxin 0.5–2.0, lithium 0.6–1.2, phenytoin 10–20, theophylline 10–20
- 谷浓度在下一剂给药前，峰浓度在给药后；氨基糖苷类需要两者都测Trough just before the next dose, peak after it; aminoglycosides need both
- 大多数适应证使用warfarin时INR为2–3；使用heparin时aPTT为对照值的1.5–2.5倍；DIC表现为fibrinogen偏低和D-dimer偏高INR 2–3 on warfarin for most indications; aPTT 1.5–2.5 times control on heparin; DIC shows low fibrinogen and high D-dimer
📖 本课术语
谷浓度水平 (Trough level): 血液中的最低药物水平，在下一剂给药前抽取，用于监测氨基糖苷类药物，以及vancomycin（除非药房采用AUC指导给药）。
digoxin水平 (Digoxin level): 治疗范围约为0.5至2.0 ng/mL；中毒会带来恶心、心动过缓和黄绿色视觉光晕。
lithium水平 (Lithium level): 治疗范围为0.6至1.2 mEq/L；高于约1.5会出现粗大震颤、呕吐和共济失调。
凝血酶原时间（PT） (Prothrombin time (PT)): 约为11至13.5秒，未用抗凝药时INR为0.8至1.2；它会因warfarin、肝病和vitamin K缺乏而延长，使用warfarin时，要报告的是INR，而不是秒数。
纤维蛋白原 (Fibrinogen): 正常约为200至400 mg/dL；在弥散性血管内凝血中它会降至100以下，因为凝血消耗了它，因此出血患者中纤维蛋白原低而D-dimer升高指向DIC。
Phenytoin水平 (Phenytoin level): 治疗范围为10到20 mcg/mL；高于20会出现眼球震颤、共济失调和言语不清，该药物长期使用还会引起牙龈增生，因此要教导良好的口腔护理，切勿突然停药。
Theophylline水平 (Theophylline level): 治疗范围约为10到20 mcg/mL（较新目标为5到15）；高于20会出现恶心、心动过速和癫痫发作，咖啡因、吸烟变化和许多抗生素会改变其水平。
Carbamazepine水平 (Carbamazepine level): 治疗范围为4到12 mcg/mL；高于约12到15会出现头晕、复视和共济失调，该药物可抑制骨髓，因此要报告发热、咽喉痛或瘀伤，并预期定期检查CBC。
Valproic acid水平 (Valproic acid level): 治疗范围为50到100 mcg/mL；高于约100到150会出现镇静、震颤和意识模糊，该药物可损伤肝脏并降低血小板，因此要检查肝酶和CBC。
Vancomycin水平 (Vancomycin level): 谷浓度目标曾为10到20 mcg/mL（严重MRSA感染为15到20）；许多药房现在按AUC为400到600给药，高于该范围的水平会威胁肾脏和听力。
Theophylline: 治疗范围狭窄的较老支气管扩张药（约为10到20 mcg/mL）；毒性表现为恶心、心动过速、烦躁不安和癫痫发作，因此要检查水平、限制咖啡因，并知晓吸烟会降低其水平，而ciprofloxacin和心力衰竭会升高其水平。
Phenytoin: 范围狭窄的癫痫药物（10到20 mcg/mL），毒性表现为眼球震颤、共济失调和言语不清；仅在生理盐水中缓慢IV推注并监测心脏，长期使用预期牙龈过度生长，口服给药前后暂停管饲。
Carbamazepine: 癫痫、三叉神经痛和双相情感障碍药物（范围为4到12 mcg/mL），带有再生障碍性贫血和Stevens-Johnson综合征的黑框警告（携带HLA-B*1502基因的亚洲血统人群最严重）；报告发热、咽喉痛、瘀伤或皮疹，监测钠，避免葡萄柚。
Valproate（valproic acid、divalproex） (Valproate (valproic acid, divalproex)): 癫痫和双相情感障碍药物（范围为50到100 mcg/mL），带有肝衰竭、胰腺炎和出生缺陷的黑框警告；检查肝酶、血小板和氨，报告腹痛、黄疸或容易瘀伤，并预期会出现体重增加和震颤。
✅ 自我测试
医嘱要求检测vancomycin谷浓度。护士应在何时抽血？A vancomycin trough level is ordered. When should the nurse draw the blood?
- 在下一剂预定给药前立即Immediately before the next scheduled dose
- 输液进行到一半时Halfway through the infusion
- 一天中的任何时间Any time of day
- 输液结束后30分钟30 minutes after the infusion ends
答案: A · 在下一剂预定给药前立即
谷浓度反映最低水平，应在下一剂到期前抽取。在输液结束后30分钟抽血得到的是峰浓度，即最高水平，与谷浓度测量的内容正好相反。
A trough reflects the lowest level and is drawn just before the next dose is due. Drawing 30 minutes after the infusion ends captures the peak, the highest level, which is the opposite of what a trough measures.
一名服用phenytoin的患者浓度为26 mcg/mL，并报告复视。哪项评估发现与中毒一致？A client taking phenytoin has a level of 26 mcg/mL and reports double vision. Which assessment finding is consistent with toxicity?
- 多尿Polyuria
- 眼球震颤Nystagmus
- 心动过缓Bradycardia
- 反射亢进Hyperreflexia
答案: B · 眼球震颤
Phenytoin中毒会引起眼球震颤、共济失调和言语含糊；浓度高于20证实了这一点。心动过缓是IV phenytoin输注过快的风险，而不是高浓度的典型征象；中毒表现为神经系统变化，如该患者的复视。
Phenytoin toxicity produces nystagmus, ataxia and slurred speech; the level above 20 confirms it. Bradycardia is a risk of infusing IV phenytoin too fast, not a classic sign of a high level; toxicity shows up as neurologic changes like this client's double vision.
一名因心房颤动服用warfarin的患者INR为1.3。护士应如何解读？A client on warfarin for atrial fibrillation has an INR of 1.3. How should the nurse interpret this?
- INR已达标The INR is at goal
- 患者有肝衰竭The client has liver failure
- INR未达到治疗水平The INR is subtherapeutic
- 患者有出血风险The client is at risk for bleeding
答案: C · INR未达到治疗水平
心房颤动时warfarin的目标是INR为2到3；1.3接近正常，因此患者抗凝不足，有血栓风险。
The warfarin goal for atrial fibrillation is an INR of 2 to 3; 1.3 is close to normal, so the client is not adequately anticoagulated and is at risk for clots.
在应用中练习 NCLEX 风格的题目，赚取 XP、保持连续天数，英文学习，中文辅助。无需注册。