✨ 精选课程 · 第2课，共8课 · 60 sec
为什么钾是最致命的电解质
Why Potassium Is the Deadliest Electrolyte
🍌 太少时心脏会颤动。太多时心脏会停跳。钾在狭窄正常范围的两端都可致命，而且它是考试中最常考的数值之一。
🍌 Too little and the heart quivers. Too much and it stops. Potassium is lethal at both ends of a narrow normal range, and it is one of the most tested numbers on the exam.
💡 核心要点
T波尖锐意味着高：calcium、insulin和dextrose，然后清除它。U波意味着低：缓慢补充，绝不推注。
Peaked T means high: calcium, insulin and dextrose, remove it. U waves mean low: replace slowly, never push.
🧠 为什么重要
正常值是3.5到5.0 mEq/L。高钾会出现高耸尖锐的T波和QRS波群增宽；先用calcium gluconate治疗心脏，然后用insulin和dextrose将钾转移到细胞内，再用结合剂或透析将其清除。低钾会出现T波低平和U波、乏力以及危险的digoxin敏感性；通过口服或用泵以每小时不超过约10 mEq的速度经外周补充。在任何情况下都绝不能IV推注。
Normal is 3.5 to 5.0 mEq/L. HIGH potassium gives tall peaked T waves and a widening QRS; treat the heart first with calcium gluconate, then shift potassium into cells with insulin and dextrose, then remove it with binders or dialysis. LOW potassium gives flat T waves and U waves, weakness and dangerous digoxin sensitivity; replace it by mouth or by pump at no more than about 10 mEq per hour peripherally. Never, under any circumstances, IV push.
🏥 真实场景
💉 一位护士曾收到“KCl 20 mEq IV”的医嘱，并把它抽进注射器。药剂师的一通电话挽救了一条生命。浓缩的钾已因正是这个原因从大多数科室移除，而且考试会一直问下去，直到每位护士都知道原因。
💉 A nurse once received an order for 'KCl 20 mEq IV' and drew it into a syringe. The pharmacist's phone call saved a life. Concentrated potassium has been removed from most units for exactly this reason, and the exam will keep asking until every nurse knows why.
📌 要点总结
- 3.5到5.0；两个方向都会引起心律失常3.5 to 5.0; both directions cause arrhythmias
- 高：calcium gluconate保护，insulin和dextrose转移，透析清除High: calcium gluconate protects, insulin and dextrose shift, dialysis removes
- 低：注意服用digoxin的患者；绝不IV推注Low: watch digoxin clients; never IV push
✅ 自我测试
哪种ECG变化提示高钾血症？Which ECG change signals hyperkalemia?
- 高耸尖锐的T波Tall peaked T waves
- PR间期缩短A shortened PR interval
- ST段抬高ST elevation
- T波低平伴U波Flattened T waves with U waves
答案: A · 高耸尖锐的T波
尖锐的T波是高钾最早的ECG表现；T波低平和U波提示低钾。
Peaked T waves are the earliest ECG sign of high potassium; flat T waves and U waves point to low potassium.
护士收到potassium chloride IV推注的医嘱，正确的做法是什么？A nurse receives an order for potassium chloride IV push. What is the correct action?
- 在5分钟内给药Give it over 5 minutes
- 用10 mL稀释后缓慢推注Dilute it in 10 mL and push slowly
- 质疑该医嘱Question the order
- 只通过中心静脉导管给药Give it only through a central line
答案: C · 质疑该医嘱
钾绝不能IV推注，无论通过何种管路或以何种速度：它可能导致心脏骤停。它始终要稀释，并通过泵以受控速度输注。
Potassium is never given IV push, through any line or at any speed: it can cause cardiac arrest. It is always diluted and infused by pump at a controlled rate.
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