🧮 剂量计算 · 第4课，共5课 · 6 min
mg/kg：儿科与安全剂量检查
mg per kg: Pediatric and Safe-Dose Checks
👶 儿科医嘱附有mg/kg的安全范围，按每天或每剂给出。考试会给你医嘱、体重和范围，并问一个没人预料到的问题：这个剂量到底能不能给？
👶 Pediatric orders come with a safe range in mg per kg, given either per day or per dose. The exam gives you the order, the weight and the range, and asks a question nobody expects: is this dose safe to give at all?
💡 核心要点
先算公斤数，然后每kg剂量乘以kg。检查范围是按每剂还是按每天：用按每剂的范围与单次剂量比较，对于按每天的范围，将每日最小值和最大值除以每天的剂量次数。任何超出范围的剂量都要暂停。
Kilograms first, then dose per kg times kg. Check whether the range is per dose or per day: compare a per-dose range with the single dose, and for a per-day range divide the daily minimum and maximum by the doses per day. Hold anything outside the range.
🧠 为什么重要
首先将体重换算为公斤。然后相乘：每kg剂量 × kg = 剂量。对于按每天给出的安全剂量范围，将范围的两端分别乘以体重，得到每日最小值和最大值，然后除以每天的剂量次数，以便与医嘱的单次剂量进行比较。例如：一名20 kg的儿童被开具250 mg每8小时一次；安全范围是30至50 mg/kg/day。每日范围：600至1,000 mg；每天三剂意味着每剂200至333 mg；250 mg在范围内，所以可以安全给予。如果医嘱剂量超出范围，应暂停给药并向开具医嘱者澄清；不要自行调整。对于体表面积给药（化疗），剂量是每平方米mg数乘以从图表或公式得到的BSA。对于持续按体重输注，例如mcg/kg/min，应逐步换算：将剂量乘以以kg计的体重，得到每分钟mcg数，乘以60得到每小时mcg数，将输液袋浓度换算为mcg/mL（mg × 1,000 ÷ mL），然后用每小时mcg数除以mcg/mL，得到mL/hr。
First convert the weight to kilograms. Then multiply: dose per kg × kg = dose. For a SAFE DOSE RANGE given per day, multiply both ends of the range by the weight to get the daily minimum and maximum, then divide by the number of doses per day to compare with the ordered single dose. Example: a 20 kg child is ordered 250 mg every 8 hours; the safe range is 30 to 50 mg/kg/day. Daily range: 600 to 1,000 mg; three doses a day means 200 to 333 mg per dose; 250 mg is within range, so it is safe to give. If the ordered dose falls outside the range, HOLD and clarify with the prescriber; do not adjust it yourself. For BODY SURFACE AREA dosing (chemotherapy), the dose is mg per square meter times the BSA from a chart or formula. For continuous weight-based infusions, such as mcg/kg/min, convert step by step: multiply the dose by the weight in kg to get mcg per minute, multiply by 60 to get mcg per hour, convert the bag concentration to mcg/mL (mg × 1,000 ÷ mL), then divide mcg per hour by mcg/mL to get mL/hr.
🏥 真实场景
🧮 一名婴儿体重8 kg。医嘱：acetaminophen 160 mg每6小时一次。安全范围：10至15 mg/kg/dose。10 × 8 = 80 mg，15 × 8 = 120 mg每剂。医嘱的160 mg超过了最大值。护士暂停该剂量，并致电开具医嘱者。计算花了30秒；它保护的肝脏才是全部意义所在。
🧮 An infant weighs 8 kg. Order: acetaminophen 160 mg every 6 hours. Safe range: 10 to 15 mg/kg/dose. 10 × 8 = 80 mg and 15 × 8 = 120 mg per dose. The ordered 160 mg exceeds the maximum. The nurse holds the dose and calls the prescriber. The calculation took 30 seconds; the liver it protected was the whole point.
📌 要点总结
- 在做任何其他事之前先换算为kgConvert to kg before anything else
- 按每天的范围：乘以体重，然后除以每天的剂量次数Per-day ranges: multiply by weight, then divide by doses per day
- 超出范围：暂停并澄清，绝不自行调整Outside the range: hold and clarify, never adjust on your own
✅ 自我测试
一名儿童体重22 lb，医嘱开具某种药物15 mg/kg，正确剂量是多少？A child weighs 22 lb. The order is for 15 mg/kg of a medication. What is the correct dose?
- 150 mg
- 100 mg
- 66 mg
- 330 mg
答案: A · 150 mg
22 ÷ 2.2 = 10 kg；15 × 10 = 150 mg。330 mg是将15乘以以磅计的体重而不是以公斤计的体重得出的，是正确剂量的2.2倍。
22 ÷ 2.2 = 10 kg; 15 × 10 = 150 mg. 330 mg comes from multiplying 15 by the weight in pounds instead of kilograms, 2.2 times the correct dose.
一名30 kg的儿童被开具某种抗生素400 mg每8小时一次，安全范围是25至50 mg/kg/day，这个剂量安全吗？A 30 kg child is ordered 400 mg of an antibiotic every 8 hours. The safe range is 25 to 50 mg/kg/day. Is the dose safe?
- 是的，它在安全范围内Yes, it is within the safe range
- 无法确定It cannot be determined
- 不，它超过了每日最大剂量No, it exceeds the maximum daily dose
- 不，它低于每日最小剂量No, it is below the minimum daily dose
答案: A · 是的，它在安全范围内
每日范围：750至1,500 mg。医嘱：400 × 3 = 1,200 mg/day，在范围内。判断它低于每日最小剂量，是将单次400 mg剂量与750 mg的每日最小值进行比较，而不是使用1,200 mg的每日总量得出的。
Daily range: 750 to 1,500 mg. Ordered: 400 × 3 = 1,200 mg/day, which is within range. Judging it below the minimum daily dose comes from comparing a single 400 mg dose with the 750 mg daily minimum instead of using the 1,200 mg daily total.
一名婴儿的医嘱剂量高于护士计算出的安全范围，护士应该怎么做？The ordered dose for an infant falls above the safe range calculated by the nurse. What should the nurse do?
- 将剂量减少到最大安全量Reduce the dose to the maximum safe amount
- 暂停该剂量，并联系开具医嘱者进行澄清Hold the dose and contact the prescriber for clarification
- 现在给一半，稍后给一半Give half now and half later
- 按医嘱给予剂量，因为开具医嘱者负责Give the dose as ordered because the prescriber is responsible
答案: B · 暂停该剂量，并联系开具医嘱者进行澄清
护士不能独立更改处方剂量；不安全的医嘱应暂停并澄清。
Nurses do not change prescribed doses independently; unsafe orders are held and clarified.
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。