The Metric Grid & ISMP Decimal Safety
A 12 kg child needs 5 mg/kg of acetaminophen. The bottle says 160 mg per 5 mL. Aaliyah has 90 seconds before the parent asks how much.
- mg → kg conversion
- Oral syringe (10 mL)
- Drug reference
- Second nurse to verify
- 1
Dose × weight
5 mg/kg × 12 kg = 60 mg total dose.
- 2
Convert dose to volume
Cross-multiply: 160 mg / 5 mL = 60 mg / x mL → x = 1.875 mL.
- 3
Round to syringe graduation
10 mL oral syringe reads 0.1 mL ticks → draw 1.9 mL.
- 4
Two-nurse verify
Pediatric high-alert med: second RN must confirm math and dose before administration.
Order reads '0.5 g' but the vial is labeled in mg. A misplaced decimal here is a 10× or 1000× overdose — the single most cited medication-error mechanism (ISMP). Move the decimal three places per metric step, always write the leading zero, never the trailing zero. Build the muscle memory before a code situation tests it.
Tap Show next step to reveal the math one piece at a time.
Convert 0.5 g to mg
Given: Order = 0.5 g; label = mg
- 1
Move decimal 3 places right
0.5 → 500.
Convert 250 mcg to mg
Given: Vial = 250 mcg
- 1
Move decimal 3 places left
250 → 0.250